A system of dental surgery

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AOS EY ES ES
‘851 .Tes 1873
ph I

INO

24503363389

LONDON :

PRINT BY W. CLOWES AND SONS, STAMTUID ST!
AND CHAKING CkOS3

$5),
TOS
1873

CONTENTS.

TEETHING,

PAGE
DEVELOPMENT OF JAW3 AND TEETH . soe . . . . 3
ERUPTION OF TEMPORARY TEETH. . . 2). . . (17
IRREGULARITIES OF TEMPORARY TEETH . 2 . 37
IRREGULARITIES OF POSITION OF TEETH. . . . . «63
ERUPTION OF PERMANENT TEETH ay . . . . . 84
IRREGULARITY OF PERMANENT TEETH . . . . . - ONT

THE DENTAL TISSUES.

ENAMEL. 008 ne 8
DENTINE. +

DISEASES OF THE TEETH.

CARIES 6 1 ee eee . e298
TREATMENT OF CARIFS. . . . . 1-7 wee 808
DENTAL EXOSTOSIS © 6. 1 1 8 1 eee duu
NECROSIS OF THE TEETH « . . «ww ew ee HU
ABSORPTION OF PERMANENT TEETH . 2... 7. HE
EROSION OF THE TEETH... eee ee ee HU
IRRITATION OF THE PULP. . «we eee 88
ACUTE INFLAMMATION OF THE PULP. . . . . « . 462

CHRONIC INFLAMMATION OF THE PULP... . . - 466

iv CONTENTS.

INFLAMMATION OF ALVEOLAR PERIOSTEUM .

WEOROSIS OP THE JAWS 1) te ow ew th el
ABSORPTION OF THE ALVEOLI. . 2 6 1 ww
HYPERTROPHY OF ALVEOLAR noRDER
MYPEROSTOSIS 2. 1 ke
STOMATITIS 2. 1-1 tt

ULCERATION OF THE ToNGY
TUMOUNS OF THR GUMS . . + » ; ee
SALIVA AND SALIVARY CAraU
ODONTAIGIA. 6 6 6 et
NEURAIGIA . 2s

SECONDARY APFECTIONS DUE TO DISEASED TEETH

BOMUMSTOM ae st jt Oh a ew

DESTIGEROUS CYSTS, . .

DIBEASES OF ANTRUM 2. 5 + ee

CLOSURE OF THE JAWS. « » 5

FRACTURE OF THE TEETH. . ,

DISLOCATION OF TIE TEETH . .

ISJURIES OF THE JAWS . . ‘ Rite! ray
PIVOTING TEETH ww er tll tw wl ww BOS
EXTRACTION OF TEETH. 2 6 1 8 we ww ww BO
WOMORRHAGE AFTER EXTRACTION . . . ~ « 706
RUMEEEOEAST ISG i oe & 2s 8 ot ee FR

APPENDIX ON DENTAL CARIFS. . «5 . ary tee ee

vi PREFACE.

from other writers have been but limited. I must, however,
express my obligation to many of those who have written
upon dental surgery, and I cannot leave unmentioned the
nares of Mr. Bell, Mr. Spence Bate, Mr. § rhit,
Mr, Chapin Harris, and Mr. Arthur, Reference is not

amuel Cartwi

wtifrequently made to a series of lectures published in 1848,
Many subjects but imperfectly touched upon in these pages
are more fully treated in that work, and many specimens

re there fixured which illustrate subjects discussed in this
volume,

The
for writing, and that little has been seriously interrupted by

pmanis of an active practice leave but little leisure

dual organization which

engagements conseq dent upon the
the dental profession hos recently undergone. From these,
and from causes less controllable, the present work has
passed very slowly through the press, many of the earlier

sheets laving been in print upwards of eighteen months.

To Mr, Bazg I am greatly indebted for the highly artistic
illustrations which he has produced from specimens in my
own collection, and from others which have been liberally
contributed by niy professional friends.

JOHN TOMES.

, CAVespin Square,
Febywary 28, 1859,

PREFACE

TO THE SECOND EDITION.

‘Tne material progress which has been made by the science
of Dental Surgery since the publication of the first edition of
this work, has necessitated large additions to the text; the
bulk of the volume has, however, been kept within con-
venient limits by a slight reduction in the size of the print.
Those portions of the book which are devoted to the
description of neuralgia, dentigerous cysts, odontomes,
secondary affections resulting from the irritation set up by
dental disease, as well as many other shorter sections, are
entirely new; and nearly sixty fresh illustrations have been
added, of which a few have been, by permission of Messrs.
Longman, borrowed from my father’s earlier work, the
lectures on dental physiology and surgery; others have
been, with the consent of the Council, reprinted from the
Transactions of the Odontological Society ; to the kindness
of Mr. Christopher Heath also I am much indebted for the
use of several figures, which have been reproduced from his
valuable work on the “ Diseases and Injuries of the Jaws,”
to which frequent reference will be found in these pages;
whilst a considerable number of woodcuts have been specially
executed for this edition by Mr. W. H. Wesley.

viii PREFACE.

‘The deseription of dental caries, with the exeeption of
some slight additions and alterations, remains much the
same as in the first edifion; but a fuller discussion of the
whole subject has been added in the form of an appendix, in
which a summary of the conclusions to be drawn from recent
investigations will be found.

Tn the section relating to the dental tissnes due prominence
has been given to the opinions of continental observers, and
references to the more important works consulted have been
inserted, though it would be impracticable, even were it de-
sirable, to encumber a text-book by tracing every statement
to its source. But 1 cannot refrain from acknowledging the
assistance which I have derived from Prof. Wedl's recent

work, * Die Pathologie der Ziihne,” as well as from the atlas
published jointly by Professors Heider and Wedl.

CHARLES 8. TOMES.

37, Cavesmisit Square,
January, 1873.

2 A SYSTEM OF DENTAL SURGERY,

from the characters they present. Butshould the conclusions
drawn from the study of these ultimately prove in some
respects incorrect, the want of accuracy can only be substan-
tiated by the study of a still more extended series. But until
such a collection is made, it will be safer to adopt the con-
ditions of the preparations at present at my disposal, as fajr
examples of the states of the dental apparatus at the several
ages, than to assume that the opinions generally extant, when
at variance with them, are in all cases correct. Feeling that
this course is the more likely one to lead to a correct
knowledge of the subject, 1 shall, in the following pages,
describe the conditions presented by individual specimens,
selecting such as appear most typical of the ages chosen for
description.

If two perfectly healthy children, whose ages are similar,
be selected for examination, we shall rarely find that they
present precisely similar conditions as regards the rate of
tecthing ; yet there will probably be no great disparity in the
conditions of the two. Each will pass through the same
phases, although, until the process of dentition is completed,
one may bea few weeks, or even months, in advance of the

‘There is, however, another source of fallacy to be guarded
against. The specimens obtained are necessarily taken from
individuals who have been the subjects of disease ; and sup-
posing the fatal illness to have been of long standing the jaws
may have been modified. That such has occurred to some
members of the series is sufficiently obvious, but the diseased
‘action appears to have influenced the growth of the jaws them-
selves, rather than the rate of development of the teeth.
Hence, even these specimens may serve to confirm the results
obtained from an examination of healthy jaws so far as the
teeth are concerned,

Those minor differences in size and form which constitute
“ok nage le by which we are enabled to distinguish one
i another, though in all essential characters they

4 A SYSTEM OF DENTAL SURGERY.

developing teeth and teeth-pulps, the former rising to the
level of the alveolar margins of the jaws, At this period
‘the erypts or alveoli aro not arranged in a perfectly uniform
line, neither are they all equally complete, The septa, which
divide into a series of cells that which at an earlier age was
but a continuous groove, are less perfect at the back than at
the front part of the mouth. The alveoli of the central in-
cisors both of the upper and lower jaws are a little larger within
than at the orifice, and this difference is made still greater
by adopression upon the lingual wall of each for the reception
of the pulp of the corresponding permanent tooth. ‘They are
divided from the crypts of the lateral incisors by a septum,
which runs obliquely backwards, and a little inwards towards
the median line, The sockets of the lateral incisors occupy
a position slightly posterior to those for the central teeth, and
are divided from the canine alveoli by a septum which pro-
ceeds obliquely backwards, and in the lower jaw (as regards
the median line of the mouth) outwards (Fig. 2), By the
arrangement of these divisions, the alveoli of the oentral in-
cisors are rendered broader in front than behind, and the
relative dimensions of the sockets of the lateral teeth are re~
versed, as shown in Figures 1 and 2. The crypts of the
canine tecth are placed a little anterior to those of the
laterals, and nearly in a line with the central incisor sockets,
giving to the jaws a somewhat flattened anterior surface.
‘The septum dividing the canine from the first temporary
molar crypt is not subject to the obliquity observed in the
two preceding examples, but proceeds directly across from
the outer to the inner alveolar margin, giving to the socket
for the canine a greater breadth in front than behind, which
peculiarity is still further increased by the anterior wall being
bulged outwards, In these alveoli we have at present no
depression provided for the pulps of the permanent teeth.

~ The for the first temporary molars are placed in the
median line of the alveolar ridge; have a somewhat square
form, with the outer margins inverted; and in the lower

TRETHING, 5

maxilla are marked on their floors by a slight groove, in
which the inferior dental nerve and artery lie. ‘The very
close approximation of the nerve to the developing teeth may
serve in some measure to explain the liability of children to
reflex nervous disturbances dependent on the teeth. The
nerve and artery enter the alveolus on either side through an
aperture in the base of the septum, which divides imperfectly
the first from the second temporary molar, and pass out to
the external surface of the jaw through an orifice in the
septum dividing the canine from the former tooth.
Posterior to the alveoli for the first temporary molars we
have a large open socket, which, in the upper maxilla, has
‘bat a very imperfect posterior wall. Projecting inwards from
the free edge of the outer and inner alveolar walls, we may
observe small spicula, the rudiments of septa which are
destined to divide the cavity into two distinct sockets, and

large alveolus. The division usnally takes place a little earlier
in the lower than the upper jaw. The groove which marks
the passage of the nerve and artery in the floor of the socket
of the first temporary molar, is continued through the alveoli
of the two posterior tecth, having entered the jaw by the
inferior dental foramen, which is situated midway between
the angle of the jaw and the edge of the inner wall of the
alveolus of the first permanent molar, a little below the floor
of pam of the last alveolus.

this period the articular process of the lower jaw is
Bat elgighove the ltal of the alveolar edge, while the
angle is projected downwards a little below the general level
of the inferior margin of the jaw. The coronoid proves rises

of the first permanent molar. In the upper jaw the zygo-
) process outwards from the anterior margin of
open socket of the second temporary molar,

6 A SYSTEM OF DENTAL SURGERY.

(}) The upper Jaw of & nine-months' foetus deprived of the soft parts,
nhowing the relative positions and dimensions of the alveoli, the partly dewe-
Joped teeth having heen removed from the sockets on the right side of tbe
jaw. a, the socket of the lateral incisor ; 6, that of ihe canine; ¢, the alveolus
Of the second temporary molar, the posterior wall at this age being absent.
‘This and the subsequent figures are two-thirds life-size,

() The lower jaw of & nine-months’ fetus, showing the condition of the
alveoli. a, the sockets of the lsteral incisors; 6, those of the canine teeth;
¢, the alveols of the second temporary and first permanent molars. A bristle
4s plactd tn the tnferior dental canal.

8 A SYSTEM OF DENTAL SURGERY.

condition, it will be seen that in the front teeth calcification
has advanced nearly to the base of the tooth pulp, which ends

Fig. 9. (4)

in @ broad flat surface; while in the canines and molars the
pulp extends a short distance below the terminal line of
calcification.

By dividing the mucous membrane and subjacent periosteum
a little below the upper margin of the alveoli, both on the
labial and lingual surfaces of the jaw, in a specimen which
has been kept « short time in spirit, and then carefully raising
the membrane from the surface of the bone, we shall be

()) The upper Jaw of mine-montha’ foetus, the soft parts having been
removed, showing the outer wurfaco of the alveolar processox, 0, the depressed
Portion corresponding to the position of the lateral incisor.

(®) The lower jaw of a nine-monthy’ fartus, showing the relative site and
position of the several parts of the bone st this age.

enabled to withdraw from their sockets the developing teeth
enclosed in their sacs, which will remain firmly attached to
the gum, The relative position of the dental sacs will be
seen to correspond with the arrangement of the alveoli
alreniy described. The union of the external coat of the
sac with the tissues of the gum, and of the lower portion of
She pulp with the bess: of she as, may ba demonstrated.

* At the age of two months but little change from the fetal

growth bas advanced rapidly in the ramus, and the angle
become less obtuse. The articular process rises above the
general level of the alveolar ridge, an indication that during
the early weeks of infancy growth is more active in the
ascending ramus than in any other part of the lower jaw. At
the point of junction of the two halves, increase in the depth
of the jaw may be observed. This has been in great part
effected by additions to the free edge of the alveoli, which
have been extended anteriorly into a somewhat larger curve.
But in addition to growth in the positions mentioned, develop-
ment has gone on from the opposed surfaces of the two halves
encroaching upon the fibro-cellular tissue which connects

suture connecting the two halves of the upper jaw. Growth
proceeds in the line of junction of the two halves, and indeed
at ach of those points where the bone is at present connected
only by soft tissue to the adjoining bones. Increase of bone
in the median line would necessarily lead to separation of the
Copnes teen this is, however, prevented by the teeth on

Mt wets Gales wi eioson tae to sockets

partake in a similar change of direction, the free edges of

10 A SYSTEM OF DENTAL SURGERY.

which are closely approximated, while the deeper parts become
separated from each other.

At the age of two months, the teeth are more advanced in
development than at the time of birth, but the change is not
80 strongly marked in thom as in the moxille., The crypt
of the pulp of the first permanent molar is yet without a
posterior wall in the upper jaw; and in the lower jaw, the

(2) The upper jaw of a male two months old, showing the general increase
of alee os compared with Uhe fertal Jaw, and the Increased depth of the alveolar
Procensos,

(2) The lower Jaw of m male two months old, showing the fneriaced size ax
compared with the fatal Jaw given in Wg. 4, and the changes in the relative
neil of the body and ascending ramus during the two tmotiths #accreding,

‘TRETHING. ll
septum dividing this from the socket of the sccond temporary
molar is i

When the third month bas been attained, the maxilla show

Pgt.

Fig. & ©)

() The dipper jaw of & male two mouths old, showing the comatition of the
[nh cas alfred ly

ot a mele two months old, showing the condita of (he
that period,

12 A SYSTEM OF DENTAL SURGERY.

4 further development in the directions already indicated.
‘The angle of the lower jaw is more pronounced, and the bone
much more solid, The alveoli, however, exhibit a considerable
change in character; their depth has increased; and the free
edges, which were before open, so that in a macerated pre-
peration the teeth readily fall out, are now turned inwards
towards the median line of the alveolar ridge, thereby con-
tmting the orifices, and affording protection to the enclosed
teeth, which are no longer liable to fall out when the bone is
examined. The direction of the rami is but little changed,

Pig. 9. (1)

Wig. w. (2)

(#) The upper jar of a mate three months old, two-thirds lfe-nize.
(*) The lower Jaw of a male three months old. In the specimen frem which
Wile figure is taken the lateral incisors are wanting.

TEETHING. 13

bot considerable addition of bone at the lower border of the
angle will be observed, the sigmoid notch at the same time
being widened. The symphysis is still strongly marked in

Pig. 11. (FY

Vig. 13. 7)

(1) ‘The opper jaw of o male thrss months old, showing the advanced com
dition of the alveoll, and the inversion of the edges of each socket, logetier
with completion of the posterior wall of the sockets which contain the second
temporary miolar and the yalp of the first permanent meinr.

() The lower Jaw of & male three months old, showing the inversion of e
alveolar edge, and cooseqment cuntraction of the apertntes, ‘The lateral

inctaors ase wanting.

lt A SYSTEM OF DENTAL SURGERY,

each half of the bone, and viewed in profile the eurved out
line is still preserved. he figures illustrating the condition
peculiar to this age are singular from the absence of lateral
incisors in the lower jaw, and in the want of a crypt for the
first permanent molar on one side of the upper jaw. In other
respects they present the characters common to jaws of similar

age.

Passing from a subject of three to one of six months old,
the differences are not at first sight very striking. The
angle formed by the borders of the body and ramus of the
lower jaw does not appear to be less obtuse than in younger
skulls, This is, however, due to a considerable increase
of bone on the lower border, especially near and about
the symphysis, at the same time that the mental promi-
nenee is beginning to appear and occupy a more forward
position than the margin of the alveolar ridge. The sockets
are generally itscreased in depth, but in a greater degree in
the anterior than at the posterior part of the line. The
posterior wall of the crypt of the first permanent molar in
the upper maxilla is still imperfect; and the septum between
the second temporary and first permanent molars in the lower
jaw is incomplete. The teeth at the age of six months are
more advanced than at the ages previously described ; but the
difference is much more marked in the incisors than in the
other teeth. The canines and second molars are more forward,
Wut the rate of progress has been slower than in the other
teeth.

‘The inversion of the edges of the alveoli, and consequent
narrowing of the apertures described as pertaining to the
jaws of three months old, is less pronounced at six months,
although as yet the tecth lie below the free edges of the
sockets. The increased size of the alveolar orifices must be

ax the first of those changes which precede the
eruption of the teeth.

‘Phe relative position of the teeth is but little changed ; the
canines of the upper jaw are even more out of the regular

‘TEETHING, 15

line than formerly, being placed at this period almost external
to the lateral teeth, thereby producing great prominence in
the jaw at these points.

‘The bony cells for the permanent central incisors are now
well marked, producing a prominence on the palatine surface
of the alveolar process, but they usnally communicate with
erypts of the temporary teeth by a large orifice. The cells for
the permanent lateral incisors aré at present indicated only by
4 depression on the lingual surface of the crypts occupied by
the temporary teeth.

At the age of eight months we may see indications of
further progress. In the specimen figured, that of a male
nine months old, the eonditions of the alveolar ridge are
becoming rapidly changed. At the front part of the mouth,
the alveoli, which have hitherto developed more rapidly
than those situated further back, now become the seat of
absorption; while the more posterior ones assume a greater
activity of growth, The central incisors of the upper jaw,
although they do not descend below the general level of the
alveolar ridge, are exposed on their anterior surfaces by the
absorption of great part of the outer wall of the sockets, at
the same time that the teeth have moved bodily a little forward.
‘The outer edges of the central teeth are in front of the lateral
teeth, the latter being still pliced in a line internal to the
canines, so that if the teeth were cut in their present posi-
tious, the arrangement would be extremely irregular, Jndica-
tions of the removal of the anterior walls of the sockets of the
lateral incisors are shown in their emarginated edges, while the
alveoli of the other teeth still preserve their inverted margins.

The crypts of the permanent central incisors are becoming
separated from those of the temporary teeth by the growth
of septa, which rise towards the surface from the deeper part
of the sockets ; and growth is continued in this direction until
the opening becomes level, or nearly #0, with the free margin
of the sockets of the temporary tooth.

"The sockets of the molar teeth, which in the foetus ex-

16 A SYSTEM OF DENTAL SURGERY.

tended to the floor of the orbit, are now separated from it by
the antrum, ‘which at this time is represented by a deep

Fig. 13.)

Fig. 14. ©)

depression, extending under the orbit in its inner two-thirds.
The septum between the socket of the second temporary

()) The upper jaw of a male nine months old, showing absorption. of the
anterior walls of the pockets of the central Incisora preparatory to the eseape
of the crowns of the teeth from thetr alveoit.

(@) The lower Jaw of 2 male mine months old, showing absorption of the
outer wails of the socket of the inckwrs preparatory to the eruption of those
teeth, Two-thirds Iife-site.

18 A SYSTEM OF DENTAL SURGERY.

down a long bone of a foetus. Now if this bone grow equally
at its two ends by deposition in its epiphyses, eventually
the process (if it remained still) would come to be very
nearly in the middle of the bone, for that approximation
towards one end which made a great difference in a small
fertal bone would make only an inappreciable difference in
an adult bone six or seven times the length of the former.
Bat as a matter of fact such is not the cise: a process
situated at a point distant from one end of a long bone by
one-third of its length preserves that proportionate distance, no
matter how much the bone may grow; obviously this can
only come about by the process shifting its position,’ and
as it were gliding along the surface of the bone. Now if
the jaw-bone were in all respects comparable to a long bone,
this fact would offer an insuperable objection to the choice
of any muscular process or foramen as a point of measures
ment. Fortunately, however, for our present purpose, the
lower jaw-bone stands in quite a different position to that
of a long bone: if we draw a horizontal line through the
level of the upper pair of spine mentales in an adult jaw
we shall about equally divide it; bat the life history of that
part which lies above the line and that which lies below
it is widely different. The lower portion is the jaw that
supports muscles of deglutition, of mastication, and the
like structures essential to the well-being of the animal, and
is progressively developed from the earliest time of ossifica-
tion until it has attained its full size without intermission;
not so however the portion of bone above our imaginary
line. This is subservient to one purpose only : that of sup-
porting the teeth when perfected, that of protecting them
whilst developing. And so far from being itself gradually
elaborated aud developed without a check, it was built up
around the calcifying temporary teeth, and then in part
removed to allow of their eruption: built up again around
their fangs, and yet once more absorbed to give exit to the
() G.M Humphrey, in Trans, Med. Chirurgical Society, vol. xiv,

TEETHING. 19

permanent teeth: then developed afresh around the roots of
the permanent set of the teeth, so that in the sockets of the
permanent teeth probably not one fragment of the original
alveolar portion of the jaw remains. And when the teeth
ave shed for the last time the alveolar portion of the jaw
is again removed. Relatively, then, to the changeable al-
veolar portion we may regard the bedy of the ramus as fixed
and immutable, and we shall not be led into any error of
consequence by taking muscular processes or foramina on
the latter as points of measurement from which to estimate
the relative proportions of these two parts of the horizontal
ramous at various ages.

The foramen mentale is particularly suitable as a point
from which to take relative dimensions, as its position may
be practically assumed as fixed, undergoing little or no
change after birth. In the full-grown fotus it is situated
at the point corresponding to the septum which divides the

of the root of the first bicuspid—that is, on a level with
the bottom of the socket of the tooth which suceeeds the
first temporary molar, Now, assuming that the position
of the latter tooth and its successor remains unchanged
during growth, while other parts undergo alterations, we

canal be examined in the fietus its orifice will be found to
be in the direct line of its course, opening forwards, but in
an adult jaw it will be found to look outwards, upwards,
and lackwands, so that its position is slightly posterior to
that which it would have assumed had it remained in
the line of the canal. his change in position is due to a
great increase in the thickness of the bone from deposition
(m its outer surface, and to that tendency to a preservatian
2

20 A SYSTEM OF DENTAL SURGERY.

of its original position relatively to the length of the jaw
already alluded to (page 18). But inasmuch as the growth
of the jaw differs in many important particulars from that
of the long hones, the foramen does not fully preserve its
original position relatively to the two ends of the bone,
but in the adult is proportionally farther from the ascending
ramus than in the foetal jaw.

An examination of a series of jaws serves to show that
almost the whole change which is effected in the position
of the foramen is completed within the first few months
after birth; after this time no marked change takes place,
it having then become opposite to the middle of the socket
of the first temporary molar, and remaining in the adult
opposite to the root of the first bicuspid.

On the inner surface of the jaw the tubercles for the
attachment of the genio-hyo-glossus and genio-hyoideus
undergo but little change during the growth of the jaw.
In the feetus they are placed opposite to and a little below
the base of the sockets of the central incisors; the two
upper tubercles being even at this early age well marked.
In the adult subject the position, as regards the central
incisors, is the same, excepting in those cases in which the
alveolar process is developed in an unusual degree, in which
case the extremities of the roots of the teeth occupy a
higher level than the spina mentales. The upper of the
two pairs of processes are at all ages nearly at the same level
as the mental foramina, though where the latter have a dis~
tinetly upward direction, a8 is sometimes the case in the
adult, they rise to a somewhat higher level.

Tf, on the inner surface of the jaw, the distance between
the junction of the septa between the sockets of the first and
second temporary molars and the inner plate of the alveoli
of either side be measured in the full-grown foetus, and in
jaws up to the age of nine months, when osseous union
‘between the two halves usuatly commences, this measure-
tment being made on a level with the attachment of the

TEETHING, 21

genio-hyo-glossus muscle, it will be found, that althongh
the jaws have with age greatly increased in size, yet the
distance between these points has not materially increased.
Again, if & line be stretched across from the above points,
and measurements be made from the centre of the line to
the upper of the two pairs of spine mentales, it will also
be found that the distance has not increased with the ageing
of the subject, But if the measurement be made from the
centre of the line to the anterior alveolar plate, it will be
seen that the distince between these two points gradually
increases with the age of the subject, and that the front teeth
contemporaneously assume a more forward position. ‘The
stationary condition of the inner, while the outer alveolar
plate and teeth are moved forward, allows the former to
increase in thickness, and afford receptacles for the pulps
of the anterior permanent teeth.

‘Three years after the publication of the preceding state~
ments in the first edition of this work, Dr. Humphrey read »
paper before the Cambridge Philosophical Society,(*) in which
an ‘identical conclusion was arrived as to the growth of the
jaw by inferences from a series of experiments performed by
inserting wires into the jaws of growing animals.

The following diagram may serve t® render this point
clearer; in ita jaw from a nine-months’ festus is placed over
an adult jaw, the limits of which are marked by unshaded
lines.

Tt will be seen that the arch of the jaw in the fetus is
as wide and as large as in the adult; the difference between
them in this part being simply due to additions to its thick-
ness, ton alight extent on the inside, but very much more
on the outside of the jaw. It will also be seen that the
inorease in size in the adult jaw is gained exclusively by
its prolongation backwards, and not by anything like inter-
‘stitial growth, As expressed by Dr. Humphrey, “ Although
the bones of the alveolar arch are lengthened, and the arch

(Q) * British Journal of Dental Science,” vol. vi, p. 548.

22 A SYSTEM OF DENTAL SURGERY.

is rendered more elliptical, it is not widened. The widening
of the jaw, in correspondence with the increasing width of
the base of the skull, takes place behind the alveolar arch
in the ascending portion, and is effected by the progression
of absorption on the inner and addition to the outer surface
of this part.” But without the aid of this modelling pro-

Fig. 16.

cess, the mere prolongation backwards of the horns would
give a considerable increase in width,

The growth of the anterior part of the jaw by addition of
hone previous to union at the symphysis, may be computed
by relative measurements of the foetal and nine-monthe’ jaws.
An increase of distance between the symphysis and mental
foramen, amounting to the eighth of an inch in favour of the

and the distance from the mental foramen to that point of
the line corresponding to the symphysis be taken, it will be
fonnd to agree with the measurement of the nine-months’
jaw between the points already described. The foregoing
facts show sufficiently clearly that the growth of the anterior
parts of the lower jaw is produced by addition of bone to the
anterior surface, rather than by any materia) increase by
development of bone in the fibro-cellular tissue which,
yeriod, unites the two halves. Development in

Jatter position appears to have ita period of activity
intra-uterine life, After birth, the process of
direction is all but suspended until the
the osseous union of the two halves of jaw,
¢ action is resumed, the fibro-cellular tissue is re-
and all further increase at this point is then
Still keeping the mental foramen as the point
which to make the computations of relative growth in
different directions, it will be found, by examining the series
of jaws, that additions have been made to the lower border
of the jaws, bat that there has been relatively a much greater
netivity shown in the alveoli, which at the age of nine
months have acquired their maximum height in the front
fart of the jaw, The length of the jaw posterior to the
mental foramen has steadily increased with the increasing
age of the subject, the direction of the growth being indi-
cated by a series of minute vascular grooves which mark

bone

Foe
s
E

THE
a iff

the bone at and near the angle of the jaw. Between these
vises into minute ridges, many of which
are cantinned to the posterior border of the ramus, and there
‘terminate in short slender spicula, giving to the border a
rough surface, which, although well marked in many dry

24 A SYSTEM OF DENTAL SURGERY.

specimens, is much more strongly pronounced before the
hone is allowed to dry, and the partly-calcified spicula to
become contracted by the loss of moisture. If these grooves
are traced through a series of specimens of progressive ages,
commencing with the fetal jaw, it will be seen that those
about the coronoid process indicate the course in which that
part has advanced; a line which, 1 shall subsequently be
able to show, is permanently marked in the adult jaw by the
external oblique line, Then, again, a similar line of grooves
indicates the course which has been taken by the articular
process in its progressive growth upwards and backwards.
Indeed, this line is also indicated by the surface being
slightly raised, there being a distinct rounded eminence along
the outer surface of the jaw, ending in the condyle, which
becomes less marked in the adult, Below, and a little pos-
terior to this line, we have the angle of the jaw, the increase
in which has been already noted.

M. Killiker has shown that the articular cartilage is of
unusual thickness for cartilage so placed ; and that, inaddition
to the usual functions of articular cartilage, it is here subser-
vient to the purposes of development, its office in one respeot
being similar to the cartilage which in childhood is placed be-
tween the epiphysis and shaft of along bone. It is not proposed
to enter upon the subject of osseous development, until the
changes of form and increase of size of the maxillw have been
traced from birth to manhood. But the discovery first re-
corded by M. Kélliker has been mentioned, in order to show
that in whatever direction the jaw has increased, the in-
crease has been produced by additions to the external sur-
face. There are no indications of interstitial growth within
and throughout the whole substance of the bone. It is not
unusual to find increased size of a bone desaribed as expan-
sion, but the term is not applicable. We may have great
increase in the size of the medullary cavity and of the cir-
cumference of a long bone, as seen in diseased limbs; but in
Such cases the enlargement of the cavity is produced by pro-

=

gressive absorption of its parietes, and the enlargement of
cote) st Rg cee orm alg ge

‘The description of the jaws of the nine-months’ child has
been given at greater length, in consequence of the specimen
having attained that stage of development which immediately
precedes the eruption of the teeth.

‘The conditions of the alveoli coincident with the progres-
sive development of the teeth, do not appear to have attracted
that amount of attention which the subject deserves ; and the
stage in which the wall or walls of the sockets are partially
absorbed preparatory to the passage of the teeth through the
gums, although an important and necessary action for the
liberation of the crown of the tooth from the socket, seems,
so far as I know, to have escaped observation altogether.

Tf the teeth of the specimen which has been under con-
sideration be removed from their sockets and examined sepa-
Tately, it will be seen that the crowns of the central incisors
are. perfected so far as their exteriors are concerned, aud that
the production of the necks of the teeth has commenced.
‘The enamel of these teeth presents the character which marks
the completion of its development—namely, the smooth and
polished surface which succeeds to the dull, opaque, and almost
chalk-like character maintained so long as the tissue is incom-
plete. The lateral incisors present similar appearances, except-
ing that the neck is less pronounced than in the central tecth.
‘The canines at present are placed deep in the sockets, the
crowns being incomplete, contrasting strongly with the tecth
immediately behind them. These, the first temporary molars,
have the crowns nearly completed, the masticatory sur-
faces of which are on a level with the alveolar margin, The
latter parts have already been slightly reduced by absorption,
and the onter apertures of the sockets have been thereby en-
larged. The second temporary and the first permanont molars,
although considerably advanced as compared with those of
‘the six-months’ subject, are still considerably below the level

=_

26 A SYSTEM OF DENTAL SURGERY.

of the alveolar margins, the outer of which is tumed very
touch inwards, and hence the openings of the sockets are
contracted, an arrangement calculated to afford protection to
the teeth.

Passing from the nine to the twelee~months’ subject, further
changes in the dental apparatus will be observed, indicating
‘that during the intervening three months the process of teeth-
ing, a8 the term is commonly understood, has fairly set in, and
at the latter age is in full activity. In the upper jaw the
two halves of the bone are becoming united; and althongh
they may be separated after maceration, yet it requires some
force to part them, a condition very different to that which
obtains at an earlier period, when they readily fall apart, It
was stated that the anterior wall of the alveoli of the central
incisors in the nine-months' jaw had been diminished by ab-
sorption, exposing to view the crowns of the teeth, although
these organs did not rise above the general level of the alveolar
ridge, At the age of twelve months the crowns of these teeth
have escaped from the sockets to the extent of half their
length, the whole of the enamel on the anterior surface being
visible. They are placed against the anterior wall, and are
separated by a considerable interval from the posterior wall
of the alveoli. The latter process at this age descends below
the level of the anterior wall of the sockets, at the same time
that an increase of thickness of the bone at this part is allowed
by the forward movement of the incisor teeth. The crypts of
the permanent teeth become enlarged, occupying the space
which has been gained. The apertures leading to the per
manent incisors are now situated near the alveolar margin,
but at present open upon the inclined surface which forms
the posterior wall of the enlarged sockets of the temporary
teeth.

‘The alveoli of the canines preserve their depth, but the
opening is somewhat larger than heretofore, indicating the
eotumencement of the change which precedes the eruption of
those teeth. The lateral incisors have escaped from their

TEETHING. 27

alveoli to the extent of two-thirds of their crowns. ‘The canine
prominences on the anterior surface of the jaw, which during
the earlier months of life form so strong a feature, are now
becoming lost; not, however, by their own subsidence, but
by the advancing forwards of the alveoli of the neighbouring

Fig. 16.0)

@) Upper jaw of a male thirteen montle old, showing the incisors, with
the crowns escaped from the alveoli, and tho emargination of the sorket of
the

98 A SYSTEM OF DENTAL SUBGERY.

teeth. The first temporary molars at this age have passed
through the apertures of the sockets, and the emargination
of the external plate is gradually becoming lost, the process
of development having succeeded to that of absorption.

ig. 18. (1)

Pig. 19, (1)

The alveolus of the first permanent molar, which at an
earlier ago was destitute of any posterior wall, and had a large
open orifice, has now become more perfect, and communicates
with the surface by a comparatively smal! opening situated on
the alveolar ridge, and in a line with the openings of the an-
torior sockets, The lingual margin of the socket is much more
strongly developed than that of the onter alveolar plate, and
indeed rises into a process continnous with the corresponding
part of the sockets of the more anterior teeth. The base is
continued outwards so as to arch over the inner part of the
developing tooth, a condition calculated to protect the latter
from mechanical injury, now that the mouth is becoming
furnished with organs of mastication.

Excepting in a general increase of size, the lower jaw does
not present any considerable change in character from that
of the nine-months’ anbject. The central incisors have risen
ont of the sockets, and the emargination of the outer plate
of the alveoli of the lateral incisors and of the first temporary
molars has commenced ; those teeth are, however, scarcely
ritised above the level of the alveolar ridge.

‘The next specimen in the series is that of a female subject,

months of age. This, as compared with the twelve-
months’ maxillx, shows an adyance in the process of dentition,
‘nt not to the extent usually assigned to the age. The crowns
of the central incisors both of the upper and lower jaws, are
fully exposed ; but the fangs, although approaching the normal
length, are a8 yet incomplete, the extremity of each present-
fing a sharp thin edge, with a lange aperture, instead of the
conical termination, perforated by a minute foramen, peculiar
to perfected teeth. ‘The lateral incisors have emerged from
their sockets, but the crowns have not reached to the level
of the central teeth, those of the upper being more forward
than the corresponding tecth of the lower jaw. The conical
points of the canines have become visible above the emar-
ginated edges of their alveoli; while the first temporary
molars have been protruded in the upper to the extent of two-

lea 7

30 A SYSTEM OF DENTAL SURGERY.

thirds of their crowns, and to one-third in the lower jaw.
‘The roots exhibit corresponding stages of development, those
of the upper jaws being nearly half their ultimate length,
and the lower ones about one-third. The second temporary
molar is at present wholly within the socket, the margins of
which are arched over so as to diminish the alveolar aper+
ture, and protect the developing tooth, an effect which is
partly produced by the edge of the external alveolar plate
being more produced in height, and at the same time more
arched over the tooth than the inner edge of the socket. The
roots of these tecth are scarcely indicated, excepting by the
septum of dentine which in each may be seen extending
across the base of the crown, and marking the position for
the future roots. he first permanent molars lie deep within
their respective sockets, the orifices of which in the lower jaw
are contracted by the inversion of the outer alveolar plate and
the base of the coronoid process, the teeth at this time being
placed with their posterior two-thirds internal to and beneath
that portion of the jaw. The posterior edge of the socket is
brought forward over the back part of the crown to the extent
of one-fourth of its antero-posterior dimensions, On the upper
surface of this, withina line of its edge, a depression in the bone
may be seen, This is the commencement of a crypt for the
second permanent molar, (Fig.19.) The corresponding teeth of
the superior maxillw occupy the tuberosity, the posterior part
of which is extremely thin, and in the median line imperfect,
This gives a long and curved opening to the socket, and a
posterior direction to its further half, In the upper jaw we
have as yet no indication of preparations for the lodgment of
the second permanent molar,

If the eighteen months’ maxillw are compared with those
of twelve or thirteen months, the relations of growth between
the teeth and sockets may be seen, The emargination of the
sockets of the central incisors, and consequent enlargement of
the alveolar apertures necessary for the evolution of the
crowns of these teeth, having been accomplished, and the

‘TRETEING. al

crowns having passed through, absorption is suspended, and
the several alveoli becoming contracted, apply themselves to
the teeth, development at the margins keeping pace with the
growth of the roots of the teeth. ‘The socket of an incisor,
so long as the crown is below the alveolar margin, is larger at
its base than at its more external boundary ; but no sooner
does the crown leave the socket, than the relative dimensions
Teverse themselves. The base contracts, by the development
of new bone, to the dimensions of the fang. The level of the
socket is not, however, at present changed. If the com-
parison of the two subjects be continued, it will be seen that
although the length of the ascending rami has considerably
increased in the older jaw, yet that the angle formed by the
two portions remains pretty much the same.

Twenty-one Months —The differences observable between
the preparation last described and the maxillm of a female
subject twenty-one months old, with the exception of a slight
general increase in size, are confined to the more a/ivanced
condition of the teeth. The four incisors of either jaw have
assumed the normal position ; the crowns being fully exposed,
although the fangs are not quite completed. The sockets
have, however, contracted, and closely embrace the implanted
_portions of the teeth, at the same time that they have grown
ap with the teeth as the latter have increased in length.
‘The canines show only their tips above the alveolar margin ;
bot the first temporary molars in the upper jaw have fully
emerged, and are closely embraced at their necks by the
margins of the sockets. In the lower jaw, these teeth have
escaped from their sockets, but as the thicker part of the
crown is scarcely through the aperture, the emargination of
the edge of the alveoli has not been obliterated by develop-
ment of bone at thexe points,

Twenty-eight Months —In a twenty-cight-months' subject,
in addition to the teeth which have been described as having
taken their permanent position in the younger jaws, the crowns
‘of the canines have partly passed out of their sockets, those

34 A SYSTEM OF DENTAL SURGERY,

a time the back teeth appear through the gums, and occupy
the space which has been gained, first by the separation
occasioned by the prior development at the front part of the
mouth, and afterwards increased by the lengthening of the
rami.

By the uninterrupted but comparatively slow elongation of
the rami, and the rapid but successive growth of the front
and back parts of the jaws, a relation of parts is brought
about by which the whole series of teeth are allowed to be
brought in contact simultaneously. If it were necessary to
find a reason why the rami should not be.subject to irregular
nites of growth, similar to, and in accordance with, such as
are seen to occur in the alveolar portions of the jaws, a
sufficient reason might be found in the fact that bone which is
developed in temporary cartilage under ordinary circumstances
increases steadily, and that the articular processes of the lower
maxilla are increased in length by development in cartilage
situated beneath the surface of the articular cartilage; the
development in this situation offering no exception to what
appears to bea general law in relation to the development of
bone in temporary cartilage. On the other hand, bone may
be formed with comparative rapidity upon a free surface of
pre-existing bone.

The more acute angle formed by the alveolar margin and
the ascending rami in the jaw of the forty-months' subject,
48 compared with younger subjects, has been already men-
tioned. But if the line formed by the lower border of the
body of the jaw be examined in relation to that bounding the
posterior portions of the rami, it will be found that the angles
formed ara more obtuse, hence preserving at these points a
greater similarity to the younger jaws; and the condition is
maintained so long as the jaw continues to increase in length,
‘Lhe deep portion of the articular cartilage is to the articular
portion of the jaw, as regards growth, what the cartilage inter=
posed between the epiphysis and apophysis is to a long bone.
1f, therefore, the lines last referred to were rectangular, as is

86 A SYSTEM OF DENTAL SURGERY.

set of teeth is not completed; and that at the commencement
of the sixth year these teeth are perfectly formed, it may be
assumed that at four and a half years of age the primary
dentition is completed.

If the maxillm of the forty-nine months’ subject be com-
pared with the one previously described, it will be seen that
the slight depressions which marked the spots destined for the
pulps of the second permanent molars, have now become large
crypts with well-defined margins, the superficial extent being
proportionately much greater than the depth. In the upper
jaw these depressions look backward towards the pterygoid
plates of the sphenoid bone: in the lower, upwards and a
little inwards, their floors Lying immediately over the inferior
dental canal, near its commencement. Situated on the floor,
near the posterior wall of the crypt, isa small foramen, which
passes through into the dental canal, and gives passage to
vessels which supply the developing tooth. Passing over the
septum, dividing the sockets of the permanent molars, is the
groove which in the younger specimen was but slightly
marked. Jn this subject it is broad and strongly pronounced,
the margins being raised into two thin processes of bone.

Having traced the progress of the temporary teeth from
the time of birth up te the period of their completion, and the
contemporaneous conditions of the jaws, the further changes
in form of the jaws will be resnmed in connexion with the
development and eruption of the permanent teeth.

In describing the different parts of individual teeth which
may or may not hold the normal position, there is some little
difficulty in writing intelligibly without first defining the
precise meaning of the terms used. The teeth being placed in
an ellipse, the terms anterior and posterior, if applied indif-
ferently in describing the surface of an incisor and a molar
tooth, would indicate different parts in the two teeth, and the
confusion would be still greater when the teeth are altogepher
ont of the usual position. In order to avoid this difficulty,

‘TRETHING, ‘ 87

arbitrary terms must be adopted and used without reference
to the actual situation of any individnal tooth, even supposing
it be misplaced. Thus, the surface which normally is directed
towards the lips or cheeks will be described as the labial, and
that directed towards the tongue as the lingual, surface. The
surface Which lies against a neighbouring tooth, and is directed
towards the point of junction of the two halves of the alveolar
ridges, will be termed the mesial surface; while that which
is directed outwards in the front,and backwards in the molar
teeth, will be called the distal surface,

Inrequarity in the position of the temporary teeth is seen in
children whose jaws have not acquired the size necessary for
the normal arrangement. The defect is, so far as 1 know,
confined to the incisors, and may be limited to slight crowding
and a consequent want of uniformity of position in several

teeth, In three children, members of a large
family, one of the central incisors of the lower jaw js in each
turned, so that the median side of the tooth stands in the
position which should be occupied by the anterior or labial
surface. The dentition in other respects is regular, both in
these and in the brothers and sisters, although the jaws in
each child are unusually small. A transverse section of a
‘central incisor of the lower jaw, when taken imme-
diately helow the enamel, gives an elongated oval, the long
axis of which corresponds in direction with the median line
ofthe mouth. Hence the turning of such a tooth in the jaw
would only crowd to a greater degree the contiguous teeth.
But the fangs of the ternporary lower incisors are cylindrical,
#0 that these teeth, when turned in the manner described,
give greater room for those near them than would have been
obtained had the normal position been preserved. Hence this
deviation from the usual arrangement must be regarded as a
means taken by nature to accommodate the want of concord-
‘ange between the size of the teeth and the size of the jaws.
Wrregularity in the number of the temporary teeth.—The

38 A SYSTEM OF DENTAL SURGERY.

number, order, and position of the deciduous tecth, as they
arise in the jaws when the development is normal, have been
described. ‘The deviations from these conditions remain for
consideration prior to entering upon the eruption, or cutting
of the teeth, as the process is commonly called.

As regards the number, a child may have either more or
less than the twenty. Tnstances are cited in which the jaws
have been entirely edentulous. I have not had an opportunity
of examining a case, either in the living subject or in a pre-
paration. Recently I met with a gentleman who informed
me that a member of his family, a female, about fifteen years
old, was then, and had been from the time of her birth, entirely
edentulons, and that the lower part of the face preserved the
appearance usually presented by a child prior to the eruption
of the teeth, Such cases, however, must be extremely rare.
A diminution in the ordinary number of temporary teeth is,
however, not 60 uncommon. I have in my own collection two
instancesin which the lateral incisors are absent—one in which
they are wanting in the lower (Fig. 12), the other in which
they are absent in the upper, jaw (a view of which will be
found in a subsequent figure), These cases of deficiency in
the number of the first teeth posacss but little practical inte
rest, and, in a physiological point of view, we can do nothing
more than recognise the bare fact, We are as little able to
account for the absence of a temporary tooth usually present,
as to determine why twenty, rather than a smaller or greater
number, constitute the normal series.

The presence of teeth in excess of the usual number de~
mands more attention, as we may in certain cases be called
upon to determine whether or not they should be allowed to
remain. I am indebted to Mr. Tbbetson for a cast taken
from a case under his charge, in which there were five incisors
in the lower jaw. They were uniformly arranged, and there was
nothing peculiar in the form of either: so similar indeed were
they, that it was difficult to determine which should be ee-
garded as the supernumerary tooth, In my own collection,

TEETHING, 39

there is an upper jaw, the age of which is prohably five years,
having two supernumerary teeth. ‘They are placed behind the
central incisors, near the median line of the jaw; have conical
crowns and roots, the latter being little short of completion,
Indications are present of their having passed throngh the
gum, or rather the palate, for they are situated posterior to
that part which is usually designated gum. The circumstance
that the other temporary teeth are fully formed, while these
are not quite completed, might lead to the question, whether
they should not be reckoned as suypernumeraries of the perma-
nent teeth; but examination of the latter shows that the
enamel of the most forward of them is at present incomplete,
and that the formation of the roots has not commenced.
Hence it is fair to conclude, that the palatal teeth are super-
mumerarics of the first set of teeth. In this case it is quite
possible that articulation was to some extent interfered with,
and if so, their immediate removal would have been desirable.

Several years since, a child, aged five years, was brought to
me, having a supernumerary tooth similar in character and
in position to those last described, ‘The tooth was removed
in consequence of a difficulty in articulation, which arose con-
temporaneously with its appearance in the palate.

Another ease caine under my treatment, py, 99, (1)
in which the central and iateral incisors were

through the istialix past! ies lodgtto the
lateral, When the time arrived for the
r of the permanent central incisor,
the removal of the three became nocessary. It was then
eon that the root of the central incisor had been absorbed,

(@) Temporary teeth, The central and lateral incleora, left side of the upper

40 A SYSTEM OF DENTAL SURGERY,

but that the corresponding parts of the other two teeth
retained their full dimensions. I have seen other instances
of an unusual namber of temporary teeth, but the excess has
always been in the incisors themselves, or in their neighbour-
hood. Similar examples are reeorded by many writers on the
subject of dental surgery.

‘The temporary appear much more exempt from individual
deformity than the permanent tecth. I have but one example,
In this a strongly-pronounced conical cusp arises from the
posterior surface of a central incisor.

Another deviation from the ordinary course of development
remains for consideration, and which, like the preceding
instances of departures from the usual laws, cannot be con-
sidered in connection with those conditions which are attri-
butable to disease. The pulps for the development of the
individual teeth are not only distinct from ¢ach other, but are
contained each one in its own crypt. Occasionally, however,
the alveolar septum is absent, and two become laterally
united, and the teeth produced from the adherent pulps form
one mass, distinguishable from one another only by the pre-
sence of a more or leas distinctly pronounced groove which
marks the line of confluence, Sometimes the crowns of the
teeth are more or less distinct, the roots only being united ;
while in others the crowns are united, and the fangs are to
some extent separated. At the points of union the dentine
is common to the two teeth, the cementum or the enamel, as
the case may be, forming a common investment, This con-
dition was known to M. Desirabode, who says, “The wnion
of the crown is a real fusion of the two teeth in which the
ivory substances are common to each other."("}

Mr. Salter has a paper in the “ Transactions of the Medico-
Chirurgieal Society” upon this subject, and gives an illus-
tration confirmatory of the fact advanced by Desirabode, but
taken from two similarly united permanent teeth.(*) Mr.

(1) American Journal of Dental Sclemor, 1847,
< (*) Medico-Chirurgical Transactions, vol. sxxv.

»

42 A SYSTEM OF DENTAL SURGERY.

the conditions of the latter so far as they are connected with
the eruption of the teeth.
If we decalcify the lower jaw of a nine monthis’ foetus, and
Fig. 23.(8) toake a section through
the gum and jaw, pass
ing through one of the
developing teeth, the tis-
sues will be exposed in
the following order:—
First, we have a thick
layer of epithelium, the
cells of which are flat-
tened, but gradually in«
crease in thickness the
further they are removed
from the surface, and
eventually terminate in a
series of slightly elongated
cells, the long axes of
which are placed at a right
angle with the surface of
the gum. Below the epi-
thelium comes a thick
layer of stellate areolar

(*) Showing the relative post
tian of the tlamnes exposed in &
‘vertical section through the liwer
jaw of a nine months’ fetus,
©. seria of elongated cells. form-
ing the bave of the epithelial
layor; }, stellate areolar tissue;
6 condensed theue, forming
dental rac,en the inner surface
of which is the enamel pulp; d,
the enamel organ ; ¢, the enamel;
J, the dentine, with the dentinal
pulps g the bene forming the
lower border of the Jaw; A, the
pericateum,

‘TEETHING, 43

tissue, the meshes of which are comparatively large and
open. Nuclei are present in the centres of the stollations,
while others may be found in fibres which have not con-
formed to the axial arrangement, or which, in progressive
growth, have not yet arrived at the stellate form. In the
meshes of the areolar tissue a few free cells may be found,
but they are not abundant, Blood-vessels traverse this
texture in considerable numbers, . Near the lower boundary
they become more abundant, are of larger size, and the
tissue itself becomes more condensed. The fibres are
placed nearer each other, and assume collectively the form of
an ill-defined fibrous membrane, which dips down within the
socket in the form of a sac—the sac or outer investment of
the developing tooth. Still prooeeding from above downwards,
after passing through the upper part of the sac we come to
the “enamel organ,” then to the dentine and the dentinal
pulp, which at its base merges into the lower portion of the
sac, without any definite line of separation or structural
distinction between the two. Below this, again, we have a
little loose areolar tissue which connects, although but feebly,
the sac with the buny socket. Then comes the bone, which
forms the base of the socket on the one surface, and the
lower border of the jaw on the other; succeeded by the
periosteam, which on its osteal surface is in great part formed
of nucleated cells, the bulk of the membrane being made up
of fibrous tissue, tending in character rather towards the
stellate areolar tissue, than to the fibrous tissue of older
subjects,
- After the crown of a tooth has been formed, before it
can be out, the aperture of the socket must be enlarged, the
cont of the sa immediately above the crown of the tooth
removed, together with the superimposed fibro-areolar tissue
nd epithelial layer. These parts—which stand inthe way
of the ernption of a tooth—may, however, be removed in
such strict accordance with the rate of growth and outward
progress of the tooth—growth and waste may be so nicely

Ae

=

44 A SYSTEM OF DENTAL SURGERY.

balanced—that the subject of these changes suffers no in
convenience. In a child who was constantly under my own
notice, tooth after tooth appeared without any premonitory
symptoms. The period of teething came and went, attracting
attention only when a new tooth was discovered. Instances of
teething such as the foregoing are, | believe, comparatively
rare, and can only occur in children who are and have been
in all respects perfectly healthy, the fulfilment of which
involves a series of conditions which our artificial state of
living does not tend to bring about, or, it may be said,
can scarcely allow,

Residence in crowded cities, even in members of the middle
Classes, seldom fails to produce some amount of injurious in-
fiuence upon childhood; and among the working classes,
insufficient or improper food greatly tends to increase the
evil which the want of a good atmosphere has been sufficient
to create, Among the agricultural population we often find
great crowding in the individual dwellings, a scarcity of
animal food, and, by way of making the matter worse, a
perfect indifference to the condition of the precincts of the
cottages. A stagnant pond or a filthy ditch, into which is
thrown the refuse from the house—one or other, or both, are
found in most of our rural villages, within a few yards of the
Jabourer’s house, The almost universal presence, in one form
or another, of these disturbing causes, is attended with a loss
of that balance of the various functions of the body which
constitutes perfect health. Hence we find that but few
children pass through the period of teething without suffering.
In some cases the attendant ailment ix slight and unimpor-
tant; in others, maladies arise which endanger life. To these
deviations from normal dentition, attention must now be
directed; but in treating upon this part of the subject, I
must borrow largely from the experience of others. The
management of children during the eruption of the temporary
teeth is seldom entrusted to those who confine their practice
to dental surgery, and therefore their knowledge of the ovin-

46 A SYSTEM OF DENTAL SURGERY,

situated beyond its cardiac orifice. Besides this, too, the
ransition from the pylorus to the intestine is gradual in the
child, while in the adult the demarcation between stomach
and intestine is well marked. The result of all this is, that
in the adult, who is an omnivorous animal, the stomach
presents a form not unlike that which it has in some of the
rodents—as the rat and the rabbit; and that the food, in the
course of digestion, undergoes somewhat of a rotatory motion,
not the simple onward movement which is communicated to
it in the stomach of the carnivora. The stomach of the
adult, then, is framed to act upon substances which may
require some time for their digestion, while that of the infant
is ill suited to retain matters long within it, and its small
size unfits it for receiving much at once. If, therefore, the
food given to an infant be such as can be digested with
facility, it soon passes out of the stomach, and the infant
speedily seeks for more. Nor are these arrangements, eal-
culated for the rapid digestion of easily-assimilated food,
confined to the stomach of the infant, but the form and
proportions of the intestines correspond thereto: the small
intestine is relatively shorter than in the adult; the large
intestine of smaller calibre; the cecum less developed ; whilst
the peristaltic action of the bowels is more rapid than in later
life; excrementitious matters are quickly expelled, and the
healthy infant passes three or four evacuations in the twenty-
four hours.”

‘Thus it is shown that while the organs of mastication are
coming forward for use, the alimentary canal is at the same
time assuming a form suitable for the digestion of substances
that require to be masticated before they are passed into the
stomach. And it may be assumed if the normal relations
existing between the dental and digestive apparatus, as regards
their respective rates of development, be disturbed, that the
child will become predisposed to disease.

‘The tables of mortality, under the head of death from
teething, give over four per cent. of the whole number of

48 A SYSTEM OF DENTAL SURGERY.

course to the empirical employment of emmenngogue medi-
cines. We examine into the cause of its absence; try to
ascertain whether it depends on the state of the health in
general, or of the uterine system in particular, and regulate
accordingly our attempts at cure, ‘The epoch of dentition is
to be Wwoked at just in the same way as that in which we
regard the epoch of puberty. Constitutional disturbance is
more common, and serious disease more frequent, at those
times than at others; but their causes lic deeper than the
tooth which irritates the gum that it has not yet pierced in
the one case, or than the womb which has not yielded the due
discharge of blood in the other. You might produce hamor-
rhage from the uterine vessels in the latter instance, or might
cut through the gum which enclosed the teeth in the former,
with no other effect than that of aggravating the condition of
your patient.”

Yet the phrase, “ Bel enfant jusqa’aux dents” gives ex-
pression to a belief very widely spread, and unfortunately
too well grounded, that this is the period at which many a
child becomes sickly, and perhaps never again recovers
strength.

Dr, Copland gives the following definition of Difficult
Dentition :-—* Slow or retarded evolution of the teeth, with
signs of local irritation and constitutional disturbance, often
with disorder manifested expecially in the digestive organs
and nervous system, occurring chiefly in weak or over-fed
children.” In describing the local symptoms I must again
borrow from Dr, West :

“ Though a perfectly natural process, dentition is yet almost
always attended with some degree of suffering, Many of us,
no doubt, can remember feeling much pain when we cut our
wisdom tecth, and children probably experience the same kind
of annoyance. This, however, is not always the case; for
Sometimes we discover that an infant has cut a tooth, who
had yet shown no sign of discomfort, nor any indication that
dentition was commencing, with the exception of an in-

‘TEETHING, 49

creased flow of saliva. More frequently, indeed, the mouth
becomes hot, and the gums look tumid, tense, and shining,
while the exaet position of each tooth is marked, for some
time before its appearance, by the prominence of the gum ; or
the eruption of the teeth is preceded or accompanied by a
somewhat different condition of the mouth, in which there are
much heat, and intense redness of the mucous membrane, an
extremely copious flow of thin saliva, and a disposition to the
formation of swall aphthous ulcerations on the tongue, at the
outer surface of the alveoiw, or at the duplicature of the lip,
though the guns themselves may not be particularly swollen
or painful. Either of these states is usually attended with
some degree of febrile disturbance, and apparently with eon-
siderable suffering to the infant, who is constantly fretful and
peevish, or cries out occasionally as if in pain. A third morbid
condition of the mouth is sometimes seen, which is usually
ushered in or attended by very considerable fever and dis-
order of the chylopoietic viscera. The gums then become
extremely hot and swollen, and unusually tender, especially
over some tooth or other in particular, and in that situation
we find the gum swollen up into a kind of little tumour.
Small unhealthy ulcerations, with a sloughy appearance, often
form apon the summit of the gum, and especially around any
tooth which has partly pierced through it. To this affection,
which is often very painful, and often difficult of cure, the
name of Odontitis Infantum has been applied by some Con-
tinental writers.”

‘One of the most common diseases incident to this period is
diarrhea, attacks of which will come on as each group of
teeth comes to the surface, and pass away in the intervals :
sometimes, however, from the long continuance of the diar-
thera, the child will pass into the condition of marasmus.

‘Many of these symptoms, according to Dr. Copland, fre-
quently precede the appearance of the teeth by several weeks,
but do not always maintain a uniform severity. Indeed, they

may altogether subside and reappear before the teeth are cut.
&

a

50 A SYSTEM OF DENTAL SURGERY.

In such cases, the oli nurses tell you that the teeth were
breeding in the first attack, and in the second cutting the
gums. A more probable explanation is, that in the one case
they were passing through the alveolar opening—in the other,
making their way through the gums. It has been pointed
out by Trousseau (') that teething is not a continuous process
which, once begun, is carried on without interruption till its
completion, but that it takes place in well marked stages.
The teeth are cut in groups, and when one group of teeth is
fairly erupted there is a period of rest till it is time for the
next group to appear, It will of course be understood by
every one who is familiarised with the numerous irregula-
rities arising in dentition, that this definite sorial order will
in some instances be departed from, though the statement is
none the less very generally true.

At an age varying from six to nine months the lower
central incisors appear, their eruption being rapid, and being
completed in from three to ten days; then comes & period of
rest of two or three months, at the end of which the four
upper incisors come down into place. Then again after the
lapse of some months the lower lateral incisors and the four
first molars are cut, their eruption being followed by a con-
siderable lapse of time, amounting often to four or five
mouths, when the four canines commence to come throngh.
‘The eruption of the canine teeth covers a very long period,
taking perhaps two or three months for its completion, and
it is during the eruption of these teeth (according to
‘Troussean) that m child suffers most severely, though a dif-
ferent opinion has been lately expressed by Dr. West,(*) who
considers that the four first molars cause the greatest amount
of constitutional disturbance during their progress from the
alveoli, The greater time taken by the canine teeth, and the
saverer symptoms occasioned by them, are accounted for by
Trousseau, by the fact that they are the only members of the

(!) Clinical Lectures, Troussesn, vol. Iv. (Sydenham Society Edition).
(*) 0n some Nervous Disorders of Chitdbood, by Charles Wert, Mul),

TEETHING. 51

temporary series which come into place between two other
previously erupted teeth, so that they are likely to meet
with greater resistance in their transit, But he appears to
have in some degree misapprehended the conditions under
which the eruption of teeth takes places when he mentions
their length of fang as being another difficulty in the way of
their easy transit; for the fang is not fully formed until the
crown is well advanced in its movement towards its final

‘Tubercle does not appear to interfere with the progress of
dentition, but rickets does so in a very great degree; in fact
great delay in the appearance of the tecth would always lead
to a suspicion of the existence of rickets.(*)

Among the collection of infantile maxillm which has been
made, there are several specimens of local disorder which may
be noticed at this point of the inquiry. In one example, taken
from a subject nearly nine months old, the teeth present no
obvious peculiarity either as regards structure or forwardness.
‘The jawa are, however, small, and the bone is unusually porons,
the alveoli being at many points imperfect, leaving the forming
teoth partly exposed on their anterior surfaces. In a second
specimen, twenty-one months old, a similar condition of the
maxille exists. The incisors and first temporary molars have
been ernpted, and appesr tolerably well developed. Nothing
is known of the history of these cases, but surely the unusual
condition of the bone of the alveolar processes must have
been attended with local indications of disorder. In a third
specimen we have the enlarged cranium peculiar to chronic
hydrocephalus, ‘ied with an absence of the outer
alveolar plate, so that the teeth are exposed over the whole
of their anterior surfaces, The bone does not exhibit any

(@) [twill be notioed on tooking over the maxille figured in this work, that
Seaman or many instances, aa far advanced as would be expected

‘duration, but that within certain timits there le some litle

52 A SYSTEM OF DENTAL SURGERY.

unusual porosity, the defect being in quantity only,—a pecu-
liarity which is extended to the whole of the bones of the
face. (Fig. 24.) I saw a patient some months since, wha
presented similar conditions. The anterior surfaces of the
teeth could be felt through the gums. ‘The child was under
the treatment of Dr. West, who tells me that he bus observed
in cases of this kind dentition is seldom attended with local
irritation or any increase of the pre-existing constitutional
disturbance. If this be a constant condition, it goes some
‘way towards showing that the local irritation so commonly
observed is consequent upon the obstruction offered to the
eruption of the teeth by the margins of the sockets, rather
than to that afforded by the gums. Further observation is

Fig. 4.0)

required before the question can be set at rest. Indeed,
this remark may be applied to the whole subject. Some
practitioners attribute almost every ailment of infancy to
dentition, without, however, attempting to explain how so
much mischief is produced, contenting themselves with the
(1) View of the facial portion of weull of child who had suffered from
sbowing the developing temporary tecth, acd the defective

anterior walls of the sockets,

-_

TEETHING. 53.

general statement, without telling us in what particulars the
series of changes which accompany the eruption of the teeth
were defective. Other medical men entertain the opinions so
clearly set forth by Dr. West.

In addition to the various characters presented by the
gums which have been already noticed, there is a condition
which I have seen in « few cases only. The gum over the
coming tooth is enlurged, but the enlargement is circum~-
seribed, has a blue or purple colour, and yields to pressure.
Tf an incision be made into it,a small quantity of transparent,
fiuid will escape, and we shall find the tooth at the bottom of
the emptied cyst. In these cases, the enlargement apparent
on the surface of the gum was obviously produced by the
secretion of fluid between the surface of the enamel and the
superjacent soft tissue, I was unable to determine whether
the lining of the cyst was composed of the fibrous tissue which
forms the base of the enamel-pulp, or of the stellate areolar
tissue which lies external to the latter, There appears to be
no connection kept ap between the enamel and the tooth sac
when onee the former is completed, and it is not improbable
that « slight amount of fluid may be present as a normal
condition, The inconvenience experienced by the patients
appeared to be very slight, and the occurrence of effusion in
the sac would merit little attention but that it offers a
probable explanation as to the source of another disease
which sometimes arises in connection with the evolution of
teeth—s subject which will be considered in a future page,

Hunter, after stating that the teeth, in their advance
towards the surface of the gum, exert pressure upon the
superimposed parts, thereby cansing inflammation and ulcer-
ation, goes on to say, “ that ulceration which takes place in
dentition is one of the species which seldom or never produces
snppuration; however, in some few cases I have found the

ulcerated, and the body of the tooth surrounded with
matter; but I believe this seldom happens till the tooth is
near cutting the skin of the gums.” The condition here

54 A SYSTEM OF DENTAL SURGERY,

described is probably subsequent to the infiltration of serous
fiuid within the capsule investing the enamel.

‘The most common result of difficult dentition is a general
febrile condition, Hunter says:

“ The fever is sometimes slight, and sometimes violent, It
is very remarkable both for its sudden rise and declension: 80
that in the first hour of this illness, the child shall be per-
feotly cool; in the second, flashed and burning hot; and in a
third, temperate again.”

Disorders of the nervous system frequently arise at this
epoch, varying in intensity from slight muscular twitching to
violent convulsions. ‘The following case occurred in the
family of a medical man :—A child, playing round the dining-
room table, suddenly fell down in a state of insensibility.
‘The father at the time was absent, and a neighbouring practi-
tioner was called in, who, on examining the mouth, found that
the gum was raised, and ina state of tension over a tempporary
molar, An incision was made down to the tooth, the child
immediately recovered its sensibility, and in a few hours
was perfectly well, Now, as no medicine was given, and as
the insensibility was continued until the gum was divided, it
would be too much to assume that the operation and the re-
covery had no further relation than mere coincidence, espe-
cially when it is remembered that the majority of those
engaged in extensive general practice conld furnish cases
similar to the one cited above, On the other hand, we may
have convulsions when teeth are about to be cut, and the
gums may be lanced with no apparent advantage, the disease
running its course towards recovery or death, uninfluenced
by the dental operation. (*)

Tnstances of epileptiform convulsions dependent on the
eruption of the temporary teeth are far from uncommon
and in some few cases where partially erupted temporary

(2) Two equally striking exes of econvulaions with consideruble pyrexia at ones
rellewed by Lancing tumid reddened gums were communicated by Mr. Stevenson

Snslth to the Edtnbungl Obstetrical Society, and are quoted in the Dental Cosmos
Vou xi, p. 20%,

TEETHING. 55
teeth have appeared to he sources of irritation, medical
men,(*) all other remedies having failed, have extracted
them with the effect of at once relieving the convulsions,
Hunter, whose work on the teeth cannot be too often referred
to by those engaged in the practice of dental surgery, or in
the treatment of disorders coincident with an abnormal state
of the dental apparatus—states: ‘The partial or local con-
sequential symptoms are the moxt varied and complicated ;
for the appearance they put on is in some degree determined
by the nature of the parts they affect ; wherefore they imitate
various diseases of the human body, These symptoms we
shall describe in the order of their most frequent occurrence :
diarrhoea, costiveness, los of appetite; eruptions on the skin,
especially on the face and scalp; cough, shortness of breath,
with a kind of convulsed respiration, similar to that observed
Sane ee ae spasms of particular parts, either by inter~

vals or continued ; an increased secretion of urine, and some-
times a diminution of that secretion; a discharge of matter
from the penis, with a difficulty and pain in making water,
imitating exactly a violent gonorrhea,”

A ease is given in which this disturbance of the urinary
organs was invariably coincident with cutting of teeth, the
‘one as it were keeping time with the other. Hunter's own
words are: “Tt was observed at last, that they (the urinary
symptoms) returned only upon his cutting a new tooth; this
happened so often, regularly, and constantly, that there was
‘no reason to doubt but that it was owing to that cause,”

Here, then, we have, on the highest authority, a long list
of the many ailments that may be consequent upon disordered
dentition; and it is for the practitioner to distinguish in in-
dividual cases, whether the disease present during the time
of teething ia consequent upon some derangement of this pro-
‘cess, or upon an abnormal condition of some other organ or
organs, of which the dental difficulty is but itself a symptom.

{ptt Observations wor l'Eptiepasie, p. 333, and Dental Cosmos, vol. xil., g
falas Liban Ye alltarwes fa wisn Of cathugen,

ie

56 A SYSTEM OF DENTAL SURGERY.

In forming this distinction, the state of the jaws must
be the principal guide, If, in the presence of symptoms
which might arise from teeth, we find that teeth are not
pressing forward towards the surface of the gums, and that
the latter maintain their normal appearance, it will be useless
to have recourse to the gum lancet; yet, even in this case,
the disorder may be due to, or much influenced by, the teeth.
They may be confined by the sockets, a difficulty beyond
the reach of mere division of the gum. It is not easy to
see how wounding the superjacent soft tissues should promote
absorption of the osseous margins of the sockets; yet there
are those who, on all occasions, have recourse to this practice,

‘There are, however, cases in which this simple operation
will at once either mitigate or entirely remove most alarming
symptoms; but in such we shall find the gum prominent,
and in a state of tension over the advancing tooth, Under
these conditions the gum should be divided down to the sur
face of the tooth, and not at a point only, but across the
whole breadth or length of the crown; in fact, the imprisoned
organ should be entirely set free,

Then, again, there are cases in which the gums may be
lanced with advantage, for the sake of local depletion, with-
out reference to the liberation of the teeth. When we find
the part inflamed and painful, this measure may be adopted:
the incisions should not, however, be deep, as in the former
case, but superficial only, and performed with a sharp instru~
ment, shaped like an ordinary lancet, and with an equally
sharp edge. The indiscriminate adoption of this treatment in
all cases when the gums are turgid and inflamed will occa-
sionally lead to mischievous results. In children who are
enfeebled, either from disease or residence in a bad atmo-
sphere, ulceration of the wounded parts may follow as a
consequence of the operation, or in some instances severe
hemorrhage, which has been known to prove fatal.

‘Trousseau expresses a strong opinion adverse to searifi-

* cation of the gum, which is, neverthcless, undoubtedly of

TEETHING. 57

(freat service in some cases, and it will be long before the
practice is abandoned, if indeed it ever will be.

For a detailed account of the symptoms and treatment of
those diseases which may be occasioned or aggravated by
abnormal dentition, 1 must refer the reader to works treating
upon the diseases of infancy and childhood. These are
subjects which seldom come under the notice of the dental
surgeon; he, having his attention constantly directed to the
organs of mastication in all their varied conditions, should
be able to point out any deviation from the normal state of
the teeth and jaws with greater precision than those whose
practice ranges over a wider field. The conditions necessary
to the acquisition of this special knowledge preclude the
possibility of his gaining an amount of practical information
upon the general subject of disease sufficient to place him
npon an equality with those who devote themselves to the
study of the diseases of infancy and childhood.

Relations of the temporary to the developing permanent teeth
at the period when the former are fully formed,—tIn following
the plan which has been adopted in arranging the matter of
the present volume, it will be necessary to point out the
normal relations of the two sets of teeth before entering
upon the irregularity in the arrangement of the permanent
organs while still within the alveoli. If we select for exami-
nation perfectly well-formed jaws from a subject in which the
first permanent molars have not appeared through the guns,

“bat in which the temporary teeth are all perfect, we sball

find that each member of the latter set has become slightly
separated from its fellow; a condition indicating that the
growth of the jaws has been in all respects normal, and eon-
sequently that a good and well-arranged set of permanent
teeth may reasonably be expected.

‘The crowns of the permanent incisors, both of the upper
and lower jaws, are perfected, excepting perhaps at that part
where the enamel terminates. There the dull and chalk-like
‘appearance which that tissue presents when the develop-"

58 A SYSTEM OR DENTAL SURGERY.

ment is progressing, may be observed. The canines are still
less advanced, while the crowns of the first bicuspids have
not attained to more than two-thirds, and those of the second
bicuspid not more than a third, of their ultimate lengths,
The crowns of the firat permanent molars are, as respects
their external surface, fully developed; and the septa of
dentine which extend across the base of the pulps marking
out the several roots yet to be developed are fully pro-
nounced, ‘The second permanent molars are at present repro
sented by about two-thirds of their crowns, and invested
with a thin layer of partially-developed enamel. The posi-
tions of the pulps of the wisdom teeth are but faintly indi-
cated by slight depressions in the bone posterior to the
sockets, which contain the forming second molars. These
marks may, however, at this period, be altogether wanting.

‘The position of the temporary teeth in the jaws differs
from that of the permanent set in being perfectly vertical.
The crowns do not occupy a more forward position in the
dental circle than their respective roots; the crown of each
tooth is directly over or under (as the case may be) its own
root, the latter standing immediately in front of one or other
of the succeeding teeth,

The permanent teeth are at this age contained within bony
cella, which have been aptly cnough compared to the dense
layer of shell which surrounds an.almond, and which, like
the dental cells, is connected with the contiguous tissue by
a comparatively porous structure, ‘he alveolar cells may be
readily isolated by breaking away the porous bone by which
they are surrounded, except at those points where they come
in contact, and blend with the dense bone which contributed
to form either the outer surface of the jaw, or the dense wall
of a neighbouring cell.

On removal of the bone from the anterior surface of the
maxilla, it will be seen that the permanent central incisors
are placed nearly parallel with each other, the cutting edges
in the upper teeth being inclined a little forwards, while the

TRETHING. 59

parts corresponding to the base of the crowns of the two
teeth respectively are placed immediately below the floor of
the nose, from which cavity they are separated by a thin
layer of bone only. The teeth at this stage of growth com-
pletely fill the cells or crypts. The corresponding lower
teeth hold a similar position in the lower jaw, but have a
strictly vertical position, and show a slight advance in de-
velopment as compared with the upper centrals,

The lateral incisors of the upper jaw have a slightly oblique
direction, the cutting edges being more forward than the base
of the crowns, which are nearly on a level with the corre-
sponding parts of the central teeth, The labial surface of each

Fig. 25. (9)

is often slightly turned, so that the mesial surface which lies

the central incisor is directed outwards, while the
mesial angle of the tooth stands in front, and a little over the
contiguous portion of the central incisor. The point at which

(1) Shows the relations of the temporary aod permanout teeth st the
Period whet the former are perfoetly formed, in an example of well-formed
waatile,

60 A SYSTEM OF DENTAL SURGERY.

the one tooth overlaps the other, corresponds to the position
of the root of the temporary Interal incisor. That side of the
lateral which in the perfected teeth lies against the canine,
here rests against the cell which contains the first bicuspid ;
while the developing canine is at this period above the latter
tooth. In the lower jaw the lateral incisors are placed less
regularly, holding a position slightly more backward than
the centrals. ‘Ihe tooth of cither side is turned from the
mesian line, and lies obliquely over the canine, to the extent
of about half of that tooth. They do not, however, as in
the upper jaw, come in contact with the cells that contain
the first bicuspids.

The permanent canine teeth at this stage of dentition are
situated above the line of the other teeth in the upper, and
below it in the inferior maxilla. Those of the upper jaw are
directed slightly forwards and ontwards, while in the lower
jaw these teeth have a direction upwards and a little in-
wards. The bicuspids are placed in cells situated between
the roots of the temporary molars.

In the specimen which I have chosen for description, and
from which the illustration is taken, we have perfectly well-
grown jaws, showing very completely the relations in position
of the first to the second set of teeth, and the relative posi-
tion of the several members of the latter to cach other. It is
very desirable that the practitioner should be well acquainted
with the conditions which this, in common with many other
similar specimens, presents. We sec in it all the early con-
ditions necessary to the development of a perfectly regular
set of teeth fulfilled.

In another specimen (Fig. 26), the arrangement is equally
normal, but differs in one respect from that which has been
described. In this case the mesial sides of the upper lateral
incisors are placed behind the distal sides of the central
teeth. The degree of overlapping is perhaps rather in excess
of what may be regarded as a perfect arrangement, and the
lateral have descended nearer to the alveolar margin than

TEETHING. 61

the central incisors; but still the specimen will serve for
illustrating the relative position of the several teoth alluded
to, at the same time that it exhibits an irregularity in the
position of the right lateral incisor in the lower jaw. This
tooth has its median edge turned outwards towards the lips
and is accompanied with a diminished size of the anterior part
of the jaw, as compared with many other jaws of similar age.

Attention may again be directed to the fact that the tem-
porary teeth are placed vertically in the jaws, and that if their

Fig. 20. (%)

successors were similarly implanted, there would not be room
in the upper jaw for the canine teeth. But the upper incisars
in the place of a vertical have an oblique direction forwards
and outwards towards the lips, while the vertical line is at
this age followed by the bicuspids. Now, if we produce an.
imaginary line through the axes of the upper incisors in
their present state, to the extent of perfected teeth, it will be

(@) Showing tho relative postion of the two sets of eth, with the upper
Interal ielsors descending tower Wine the central teeth, and the right lower
Taveral with ita dtintal edge tarned outwards,

62 A SYSTEM OF DENTAL SURGERY.

seen that the difference in the direction of the line of growth
between the incisors and the bicuspids will lead to a separa~
tion between these tecth sufficient to admit the canine into
the dental line. In order that this result shall be attained,
it is necessary that the relative rate of growth between the
several teeth shall remain undisturbed. If, for instance, the
canine advances too rapidly npon the lateral incisor, and
makes its appearance through the gum before the lateral tooth
has advanced sufficiently forwards and outwards, both teeth
will be displaced : the lateral will be forced within the proper
line, and the canine will occupy a place external to it.

Many children, however, either from hereditary tendency
or from ill-health and consequent defective growth in the
jaws, have the permanent teeth during their development
placed irregularly. Attention has already been directed to
the fact that the size of the crowns of the teeth is determined
at an early age, and is not capable of subsequent alteration.
It would appear, however, that a want of proper relation in
respect of size between the teeth and the jaws may become
a permanent hereditary character, quite apart from the influ-
ences of health and disease. In certain families we may see
large teeth associated with small jaws, the want of the requi-
site size in the latter parts necessitating the removal of two
or more of the permanent teeth before the regular arrange-
ment of the remaining ones can be assumed—and this
without any indication either of want of constitutional vigour,
or of predisposition to disease. It is, in fact, a peculiarity
transmitted from parent to child, and must be regarded rather
as an hereditary characteristic, than as an abnormal condition
resulting from an arrest in the development of the maxillm,
capable of amendment if the patient be subjected to treat-
ment during the period of childhood. It is very necessary
that this part of dental surgery should receive far more con-
sideration in an anatomical and physiological point of view
than it has hitherto done. In the absence of precise know-
ledge upon the subject, there is room for great disparity

of opinion as regards treatment, leaving a wide and very pro-
ductive field for the cultivation of the charlatan, who sees
in every case of irregular disposition of the teeth an oppor-
tunity for mechanical interference, in some cases securing to
himself a large fee for doing by means of mechanism that
whieh Nature would have effected, had the opportunity been
allowed ; and in other cases submitting the patient to a long
course of treatment, which entails no useful result.

In the subsequent pages, an attempt is made to bring
together a series of conditions connected with the subject of
ag Leg ang sor og ey fat peti
an earlier period than is usually done, and tracing the devia-
tions onward until the teeth are matured,

Irregularity in the position of the permanent, during the
existence of the temporary, teeth,—The first example selected
for description in illustration of irregularity in the position of
the permanent teeth, will be that of a child who died when a
little over the age of four years. ‘he temporary teeth in the
front part of the mouth are crowded, the mesial edges of the
lateral incisors of the upper jaw being directed forward,
from insufficient space for a more regular position of these
teeth. The permanent central incisors, although uniform as
regards each other, hold an unusnal position. ‘The mesial
edges are turned forward, and the cutting edges of the teeth,
from the obliquity of the crowns, are directed towards the
mesial line. The upper lateral incisors lie in front of the ,
distal edges of the central teeth, and the canines are placed
immediately over the roots of the first temporary molars, and
consequently immediately over the developing cusps of the
first bicuspids. We have in this case a deranged position
which, until the teeth have passed through the gums, cannot
be materially changed. The development of the teeth has
been continued while the jaws have been comparatively
Stationary. ‘The oblique and twisted position of the central
incisors will be maintained until they are acted upon by the
antagonistic teeth of the lower jaw; and the first bicuspids,

a

64 A SYSTEM OF DENTAL SURGERY.

which have been encroached upon and retarded in growth by
the canines, will be crooked and misshaped, at the same time
that they will be forced into an irregular position in common
with the impinging canines, leading probably to one or other
of the permanent forms of displacement of the later teeth,

considered in a future page. In this case, the teeth in the
lower jaws are subject to but slight irregularity,

Pig. 28. (*)

©) Showing the permanent central tnolsors, with their median aides
directed forwards and outwards, while the dlstal odges lie behind the median
aides of the laterals,

(2) Side view of the same specimen, showing the rolative positions of tbe
central and lateral Incksors, the canine and the fret bicusplids, the latter tooth
boing Interrupted in Ita development by the canine,

TEETHING. 65

Tn another specimen, from a subject who died at the age
of four years and thirty-six days, the lateral incisors of the
upper jaw are placed behind the contrals, the latter teeth
and canines being separated only by the common wall of
‘their respective crypts.

Ina third specimen, the mesial surface of the left upper
central is turned outwards, while the corresponding part of

the fellow tooth is turned inwards. The mesial side of the
left lateral incisor lies in front of the distal side of the cen-
tral, and on the opposite side of the jaw the mesial side of
the lnteral is placed behind the distal side of its contiguous
central tooth. The canine and bicuspid teeth hold the
normal position.
Tn a fourth specimen we have an arrangement of teeth
which may not unfrequently be seen in the adult. The
deviation from the natural form is but slight; yet gives avery
charseteristic appearance to the mouth, and one which indi-
cates a want of activity in the growth of the jaw during
(1) Shows mal-position of the incisors. ‘The left central bas its median
edge turned outwards, with the lateral tying in front of the distal edge. ‘The
fight ectstval incisor has tte distal aide everted, with the lateral placed

r

66 A SYSTEM OF DENTAL &URGERY.

childhood. In this the distal sides of the upper centrals are
slightly everted, while the crown of each tooth, regarded in
its length, slants outwards from the mesian line. Usually,
the upper and smaller parts are separated by a wider interval
than the lower portions of the crown ; in this case the mesial
surfaces are parallel throughout the whole length of the
crowns. Hence tho eversion.

Wig. 20.01)

Hitherto, the relations of the teeth to each other and to the
jaws, have been considered in cases where the maxillw present
the normal structural appearance, as distinguished from cases
in which there are obvious marks of a discased condition of
the bone. In the specimen from which the two sucoceding
figures are taken, the bone is defective both in the quantity
and in the quality of the tissue. The temporary teeth are
almost devoid of sockets, while the developing permanent
teeth—in the absence of sufficient bone to admit of the
existence of normally-formed crypts—are covered at certain
points by soft parts only. The subject—a male—from which
the maxillm were taken, died exhausted by strumons abcesses

(®) Shows the centrale symmetrically arranged, bot with the distal side of
ach tooth tarved slightly outwards,

TERTHING. 67

when he was said to be six years old, Both in the wpper and
lower jaws, the incisors and canines are almost without
sockets, and the molars have but imperfect ones. The
general dimensions of the jaws, even supposing the age to be
overstated to the extent of eighteen months, are third below
the normal size, This bas led to the mal-position of the
permanent teeth. The central incisors of the upper jaws are
of the usual size and shape, although the enamel is at
certain points defective.

Fig. 31. (1)

‘The canines lie with their median surfaces in contact with
the distal sides of tho central teeth, leaving no space what-
ever for the lateral incisors. These are placed within the
dental line, behind the temporary canines (Fig. 52), lodged
in very imperfect crypts, and placed at right angles to their
proper position, the cutting edge of each tooth being directed
outwards instead ofdownwards, ‘The first permanent molats
have their crowns nearly perfected, and are placed with the

2) Front view of the upper jaw of « male subject who died at the age of

six years, showing o detective condition of the outer alveolar plate aad au
Imperfect Implanta)ton of the temporary teeth.

68 A SYSTEM OF DENTAL SURGERY.

masticating surfaces directed obliquely backwards, the base
of the crown running over the fangs of the second temporary
molar, and eneroaching upon the space which should be
occupied by the second bicuspids.

The second permanent molar, the cusps of which are calei-
fied and united the one to the other, is altogether without an
osseous receptacle,

In this specimen we have a remarkably good example of

Pig. 52.(8)

the effects produced from the development of the maxillw
having been suspended, while that of the permanent teeth
was continued, We here eee the great amount of displace-
ment that may arise from the presence of long-standing
constitutional disease.

Local disease in the temporary may also affect the perma-
nent teeth; but the effect will be Limited to those in the
immediate neighbourhood of the disease. Caries, and con-
sequent alveolar abscess, arising in a temporary tooth, some~
times produces injurious effects upon, and even displacement
of the succeeding tooth; and this is, I think, a more fre-
quent consequence when the disease is situated in the first

(1) Palatal view of the specimen {llustrated tm the lost figure, showing

an abmormal condition of the bone and the exposure of the permanent
eamnlnes.

TEETHING. 69

or second temporary molars, than when the front teeth are
affected. Ina preparation figured to illustrate the effects of
dead teeth, it may be seen that the developing first bicuspid
of the upper jaw has been driven outwards by the mischiof
arising from the presence of a dead temporary molar,

Fig. 3. (1)

Tn addition to the causes already enumerated, mechanical
injury of the maxillw or of the temporary teeth, may be cited
as producing displacement of the permanent teeth while
lodged within the dental crypts.

Among mechanical causes, the extraction of temporary
teeth may be placed, We have most of us seen examples
where removal of the second temporary molar has been

(@) The upper and lower Jawa at the age when the permanent incisors are
about to appear through the gums, showing the relative position of the two
gets of tooth. ‘Tho left lateral incisor of the upper jaw is !mperfectly developed,
‘sped placed external to the central tooth ; and the first bieaspld of the some side
has been forced outwards by diseass, and subsequent death, of the preceding
temporsry molar,

70 A SYSTEM OF DENTAL SURGERY.

accompanied by that of the partly-formed second bicuspid, an
accident which has arisen either from the unusual convergence
of the roots of the temporary, or from the absorption of the
walls of the crypt of the permanent tooth. The latter
condition is not, I think, extremely rarein those cases where
alveolar abscess is consequent upon disease in the temporary
molar. Acertain degree of inflammatory action of the soft
parts in the immediate vicinity of bone leads to more or less
absorption of the latter, and at the same time the former be~
come glued together by effused lymph. Supposing these con-
ditions to prevail, it will not be difficult to conceive how, in
attempting the extraction of one, both teeth may be removed.

Taking the phases of dentition in the order of their occur
rence, the next point which presents itself for consideration
is the absorption of the roots of the temporary teeth.

Shedding of the temporary teeth,—No sooner is the tempo-
rary sot of tecth fully formed, than a process is set up for the
removal of some of its members. Within twelve or eighteen
months of the completion of the roots of the second molars
and canines, the fangs of the incisors are attacked by
absorption.

The destruction may commence on any part of the root, or
at several spots simultaneously. Particle after particle is by
degrees carried away, until nothing but the crown of the tooth
is left, and even this is often so much hollowed out, that
little save the enamel remains, and sometimes not all of that.

Although among a number of temporary teeth we may find
that absorption has commenced at several and distant points,
and not uncommonly on the labial surface of the root; yet,
in the majority of cases, that part which lies nearest to the
growing tooth will be the first to show indications of wasting,
and upon which the process will be the most active. The
opposed surfaces of the roots of the lower temporary molars,
embracing bicuspids, are acted upon, while the outer surfaces
usually escape. The lingual surface of the fang of a front
tooth is commonly attacked, the process commencing at

THETHING, 7

or near the extremity; but the proximity of the permanent
tooth is not by any means 4 necessary point. I have
examined many specimens, in which a portion of the Isbial
surface midway between the neck and the point of the root
has been carried away.

Having latterly had occasion to devote considerable atten-
tion to the phenomena attending the absorption of bone and

the wasting of the roots of the deciduous teeth, several con-
ditions relative to absorption have come under my notioe,
which, as applied to teeth, had, I think, hitherto escaped
observation. The cementum is first attacked, then the dentine
disappears, and the enamel at those points where the dentine
has been entirely removed suffers from the same action. But

18) A wectlon from a temporary tooth, in which the dent{ne (a) and the
eer ate enerenee ar mea. Seng io Seesaw

72 A SYSTEM OF DENTAL SURGERY.

whichever of the three tissues is attacked, we see the same
characteristic surfaceas that shown by bone when undergoing
a similar action—namely a surface full of deep indentations, as
though they had been made by a sharp piercing instrument,
having a semicircular extremity. These minute holes or
depressions proceed in various directions, several advancing
from contrary points towards the same spot, not unfrequently
isolated pieces of dentine, If a section be taken through
the substance of a tooth, so as to cut the wasting part
at a right angle, we shall find the surface acted upon

to have an irregular festooned outline, so characteristic
in appearance, that when once seen it cannot fail to be again
recognised.

Closely applied to this surface a cellular mass will be found,
which is but slightly adherent, the wasting and growing
surfaces readily parting, unless the two are held together by
the irregularities on the surface of the former. It will some-
times happen that the cellular mass penetrates into the
dentine through a small opening, and there dilates, in which
case its withdrawal becomes impeded. his condition is now
and then found in sections prepared for examination, and

(!) Shows the compound cells which form the surfaco of the absorbeat
papilla.

—"

TERTHING, 73

affords a favourable opportunity for examining the two tissues
in situ, Indeed, we may find a fow cells adherent to the sur-
face of the dentine whore less deep burrowing has occurred,
By the aid of the microscope, the structure of this peculiar
organ can be determined. The surface is made up of peculiar
multiform cells, each one being composed of several smaller
cells, the nomber varying from two or three to as many a8
fourteen or fifteen. The form is variable, but egg-shaped or
spherical figures are found to prevail, although some few
deviate from these forms, and offer a very strong resemblance
to those cells described by M. Kalliker as myeloid cells,

‘The relation the more superficial of these cells bear to the
wasting surface of the dental tissues is peculiarly interesting.
Tt has been already stated that the surface of the papilla is
closely applied to the wasting surface of the tooth; and in
favourable specimens it may be shown that the individual
indentations correspond to, and are occupied by, these large
cells. On several occasions I have obtained specimens in
which the two retained their natural positions. Each semi-
cirenlar indentation in the dentine was occupied by a com
pound cell. Very possible in other cases several cells may
take the place of a single cell. Below the surface the
papilla is made up of ordinary nucleated cells and free nuclei,
similar to those contained in the superficial compound cells ;
while at and near the base, the tissue assumes the charac-
teristics of developing fibrous tissue.

Ifa tooth which has lost its fang be carefully removed, we
shall find remaining in its place the growing papilla, corre-
sponding exactly in size and form to the surface from which
it has been separated; and this separation may often be
tfiectéd with so little injury, that no blood appears upon its
surface after the operation, although the organ is highly vas-
cular and readily torn.(*) The superficial extent of the papilla
vitae a ving nt oe

74 A SYSTEM OF DENTAL SURGERY,

will be equal to that part of the tooth undergoing waste, but
the extent, as regards depth, is slight; for, as the root of the
tooth disappears, the socket is contracted by the deposition
of bone, which forms at the base of the absorbent organ as
rapidly as the cellular surface encroaches upon the tooth,
The cases in which we find an exception to this condition are
those in which the permanent has advanced close to the fangs
of the temporary tooth, when the crypt containing the one
communicates with the socket of the other, indicating that
the rate of growth of the permanent, has been equal to if not
greater than the absorption of the deciduous, organ. But
even in these cases we may occasionally observe some part
in which the contraction of the socket has been coincident
with the absorption of the occupant fang. From the follow-
ing quotation, it does not appear that Mr. Bell observed these
conditions ;

“Tt has been already stated, that the permanent teeth
daring their formation are crowded together in the jaw, by
being placed in a smaller arch than they would oceupy if
regularly placed side by side, As the latter, however, is
their destined situation, we find that as soon as they are
advanced to a certain point of their formation, and can no
longer be contained within the alveoli, absorption takes place
in the anterior parietes of the cavities, by which means the
teeth are allowed to come in some measure forward. Jn
consequence of this absorption it often happens, that not
only the socket of the corresponding temporary tooth, but
that of the tooth on each side, is also opened to the perma-
nent one. Absorption now commences in the root of the
temporary tooth, generally on that part nearest its successor,
and thus goes on by degrees as the latter advances, until the
root is completely removed, the crown at length falls off,
leaving room for the permanent tooth to supply its place,”

Mr. Bell, however, rejects the idea that mere pressure of
the one tooth against the other has anything to do with the
absorption of the first set ; an opinion that he would probably

TEETHING. 75

have expressed even more strongly, had he observed the
shallow but perfect sockets which are formed when the
temporary teeth are shed before their successors are ready
to appear, This, however, must be a very common condition,

Fig. 36. (2)

(®) Tho upper and lower Jaw of o female suljject, six yearw and five months
‘old, showing the layer of bene which forma the bottom of the socket of tbo
Aemporury incisors after the roots have been absorbed,

TRETHING. 75

have expressed even more strongly, had he observed the
shallow but perfect sockets which are formed when the
temporary teeth are shed before their successors are ready
to appear. ‘This, however, must be a very common condition,

ig. 38, (1)

end lower Jaw of » female watject, etx years and five months
lager of bone which forme the botum of the socket of tw
‘ afer the rocts have been absorbed.

76 A SYSTEM OF DENTAL SURGERY,

as I have in my own collection several specimens illustrating
the point.

The fact was not overlooked, I think, by Hunter, although
his description is not very clear. He states, at page 99 in
his “ Natural History of the Teeth ”"—*The new aleeolé rise
with the new teeth, and the old alveoli decay in proportion
as the old teeth decay; and when the first set falls out, the
succeeding tecth are so far from having destroyed by their
pressure the parts against which they might be supposed to
push, that they are still enclosed and covered by a complete
bony socket. From this we see that the change is not
produced by a mechanical pressure, but by a particular
process in the animal economy.”

But there is still a disposition on the part of many who are
entrusted with the treatment of teeth, to attribute the absorp-
tion of the roots of the one tooth to pressure occasioned by
the growth of its successor; and the development of the
permanent may have something to do with the shedding of
the other. But this does not offer a satisfactory explanation
of all the circumstances attending the absorption of the fangs
of teeth. In the first place, we sometimes meet with cases in
which the fangs of permanent teeth are as completely ab-
sorbed as those of the temporary organs. Then, again, the
fangs of temporary teeth, which have no successors, are also
absorbed: and it not uncommonly happens that absorption
takes place at several points on the fang, some of which are
far removed from the successor, being oftentimes on the
opposite side of the root, These circumstances, taken with
the hitherto overlooked fact, that with the waste of the tem~
porary tooth we have in many casea a corresponding develop-
ment of bone within the socket, to be removed before the
permanent tooth appears through the gum, render the pres-
sure theory altogether untenable. Another condition may
be adduced, tending also against that opinion,—namely, that
temporary teeth occasionally maintain their place to the
exclusion of the permanent ones, which are then kept

TRETHING. 7

within the substance of the jaw, or appear in some unusual
position.

The relations as regards time between the absorption and
shedding of temporary teeth and the appearance of the suc-
ceeding permanent teeth, are by no means constant. In some
cases the temporary teeth are thrown off two years before
the corresponding permanent ones come through the gums,
In others, again, the new will replace the old ones in as many
weeks or even days.

Before the laws which regulate the absorption of the fangs
of teeth can be fully recognised, a more perfect knowledge of
the condition attending the process must be acquired. Recent
examinations have enabled me to add the following additional
facts bearing upon this subject to those already known.
When the process of absorption has once commenced, it
appears to have been assumed that the action would be con-
tinued, with more or less rapidity, until the tooth falls ont.
Such, however, is not constantly the case. Not only is the
action of absorption suspended, but one of development takes
its place, We find the excavated surface of the dentine,
cementum, and enamel covered with cementum, the latter fol-
lowing all the irregularitics of the former tissues, and closely
united to them. (Fig. 37.) In cases where this development is
going on, or in which the new tissue is retained, the teeth
offer considerable resistance when their removal is attempted.
In those instances where the first teeth have remained, and
tend to the displacement of the second set, this deposit of
cementum will be found to exist in considerable quantity.

The development of bone upon the surface which had
formerly beon the seat of absorption, by no means indicates
that the tooth will not again be subject to destructive action.
On the contrary, specimens in my collection show that the
bone deposited under the above circumstances may itself
become the subject of absorption, that this process may be
again suspended and development be renewed, that the
absorption may again take the place of development; in fact,
that wasting ond reparation may alternate until, by the

[a

78 A SYSTEM OF DENTAL SURGERY,

preponderance of the former, the tooth is shed. In sections
of teeth showing this peculiar condition of development, we
may find upon the growing bone numerous osteal cells, with
here and there a lacunal cell, A bone lacuna, situated with-
in a semi-circular indentation in the dentine, gives the ap-
pearance of a Incunal cell, and a lacuna similarly situated in

Fig, 31. (8)

the cementum (a circumstance of common occurrence), has
possibly been supposed by Mr. J. Salter to be what has been
described in the paper before referred to as a lacunal cell.(?)
‘The part of a tooth which has the greatest power of resisting
absorption is that which isin immediate contact with the pulp.

(*) A section from the fang of « tooth in which the dentine (a) has been
femoved, together with the cementum (¢), and again male good by the depo-
fitten of cementum, The apposrance presented at the junction of the deti+
fine and cementum, where ateorption has not encroached upon the themes
at that point, Is shown at (0). The curved frreguiar line in the cementutn
indicate the extent of absorption at various periods, and the boundaries of the
these which has replacst the lost parts,

(F) Tramsactions of the Pathologloal Society, vol. x1, p, 169.

TRETHING. 79

We find examples in which a thin shell of dentine encircles
that organ, while all around it has been in great part taken
away. his is, however, eventually removed, and the pulp
itself changes its character, and becomes an absorbent organ,
or makes way for that which is. In a fortunate selection we
may find sections showing in one part dentine which has been

and both tlasues coated over with new cementum. a, the dentine; 6, the
+6 the cementum; «, the Janctlon of the absorbed surface of the

80 A SYSTEM OF DENTAL SURGERY.

but recently formed, with its nodular outline and contiguous
cells capable of developing dentine; in another part, absorp~
tion in active progress; and in a third, the deposition of
bone on the surface of the wasted dentine. In no instance,
however, have I seen dentine deposited upon the surface of
that which has been diminished by absorption.

It would appear that the dentinal pulp, although its fune-
tion may be changed into that of absorption, or its place be
taken by an absorbent organ, and this, again, changed to one
for the development of bone, is incapable of resuming under
any recognised circumstances its primary function of dentinal
development. In other words, that a portion of dentine when
removed by absorption, cannot be replaced; while in bone,
or cementum, the renewal of a lost portion is of frequent
occurrence.

It will be seen that the foregoing facts bear upon the
opinions advanced by Mr. De Morgan and myself, in the
paper on the structure and development of bone before cited ;
that we have indications in teeth, as in bone, of alternations
of removal and of deposition of tissue. In the young subject,
the development of bone tissue is in excess of absorption,
allowing the bones to increase in size; in middle life the two
powers, under ordinary circumstances, balance each other,
and the bones preserve their adult dimensions ; while in old
age the absorbent action appears to preponderate, Con-
ditions pretty nearly parallel occur in the dental tissnes after
the temporary tooth has been fully formed; portions of ce-
mentum are removed, and with them, in some cases, a little
dentine; the lost parts are replaced by cementum, and the
tooth is again perfect. When the time approaches for shed~
ding the teeth, the two actions alternate; but the absorption
being in excess of the development, the tissues disappear,
and the tooth is shed. After the formation of the permanent
tecth we have occasional alternations of the two actions; but
they are balanced, and neither increase nor diminution in
size is observed. But as age comes on, it often happens that

TEETHING. 81

absorption is in excess, the fangs diminish in size, the teeth
become loose, and eventually fall out.

The normal shedding of one or more of the temporary
teeth is, however, sometimes subject to interruption. The
absorption of the roots is suspended, and the tooth holds its
place, while its successor is matured within the jaw in some
unusual position; or the permanent tooth may be altogether
wanting. It ia not uncommon to find the temporary incisors
firmly implanted, with the permanent teeth appearing through
the gum behind them, In instances of this kind it is diffi-
cult to determine whetber or not the permanent teeth were
developed, in a perfectly normal position, and their position
subsequently changed by the persistence of the milk teeth
consequent on the arrest of absorption, or whether the relative
position of the two sets has been from the first irregular.
Judging from the conditions presented in my own specimens,
I should incline to the opinion that the presence of the
temporary teeth is in such cases due to some extent to
original mulposition of the developing permunent organs.
Many instances in which the second temporary molars have
been retained until the middle period of life has passed, have
come under my notice. The second bicuspid has been want-
ing, and the temporary tooth has retained its original position.

The influence of the first and second sets of teeth upon
each other at the time of replacement is so constant, and so
varied in character, that it becomes impossible to treat fully
of all that relates to the disappearance of the one, prior to
entering upon the relations of the other. It will therefore
be convenient to revert to several points connected with the
shedding of the temporary (and especially those relating to
treatment), in connection with the eruption and arrangement
of the permanent teeth.

Before we dismiss the subject of absorption, a few lines
tmay be devoted to the consideration of the manner in which
theabsorbent organ is developed, and of the tissues from which
itarises; both are points of great physiological interest,

a

82 A SYSTEM OF DENTAL SURGERY,

In a paper read before the Odontological Society, Mr.
Spence Bate advanced the opinion that the outer surface of
the enamel organ assumed an increased degree of vascularity,
snd took upon itself the office of absorption. If our observa
tions were restricted to the phenomenon as it is usually pre-
sented in the temporary molars, this opinion might, perhaps,
be maintained ; but when we find absorption commenced and
continued upon the labial surfaces of the front tecth, where
no enamel organ exists; and when we find a number of
specimens in which a layer of bone separated the di
tooth from the one undergoing absorption, considerable doubt
is thrown upon the accuracy of Mr, Bate’s views, «He, how-
ever, considers the foregoing as exceptional cases, and regards
them as abnormal. Any vascular tissne, on assuming an
increased degree of vascularity, may, he considers, exercise
the function of absorption. But the wasting of the fangs of
permanent teeth, together with the class of cases cited above,
he regards as instances of abnormal action, the absorption
being performed by the peridental membrane, the vascularity
of which has been increased by irritation at the same time
that it has become detached from the surface of the tooth.
The admission of this distinction into normal and abnormal
absorption, in respect to the removal of the tissues of tem-
porary teeth, will not, I think, help us to a better compre-
hension of the subject; for in the one case we cannot know
when the action has commenced on a part distant from the
enamel organ until the tooth has been removed, and in the
other the septum of bone cannot be recognised but by
dissection, But the most fatal objection of all to such a far-
fetched supposition is, that at the period when absorption of
the fang of the temporary tooth is going on with the utmost
activity, the enamel organ of its successor has not only long
ceased to be vascular, but has in most instances actually ceased
to exist, the external epitheim of the enamel organ having
become inseparably attached to the surface of the enamel.

All recent observers will, 1 think, admit that the dental

‘TRETHING. 83

tissues are removed through the agency of a growing
papilla, and I do not think a difference of structure or func-
tion, referable to the particular tissue from which it may
have arisen, can be established, Whether the development
takes place from the enamel capsule or from the peridental
membrane, the stracture and the function of the papilla will
be the same. The precise nature of the action by which
the cells eat away the hard tooth structures still remains
& matter of great uncertainty. Kehrer, having observed
chalk granules in the protoplasm of young cells, believes
that the ameboid cells of the granulations destroy the
dental tissue by a kind of mining process, effected by their
psoudopodia, (Waldeyer, in Stricker's Human and Com-
parative Histology.)

Tn 9 paper published in the “Philosophical Transactions,”
some of the foregoing facts are described in connection with
the absorption of bone, and an opinion was advanced, to the
effect that the absorbent organ grew at the expense of the
wasting bone or dental tissue, asthe case may be. At that
time the peculiar character of the superficial compound cells,
and their correspondence to and lodgment in the minute
concavities of the wasting tissue, had not been observed.
But when it is considered that the dental tissue is decreasing,
while the compound or mother cells (as they have been
called) are increasing, and that the convexities of the latter
te fitted into the concavities of the former, we are irresistibly
led, not only to the conclusion that the growing papilla is
the absorbent organ, but also to the belief that the superficial
compound cells are the immediate agents by which the
tissues are removed, and that the peculiar surface presented
‘by either bone or dental tissues, is secondary to, and produced
by the cells which form the surface of the papilla.

\ Perhaps Mr. Spence Bate might be right were he to assert
that the onter surface of the capsule of the developing per-
tanent tooth, may become the seat of the vascular structure
‘Which fulfils the office of absorption, But Tam unwilling to

ae

84 A SYSTEM OF DENTAL SURGERY.

admit that a similar stracture arising in other parts and
under other circumstances, is to be regarded as abnormal.
Supposing the distinction to hold good, we must regard the
action by which bone is at all periods of life removed, prior
to the development of new tissue, as an abnormal process,
and also the corresponding changes which go on in the
cementum clothing the roots of permanent teeth. It would
appear rather, that wherever the necessity for the removal of
osseous tissue arises, the structure capable of fulfilling the
office is developed, and in a vast namber of cases quite in-
dependently of abnormal action, .and that the seat of the
development may be in any vascular structure.

The observations at present at our disposal are not suffi-
ciently numerous and varied to admit of the deduction of
any general law, as regards the power by which absorption of
one tissue by another is effected, But I think they point
strongly to the idea, that a cell structure in an active state
of development, is capable of appropriating or removing out
of its way a matured tissue.

The eruption of the permanent teeth—Attention has already
been dirceted to the changes in the condition of the alveolar
processes antecedent to the eruption of the temporary teeth.
Very similar conditions prevail when the permanent organs
are about to make their appearance through the gums. It
has been shown that absorption of the alveolar margin of the
sockets of the first teeth is not necessarily coincident with
the removal of their roots, but that the opposite condition
very commonly obtains; that absorption of the dental tissues
may be accompanied by development of osseous structure.
When, however, the permanent tooth is ready to emerge
froua its bony cell, absorption is again set up, and in this
case the bone which lies over the crown of the growing tooth
is attacked, The coronal portion of the crypt is enlarged,
and the outer alveolar plate emarginated in the manner
which we have seen precedes the evolution of the temporary
tooth, ‘The aperture becomes enlarged until the crown of

86 A SYSTEM OF DENTAL SURGERY,

- If adult specimens in which the teeth and jaws are well

formed, be examined, it will be found that growth in the
direction indicated has been continued until the parts have
arrived at maturity. In the adult the crowns of the front
teeth are placed in advance of the base of the nose; in the
child they are in a line vertical to it: and if we measure the
ellipse formed by the anterior surface of the upper jaw in @
horizontal line with the last-named point, extending on
either side to the second bicuspids, and then apply the
measure to the corresponding part in an adult, or in an
edentulous old person, we shall find the result in each case
very nearly similar, In tracing the permanent teeth as they
are respectively protruded and take their position in the
dental arch, it is desirable to bear the foregoing points in
mind. In certain cases we shall find mischief arises from
want of growth in the facial bones at the earlier periods of
life, but in many instances the deviations from the normal
position of the teeth and alveoli are independent of insufficient
size of the bodies of the maxillm; or in other words, cases in
which the basal line has attained its usual extent, while the
teeth are irregularly placed in an irrégularly-formed arch.

It is necessary to draw a distinction between the bodies of
the maxillw and the alveolar processes, as it will subsequently
be shown that in cases of irregular dentition, the irregularity
may depend upon a want of accordance between the general
dimensions of the jaws and the determined size of the teeth;
or the mal-arrangement may depend solely upon imperfect
development, in respect to position, of the teeth and the
alveoli.

Tn describing the evolution of the teeth individually, and
the coincident conditions, the chronological order in which
they usually appear will be followed.

The first permanent molar of the upper not uncommonly
precedes by a few weeks the corresponding tooth of the lower
jaw; but I do not know that, in respect to priority, any great
uniformity prevails. The conditions presented by these teeth

BS A SYSTEM OF DENTAL SURGERY.

In the accompanying figure (Fig. 89), the molar of the
right is in advance of the corresponding tooth of the opposite
side of the jaw. On the one side the tooth had appeared
through the gum, while on the other the surface of the mucons
membrane had not been pierced. The position of the second
molar is indicated by the asterisk. In the specimen previously
described, the first molars occupied the terminal portion of

Pig. 99.(")

the alveolar arch; in the present case a small amount of
space posterior to them is gained, and the second molars,
which were placed at the back part of the tuberosity and
directed backwards, are now descending into the dental line,
and are directed obliquely downwards and backwards,

In the specimens which have been described, the new teeth
in their implanted portions are quite equal to the depth of
the sockets, the bottoms of which reach in the upper jaw to
the floor of the antrum, and in the lower maxilla to the
inferior dental canal. This leaves no room for growth in the

(1) Showing the condition of the atveotns of the first permanent molar at

the time the tooih is advancing to the surface of the gum. The tooth on the
right side tsa little In advance of that on the left side of the mouth, *The

‘erypt of the second permanent molar,

TEETHING. 89

direction of the deeper parts. The increasing length of each
tooth must therefore be uccompanied by an increased depth
of socket produced by addition of bone to the free margin
of the alveolus.

The development proceeds rapidly until the opposing
teeth come in contact, when the antagonism becomes ad-
justed, a process which is rendered easy by the comparatively
loose implantation of the teeth.

The teeth which usually succeed the first permanent

molars in the order of emergence, are the central incisors of
the lower jaw. After the temporary central incisors have
been shed, absorption of the corresponding edges of the
alveoli. commences, and commonly carries away the outer

(7) Shows-the relative position of the two sets of teeth, and tho absorption
of the anterior plate ef the alveoll of the lower central incieors antecedent
to thelt emergence. In the upper Jaw the roots of the temporary incisor
have been removed, and absorption of the edge of the alveolus of the left
fentral incisor has commenced. It will be seen that the depth of the alveoll
Wat this poiut te equal to the length of the developing tects

90 A SYSTEM OF DENTAL SURGERY.

plate to a considerable depth, ‘The condition is shown in
Fig. 40; in this case the whole of the bone which lay in
front of the crowns of the new tecth has been absorbed. In
other instances the waste may be rather more limited, but in
all cases the depth of the jaw becomes diminished at the
points corresponding to the teeth, which are about to advance
from their osseous crypts to the surface of the gums. The
posterior alveolar plate, although diminished in height,
usually suffers in a much less degree than the outer surface
of the jaw, and consequently offers a less broken outline than
that shown in the last figure. Ifthe specimen under con-
sideration be compared with an adult jaw from which the
outer alveolar plate has been removed, it will be seen that
the terminations of the two advancing incisors hold the
position which the ends of the roots of the fully formed
teeth occupy.

The conditions which have been described as pertaining to
the eruption of the lower central incisors, will be found to
accompany the evolution of the upper central teeth; the
amount of bone removed by absorption varying with the
position and size of the tecth, It is, however, by no means
easy to obtain specimens of the age required to illustrate the
changes attendant upon the eruption of the permanent teeth,
The dealers do not appear to regard them as saleable, and.
they can be acquired from other sources only at uncertain
intervals. ‘

The subject (a female) from which the following figure has
been taken, died at the age of seven years and eight months.
The central incisors have emerged from the alveoli to the
extent of about two-thirds of the length of their crowns, the
right being a little in advance of its fellow tooth. The
respective alveolar apertures are greatly enlarged, allowing
the teeth to be moved either outwards or inwards,

Tn this instance, the jaw is rather contracted in size, and
the new teeth, in the absence of the temporary laterals, have
their distal sides situated but a short distance from the

‘TRETHING, 91

canines, leaving insnflicient space for the permanent lateral
tectl:, supposing the present position of the centnils to be
maintained. But the provision afforded for adjustment by
the enlarged sockets, will allow the crowns of the teeth to

take a more forward position, which, as they descend obliquely
ontwards, will bo still farther increased when the teeth have
attained their full length, And thus the space, at present

too limited for the normal arrangement of the neighbouring
teeth, will eventually become sufficiently extended.
The

‘an influence as regards their position, from which the central
incisors are exempt, The canines are at this period far
advanced in development, and their large, rounded, mesial
nat na ut pom te Ts ah

‘
92 A SYSTEM OF DENTAL SURGERY.

sides not unfrequently interfore with the direction of the
roote of the lateral tecth, and thus tend to turn the crowns of
‘the teeth ont of their nataral position—an evil which is
usually remedied by the further descent of the canines
towards the alveolar margin. ‘The normal position of the
incisors after falling into line, is shown in Fig. 42.

Fig. 42. (¥)

‘Taking what may be regarded as the normal order of
eruption, the first bicuspids will sueceed the lateral incisors.
If Fig. 40 be examined, it may be seen that the convex distal
side of the crown of the upper canine lies upon the mesial
side of the neck of the first bicuspid, and necessitates the
flattened or grooved surface which characterises that part
of the tooth, while the distal side of the tooth is similarly
influenced (although in a less degree) by the second bi-
cuspid.

After the first bicuspid has taken its position, the canines
are the next to appear in the line of the erupted teeth. The

(@) Showing the permanent central end lateral incisors in their normind
‘position in the dental arch, with the cankne and bicusplds within the Jaw.

TEETHING. 93

appearances presented by the teeth in a favourable specimen
are shown in Fig. 43.

Fig. 42.(1)

After the canines, the second bicuspids appear through the
gums,and make up the full complement of those which have
been preceded by temporary teeth. The preceding may be
looked upon as the natural order in which the first permanent
molars, and the teeth anterior to them, appear; bat this
order is frequently subverted, and in very many casea with-
out entailing any evil consequences. It will, however, be
convenient to consider all the deviations from that which is
regarded as the normal order, under one general heading,
after the evolution of the second permanent molar has been
considered, and after the changes in the form and size of

() Showing the conditions of the permanent teeth after the eruption of
She canines; In the upper Jew, the second bicuspid.

94 A SYSTEM OF DENTAL SURGERY,

the jaws coincident with the eruption of the permanent teeth
have been traced.

Between the age of twelve and thirteen years, the second
permanent molars advance towards the surface of the gums,
their advance being accompanied by alveolar changes similar
to those which have been described in connection with the
emergence of other teeth. At this time the crypts for the
third molars hold the positions which those for the second
molars held when the first molars emerged from their bony
cells, and occupied the terminal portion of the alveolar tract.

If the mouth be examined immediately after the eruption
of the second molars, the dental arches will appear fully
occupied. In the lower jaw, a tooth on either side will be
placed close to the base of the coronoid processes, and in the
upper maxilla at the extremities of the alveolar portion of
the bone. But by the time the patient has reached the
siateenth or twentieth year, the jaws will have lengthened
posteriorly to an extent sufficient for four new» teeth to
take their respective positions in the dental arches. Under
favourable circumstances, the development and eruption of
the wisdom teeth is but a repetition of those progressive
changes which have already been described in respect to the
first and second molars, and therefore need not be dwelt upon.
No doubt these teeth are seldom cut without greater incen-
venience to the patient than the anterior molars, and the
period of emergence is less defined; but we have hitherto
considered the eruption of the permanent teeth when the
process has been perfectly normal, the deviations from which
have yet to be considered,

‘The periods of eruption of the permanent teeth have in
the foregoing pages been traced from preparations, But the
subject has been examined statistically.

Jn 1887, Mr. Saunders published a monograph, entitled,
©The Teeth a Test of Age.” About this time, the miseries
entailed by employing young children in factories were, not
for the first time, forced upon the attention of the Legislature.

TEETHING. 95

The necessity of restricting the hours of labour and of esta-
blishing laws for defining the period at which children should
be allowed to enter upon factory labour, was admitted, But
a difficulty arose as to the principles upon which this period
should be fixed. It was contended by some that a certain
state of physical development should be taken as the
standard, while others thought that the age would form a
better criterion of the capabilities of enduring labour without
injury. The statements of parents as respects the ages of
their children could not be depended upon; hence it became
necessary that some means should be found whereby the age
of a child conld be determined independently of the repre-
sentations of interested parties. With this view, Mr. Saunders
entered upon an inquiry respecting the relations of the
eruption of the permanent teeth to the age of the individual.
He visited many of the large metropolitan schools, and
selected for examination those children who had reached the
ninth and the thirteenth year, and published the results in
a series of tables, of which the following are characteristic

Dicom

| ewe ee

96 A SYSTEM OF DENTAL SURGERY.

Mr, Saunders sums up the results of his investigations in
the following words :

“Thus, then, it appears that of 708 children of nine years
of age, 389 would have been pronounced, on an application
of this test, to be near the completion of the ninth year;
that is, they presented the full development for that age.
But on the principle already stated, that of reckoning the
fourth tooth as present when the three are fully developed, a
still larger majority would be obtained, and instead of 389,
the proportion would be as follows: of 708 children, no less
a number than 530 will be fully nine years of age, What,
then, are the deviations in the remaining 178? They are the
following: 126 would be pronounced eight years and six
months, and the remaining 52 eight years of age, so that the
extreme deviations are only twelve months, and these only
in the inconsiderable proportion (when compared with the
results obtained by other criteria) of 52 in 708.

“ Again, of 338 children under thirteen years of age, no
less than 294 might have been pronounced with confidence
to be of that age. The remaining 44 would have been
considered as follows: 36 in their thirteenth and cight near
the completion of their twelfth year.”

More recently Mr. 8, Cartwright, jun. has published a
‘Table which embraces a much more extended period, and gives
results obtained from 3074 cases. After describing the order
and the periods of eruption of the permanent teeth, he makes
the following remark:

“These periods I find form « moderately fair average, I
have particularised them for the sake of affording you some
idea of the times of replacement of the various classes of
teeth; but exceptions are so frequent, that it is not possible
to give with accuracy the exact time for their change. These
tables will show you the times of appearance of the teeth in
the given number of cases—upwards of 3000—which I have
collected and which have come under my notice.”

‘The following Js a reprint from his fourth lecture, published
in the “ British Journal of Dental Science,” May, 1857:

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98 A SYSTEM OP DENTAL SURGERY.

Before we enter upon the subject of irregularities in the
development of the permanent teeth, and the various dis-
turbing causes, it will be advantageous to give some further
attention to the conditions under which the alveolar pro-
cesses are formed, and to the laws which regulate the growth
of the jaws.

Development of the alveolar processes in connection with
second dentition,—In the earlier pages, it was stated that the
alveolar processes are formed after the dental papillm are
developed, and that at the time of birth they have risen up
to the level of the developing teeth. Within two or three
months they arch over and nearly enclose the tecth, thereby
evineing a more rapid rate of growth than the teeth them-
solves, When the teeth are ready for eruption, the anterior
wall of each alveolus is absorbed to the extent of about half
its whole depth. ‘The teeth emerge, and the alveolar pro-
cesses again commence to grow; but not as in the former
eases, more rapidly than the teeth, They now keep pace
with the teeth. At the time the development of the several
teeth is commenced, the papille are placed at the ultimate
depth in the jaws, They do not grow into, but up from the
maxillm, and the alveoli grow with them. At the period of
eruption the lower end of the truncated and unfinished root
reaches to the bottom of the socket, the position of which, as
regards depth, is not changed with the gradual lengthening
of the root of the tooth. After emergence, the depth of the
alyeolus is equal to the length of the root of the inclosed
tooth, the subsequent growth of the root at its base being
equalled by the development of the alveolus at its free edge.

When the permanent teeth are ready to emerge, the pro-
ceas of absorption is again called into requisition, and the
lnbial wall of each alveolus is, in the anterior part of the jaws,
removed, the loss of bone being extended to a point corre-
sponding to the neck of the emerging tooth. This condition
is shown in Figs. 38 and 40; but the accompanying illnstra-
tions exhibit in a remarkable manner the dependency of

alveolar on dental de¥elopment. The dentition is in many
respects irregular; but the point to which I would draw
attention is the extremely broken line described by the
alveolar margin, both in the upper and lower jaws, It may
be seen that the terminal edge of each socket corresponds

Fig. 44. (#)

with the neck of the contained tooth, however irregularly the
latter may be placed with respect to its fellows, exception of
course being made to those teeth which have not yet passed
through the gam. On the right side of the lower jaw, the
firet temporary molar is retained ; and on the left, the second

(1) The upper and lower jaws of a subject about fourteen years of age;
showing the rolations of the alveolar processes to the teeth. In the upper

teen chatructed tn its descent, and the rot consequently carved. The
permanent canine ts fer advanced In its development, but its descent tx
obstructed by the supernumerary tooth and the lateral tncisor. In the lower
Jaw the first temporary molar has teen retained, anit raised tn a higher bevel
‘than tumal, and with if the alveoties.

100 A SYSTEM OF DENTAL SURGERY.

temporary molar ia present. Tn each ease the tooth and its
alveolus is raised to a higher level than is usually attained by
the temporary teeth, and higher than the adjoining first
permanent molars and their sockets. This elevating process

has no doubt been effected after the tooth itself had been
matured, and shows in a remarkable mamer the relation of
alveolar development to the changes of position in tha teeth,
It is not uncommon to find temporary molars present, even.
in patients of advanced age. 1 occasionally sce a gentleman,
over fifty years of age, in whose lower jaw the second
temporary molars have been retained. They range with
the adjoining teeth, and perform their part in mastication,

(1) View of the left side of tho speclmen Aigured No. #4. In the opper
Juw, the Irregular line deseribed by the alveolar margin is shows in connection
wiih the permanent teeth, Inthe lower jaw, the first and second temporary
molars ore retained, and both the teeth and their alvect! are raise sbove
the level of the permanent teeth and thelr sockets, Horn this and the proe

coding figure Siustrate irregularities In the posithon of the permanent yeoth,
and Will be referred to In connection with the subject of irregularity.

TERTHING, 101

The teeth generally are of the usual size, and the jaw and
alveolar processes maintain the usnal depth. In this case
the temporary teeth and their alveoli must, at the period of
second dentition, have been raised to the level of the adjoin-
ing parts of the dental arch. Other instances present them-
selves in which the persistent temporary teeth do not gain
the general level. The cause is, however, usually very appa-
rent: the contiguous teeth hang over, and as it were hold
down the depressed tooth; and here again the socket corre-
sponds to the level of the neck of the tooth. There is no
disposition on the part of the bone at this point to grow up
to the general line of the alveolar processes, independently of
the tooth to which it gives implantation. In the one case
we have a tooth raised above, and in the other held down to,
the normal height of a temporary tooth; and in each the
alveolar development bas strictly conformed to the position
of the tooth.

‘The appreciation of the foregoing conditions will be found
of great practical value in respect to the treatment of irregu-
larities in the position of the permanent teeth. Diseased
action in the structures may, however, modify the relations of
the one part to the other. Ihave seen a case in which the
alveolar processes were enormously thickened, and so raised
that the teeth lay in grooves ; and instances are not very un-
common in which development of the osseous tissue is arrested.
But the results of normal action only have as yet been con-
sidered. The consequences entailed by disease upon the
permanent teeth and their sockets, will be treated in a future

page.

Growth of the maxille during second dentition—In pursu-
ing this inquiry, the natural variation in absolute size and in
the minor details of form, which the jaws, in common with
other parts of the body, present in different individuals, must
be kept in view, It will be desirable, therefore, in repeating
these observations, to select for examination specimens which
present the average condition of the parts.

102 A SYSTEM OF DENTAL SURGERY.

On comparing the jaws of a child in whom the first per-
manent molars are advancing towards the surface with the
maxille in which the wisdom tecth have taken their ultimate
position, we are at once struck with the great difference in
size, not only of the teeth, but of the jaws themselves; and
it seems at first sight very diffienlt to explain how the smaller
can assume the characters of the older specimen, withont
having recourse to the undefined idea of general expansion
by interstitial growth throughout the whole substance of the
bones.

It has been shown how the alveolar portions grow up, are
partly removed, and again grow up; how they are from time
to time moulded to the required forms; and it will not be
difficult to point out how the other parts of the jaw are, by
the progress of developmental changes, gradually advanced
towards the adult form.

At a preceding page (page 19) mention was made of certain
points as convenient for the purposes of measurement, as being
liable to little alteration during the growth of the maxille, the
tubercles for the attachment of the genio-hyo-glossns and
the mental foramen being selected as the most suitable for
the purpose. When rightly interpreted, measurements taken
from these two points give identical results; but before pro-
ceeding further it will be well to explain that at first sight
measurements taken from the mental foramen will give mis-
leading results, owing to an abrupt change in the direction of
the canal at its anterior extremity. If the onter surface of
the bone be removed so as to expose the whole length of the
inferior dental canal in a series of specimens of different ages,
the manner in which the mental foramen bas become raised
will be apparent. In the nine months’ subject the orifice is
on a level with the course of the canal and looks forwards :
now the portion of the canal already formed does not undergo
any further change, but, as the thickness of the bone is aug-
mented by deposition on its outer surface, the canal comes to
lie at a greater depth within the bone.

TEETHING. 103

The necessary addition to the lensth of the canal before it
can reach the surface does not, as might perhaps have been
expected, take place in direct continuation of its previous
course; but, in obedience to a law already alluded to (page 18),
gives to the added portion of canal an upward and backward
direction,

‘This fresh addition to the canal therefore forms within the
thickness of the jaw an angle with that previously existing,
nd this angle corresponds in position with the opening or men-
tal foramen in the foetal jaw. If then we rasp off the surface
till we reach this angle, and take our measurements from it
instead of from the external opening, we shall have an on-
changing point, and the results of our inqniry will be con-
sistent, with those attained when the tubercles were chosen
as the fixed points. In old age nature performs this operation
for us and removes the bone till this angle is nearly, or quite,
reached—hence the foramen is brought down nearer to the
lower border of the jaw. But with the exception of additions
to either end during the period of growth and consequent
alterations of the aperture, there is not the smallest reason to
suppose that the position of the canal is in any way changed
at any period of development.

Jn the former edition of this work certain actual measure-
ments of a particular series of jaws were given ; but.as] have
found that students have experienced some little difficulty in
grasping the meaning of the passage when placed before them
in this form, it has scemed preferable to embody the results
of these investigations in the accompanying diagrams.

As some variations, due to individual peculiarities such as
greater or less development of the chin, exist between dif-
ferent specimens, these diagrams are drawn up according to
average dimensions taken from a considerable number of jaws,
and are drawn to scale.

‘The horizontal line represents the level of the anterior
portion of the inferior dental canal in the foetus, and the cor-
responding portion in the adult jaw, which may be taken as

104 A SYSTEM OF DENTAL SURGERY.

separating the alveolar portion, strictly subservient to the
lodgment of the teeth, from the basal portion which subserves

other purposes,

Figs. 46 and at. (4)
Ft ar 9 months

On comparing the jaw of the nine months’ foetus with that
of a seven years’ child itis seen that that portion which lies

(2) Pige. 48, 47, 48—In these figures the horizontal line marks the corre
sponding parts of the several jaws, so that the relative Increase above and
below it, that Is to say, in tbe alveolar and basal portions of the Jaw, may be
readily sewn.

TEETHING. 105

below the line has more than doubled in its depth ; but on
looking at the adult and the aged jaw it is apparent that this
portion of the bone has attained its fall development in
depth, or very nearly 80, at the age of seven years, and that
it remains comparatively anchanged after that time until the
death of the individual.

Looking, however, at the alveolar portion above the hori-
zontal line, it is apparent that it does not attain to its full

Pig. 49.01)

development till after the permanent teeth are in place, and
that ao soon as the teeth are lost, it disappears, so that in the
aged jaw here figured it is almost absent.

Such measurements prove very conolnsively the difference
between the basal and alveolar portions of the jaw, and bring
prominently forward the entire dependence of the Istter on
the teeth, a point which cannot be too strongly insisted on,
a5 it has practical bearings to be alluded to in a future page.

In the nine months’ subject, when the anterior tecth are

(2) The Gotted line in this figure represents the outline which would have
‘eon prevented by the same Jaw during the middle period of life, the parts
Intervening between this line aml the drawing baving been removed by
abnorption, after the low of the teeth,

106 A SYSTEM OF DENTAL SURGERY.

about to be cut, the canal is nearly straight from end to end,
its whole length corresponding to that portion which in the
adult lies under the bicuspids and first permanent molar, and
forming scarcely more than one-third of its entire length in the
adult. The straightness of this portion is permanently pre-
served in all the specimens I have examined, The middle
third is slightly curved upwards, and the posterior portion is
still more curved, and if prolonged, would pass through or im-
mediately in front of the articular process, ‘The course of this
posterior third traverses the ascending ramus of the adult
jaw rather obliquely, and in the great majority of cases corre-
sponds with the direction of the condyle rather than that of
the ramus, These points have been entered upon with some
degree of mimuteness, in consequence of their affording evi-
dence as to the manner in which the jaw becomes lengthened
to so great an extent by additions at its posterior portions,

In tracing the growth of the jaw backwards, we may take
the inferior dental canal as marking pretty accurately the line
of growth followed by the condyle, and the external oblique
line as that which has been followed by the base of the eoro-
noid process, For the sake of facilitating description, it may
be assumed that the backward growth takes place at three
points—in the sub-articular cartilage of the condyle, in the
periosteum investing the coronoid process, and in that in-
vesting the angle.

The condyle stands with its long axis directed nearly trans-
versely across the ramus, the one extremity lying nearly on
a plane with the outer surface of the bone, while the other
overhangs to a considerable extent the inner surface of the
ramus. Now, if we take a thin vertical section, suitable for
microscopic examination, from a perfectly fresh young jaw, it
will be seen that new bone is developing in the temporary
sub-articular cartilago—not, however, in the linear manner
usual in the temporary cartilage of long bones, but by the
extension of ossification among small groups of cells. As the
action extends throughout the articular extremity, the bone so

TEETHING, 107

produced would, if permanently retained, assume the form of
4 broad process, marking the course through which growth
proceeded. On the onter surface we frequently can discern
a slight ridge, extending a short distance from the head of
the bone; but if the prominence were preserved on the inner
surface, the inferior dental artery and nerve would be turned
from its course towards the canal. Hence the hard tissue,
although produced, is at this point speedily removed, and in
the place of a ridge extending from the articular process
downwards, we have a concavity immediately below the arti-
culation, and along it the vessels and nerves pass before
entering the bone. A section taken from this part will show
that the newly-formed bone has been removed by absorption.

The progressive growth of the coronoid process is effected
in the usual manner of sub-periosteal development—that is,
by the ossification of cells and connective blastema; and here,
again, the modelling process effected by the supervention of
absorption is called into requisition, If all the bone which is
developed were retained, we should have a breadth of ramus
extending forward over half the alveolar margin. If a trans-
verse section be taken from the base of the ramus of a growing
jaw, it will be found that indications of absorption are pre-
sented at the anterior edge; and at the point corresponding
to the posterior border of the jaw, evidences of osseous deve-
lopment are present. The fact, that the enlargement of the
jaw takes place by backward growth almost exclusivoly, has
been already alluded to (page 22); in this respect also Dr.
aapureys experiments are confirmatory of the inference

drawn.

The correctness of the above views, as to the development
of the jaw, has received a somewhat unexpected confirmation
from two examples of arrested development of the one ramus
of the jaw whilst the other has attained its normal size. The
first of these two specimens (") was brought before the Patho-

So ipeal ent detindio Pathological Society's Transactions, vol, xii, 1861,
Pp

108 A SYSTEM OF DENTAL SURGERY.

logical Society by Mr. Edward Canton ; it occurred in a girl
of generally stunted growth, in whom the whole left side of the
face was flattened, and the external ear was almost absent.
At the post-mortem examination the zygomatic and auditory
processes were found to be altogether absent, while the glenoid
cavity was represented by a perfectly smooth surface.

As is seen in the figure, on the left side of the jaw the
ascending ramus isa very short, narrow process terminating
in two points, which may perhaps represent the coronoid and
condyloid processes, But there is nothing to be seen at all
like a condyle at the summit of this process, and therefore,
there being no articular surface, there can be no articular
cartilage.

But it has just been pointed out that the backward and
upward elongation of the jaw takes place in great part by
ossification in this articular cartilage, just as a long bone
grows by ossification progressing in its epiphyses. Hence the
absence of the condyle accounts perfectly for the arrest in
the development of this portion of the jaw; it will however
be noticed that the vertical development of the horizontal
ramus, which is entirely correlative with that of the teeth,
has not suffered in a like degree: the teeth have been deve-
loped, and consequently the alveolar portion of the jaw has
attained to something approachiug its normal depth and
width. The length of this aborted side of the jaw does not
exceed that attained by that of a child aged two years and 4
half.

The great elevation of the incisor teeth is simply the con-

TEETHING. 109

sequence of imperfect antagonism, an explanation rendered
the more certain by their serrated edges, which have obviously
not come into contact with the upper teeth.

On the inner surface of the stunted process, at a level cor-
responding to that of the crown of the second molar tooth, is
the Inferior Dental Foramen, which is much smaller than
that of the rightside. The mental foramen is entirely absent,
the nerves and yessels having been apparently wholly used
up in the substance of the bone.

The second specimen, which is in the museum of the
Odontological Society (+), presents somewhat similar chn-
racters ; of its history nothing whatever is known, but it
appears to be the jaw of quite an aged person, and the alveolar
portions of the jaw having been for the most part absorbed
after the loss of the tecth, the fact of the entire dependence
of the growth of this region-of the jaw on the presence of the
teeth is not so strongly exemplified as was the case in the
last-mentioned specimen, But that the aborted ramus has
stone time been of a depth apparently disproportionate to
its backward elongation, is probable from the presence along
its upper surface of the sharp ridge which is usually left after
absorption of alveoli, consequent on the loss of the teeth. In
the spinous process which terminates this stunted ramus, no
separate representatives of coronoid and condyloid processes
can be triced: it is a simple spine, which from its relation
with the external oblique ridge would correspond more nearly
with the coronoid than with the condyloid process, and
Presents on its inner surface a prominence apparently giving
attachment to ligaments or muscles, There is not a trace of
an inferior dental canal, and consequently no mental foramen ;
but whether this absence of its proper vascular supply is to
be regarded ag a cause or an effect of the stunted growth is
an almost insoluble problem, The tubercles for the attach-
ment of the genio-hyoid and genio-hyo-glossus, which probably
marked the median line of the body, do not correspond with

(1) Transactions, Odontologieal Soctety, March, 1872,

110 A SYSTEM OF DENTAL SURGERY.

the position of the mental prominence on the outside of the
jaw, which latter has partaken in the asymmetrical develop-
ment of face which must have existed, and is considerably
displaced towards the right side,

In examining a series of suitable preparations, it may be
seen that the crypts for the permanent molar teeth are in
the first instance formed internal to the ridge of bone which
forms externally the base of the coronoid process, and that this
ridge is continuous with the external oblique line of the jaw.
Absorption in this neighbourhood appears to stop short before
reaching the absolute base, and leaves a trace of the ridge
alluded to: the trace constituting the oblique line within
which the alveoli of the molar teeth crow up.

The development of the jaw may, in some respects, be
compared to modelling. Vortions of new tissue are laid
upon that already formed, aud reduced to the fitting size and
shape, and again renewed at such points as the attainment
of the ultimate form of the part may require.

Still, even during manhood, the maintenance of the form
of the jaw is dependent to a great extent upon the teeth,
When the organs of mastication are lost, the whole of the
alveolar processes are hy degrees removed, the process of ab-
sorption being arrested only at those points where muscles are
inserted (see Fig. 49); neither is the waste limited to the
alveolar margin. Both the outer and inner surfaces of the
bone are reduced, and even the interior hecomes more porous
than during the period when the teeth were present. The
spinm mentales, however, retain nearly their full size, although
the angle of the jaw about which the masseter muscle is in-
serted, suffers considerable loss—not however until that muscle
is thrown partly out of use by the loss of the tecth, and con-
sequently of the capability of mastication. If two jaws be
taken, the one full of teeth, the other from an old edentulous
subject, and in each the dental canal be exposed throughout
its length, we may then, by the use of a file, taking the canal
as our guide in removing the bone, reduce the younger to

I-

‘TRETHING. 1

‘the form of the older jaw. In the one case we have a jaw
for the implantation of teeth, and for the insertion of power-
ful muscles for bringing the teeth inte effective use, in
addition to affording attachment for muscles connected with
the organs of speech and deglutition; and in the other, the
jaw Is subservient only to the latter purposes.

We have hitherto spoken of the lower jaw, which, from
ta slight connection with the other bones of the face, can be
studied in its progressive changes of form and size more
readily than the superior maxilla. Mr. Hilton, in his mono-
graph on the development of certain portions of the cranium,
makes the following statement :

“The sphenoid bone forms the centre around which all
the other bones, both of the cranium and face, are developed.
It is truly and literally indeed a wedge, as its name implies ;
and thos impacted or wedged in amongst all the other cranial
and facial ixmes, its progressive development spreading its dif-
ferent processes out in all directions, plays a most important
part; not only in determining the adult configuration of the
skull, but in adopting the final conformation of the organs
of the face to the increasing perfection of their associated
functions. The mouth, nose, orbits, and pharynx, are all
more or less directly influenced, and contemporancously ren-
dered more perfect in form by the complete development of
this bone.

“ The primary idea, or primary intention of the develop-
ment of the sphenoid, seems chiefly with reference to the
masticatory function; but in the changes that it produces in
the direction of the cranial and facial bones, it may not
inaptly be compared to the scaphoid bones of the carpus and
tarsus; for in its growth and final development it effects
for the cranium and face precisely the same object that these
bones effect. for the hand and foot.

* Like these bones, then, the growth and completion of the

in spreading out the cranium, and in enlarging the
cavities of the organs belonging to the face, supplies the defi-

S——-
a

112 A SYSTEM OF DENTAL SURGERY,

ciency of the muscular tension which in other parts of the
body has so large a share in determining the final or perfect
forms of the bones,”(*)

Of the different parts of the sphenoid bone, those which
undergo the greatest change during the period under con-
sideration, as regards size, and which are also the most directly
connected with the present inquiry, are the pterygoid plates.
These parts increase to the extent of one-third of their ulti-
mate length between the age of seven and twenty-one years,
In a specimen of seven years, the anterior surface of the
pterygoid process is separated from the first permanent molar
by a distance scarcely exceeding a quarter of an inch, and
the nascent second molar lies in the tuberosity, in great part
external to the sphenoidal processes, The space, at present
80 inconsiderable, has, before the adult form is acquired, to
be increased fully two-thirds, accompanied by an increased
length of the pterygoid plates, the general direction of which
remains unchanged, The general principles which have been
pointed out as pertaining to the development of the lower
jaw, may be applied to those facial bones which are connected
with the masticatory apparatus. The tuberosity is to the
upper what the base of the coronoid process is to the lower
jaw. From this point the alveolar line is lengthened. In
the specimen last mentioned, the second molar is buried high
up in the tuberosity. Soon after the expiration of the twelfth
year, the distance between the pterygoid process and the
first molar will have increased sufficiently to allow the second
molar to take its place in the dental line, and by the expira-
tion of the twentieth year the third molar is usually found
in its normal position. Up to this period, the facial bones
are connected to each other and to the bones of the cranium
by sutures only; and in the soft tissue within these, develop-
ment of bone takes place,

@) Notes on somo of the Developmental and Functional Relations of certain
Bones of the Cranium, Selected by ¥. W.Payy, MLD, from Lectures on
Anatomy by John Hilton, P.RS. 1855,

a

TEETHING. 8

The maxillary bones, while their processes are increased in
length, are moved bodily forward, the rate of growth keeping
pace with the inerease at the tuberosity. Coincident with
development, the modelling of certain parts by superficial
absorption i# carried on. By this process, the anterior sur-
face of the lower border of the malar process is removed, and
thus thrown backward, In the seven-years’ specimen, it lies
immediately above the anterior third of the first molar; at
twenty-one it holds similar position with respect to the
second molar, thus showing a recedence equal to the width
of one tooth.

As respects the changes of form and position which the
glenoid cavity undergoes during growth, but little need be
said, Here we have articular cartilage, beneath which the
required amount of bone is slowly developed in the same
manner as in the sub-articular cartilage of the lower jaw.

The growth of the alveolar process need not be again
referred to,

After the teeth are lost, the upper jaw undergoes great
change both in size and in form, not, however, from what is
called interstitial absorption, but simply from progressive
auperficial absorption. The alveolar proceases are gradually
lost, and the whole bone is reduced in thickness. The ptery-
goid plates of the sphenoid bone become greatly diminished
in size and strength, while the glenoid cavity loses its strongly-
pronounced margin, and hence becomes flattened.

Certain forms of irregularity in the conformation of the
jaws being closely connected with deviation from the normal
arrangement of the teeth, will be considered in connection
with the latter subject.

Trrequiarity of the Permanent Teeth.—Hitherto the de-
scription of the permanent teeth has heen confined to their
evolution when those general laws which regulate the time
of appearance, the position, the form of the individual mem-
bers, and the implantation of the whole set, have operated
without interruption.

I

lid A SYSTEM OF DENTAL SURGERY.

The deviations from the normal conditions as respects
arrangement, number, form, and the period of eruption, have
yet to be considered before we come to the conclusion of that
division of the subject which has been placed under the
general head of teething. The divisions of this subject will
be treated in the order in which they have been enume-
rated.

But before passing to the consideration in detail of these
several irregularities, it will be interesting to inquire into
the conditions under which deviations from a normal type
cceur, In a very considerable number of cases the whole
abnormality is caused by purely mechanical agencies, such
as the undue retention of temporary teeth, and may be
almost regarded as accidental in their origin, The crowns
of the teeth in such cases deviate from their normal posi-
tion far more considerably than their roots, the apices of
whieh will very generally be found to occupy their proper
places.

But it is far from uncommon for the alveolar border, or
even the whole jaw, to be malformed, so that the whole
length of the implanted portions of the teeth will participate
in the irregularity.

‘The origin of such malformations must be sought at a
period long antecedent to the eruption of the permanent
teeth; they are, in fact, often congenital, and traceable to
hereditary tendencies.

It must not however be supposed that because an abnor-
mality is slight, and is apparently due to some mechanical
cause, it may not have been inherited,

There is no lack of evidence to prove that variations in the
position or number of tecth which might at first sight seem
accidental are transmitted from parents to children; of this
Dr. M'Quillen gives some striking examples.(') Thus, he
found the upper lateral incisors biting inside the corre-
sponding lower teeth in a gentleman, and in three out of

(!) Dental Cosmos, vol. xil., pp. 75, et seq.

TEETHING. 115

four of his children; the fourth child had not cut these
teeth at the time when the observation was made, In
another family a gentleman, his son, and his grandson alike
never had any lateral incisora in the upper jaw; a second
son of the same gentleman had them exceedingly dwarfed,
and in some of his children these dwarfed lateral incisors
had been so unsightly as to lead to the teeth being extracted
and artificial substitutes put in their place. In a later num-
ber(!) of the same journal a family is mentioned as well
known to American dentists, in whom no permanent teeth
at all are found.

An instance of the congenital absence of bicuspid teeth is
given by Mr. Heath (*), and in my own practice I have lately
met with an example of the absence of the left upper lateral
incisor in three sisters; on the right side these teeth are
present,

Irregularities apparently most trivial may be, in fact, con-
genital: thus I have lately seen an instance in which,
although there is no crowding in the jaw sufficient to
account for it, the right upper central incisor is to a slight
extent twisted on its axis, and lies a little behind its fellow
tooth: precisely the same irregularity exists in the father
of the child, and will apparently be repeated in another
child, in whom the tooth is as yet only partially erupted.
A case is quoted by Mr. Sedgwick in which, during both
dentitions, « double tooth took the place of the left lateral
incisor, this peculiarity being inherited from a paternal
grandfather, (°)

Numerous other examples might be collected, but the
foregoing will sufficiently serve to illustrate that strong
tendency to hereditary transmission of peculiarities which is
found to exist, and to suffice to cause dental irregularities,

Correlations of growth are found to exist between parts

(1) Dental Cosmos, vol. xili., p. 123.
() Injuries and Diseases of the Jawa, p. 1x5.
@) British and Porvign MedicoChirurg. Review, April, 1863.

116 A SYSTEM OF DENTAL SURGERY.

of the organism, which, so far as we know at present, have
little or nothing to do with one. another; but in other
examples of this concomitant variation some homological
relation can be traced between the varying organs. Such
is the case with hair and teeth, which in their origin are
closely similar, and which only become strongly differenti-
ated in their after development.

For example, the hairless, naked Turkish dog is extremely
deficient in its teeth, often having none except one molar
on each side, and perhaps one or two imperfect incisors (*);
and the same fact has been observed in a hairless. terrier.
Inherited baldness has beon found associated with inherited
deficiency of the teeth, and it is stated by Mr. Sedgwick @)
that in rare cases where the hair has been renewed in old
age this has usually been accompanied by a renewal of the
teeth,

Mr. Craufurd, as quoted by Mr. Darwin, states that at
the Burmese Court there was a man covered with straight
silky hair, which on the’ spine and shoulders was as mouch
ag five inches in length, He had no molar teeth, and the
incisors were very small; his daughter inherited the pecu-
liarity of a hairy skin, her face, even including the nose,
being covered with silky hair, and, like hor father, she had
neither molar nor bicuspid teeth.

‘These hairy persons did not present any marked pecu-
liarity at birth, save that there was a little hair about the
ears, whence it spread all over the body; and it is a signifi-
vant fact that there was nothing abnormal in their milk
dentition. In the case of Julia Pastrana, rendered famous
by the exhibition of her stnffed skin after her death, the
forehead and the chin were densely covered with hair, and
there were so many supernumerary tecth in the mouth that
the appearance of a double row of teeth in each jaw was
presented,

(@) Darwin, Animals and Plants under Domestication, vol. i., p. 34.
(@) British and Foreign Modico-Chirurg. Review, April, 1863.

TRETHING. 117

It is remarked by Mr. Darwin (") that those orders of the
Mammalia which are most aberrant in their dermal cover-
ings, namely, the Cetacea and Edentata, are also remark-
able for deficiency or redundancy in the number of their
teeth.

The assoviation of certain forms of maxillary deformity
with other defects, such as congenital idiocy, may perhaps
be explained on the principle of correlation of growth, but it
will be more convenient to defer the discussion of this
branch of the subject until the special irregularities alluded
to are described.

Dental irregularities in some few instances only are refer-
able to the action of the law of “ correlation of growth ;” in
all the instances with which I am acquainted this law has
operated in producing either deficiency or redundancy in the
number of the teeth, rather than in causing the assumption
of abnormal forms or position,

Trregularity in the position of the permanent teeth, irce-
spective of the number involved, admits of division into two
distinct groups, Ist. Irregularity in the position of the
crowns, while the roots at their terminal points hold the
usual place. 2nd. Irregularity both in the position of the
crowns and roots. The former usually admit of treatment
which does not necessarily involve the loss of either the
misplaced or a neighbouring tooth; while the latter cases do
not admit remedy, excepting by removal of the malplaced
organs.

Those examples which fall within the first division will be
first considered.

‘Tho front teeth of the upper jaw, including the canines,
may deviate from the usnal position either by projecting
forward or retreating backward. In the former deformity,
the prominence is sometimes sufficient to prevent the lips
from closing; hence the teeth are constantly exposed, oven

() Animals and Plants under Domesticatiun, p. 323.

118 A SYSTEM OF DENTAL SURGERY.

when the mouth is shut. The lower lip, instead of lying
over the edges of the tecth, passes behind them, while the
lower teeth mect the gum posterior to the necks of the upper
teeth. In searching for the cause of this unsightly form of
irregularity, we must examine the condition of both the
upper and lower jaws, and also the state of antagonism of the
upper and lower teeth.

The deformity may result from excessive development of
the alveolar processes of the anterior part of the upper jaw,
but more commonly we shall find that the molar teeth are
unusually short, thereby allowing the incisor teeth of the
lower to press unduly upon the inclined lingual surfaces
of the tecth of the upper jaw. The upper teeth, yielding to
the pressure, are forced outward, and are retained in the
matposition by the teeth which have led to the displacement.
Tf, in cases resulting from the latter cause, the inquiry be
extended to the condition of the lower jaw, it will be found
that with the short molar teeth we have a short alveolar
fange and short rectangular ramus. ‘This conformation is
probably the primary cause of the mischief. Supposing the
line of growth in the ramus to have become nearly rectan-
gular, as regards the body of the jaw, prior to the develop-
ment of the wisdom teeth, and the amount of growth in the
vertical direction to have been deficient, the molar teeth
would be limited in height by the antagonism of the corre-
sponding teeth of the upper jaw. That the length of the
molar teeth is influenced by the growth and position of the
ramus, a case at present under my treatment satisfactorily
demonstrates, In this instance the ramus has preserved the
obliquity characteristic of childhood, and occasions the per-
manent separation of the upper and lower front tecth when
the mouth is closed. ‘The patient is upwards of fifteen, and
the usual number of teeth are present, but the second per-
manent molars are the only teeth that come in contact, and
these scarcely project above the level of the gums. Here
the ramus is sufficient in actual length, but the obliquity

TEETHING. 119

renders its length unavailable for the vertical development
of the molar teeth. If, then, we have a rectangular ramus
of diminished length, with short grinding teeth coincident
with well-developed incisors, it is not difficult to see that the
upper will be driven outwards by the lower front teeth.
‘The condition under consideration may also arise from the
tardy ernption of the molar teeth leaving the incisors to act
for a time upon each other, as they do when from any canse
the back teeth are lost. Then, again, the incisors of the
lower jaw may attain an unusual height, or they may project
in an unosusl degree, and produce the mischief. Or the
result may be consequent upon a regular linear arrangement
of large teeth in a jaw having « small alveolar base, in which

between the lingual surface of the upper and labial surface
of the lower teeth, The habitual position of the under lip
was behind the upper front teeth—a habit which in. itself
no doubt tended to increase the amount of deformity. The
arrangement of the teeth, as respects each other, was per-

mored; 4 metal plate was then fitted to the labial surface
of the projecting teeth as far on either side as the canine,

120 A SYSTEM OF DENTAL SURGERY,

mud was extended inwards below the edges of the teeth in such
4 manner as to prevent the under lip from passing behind
the upper teeth. A strong band of vulcanized caoutchouc
was connected with the plate, and passed round the back of
the head. By means of this apparatus the teeth were in the
course of six weeks pressed into a very good position, The
lips could be closed in the usual manner, and the mouth
when seen in profile had lost its objectionable prominence,
The patient on leaving for the country was directed to wear
the apparatus during the night for six months. After the
lapse of cighteen months she returned to town with the
mouth just as prominent as it had been before treatment.
On inquiry I found that she wore the plate for one month
only, the elastic bands had then given way, and the precau-
tionary measures bad from that time been neglected. In the
interval the wisdom teeth of the upper jaw had been cnt,
and they seemed to have exercised some influence in forcing
the teeth into the forward position, But some other cause
than this was also in operation, as the teeth, although pro-
tminent, were not now, as formerly, in close lateral contact,
The wisdom teeth, from their position, being perfectly use-
loss, were removed, and the treatment already described was
renewed, and with the former suecess. The teeth have now
settled down into a position intermediate between that which
they held before they were subjected to treatment, and that
to which they were reduced by the use of the plate,

The foregoing case may, I think, be regarded as pre-
senting typical characters, and may therefore be dwelt upon
for the purpose of elucidating some of the general features
conriected with irregularities before we advance further,
Possibly the front teeth, while within the alveolar crypts,
assomed an unusual obliquity of position, and thus grew
outwards independently of any influence exerted by the
antagonistic teeth. But whatever may have been the cause
of malposition, the growth of the teeth was accompanied by
the development of strongly-pronounced alveoli, correspond-

122 A SYSTEM OF DENTAL SURGERY.

Tn the absence of well-established facts gained from dis+
sections, in respect to the period required either for the re-
development of alveoli, or the degree to which restoration is
carried, we are thrown upon the general results obtained in
the treatment of cases, and upon the conditions which are
found to obtain in the development of alveoli during the erap=
tive period of dentition. It has been shown that the socket
grows up cotemporaneousiy with the gradual development of
the tooth, but in this case the process of growth is extended
over many months, and the results obtained in the redue-
tion of irregularities do not tend to show that the alveolar
Teparation is more rapid than the original alveolar develop-
ment.

If, for example, slightly projecting teeth are by means of
pressure brought rapidly into the proper line, and are then
left without mechanical restraint, they will speedily return to
their former place, and become firmly fixed in their sockets in
a much shorter time than they would have done if retained
in the newly-acquired position. This circumstance would
seem to indicate that in moving the teeth the sockets had
been stretched or bent rather than absorbed; but there are
many cases in which the assumption that the bone yields by
its elasticity in the direction of the pressure applied to the
teeth, does not offer a satisfactory explanation; and I am
disposed to think that even in the cases where this expla-
nation would at first sight appear tenable, the phenomena
may be attributed to other causes.

The immediate consequence of continued pressure upon
the crown of a tooth, is irritation and thickening of the peri-
dental membrane ; and this results in the tooth being raised
in its socket to an amount équal to the increased thickness
of the membrane.

The root of the tooth, from its more or less conical form,
acquires, when raised in the socket, an increased capability of
motion, without the alveolus itself becoming enlarged. In-
stances in which these conditions are produced by disease are

124 A SYSTEM OF DENTAL SURGERY.

pressure be too great, and if it be too slight the teeth will not
move, or the movement be so slow that both the patient and
practitioner will become wearied before a successful result has
been gained. A certain amount of irritation in the socket is
a necessary attendant upon the treatment, otherwise absorp.
tion of the socket would not be induced. Other conditions
being the same, the age of the patient will influence the
results. The younger the patient, the more readily can the
teeth be moved ; the older, the more difficult will the operation
become.

Supposing the irregular teeth to have been reduced toa
proper position, and that the movement of them has been
attended witha certain amonnt of destruction of the existing
socket, we haye then to inquire whether the lost parts will be
fully replaced, and if so, the length of time required for the
formation of the new bone. It is not probable that a series
of preparations, illustrating the condition of the parts at
different stages of treatment, will be obtained; we must
therefore be content with less positive information than sueh
a series would furnish, and avail ourselves of such facts as
can be gathered from those cases in which teeth have been
forced from their former position by a loss of proper antago-
nism, The dissecting-room will furnish examples of this
character, and in them we shall find that the shifted teeth
have a less perfect implantation than those which have been
undisturbed. ‘The sockets will not rise to the level of those
of the other teeth; from which it muy be inferred that the
loss of the displaced teeth will be hastened. Whether the
same conditions obtain in teeth which have in early life been
intentionally moved, observations directed to individual cases
over very many years can alone determine. But supposing
they do, we must put against the disadvantage the fact that
the labial walls of the sockets of outstanding teeth are very
commonly deficient in strength, or imperfect, and that teeth
so placed are liable to become loose prematurely.

_ Admitting, then, that sockets partly removed under treat-

TEETHING. 125

ment will be restored, the question arises as to the time which
will be occupied in the restoration,—in other words, how
long it will be necessary to hold the teeth in the newly-
soquired situation. If unrestrained by mechanical means,
and uninfluenced by antagonistic teeth, the old position will
soon be regained, and the teeth will become firmly fixed in a
much shorter time than they would do in the acquired posi-
tion. It would appear as if there were a natural law tending
towards the maintenance of a conformation when once as-
sumed, although an irregular one, and which calls into action
the reproduction of a lost part more rapidly in the place in
which a tooth has been moved from, than in that into which
it has been moved,

We constantly hear of and see cases in which outstanding
front teeth have been reduced to regularity, and have subse-
quently regained the objectionable position, notwithstanding
the assurances which have been held ont that such untoward
results are consequent upon want of proper management on
the part of the practitioner. There is, perhaps, no point in
the whole field of dental surgery that yields a finer harvest to
the charlatan than that afforded by the treatment of irregular
teeth. The patients are necessarily young people who have
not passed from the care of their parents. There is a great
desire on the part of the latter that the teeth should be good-
looking, or at least not ill-looking; at the same time, there is
great unwillingness, both with the patient and the parent,
that the treatment should be extended over a long period of
time. The presence in the month of a mechanical apparatus
pressing ipon the teeth interferes with the comfort of the
young patient, and the frequent attendance at the house of
the dentist encroaches upon the hours allotted for study.
Both circumstances render prolonged treatment irksome,
impstience is shown, the instructions are neglected, and, as
& natuml consequence, the results fall short of those which
might have been obtainod had the treatment been consistent.
1 believe it is in accordance with the experience of those

126 A SYSTEM OF DENTAL SURGERY.

who have devoted their attention to the treatment of irregn-
larities, that where the front teeth have been brought in
by mechanical means, snd where mechanical means are
required to hold them in place until they become perma-

+ nently fixed, the treatment must be continued for twelve
months, It may not be necessary that the apparatus should
be constantly worn for the whole period, but it cannot be
wholly thrown aside, Towards the latter part of the time,
it may be worn occasionally only; but even after the lapse
of twelve months, should the teeth show any indication of
movement from the desired position, mechanical restraint
must be resumed.

The foregoing remarks apply generally, but each case will
present its own peculiar characteristics, and the treatment
must be varied to meet them. The age of the patient, the
state of health, the degree of susceptibility to irritation and
pain, the number and condition of teeth present, the size
of the teeth themselves, the size and form of the base of the
alveolar portion of the jaw, and the configuration of the
same part in the parents—all these points must be taken
into consideration before a course of treatment is deter-
mined on.

Reverting to the case related for the purpose of introducing
a statement of those conditions which prevail more or less
in all cases of malposition of the tecth, it may be observed
that other methods than that adopted might have been pur-
sued for bringing inwards the projecting teeth. Thus, a
plate either of yulcanite or of metal might have been fitted
to the hard palate and to the necks of the molar teeth, and
to this the front teeth might have been tied, either with silk
or caoutehouc ligatures; or a metal plate might have been
fitted to the palate, and extended to the labial surfaces of
the molar teeth, and on either side attachments for a band of
india-rubber stretched over the labial surfaces of the front
teeth might have been made, The apparatus adopted, how-
ever, possessed an advantage over these; it prevented tho

TEETHING. 7

under lip from exercising an antagonistic influence, while it
was simple in construction, and readily applied.

An opposite form of displacement to that which has been
desoriled is far from uncommon.—The anterior tecth, instead
of standing out far in front of those of the lower jaw when
the month is closed, are directed inwards, and pass behind
them. The patient is said to be under-hung. The upper lip
is generally short and retreating, while the lower lip and
chin hold an unusually forward position.

Tf the coincident conditions of the jaws be examined, it
will be found either that the alveolar ridge of the upper

Pig. 61. (1)

maxilla is unusually small, as shown in the sccompanying
figure, or that the lower jaw has departed from the normal
form. In the specimen from which the illustration is taken,
the inferior maxilla does not differ, either in general dimen-
sions or in configuration, from the normal specimens; but
the upper jaw in its alveolar portion is beluw the usual di-
* (2) Showing the condition of the teeth and Jaws Ina specimen In which the
anterior upper teeth were averted coincidently with defective size in tho
superior maxtils.

128 A SY8TRM OF DENTAL SURGERY.

mensions. The teeth are placed regularly, but the alveolar
line is fully occupied, to the exclusion of the wisdom teeth ;
and the second molar closes upon the third molar of the
lower jaw in the position usually assigned to the wisdom
tooth, which, from its backward direction, is thrown alto-
gether ont of use.

The figure which illustrates the inversion of the upper
teeth coincident with s well-grown upper jaw, is taken from

Pig. 92.0%)

4 specimen in which the temporary teeth are present. In
this case we have an excess of growth in the lower jaw, the
body of which is unusually long, and is associated with a
ramus which has preserved the obliquity characteristic of an
eatlior age. The line of growth, as indicated by the position
of the articular process, is calculated to give great length of

() Shows inversion of the upper front teeth coincident with unaeyal

development of the lower jaw, the upper maxilla having attained the normal
dimensions.

TRETHING, 129

jaw at the expense of depth in the posterior portions of the
alveolar line.

‘The cause of this want of proper relationship between the
upper and lower jaws and their respective teeth, is in many
cases very obscure. In certain families it occurs as an
hereditary character, In other cases, the deformity may
have been conseqnent upon the relatively tardy eruption or
the inverted position of the upper teeth in infancy,

But whatever. may have been the cause, the malposition
will be persistent, unless remedied by mechanical interfe-
rence. The under teeth will present a barrier to the out-
ward movement of the inturned teeth.

If subjected to treatment at a sufliciently early period,
these cases may be brought to a successful issue with much
Jess difficulty than those in which the teeth are everted. The
difficulty of keeping the teeth in the position into which they
have been moved is remedied by the antagonistic teeth of the
lower jaw. When, therefore, the upper are brought suffi-
ciently forward to close in front of the lower teeth, our treat-
ment may be discontinued.

Now there can be no difference of opinion as to the
propriety of adopting measures for reducing to a normal
position teeth which are permanently turned‘inwards. We
have therefore to consider the age at which the operation
an be most advantageously undertaken, and the matiner of
performing it,

The anatomical conditions of the teeth, and the parts about
therp, at the period of eruption, have been already described.
If these conditions are understood, but little doubt will be
entertained upon the propriety of adopting mechanical treat-
ment at a comparatively carly petiod. There would be no
advantage gained by waiting till the sockets are fully formed,
a5 the treatment must then involve their partial destruction,
and the reproduction of new ones. On the other hand, if the
treatment be commenced sufficiently early, the large open
sockets will allow the growing teeth to be moved forward,

x

130 A SYSTEM OF DENTAL SURGERY.

and those parts of the sockets as yet unformed will be deve-
loped in accordance with the direction given to the teeth,
So soon, therefore, as it is discovered that the upper fall
within the lower front tecth, the treatment may be com-
menced. If measures were adopted prior to the establish-
ment of irregular antagonism, we should perhaps be effecting
by mechanical interference that which nature would have
accomplished with much less inconvenience to the patient.
Few can have failed to remark the much greater prevalence
of irregularity in the permanent teeth about the time of their
eruption, than at a later period, in that class of society the
members of which do not avail themselves of the services of
the dentist, excepting when the presence of an aching tooth
can no longer be borne. That in many instances teeth which
on their first appearance through the gums hold an objec-
tionable position, will, if left to themselves, ultimately fall
into the proper line, is a fact sufficiently well established to
warn us against interference until it is clearly shown that
our assistance is required.

From tho frequency with which irregularities are remedied
by nature, it has been supposed that there is a strong in-
herent tendency towards the assumption of a normal position,
and that teeth will in consequence of this tendency, all
mechanical obstacles being removed, take up a regular
arrangement.

This explanation is not, however, wholly satisfactory, in-
nsmuch as it ignores the existence of certain mechanical
agencies which are in constant operation, namely the
pressure exerted by the tongue and by the lips. If any
tooth project outwards or inwards beyond the line of the
surrounding teeth, it will obviously sustain more than its
share of the pressure exerted by the muscles of the lips or of
the tongue. And as the lips and tongue act evenly and
symmetrically on every part of the alveolar arch, their action
will obviously tend to the correction of any irregularity
that may have occurred, if a regular disposition of the teeth

182 A SYSTEM OF DENTAL SURGERY.

wood are placed, in cavities cut in the vulcanite for their re-
ception, Each instanding tooth will have its corresponding
cavity in the plate, the formation of which requires some
little attention, The form should be similar to that of a
shallow drawer, the front of which has been removed, and so
proportioned as regards the upper and lower surfaces of the
plate in which it is cut, that the section of wood will not
fallout into the mouth. The wood should be fitted to the
cavity, and left a little thicker at that end which lies towards
the gum. The plate having been adjusted to the mouth,
holes must be drilled through it for the admission of liga-
tures, which may be passed round and tied to one or other of
the molar teeth on each side of the mouth.

Th arranging the ligatures, care must be taken that they do
not press upon aud irritate the gums. It will be remembered
that the gums approach nearer to the masticating surfaces of
the tecth on the lingual than on the labial side, Hence, the
holes in the plate should be made at the point corresponding
to the free edge of the gum against which it rests, and con-
tinued obliquely in a direction continuous with the line fol-
lowed by the gum in its passage between the teeth, If this
precaution be observed, the ligature when tied will pass in a
straight line from the labial surface of the tooth to the lingual
surface of the plate, without interfering with the gums, In
selecting the teeth around which the ligatures are to be
passed, we must be guided by the forms and the position of
the teeth available for the purpose; but should the temporary
molars be present it will be well to make use of them in
preference to the permanent tecth, The abrupt termination
of the enamel renders them particularly suitable for the
purpose, and the short period during which they will be
retained renders their injury a matter of little consequence.

By the foregoing means the plate may be firmly fixed in
order to afford a point @appud for the action of the com-
pressed wood, the cells for the reception of which will be
formed on the one side by the teeth to be moved, and on

TEETHING. 133

the other three sides by the plate. After compressing for
some hours a piece of dry willow, plane, or some other soft
wood, smnall strips may be cut off, and from thesa fragments
must be prepared which will fit with moderate accuracy to

Wg 83.0)

the spaces formed by the plate and teeth, taking care that
the grain of the wood runs parallel with the long axes of the
teeth. So soon as the wood commences to absorb moisture
it will expand, and in a direction transverse to that of its
gniin. In expanding, either the tooth in front of it must move
outwards, or the plate must be driven backwards, and with
it the molar teeth to which it ix fitted. But as the front teeth

= @) Showing a vnloanite plate fitted to the upper jaw, for the purpose of

passed through the vuleanite and round the temporary molars; posterior wo
the central incisors, the apertares of the cells for the reception of the com-

length, with tho plece of wood removed and placed underneath. 1 am in~
‘to my friend, Mr, Harrison, for the specimen from which this Ogure has
bean taken.

184 A SYSTEM OF DENTAL SURGERY.

are capable of the least resistance, they are the first to yield,
and therefore gradually advance before the expanding wood.
From time to time the wedges must be renewed, each new
piece being slightly larger than its predecessor; and as the
teeth move upon an axis situated near the apices of their re-
spective roots, the receptacles become changed in form, and it
will be necessary to modify the form of the grooves in the
vulcanite plate, If this precaution be neglected, there will
be a difficulty in retaining the wood after the tecth have been
moved from their original position, The receptacle will have
changed in form as respects the relative sizeof the upper and
lower portions. Hence it becomes necessary to deepen that
end of the groove which lies near the gum, and the exca-
vation must be made sufficiently deep to restore the paral-
lelism which has been lost by the outward movement of the
tooth. When the required amount of change in position is
considerable, and the half of this has been gained, it may be
necessary to discard the original plate, and substitute a new
one fitted close to the teeth operated upon, 50 as to admit a
thinner and more manageable wedge than that which would
have been required had the treatment been continued with
the first-made apparatus.

It is doubtful whether, as a general rale, more than two
teeth can be advantageously operated upon at the same time,
Tf, for instance, the four iucisors are involved in the irregu-
larity, it may be desirable to push forward the central teeth
first, and then move the lateral teeth, or vice versé, But in
adopting this plan we must not neglect to take means to
prevent the teeth first operated upon from retreating to their
old place while the others are being forced forward. ‘This
may be accomplished by inserting into the vulcanite frame
peas of wood, the free ends of which rest upon the backs of
the moved teeth. In this application of the wood the end of
the grain will rest upon the tooth, and as there is but very
slight expansion lengthwise of the grain, the teeth will be
simply held in position.

TRETHING. 135

When the whole of the instanding teeth have been moved
outwards to an extent sufficient to ensure their passing in
front of the lower teeth on the mouth being closed, the tise
of the apparatus may be discontinued. Sometimes, however,
it will be found that the back teeth of the upper and lower
jaws, from having been kept apart during the treatment,
lose their proper antagonism. ‘They become raised in their
sockets, and prevent the front teeth from meeting each other ;
under these circumstances, those portions of the vulcanite
plate which extended over the masticating surfaces of the
back teeth mist be removed so as to allow the teeth to come
in contact, while the plate prevents the front teeth from
falling back into the former position. In a few days the
proper antagonism will be restored, and the plate may be
disearded.

Tnstead of using vulcanite, metal may be used for the plate.
The molar teeth on either side are capped with gold, the caps

Fig. 4.)

>
being mude #0 that they fit tightly upon the teeth. From
these a band of metal is extended in front of the teeth.

(1) Shows metal caps fitted to the molar veth, with « band extending frow
thean in front of the incisors. To the metal band wo fixed, ligatures, afer
bebig passed round the front teeth, were attached, and drew the laverted teeth
forward Untill they came In conlset with tho band, The caso was treated by
‘Mr. Harrison, to whom I am indetted for the specimen given in the figure.

186 A SYSTEM OF DENTAL SURGERY,

Holes are drilled in the band opposite to the teeth, and
strong silk thread is passed round the neck of each tooth and
through the corresponding holes,and tied tightly on the outer
surface of the band, The teeth will by degrees be drawn
towards the band, but the process is a slow one, and requires
frequent renewal of the ligatures,

1 have commonly used vulcanized caoutchouc in the place
of silk; with this material, the tension is more uniform, and
the renewals need not be made so frequently. ‘The fixing of
the india-rubber to the band was at first a difficulty; tying
was impracticable, and hooks could net well be used. I
found, however, that by cutting fine slits with a hair saw
obliquely through the metal band, and then passing the two
ends of the caoutchouc in a state of tension into them, the
ligatures were firmly retained. Silk ligatures require renewal
every second day, but the caoutchouc will last double the
time, and will produce a much more rapid effect. I have in
favourable cases succeeded in bringing teeth out in the course
of a fortnight, and the case hds been dismissed.

Tn the place of using metal in the foregoing manner, a plate
may be fitted to the palate, and retained by bands passing
round the back teeth, or by portions of wire extended over
the crowns and bent down so as to clasp the necks of the
teeth. To the palatal portion of the plate, bands of metal
rendered elastic by hammering, may be attached, adjusting
the free ends so that they shall press upon the backs of the
malplaced teeth, This manner of proceeding is inferior to
the two preceding methods where a number of teeth are in-
volved, although in cases where two or three teeth only are
required to be shifted, not only outwards or*inwards, but also
upon their axes, it offers some advantages,

The treatment upon the principle of elongating the lower
teeth need not be recurred to, as it has nothing whatever to
recommend it. The plates used may be made of vulcanite
or of gold, each having its special advantages, Excepting in
those cases where the antagonistic teeth serve for maintaining

138 A SYSTEM OF DENTAL SURGERY.

Ligatures or elastic bands may be adapted to the tooth
which it is required to move in such ways as the ingenuity
of the operator may devise, always bearing in mind, however,
that unless a considerable number of teeth are embraced by
it, those taken as the supports will probably beas much acted
on a8 the tooth which is to be moved.

But whatever course of procedure is decided npon, there is
one point which must carefully be kept in mind: the direc-
tion of the long axis of the tooth may be changed, but that
is all. The apex of the fang will remain fixed, or nearly so;
while the crown of the tooth will move in an are of a cirele
the centre of which lies at or very near to the apex of the
fang. It is therefore of the utmost importance in estimating
the probability of success to ascertain as far as possible the

Pig. 83. 0)

position of the apex of the fang; and it is obvious that those
cases in which the irregularity is due to some such mecha-
nical cause as the retention of temporary teeth will yield to

Q) Showing the front teeth morting edge to edge.

140 A SYSTEM OF DENTAL SURGERY.

(Fig. 56), the degree of separation is moderate in amount, as
compared with many cases presented to the practitioner; bat
it affords an opportunity of showing a peculiarity in the con-
formation of the lower jaw usually coincident with this form
of irregularity. Tt consists in a great development of the
anterior part of the jaw in the vertical direction, with a dimi-
nished depth in the parts which sustain the molar teeth, asso-
ciated with an unusual obliquity of the ascending ramus,
The line of growth in the latter part has not taken the rect-
angular direction which characterizes the well-formed adult
jaw. The anterior part of the alveolar ridge of the upper
maxilla has not attained the normal depth—a peculiarity
which the accompanying illustration does not exhibit in the
degree commonly seen in cases of this nature. I have seen
several instances in which in the closed mouth the finger
could be passed between the front teeth.

The teeth themselves, and especially the first permanent
molars, usually present indications of imperfect development
of their tissues. The surface of the enamel is irregular, and
marked with pits and transyerse grooves, is yellow in colour,
and readily broken down.

The anatomical conditions which are coincident with this
form of irregularity are readily distinguished, but the causes
which have destroyed the relations of the several parts of
the jaws during development are very obscure. In most
instances the patients have been unable without effort to
breathe through the nose, and the mouth has consequently
been habitually kept open, even during sleep. Possibly the
constant traction exercised upon the anterior part of the jaw
in keeping the mouth open may have had some influence in
determining the peculiarity of form, and the freedom from
the pressure exercised mutually by the antagonistic molar
teeth upon each other, may have led to their rising higher
with their sockets than they do when their conformation is
normal.

I have attempted to diminish the amount of deformity

142 A SYSTEM OF DENTAL SURGERY,

quity at which the ramus is placed with respect to the body
of the lower jaw. The line of growth has been almost directly
backwards, and the inferior dental canal, instead of being
carried upwards in its posterior third, is almost straight from
end toend. That form in which the rectangular position has
been prematurely assumed, and the ascending ramus below
the usual height, has already been adverted to, Here we
have a class of cases in which the obliquity peculiar to infancy
has been maintained throughout the whole period of growth,
and, a8 a consequence, an alveolar line of unusual length is
produced. In the prematurely rectangular jaw we seldom
find sufficient space for the normal implantation of the wis-
dom tooth; in the oblique maxilla, on the contrary, there is
room even for a fourth molar,

The specimen from which the preceding figure (Fig. 46)
has been taken, affords a better opportunity of examining the
anatomical relations of the several parts of the jaw than is
afforded in the living subject. In this we shall see that, had
the alveolar portion been developed in accordance with the
usyal form, while the obliquity of the line of development
was preserved, the separation of the front teeth would have
been far greater than it is; but nature, having departed from
the normal form in one particular, to a certain extent counter-
balances the deformity by a deviation in another direction.
Here, the alveolar processes at the back part are unusually
shallow, and in the front part of the jaw are unusually deep;
the back teeth are kept down to a low, and the front teeth
are ruised to a high, level. The treatment adopted in the case
already cited was in accordance with the indications afforded
by the specimen; the back formed the fulcrum by the aid
of which the elastic bands pressed the front part of the jaw
upwards, and drew the ramus downwards,

‘The following interesting case shows to what extent the
form of the jaw may bo modified by the maintenance of con-
stant pressure during early life. The patient was a strong
healthy young woman, twenty-two years of age, Her chin

144 A SYSTEM OF DENTAL SURGERY.

position, came into operation when the permanent teeth were
passing through the gums, and when their alveolar processes
were growing up with them, As the permanent alveoli were
for the most part developed under the influence of the ever-
contracting cicatrix, we shall be justified in assuming that
they were originally formed in the everted position shown
in the figure, rather than that they were developed in
the normal position, and bent outwards and downwards
subsequently, But whatever explanation may be adopted
as regards the process by which the deformity has been pro-
duced, the case offers a very instructive illustration of the
amount of change in form that a force incessant in its
operation may bring about in the jaw during the period of
growth.

There is yet another form of irregularity in which the
whole of the teeth of one or of both jaws are more or less in-
volved, It is that which is commonly called the V or wedge-
shaped mouth; the teeth, in place of holding the elliptical
arrangement, occupy two converging lines which meet at
an angle in the anterior part of the jaw, producing, as an
almost invariable result, an extremely high and vanlted
palate. The position of the teeth on the two sides of the
jaws may be perfectly symmetrical, and the conformation
may, in rare instances, correspond in the upper and lower
maxilla. More commonly, however, the deformity is con-
fined to, or exists in a much greater degree in, the upper
jaw, the central incisors of which frequently slant forward
aod stand in advance of those of the lower maxilla. There
is an appearance of contraction across the line of the bicuspid
teeth, looking as if the jaw had been pinched inwards at this
point (see Fig. 57); behind this the molar teeth rapidly
diverge. Each case will present its special peculiarities, In
one, the median sides of the central incisors will project
forwards and meet at angle; in another, angles will be formed
at the junction of the lateral and central incisors; in a third,
the central incisors will form at the junction of their median

146 A SYSTEM OF DENTAL SURGERY,

stamp of a higher civilisation—in other words, may be
speken of as “ well bred.”

‘Taking children of * well-bred aspect,” no less than sixty-
hine per cent. were found to have more or less contracted,
badly developed jaws; whereas taking children of decidedly
jow aspect, only from seven to cight per cent. manifested this
condition of the jaws. Amongst children of doubtful aspect,
who could not certainly be referred to either of the above
classes, twenty-four per cent, had contracted jaws, thus
coming in an intermediate position betwixt the first two
classes.

Tt was remarked by Mr. Mummery (*), in the course of
very extended series of observations on the teeth of savage
races, that irregularities of the teeth and contracted jaws
were as rare as destructive attrition was common
them, whilst precisely the contrary is true of civilised races,

And Messrs. Cartwright and Coleman report that they did
not find any example of contracted jaws in the large collee-
tion of skulls contained in the crypt of Hythe Chureh;
skulls which are certainly of very great antiquity, though
their precise history is, 1 believe, a matter of dispute,

That the comparative disuse of the organs of mastication
among civilised races, who cook and thoroughly doften their
food before masticating it, should have led to a less powerful
development of the jaws, is a thing that, might fairly be
expected, and were the occurrence of contracted jaws a thing
per se, it would have comparatively little significance. But
it happens that the V-shaped conformation of the jaws is
very often associated with other deviations from the standard
of healthy onganisation; thus it is extremely common fur
the subjects of this malformation to suffer from enlarged
tonsils, and to present many indications of weak health,
whilst it is rare to meet with it in strong robust persons.

And Dr, Langdon Down (*), after making observations on

(1) Tramactions of the Odlontologieal Society, new meries, wel.
() Wbid., vol. ie, p. 16, 1871. ~

148 . A SYSTEM OF DENTAL SURGERY,

region, which remains through life as a mark of malforma-
tion, scarcely noticeable at the time, which occurred during
intra-uterine life. This serves to explain how it is that a
character of permanent dentition may come to be diagnostic
of congenital disease, and also how it is that the lower jaw
is so seldom affected by this malformation, or, as has
lwen more fully described elsewhere ('), the cornua of the
alveolar border of the lower jaw have attained to their poste-
tior divergence at a period when the corresponding parts in
the upper jaw are as yet parallel.

Tn some instances the deformity is confined to the al-
voolur ridges, whilst in others the whole base of the jaw is
involved.

(@) Charles 5, Tomes, “On the Devclopmental Origin of the V-shaped
Maxtila." Moothly Review of Dental Setence, June, 1872,

(® Shows a owe if which the V-shaped conformation was attended with
uhesial contraction In the neighbourhood of the bicuspid and Grst permanent
molar teeth, On the left ake both of the bicuspids were removed, and in the
Fight the second bicuspid was extracted without any advantage being gained as
emurds the contracted condition of the palate. I am indebted to Mr, Harrison

for the use of this Interesting spoctmen,

150 A SYSTEM OF DENTAL suRGERY,

inflicted on the mother’s nipple, the laterals when erupted do
hot obliterate the space,

Pig. 90. (1)

Then again, if specimens be examined in which the two
sets of teeth are present, it will be seen that the implantation
of the temporary teeth occupies but a very small space in
the alveolar ridge, as compared with that oceupied by the
crowns of the permanent teeth: Now, it is extremely diffi-
oult to conceive how the removal of the temporary teeth can
induce the jaw to contract upon the crowned and growing
permanent teeth. Orguns in an active state of development
induce the expansion of parts nbout them, and there is no
good reason for supposing that the jaw forms an exception
to this rule. The persistence of the first, which are placed
immediately in front of the second set, may, and frequently
does, interfere with the outward progress of the latter; but
T cannot see how the removal of the temporary can produce

(*) The upper jave of a wubjoct between six and seven years old. ‘The central
incisors had been lost, and the alveolar ridge had become rormdet by the
obliteration of the sockets of the temporary weth and the development of new

bone. If the premature lo of the temperary teeth were followed by contrac-
ton ef the Jaw, the condition sbotld be shown im this case.

152 A SYSTEM OF DENTAL SURGERY,

equally important that we should learn whether the mal-
position of the second, has arisen from the tardy shedding of
the temporary, set, If the case presented for treatment
exhibits a form common to the family of which the child is
a member, we shall probably have to encounter greater difli-
culty than if it be a solitary example. After the teeth have
been removed, there will be a greater tendency in the one
case than in the other to return to the original position,
Supposing the V-shaped arch be forced into the elliptic form
in a case where the base of the jaws is below the normal
size, the position of the teeth individually will be so oblique,
as respects the jaw, that they will become unsightly; and
moreover, it is questionable whether the subsequent alveolar
development will be sufficient to Secure a firm implantation.
Hence, in cases which present this character, it may be
desirable to remove permanent teeth, one 6n cither side of
the jaw, more especially when the front teeth are onduly
prominent, and consequently require to be brought inwards,
If the mal-position has resulted from the persistence of
temporary teeth, the permanent teeth will tend to fall into
the elliptical arrangement so soon as the obstruction is
removed, from causes which have been explained on a
preceding page (p, 130),

When there is every reason to suppose that the hase of
the jaw is free from contraction, the teeth may then be
forced outwards till the desired conformation is attained ;
and in cases where the deformity has been equal both in the
upper and lower jaws, and the antagonism perfect, it will be
necessary, after the upper teeth have been re-arranged, to
repeat the operation in the lower teeth, and thereby restore
the antagonism which would otherwise be disturbed, and in
the efforts of re-adjustment, influence unfavourably the
results of the operation.

‘The form of apparatus suitable for expanding the V-shaped
dental arch need not be minutely described, as either the
ivory or the meial plate—a description of each of which

ren

154 A SYSTEM OF DENTAL SURGERY.

of the lower bite outside those of the upper jaw. But little
can be done to remedy such extended malformation by
treatment; it is, however, interesting to note that this, like
the ocourrence of the V-shaped upper mhxilla, is ina measure
the retention in the adult of a condition of things which in
the fetus is normal. For at the period of development
already alluded to (p. 148), the posterior divergence of the
lower jaw would, if there were teeth in it, lead to their
biting outside those of the upper maxilla nt the back part
of the mouth.

Javersion or eversion of the central incisors is not uncom-
monly seen in cases where the ejection of the temporary
tecth has been delayed, and the successors have come down
either behind or in front of them, or when the eruption has
been postponed until the lower teeth have attained their full
height, and im the absence of any counteracting influence
from antagonistic teeth, have cither taken a higher or a
more forward position than they should have done; conse-
quently the upper teeth have been driven, when in a state of
active growth, either outwards or backwards, just as they
may strike on the labial or lingual surfaces immediately
after emergence.

On the other hand, the lateral incisors may, as in the case
figured at page 64, lie in front of the central teeth during,
development, and the four teeth, advancing in growth with
equal rapidity, oblige the latter, at the time of eruption, to
take a backward place.

But by far the most common cause of displacement is the
persistence of the temporary teeth, The following figure
may be taken as a fair example of irregularity arising from
this cause. The temporary teeth being retained, their
successors have consequently taken a posterior position,
which allows the lower teeth, when the mouth is closed, to
pass in front of them; and thus, in the absence of mechani-
eal interference, render permanent the mal-position.

Whatever may be the cause of the irregularity, a

156 A SYSTEM OF DENTAL SURGERY.

our treatment must commence by forcing the former out-
wards from the median line, until they cease to embarrass
the operation. This may in most eases be done by placing
pieces of india-ruabber between the lateral and central teeth.
It is scarcely necessary to repeat, that when the lower teeth
close in front or upon the edges of the upper, the plate must
be made sufficiently thick at those parts which pass over the
back teeth to prevent the antagonistic influence.

Torsion, or twisting of the central incisors upon their axis,
is far from rare, The defect in position may be common to,
and equal in each tooth, or it may be greater in the one than
in the other, or it may be confined to one tooth only. BRither
the mesial sides may be directed towards the palate, or they
may be turned towards the lips; or the one tooth may be
twisted in the one, and the fellow tooth in the other direc-
tion (Fig. 29),

In a case recently under treatment, the right incisor made
its appearance at the age of thirteen, with the lingual sur-
face parallel with the median line of the mouth. In this case
the tooth is a quarter of a turn out of place, but instances
are recorded in which the twisting has extended to as
much as half a turn, 80 that the lingual surface presents to
lips. Ibave one example showing this amount of torsion
in a bicuspid tooth, In many cases of this kind the mal-®
position has been assumed during the period of development,
and,is then consequent upon arrested development of the
anterior part of the jaw. Sometimes, however, it results
from the retention of the temporary incisors. And it is not
improbable that the root of a temporary tooth, if displaced
by a blow or by a rude operation, may disturb and turn the
successor upon its axis while within its crypt. The retarded
development or eruption of a tooth may also be cited asa
cause of its torsion; and it is not difficult to see how the
mal-position is then produced. The adjoining teeth being
already through the gums, lean toward the unoccupied space,
and offer an impediment to the progressing tooth, which,

158 A SYSTEM OF DENTAL SURGERY.

As respects the treatment to be adopted, I cannot do
better than describe the course pursued in the following case,
inasmuch as the illustrations necessary for the elucidation of
details will serve the further purpose of showing the method
applicable to cases of irregularities affecting other teeth. The
patient was a female, aged fourteen years, The left central
incisor up to the age of thirteen did not make its appearance,
consequently the crown of the right lateral and left central
teeth leaned towards each other, leaving an interval insuffi-
cient for the missing tooth to take its natural position. At
thirteen, however, the tooth appeared, with its median side
directed towards the lip, but it was not till a year had
lapsed that the case came ander treatment. The succeed-
ing figure will show the general position of the teeth, and it
may be remarked that the canines were slightly more pro-
minent than the anterior teeth. A careful examination led
to the conclusion that, supposing the laterals and the left
central incisor were pressed ont, 80 a5 to range evenly with
the canines, sufficient space would thereby be gained to
allow the twisted tooth to hold the normal position. Acting
under this impression, a plate was made to fit the palate,
and attached to the bicuspids by wire continued over the
crowns of those tecth on either side of the mouth, and
terminated by a small T-like extremity, which, by way of
protecting the teeth, was covered with a thin investment of
floss silk. In this manner the plate was firmly retained in
its place.

The next proceeding consisted in soldering to the back
part of the plate two bands, composed of gold, rendered
elastic by the addition of three grains of platinum to one
pennyweight of the ordinary eighteen-carat gold. The free
ends of the bands were adjusted to press outwards and from
the irregular tooth, the two contiguous teeth, in the manner
shown in the accompanying figure.

Tn the course of nine days, sufficient effect had been pro-

duced to render it desirable that the incisor itself should be

160 A SYSTEM OF DENTAL SURGERY,

the slowly turning tooth, In a few days it became neoes-
sary to alter the position of the receptacles for the wood, and
subsequently to move them from time to time towards the
retreating angles of the tooth. ¥

After the second plate had been in use three weeks, the
tooth had so far changed its position that the mesial side
stood slightly in front of thie left incisor, and the distal side

Pig. 62.0)

a little posterior to the lateral incisor, presenting a degree of
irregularity which would attract but little notice.

As the left incisor was still a little internal to the arch
which would be described if the canines were taken as the
guide for its formation, a cell was adjusted upon the plate
behind that tooth, and the wood brought into operation,
At the same time, the operation upon the lingual surface
near the distal angle was continued, and the degree of
pressure upon the labial surface was considerably reduced.

(2) Shows the condition of the case illustrated in the preceding figure after
the adjoining teoth have been separated by tho elasthe bands, and the displaced
tooth turned slightly from ta criginal position, ‘The plate used in this, the
scounil stage of the operation, ts shown fm situ, with the metallic boxes for the
teerption of the compressed wood in the positions suitable for effecting the
further progress of the treatment. It will be apparent that the boxes will
require a change of position when the tooth has moved away from them.

162 A SYSTEM OF DENTAL SURGERY.

But the process of twisting a tooth on its own axis by
means of gradual pressure is one that necessitates the use of
a plate for a very considerable length of time, and inflicts no
stnall discomfort on the patient; and it has been found that
the same end may be attained by seizing the tooth in a pair
of forceps and forcibly twisting it round.

It might have been anticipated that such a procedure
would be followed by the death of the pulp and consequent
alveolar abscess, but this untoward result happens very
rarely, and may almost always be avoided by performing
the operation only on favourable cases.

Before deciding on forcibly twisting the teoth, the operator
should satisfy himself that there is sufficient space for the
crown in its new position, and also that the direction of the
root is such that it will allow of the crown ranging regularly
with the surrounding teeth.

The most favourable period for its performance appears to
be the age of eight or nine years, when the teeth are fully
erupted, but their sockets have not yet attained their full
strength. Ihave however successfully twisted the central
incisors in a patient aged fifteen, and in several instances in
patients aged thirteen; but, asa rule, it should be done at a
much earlier age, for the sockets become very dense and un-
yielding, 80 much so that in several cases I have failed to
move the teeth with any degree of force which it has seemed
safe to apply, and have been therefore compelled to abandon
the attempt.

The tooth may be seized by its Inbial and lingual, or by
its mesial and distal surfaces; and it will often be con-
veniont to change the hold of the forceps after the tooth is
partially twisted. Thus, if the tooth stands nearly at right
angles to its proper position (as, for example, the right
central incisor in Fig. 61), it would be easiest to apply ane
blade of the forceps to the mesial and the other to the distal
surface, but it would not be possible to complete the torsion
with the blades in this position, as they would come in

164 A SYSTEM OF DENTAL SURGERY.

it is advisable to soften a piece of gutta-percha and press it
over the incisors and canines of the upper jaw immediately
after the operation, directing the patient to bite the lower
teeth into it gwhile it is still soft.

‘This will keep in its place, and should be worn for twenty-
four hours at least, or longer if the tooth remains very loose ;
of course it must be removed during meals, but it is safer to
confine the patient’s diet to soft things for a day. The
extreme tenderness and looseness will pass off in a day or
two, when tho use of the gutta-percha splint may be diseon-
tinued. Jf there is swelling and tenderness over the socket,
this may he painted strongly with tincture of iodine, or a
leech applied; lut the necessity for any such treatment
seldom arises.

I am acquainted with one case only in which necrosis
of the tooth ensued; the patient was a child of suitable age,
but was a hospital patient, apparently not much tended by
its parents, and probably no care was taken after the
operation to preserve the tooth from movement. In this case,
I believe, the pulp cavity was drilled into, through the
lingual surface of the crown, and the fang filled with cotton
wool steeped in carbolic acid, This treatment was per-
fectly successful, and the tooth after a short time became
firmly fixed in its socket. I do not know through what
distance the tooth was turned, nor whether it offered more
than usual resistance, but the untoward result was attri-
buted to the want of proper care exercised after the opera-
tion,

Irreqularity in the position of the lateral incisors—In the
upper jaw these teeth may be misplaced in any of the
directions enumerated and described in the preceding pages
in connection with malpositions of tle central incisors, hence
the description which has served for the one may be applied
to the other series of deformities, Perhaps the most commen
form of irregularity of the lateral incisors is that in which
they take a posterior position, the median edge of each lying

166 A SYSTEM OF DENTAL SURGERY.

taken, there is no indication of contraction of the jaw, On
the one side of the mouth, the teeth are perfectly regular;
on the other, the lateral incisor and the canine are directed
inwards, and pass, when the mouth is shut, behind the
corresponding teeth of the lower jaw. The arch being at
this point bent inwards, and the alveolar space thereby
contracted, the teeth, in order to find a place for themselves,
have forced the central incisor forward, and driven its median
edge over the labial surface of the adjoining tooth. In this

Fig. 64. (")

specimen we have an example of irregularity consequent on
the teeth, from some cause (probably the retarded ejection of
the temporary teeth), taking an improper direction at the
time of eruption, the jaw being normal in size; in the pre-
ceding case, an illustration of irregularity consequent upon
& contracted maxilla.

A slight degree of eversion and separation of the lateral

(1) Showing the lateral incisor ant canine inverted, and the central incisor
driven outwards and across the fellow tooth, tho alveolar arch at its base being
free from contraction.

168 A SYSTEM OF DENTAL SURGERY.

be given, taken from a case in which the lateral incisor has
been driven outwards towards the lip, by the canine coming
through the gum immediately behind the former tooth
(Pig. 67).

The principles which have been laid down for the treat-
ment of the various forms of irregularity in the central, apply
equally to the lateral tooth, when similarly situated, exeept-
ing that the one is, as respects appearance, a less valuable
tooth than the other, and may therefore, under certain
circumstances, be sacrificed with less hesitation. When,
for instance, the lateral teeth are situated as in Fig. 63, we
need not hesitate to remove them, supposing the antagonism
is normal, and a more forward position of the central teeth
would leave a wide interval between the lingual surface of
the upper and labial surface of the lower teeth on the mouth
being closed. But if the central incisors in such a case
passed behind the corresponding tecth of the lower jaw, it
would then be our duty to bring them forward, and after-
wards force the laterals into the space which the previous
operation had gained. In cases presenting the peculiarities
shown in the Fig. 64, the operation is very simple. We
haye only to bring the inverted tooth, or teeth, outwards,
and the antagonising tecth will keep them there.

Supposing the displacement to be caused by the canine
when about to take its place in the series, we must wait
until the evolution is completed, removing, of course, any
temporary tooth which may operate in disturbing its course,
If after the eruption of the canine the lateral does not regain
the proper position, the usual means must then be adopted
for its restoration. But it may happen that the teeth are
driven inwards or ontwards, or are twisted by the canines,
which, in the absence of sufficient space for their proper
evolution, take a position either external or internal to the
dental line.

Irrogularity in the position of the canine teeth.—Of all the
teeth, none are so frequently out of the normal position at

170 A SYSTEM OF DENTAL SURGERY,

guided by the principles laid down in respect to the treat-
ment of similar forms of irregularity occurring in other teeth.
Whether the involved tooth is external or internal to the
dental line, either the arch must be expanded or a tooth
must be removed, before sufficient space can be gained for its
admission to nniformity. We have the alternative of press~
ing outwards the neighbouring teeth or sacrificing a tooth.

‘The canine is the most durable member of the whole series,
hence it must, if possible, be brought into place; moreover,
the pointed form of the canine gives it a character not
shared by the other teeth, so that its absence is noticeable.
But circumstances arise under which its extraction becomes
expedient. If, for instance, the tooth pierces the gum con-
siderably above the alveolar margin, and is directed outwards,
and the interval between the lateral and first bicuspid but
slight, we shall then do well to remove it. Teeth so situated,
being very frequently short, and having imperfectly-formed
curved roots, are often incapable of taking their proper place
in the series. A case presented itself, only a few days since,
in which the right canine was so placed. On removal, the
root was found to be short and curved. Had an attempt
been made to bring it into line, the apex of the root would
have been forced through the Inbial surface of the gum, and
the crown would have stood at a higher level than the
corresponding parts of the neighbouring teeth. To have
sacrificed the lateral or bicuspid for this defectively-developed
tooth, would have been an obvious error; and to have forced
the anterior teeth outwards would have been equivalent to
producing a deformity in the whole in order to meet that
which had arisen in one of the front teeth, Hence, although
the rule that the canine should be preserved is a sound one,
it must not be blindly followed in every case, but the ul-
timate prospect of getting it into place must be carefully
considered.

When we have reason to suppose that an out or instanding
canine is not in any way defective, yet the space accorded to

172 A SYSTEM OF DENTAL SURGERY.

would present a serious obstacle to its movement back-
wards.

Should it be determined to bring an outstanding canine
into the dental line, either by acting on the tooth itself, or
by operating on the neighbouring teeth, as well as upon the
canine, the method described as having been successful in
turning into place a twisted central incisor will be found
offective ; or a vuleanite plate may be used, if the operator
regards metallic regulation plates with distrust.

Irvegularity in the position of the bicuspids—It rarely
happens that the front teeth are crowded, without the
Dieuspids to some extent participating in the general irregu-
larity, They are usually situated internally to the normal
position, and are instrumental in throwing the canines
out of the proper line, or in giving the appearance of
undue prominence to those teeth. The bicuspids may be
regarded as forming the base of the semicirealar dental
curve, which, if contracted, necessarily involves either 4
deviation from the normal figure, as seen in the V-shaped
mouth, or it obliges some of the teeth to take cither an
external or an internal position.

If the curve described by a perfoctly well-arranged set of
teeth be examined, it will be found that it ay es a
semicircle as far as the bicuspids, and that the molars occupy
curvilinear lines, diverging slightly us they proceed back-
wards. The arch admits of division into two parts; the
anterior semicircular portion being occupied by the successors
of the deciduous teeth, the posterior division by the true
molars—teeth which have no predecessors. Should, there-
fore, the breadth of the jaw at the junction of the two
divisions fall below the proper extent, and the bienspids of
either side consequently approach too near the median line,
not only will the front teeth be thrown out of the semi-
circular curve, but the molar teeth will occupy lines which,
although diverging from the starting-points, will nevertheless
+ fail to attain an amount of separation as respects the two

174 A SYSTEM OF DENTAL SURGERY.

movement possible without derangement of the anterior part
of the dental arch, we must then adopt a plate, and have
recourse to the compressed-wood wedges, Either metal or
vulcanite may be used in constructing the apparatus, and
the wedges, if properly proportioned, will serve for its
retention without the aid of ligatures or clasps. The move-
ment is very readily effected, being sometimes uninten-
tiénally bronght about by the very moderate pressure of
artificial teeth, but we must not neglect to take into account
the antagonism of the opposing teeth; usually the lingual
cusps of the upper close between the outer and inner cusps
of the lower teeth, and unless the lower bicuspids are moved
outwards contemporaneously with the upper teeth, the
normal antagonism will be destroyed, Moreover, there will
bo a strong counteracting force oxercised by the stationary
teeth upon those under operation, If the upper teeth, for
example, are moved outwards so that the lingual cusps close
on the apices of the labial tubercles of the lower teeth, the
other tecth will be kept apart until the lingual cusps of the
moved teeth slide down either upon the inner or outer sur-
face of the labial cusps of the lower teeth. In those cases in
which we find « faulty antagonism, our treatment becomes
more simple. Tf, for example, an upper tooth closes exter-
nally or internally to its antagonist, our operation will be
confined to the malplaced tooth, which, so soon as it ap-
proaches its proper position, will be carried onwards in the
proper direction by the influence exerted by the antagonising
tooth of the lower jaw, in the manner described in connection
with misplaced central and lateral incisors,

Trregularity in the position of the crowns of the permanent
molars, without the roots participating in the displacement,
is of less frequent occurence than derangement of the more
anterior teeth; still, cases sometimes present themselves in
which the normal positions are not maintained. Perhaps
the most common form of deviation is that in which the
second permanent molar on either side is turned inwards

176 A SYSTEM OF DENTAL SUROERY.

most part to the teeth of the upper jaw, under the impres-
sion that it would be unnecessary to give a detailed account
of the defects of arrangement in the corresponding organs
in the lower maxilla. It may, however, be stated generally,
that the forms of irregularity which occur in the upper may
also arise in the lower teeth, and that the treatment suitable
for the one will be equally fitted for the other, The con-
struction of the plate, whether metal or vuleanite be used, will
of course be modified. We have here to adapt the apparatus
to the teeth and the lingual surface of the gums only; ex-
cepting in the foregoing particulars, the methods of operation
will be precisely similar to those already deseribed. The
vertical position of the lower teeth renders the retention of
the compressed wedges of wood particularly easy, and this
advantage is still further increased when the teeth so operated
upon are inclined either outwards or inwards. The opera-
tions for the adjustment of irregularities of position are,
however, leas frequently attempted on the lower than the
upper jaw, owing to the former being hidden to a great
extent by the lip, so that they fail to attract that amount of
attention which is given to upper teeth.

Irregularities of the permanent teeth in which both the crowns
and the roots are aut of the normal position—total or com-
prete displacement of the permanent teeth—Transposed teeth
come under this head, but as they do not admit of restorative
treatment, examples illustrative of this form of departure
from the normal arrangement may be given at the conclusion
of the present division of the subject.

The following illustration (Tig. 66) shows the amount to
which a central incisor may be thrown ont of the proper
position. Here the cause is sufficiently obvious in the
presence of a supernumerary tooth. Cases in which the
centrals are completely displaced are, however, comparatively
‘rare, All attempts at treatment would in any such case 03
‘that which is figured nocessarily be useless, supposing the
development of the Toot to have been advanced. Had the

178 A SYSTEM OF DENTAL SURGERY.

subject of Fig, 67, restoration to the normal arrangement,
though perhapa not impossible, would be attended with
difficulty. The question then arises as to which of the teeth
should be removed. ‘The temporary canine, if left, may
endure for some years, but if it be extracted we may be
unable to force the permanent tooth into its place, and should
we succeed, the crown only would be moved, hence the tooth
would hold a slanting and probably unsightly position. My

~ Big At),

own choice would fall upon the canine. Tt would, T think,
be more easy to press the lateral tooth inwards, the terminal
portion of the reot of which is not displaced, than to draw
outwards into line the canine. In deciding on our treatment,
we must in no case lose sight of the fact, that althongh it
may be quite possible to foree a tooth from an irregular into
a regular position, yet that the operation may, under some

() Shows the left canine placed behind the dental Unc, its crown helding a
vertical position, and the root. anless greatly eurved, equally with the crown,
isplaced, The lateral incisor has bon cverted by the ennine, while the
temporary canine holds the position which should have been oocupled by the
displaced tooth, The right temporary canine is retained, and the permanemt
Aeothi placed borizuntally, « portion of the crown only being seen.

TEETHING. 179

cirournstanoes, be so prolonged and painful, that the proposed
mivantage will not compensate for the suffering which its
accomplishment would entail.

Tn the preceding figure a case is shown in which the right
canine is placed across the dental arch, the root being
directed towards the median line of the palate, and the
crown towards the cheek. The point of the crown was the
only part which was not completely buried in bone. The
latter tissue has been cut away for the purpose of showing
the course taken by the tooth.

A horizontal position in the base of the alveolar ridge is
sometimes taken by the canine, the apex of the crown being
nage to view, or covered only by gum or imbedded in

Preeith so placed may remain without producing incon-
venience through a long life, and be discovered only towards

(1) Shows the right canine placet transversely in the base of the alfeolar
Hract, the crown betng direct! towants the cheek, and the root towards the
‘ToAlian fine of the mouth. The bone has been removed to show the course
takea by Wie root of the displaced tovth.

180 A SYSTEM OF DENTAL SURGERY.

its close. When with advancing age the teeth fall ont, and
the alveolar processes disappear, the long-hidden teeth are
brought to light, and the patient fancies he is cutting a third

Fig, (3)

set of teeth. The two following illustrations are taken from
a remarkable specimen given to me by Dr. Brinton, in which
the canines wore symmetrically arranged in the horizontal
position deseribed in a preceding case,

A patient admitted into the Middlesex Hospital under the
care of Mr. De Morgan, lost a portion of the upper maxilla
from syphilis. ‘The dead bone on its coming away was found
to contain a canine tooth, which ran under the floor of the
nose in a direction parallel with the median line of the palate
(Pig. 72). Excepting the absence of the canine, the dental

@) Shows the right canine of the upper Jaw buried In the base of the
alveolar prominence, tts course correspooding: with that of Ube latter part.
‘The bone has Deon out away to show the direction taken by the tooth, The
first bicuspid has beoome slightly twisted on its axis by the malplaced canine.
Ou the left side of the maxilla the second bicuspid has been twisted round until
t Ungual surfuce is directed towanis the cheek. The presenee of the teot
Of the second temporary molar has probably been Instrumental in predoeing
‘his change from the’ normal position. This case is referred to in a previows
eee.

182 A SYSTEM OF DENTAL SURGERY.

Although total displacement of the canine teeth is less
common in the lower than in the upper series, examples of
this form of irregularity in the lower jaw are sometimes met

Pig. 72.8)

Py. 13. ©)

(©) Shows a sequestrum from the upper Jaw which became detached during
an attack of syphilis. 11 contains a canine tooth situated borteontally im the
feor of the nose, [ts direction being parallel with the median Line of the palate,

(#) From a specimen in which the temporary canines were persistent, and
the permanent canines placed horizontally, On the left side, a sufficient
amount of bone has been removed to show the positim of the buried tooth.
‘On the right side the point of the canite may be seen between the lateral and
the central incisor. The right temporary lateral incisor has been retained,
wedged between the permanent central and laveral teeth.

184 A SYSTEM OF DENTAL SURGERY.

the jaw. The retention of the temporary may be adduced
as the prevailing canse of total displacement of the permanent
canine, In several of the preceding illustrations, these
members of the temporary set are present. In other cases,
however, the arch is fully occupied by the permanent teeth,
to the exclusion of the canines, and as these are commonly
the last to take their respective places in the series, they are,
when so excluded, liable to be turned completely out of their
normal position.

The presence of disease, or the occurrence of mechanical
injury in that part of the jaw in which the canines are situ-
ated when undergoing development, may drive them from
their proper position. I caunot, however, call to mind a
case which would serve for illustration on this point.

The results entailed by total malposition of the canines
are usually unimportant. Tumours arising in the osseous
structure of the jaw have however, in a few cases, been
found to contain a hidden tcoth in their centre, and the teeth
so placed have been regarded as the cause of the disease;
and in more than one instance, a missing tooth has been
removed from the interior of a tumour, and the operation
lwen followed by subsidence of the disease. ‘That teeth
embedded in the substance of the jaw may become a source
of irritation, and predispose to disease in the part in which
they are situated, can scarcely be doubted. In the case shown
in Fig. 72, it is probable that the presence of the canine not
only determined the site of the necrosis, but also the occur-
rence of the disease, seeing that the loss of the bone was, as
regards the alveolar portion of the jaw, limited to the parts
immediately around the tooth. In the year 1859 a speci-
men was exhibited to the members of the Gdontological
Society, in which a canine tooth lay horizontally on the
floor of a large cavity formed in the substance of the lower
jaw near its lower border. The history of the case, with the
characters presented by the enlargement of the bone, induced
the surgeon to excise that portion of the maxilla in which

TERTHING, 185

the disense was situated, and it was the excised portion
which was shown at the Society. ‘This case will be found
more fully described in the chapter treating on diseases of
the jaws induced by misplaced teeth.

Complete irregularity in the position of the bicuspids to
the extent shown in some of the preceding figures of mis-
placed teeth, is of very rare occurrence. In the most strongly
pronounced case which has come under my own observation,
the root of the second bicuspid of the upper jaw passed
Yackwards between the lingual and labial roota of the first
molar, In the case illustrated, the direction of the tooth

Fig. 79.0)

is much the same as in the foregoing case, although situated
in the lower jaw. The first molar had been lost, hence the
relations between the roots of that and the displaced bicuspid
can only he surmised.

Examples in which a bicuspid stands obliquely across the
dental line are not uncommon, but in these the displacement
is rarely complete; the extremity of the root is usually in the

Shows a lower maxills in which we gets blemepid Is placed
‘ly, the root being directed buckwardy, The crown, though exposed,
does net rise above the level of the alveolar margin,

|

186 A SYSTEM OF DENTAL SURGERY.

normal position, and the crown, if there were sufficient space
in the dental line, could be brought into the normal position,
Now and then, however, # bicuspid may be found with the
crown directed towards the tongue, and situated below the
alveolar margin. Such a case is figured by Goddard. (*)

‘The first permanent molar appearing, as it does, posteriorly
to the temporary teeth, at a time when the jaw is in a state
of active growth, seldom, if ever, becomes the subject of com-
plete displacement; and I know only of one case in which a
fully-developed second permanent molar has been found below
the alveolar margin. It is figured by Goddard from a pre-
paration in the cabinet of the University of Pennsylvania,

The third molars, or wisdom teeth, being the last to take
their place in the series, are, from the obstacles opposed to
their eruption, a frequent cause of suffering, more especially
those of the lower jaw. The second molar immediately iu
front, and the terminal point of the alveolar line Iwhind,
bound the space accorded to the wisdom tooth; each tooth
which has no deciduous predecessor is developed beneath the
base of the coronoid process in the first instance, and as the
coronoid procesa recedes by absorption on its anterior and
deposition on its posterior surfaces, the tooth is enabled to
come into its proper position; but if the backward develop-
ment of the maxillw has been arrested, the interval will be
insufficient for the normal arrangement of the presenting
tooth, It would appear to be the exception rather than the
rule for the wisdom teeth, especially of the lower jaw, to take
their place among the organs of mastication, without pro
ducing some amount of suffering at the time of their eruption,
and the degree of inconvenience experienced is often sufti-
ciently great to induce the sufferer to apply for professional
assistance. In many of the cases which arise in the lower
maxilla the teeth can scarcely be said to be displaced, The
deviation from the normal conditions is confined to the jaw

(2) The Anatomy and Physiology of the Human Teeth. By Paul B, Goddard,
Pulladelphia, 1844,

TEETHING, 187

itself. The tooth takes its natural direction, but the space
into which it has to force itself is insufficient, consequently
the distal side lies close against the anterior surface of the
coronoid process, leaving no room for the gum. The latter
part, under these circumstances, is pressed upwards, and lies
more or less over the masticating surface of the tooth, and
is consequently subject to be bruised from time to time by
the tooth or teeth of the upper jaw, In this manner inflam-
mation in the gum is set up and maintained. The disease
seldom limits itself to the part injured. It more commonly
extends to the adjoining parts, involving the soft textures
about the ascending ramus, and extending from thence to
the faces. The act of deglutition becomes painful, and the
motions of the jaw are restricted. The patient tells you
that it is quite impossible for him to open the mouth suffi-
ciently wide for you to make an examination of the tooth
which has occasioned his misery. After a time, the over-
lying gum suppurates, and the moyement of the jaw becomes
less constrained.

‘The patient, however, is extremely cautions in using the
teeth, until the inflammatory action has subsided, leaving
in some cases the gum in « position to be again wounded
by the upper teeth; in other cases leaving the whole of the
masticating surface of the tooth perfectly uncovered. If the
patient be seen before any great difficulty in opening the
mouth has arisen, the tooth may be removed; indeed, in all
tases where the tooth is wedged tightly between the parts
already described, this treatment will be the most judicious
we can adopt; for should the gum, after the inflammatory
symptoms subside, retreat behind the tooth, still the back-
ward position renders the latter useless as an organ of mas-
fication. And should the gum retain its unnatural position,
the patient will be liable to repeated attacks of inflammation
watil either the gum-coyered tooth or its antagonist has been

There may not, however, be sufficient space between the

188 A SYSTEM OF DENTAL SURGERY,

second molar and the ramus for the wisdom tooth to protrude
itself; it then either becomes developed below the alveolar
targin, or it comes up partly within the base of the ramus—
one half of the crown of the tooth being covered by bone, the
other by gum. In either of these cases the patient may or may
not be subjected to suffering, consequent upon the abnormal
position of the tooth; and the absence or presence of mis

Fig, VD

chief will be determined partly by the height to which the
tooth rises in the jaw, as respects the antagonistic tooth,
and partly by the constitutional state of the pationt. The
sime condition of parts which in one person would lead to
little or no inconvenience, would in a less healthy subject
produce great irritation, and even necrosis; the extent of the
disease varying, again, with the susceptibility of the indi-
vidual, In any case the involved tooth should be extracted
80 s00n a8 it is found to be a source of irritation. *

(From a spectmen tn which the third molar has been developed below

the alveolar margin, with the distal side under the base of the ascending
Tamms of the lower Jaw.

190 A SYSTEM OF DENTAL SURGERY.

it is desirable that it should be borne in mind, when disease
about the posterior part of the jaws is coincident with the
absence of the wisdom teeth from the usual situation, that
the lost teeth may lie buried in the substance of the bone,
and be the exciting cause of mischief.

In the majority of cases, however, the third molars, when
misplaced, lose the vertical position, ‘They commonly take
an oblique direction, either forwards, outwards, inwards, or
backwards, In the lower jaw, the forward direction is by
far the most common form of irregularity, the degree varying
from « slightly oblique to a perfectly horizontal direction.
‘The succeeding series of figures show various degrevs of this
form of misplacement,

Fig. 19.0)

Tn endeavouring to trace the causes which have produced
this class of irregularities, we must recognise two distinct
conditions. In the one, the tooth, in pressing forwards, has
taken the direction in which the least resistance was offered
to its progress; in the other the malposition has been
assumed at a comparatively early period of development,

(@) View of the inner surface of loft sido of the lower Jaw, the bobe being
Temored to show the oblique direction of the third molar.

192 A SYSTEM OF DENTAL SURGERY.

the median edge or angle of the crowns impinged upon the
necks of the anterior molars, ‘he forward movements of the
tecth then became completely arrested. Jn Figs. 81 and
82, the teeth must have been from the first formed. pretty
tnuch in the position which they are shown to occupy.

Fig. 82.(1)

In the upper wisdom teeth the oblique direction forwards is
less frequently assumed. The following figure will, however,
illustrate the form of irregularity in the upper maxilla
(Fig. 83),

In the lower jaw it is not common to find the third molar
directed obliquely outward, although cases have occurred in
which it has assumed that position, In one or two instances
Thave seen the crown of the tooth buried in the substance
of the cheek, and so much obscured by the swelling and
inflammation of the soft parts around, that its presence was
detected with some difficulty,

In the upper jaw, however, the outward direction is more
frequently taken. In the accompanying figure (Fig. 84),
taken from a specimen in my own collection, this form of

(1) Shows « lower jaw in which the wielom tooth has taken a horizontal
position below the level of the alveolar margin.

194 A SYSTEM OF DENTAL SURGERY.

pierced the cheek. The crown of the tooth was, however,
hidden by the whiskers, and appeared to produce no inoon-
venience. Casts of the cheek, with the projecting tooth, were
taken, and [ believe one of them may be seen in the museum
of the College of Surgeons,

A case occurred in the practice of the late Mr. Craigie, in
which 4 lower wisdom tooth had made its way to the sur-
face and pierced the skin close to the angle of the lower jaw-
The crown of the tooth, as is seen in the accompanying
figure, was firmly embraced by the puckerod skin, which
presented the appearance of cicatricial tissue.

Pig. #3. (8)

.

In this case the tooth was removed, and the opening in
the skin closed spontancously, without necessitating any
further surgical interference,

(Cases in which the third molar is directed with more or
less obliquity inwards are met with in the lower jaw, but
in the upper maxilla they are very uncommon. Examples
of teeth which lean inwards in # slight degree may be seen
from time to time, but such hardly call for deseription in
this place.

Ido not remember to have seen a case in which a lower

(*) The figure is taken from a wax model belonging to Mer. Cartwright,
which ls deposited in the museum of the Odlantotogical Sockety,

196 A SYSTEM OF DENTAL SURGERY,

rare form of displacement came into my possession with the
following history, The patient suffered pain from a carious

Fig. 37-0)

second molar of the upper jaw. The aching tooth was re-
moved, and with it came the third molar, the fangs of which

Pig. 88. 7)

(2) Shows the wisdom touth of the right side of the upper jaw placed hor.
mortally, and the crown directed backwards and a litte outwards. The bone
has been removed to show the position of the tooth.

(®) A second molar of the upper Jaw, with tho wisdom tooth inverted and
embraced within the roots.

198 A SYSTEM OF DENTAL SURGERY.

directed either forwards or backwards, the tooth in its
descent may lose the proper position, and come either between
the incisors or the first and second bicuspids.

Trreqularity in the number of the permanent teeth presents
itself as the next subject for consideration. Thirty-two
being the number in a normal series of permanent teeth, any
deviation, whether it be in an excess or in a diminution of
that number, will constitute an irregularity. In other words,
there may be irregularity from too many or too few teeth.
Each of these forms of departure from the normal series is _
far from rare; but of the two forms it is perhaps more
common to find that in which the teeth are in excess, one or
two supernumerary teeth, as they are termed, being present.
‘The connection which seems to exist between the hair and
teeth in respect of abnormal development has already been
noticed (page 116), as was also the fact that such abnor-
malities are often inherited. At all events we will first
consider that condition in which the teeth exceed the proper
number.

Supernumerary teeth may spring up during the second
dentition in any part of the alveolar arch, and the forms
of such tecth may cither resemble those of special members
of the normal series, or they may deviate from each of the
recognised forms, and assume a somewhat irregular conical
shape, sufficiently characteristic in itself to be at once recog-
nised as that of a supernumerary tooth. (1)

Several cases, occurring either in the first or the second
dentition, have come under my own observation in which
five equally well-formed incisors oceupied the lower jaw,
Th neither case was it possible to determine from an examina-
tion of the crowns of the teeth which was the supple
mental tooth. A third lateral incisor in the upper jaw,

(1) Seeing that supernumerary tect assume two diafinet forms, the ene
being regular, the other Irmogalar, It might, perhaps, be advantageous
f those which fm tio respect differ from members of the

, Leseovypes Seibel pberiahn ey ravets pasties
the irregular-shaped teeth.

200 A SYSTEM OF DENTAL SURGERY.

large to justify the observer in regarding any peculiarity of
form which prevails throughout the collection as a special
characteristic of supernumerary teeth. After removing from
the series those which are not distinguishable from normal
forms, we have remaining, teeth the crowns of which exhibit
the following characters:—The lingual and labial surfaces
are not distinguished by any difference of form. The enamel
terminates on the neck of the tooth in an even line, differing
in this respect from the terminal line in ordinary tecth. The
erown of the tooth will, in the majority of cases, present a
simple cone with a sharp apex; in other instances, the point
will be replaced by an irregularly depressed surface, oor-

Fig. 0.0)

responding in character to the masticating surface of a bi-
cuspid or molar. More rarely the conical or cylindrical form
is lost, und in its place we have a more or less flattened
crown, the grinding surface being marked longitudinally with
# deep fissure. Several examples have come under my
observation, in which the crown has been divided into three
ot four plates, meeting at » common centre in such a manner
as to produce a cross. It would, however, be hopeless to
attempt to describe more than the general characters of super-
numerary teeth, inasmuch as the minor differences of form
are infinitely varied; no two are precisely similar.

The roots of supernumerary teeth are, I think, almost

(*) Shows the front view of a specimen in which supernumerary tooth

external to the front teeth cccuples the space between the lateral incisor and
canine teeth.

202 A SYSTEM OF DENTAL SURGERY.

two supernumerary teeth (Fig. 93) occupy the place of the
central incisors. One of the excluded teeth has come throngh
above the alveolar line.

Again, in Fig. 92 there are two snpernnmerary teeth, and
one of these has to a certain extent interfered with the posi-

Pig. 92.0)

tion of the central incisor. Now, in each of these instances
the abnormal have preceded the normal teeth, and occasioned
the malposition of the latter. But it may happen that a
snpernumerary tooth appears in the place and at the time of
a normal tooth, the latter having been retarded in its
development by the presence of the former, In one case a
central incisor of the upper jaw waS cut at the usual time,
and by the side of it a supernumerary, The latter was at
once removed, onder the strong belief that the absent central
tooth would after a time make its appearance. The expecta-
tion was realised, but three years elapsed first. The neigh-
bourhood of the incisors must be regarded as the most
common position for supernumerary teeth to take, and the
upper is more frequently favoured than the lower jaw.
Tnstances, however, are not wanting in which the additional
teeth appear among the molar division of the series. Ina

@) Shows the appesrances presented by a cast taken from « month In

which two supernumorery feeth appeared behind tho incisor, one reembling
to some extent an Incisor, the other altogether irregular tn shape.

206 A SYSTEM OF DENTAL SURGERY.

gum, bunt had its extraction been performed after the com-
pletion both of itself and of the displaced central tooth, no
advantage would have been gained by the operation. The
position of the central incisor. having been unalterably
determined, the space left by the extraction of the intruder
would have remained nnoceupied.

Under the head of irregularity in the number of the per-
manent teeth, those cases in which the dental series is more
or less defective, yet remain to be considered.

Tnstances have been cited of a total absence of the perma-
nent teeth. (*) One or two such cases have been described
to me by gentlemen who have examined the subjects for
themselves. In my own practice, however, I have failed to
meet with an individual who from the first was perfectly
destitute of permanent teeth, ‘The nearest approach to the
edentate condition which has in any way come utder my
own observation, is exhibited in two casts taken by Mr.
Harrison from a patient under his treatment. One molar
occupied each side of the upper and lower jaws, ‘These four
molar teeth, with four incisors (two in each jaw), were all
the permanent teeth.

According to the statements of the patient and of her
friends, the temporary teeth presented no peculiarities either
as regards their number or the manner or the time of their
shedding. A temporary canine tooth was retained in the
upper and lower jaw; the other members of the deciduous
set dropped out at the usual time, but, with the exception of
the four central incisors, their successors were wanting. A
case has been already described, in which there was an
almost, total absence of the temporary series, yet permanent
teeth not only made their appearance at the usual time, but
took their place with great regularity as respects arrange-

() [n the musenm of the Odontological Soelety are several motets of casos
in whieh the teeth were deficient (sce Catalogue, page 23), and allusion bas
already been made to the subject In disenssing the origin of various abnor-
malities (page 116).

208 A SYSTEM OF DENTAL SURGERY.

I am indebted to Mr. James Parkinson for a specimen of a
young jaw in which both the temporary and permanent
lateral incisors are wanting.

The son and danghter of a gentleman who had no lateral
incisors in the upper jaw, each bore the marks of their
parentage in respect to the teeth. The son -hnd but one
lateral incisor, and that was a very small and imperfectly-
developed tooth. The daughter had, however, two lateral
incisors. They made their appearance at a very late period,
and presented the characters common to supernumerary
tecth, cach tooth being nothing more than a small sharp-
pointed cone; and other instances of inherited peculiarities
have already been given at page 114,

Pig. 98. (1)

I believe when one description of tooth only is wanting, it
will generally be found that the lateral incisor is the missing
member. Perhaps we should except from this rule the
wisdom teeth. They, however, are so extremely irregular in
all respects, as compared with the other teeth, that we are
seldom in a position to declare them absent, although they
may not have appeared above the surface of the gums, But
if the third molars are less frequently absent than the lateral

() Shows « woll-leveloped adult Jaw, in which the second temporary
molar Is persistent, uo secand bleaxpld having been developed.

210 A SYSTEM OF DENTAL SURGERY.

(©) A front view, lifesize, of an unnwmally large act of fromt teeth, of the

‘upper and Jower Jaws.
@) A front view, life-size, of an extremely small set of permanent front
teeth from the upper aud lower Jaws.

212 | A SYSTEM OF DENTAL SURGERY.

gum; this, with the unsightly character of the tooth itself,
led to its being extracted. The tecth adjoining the vacated
space were, by means of ligatures, gradually brought towards
each other, and eventually so far reduced the interval, that
the absence of the faulty central was not missed.

The irregularity as regards size will sometimes be limited
to the root of # tooth. In the example’ from which the
preceding illustration was taken, the crown has attained the
usual size; the enamel, however, exhibits indications of
defective organisation, and the root is most imperfectly
developed. ‘The tooth was removed within two years of its
appearance, in consequence of the irritation it excited in the
surrounding gum (Fig. 103), Tt can scarcely be supposed
that any constitntional condition would cause the production
of one defective tooth, and leave nninfluenced other teeth
developing at the same time. A strictly local cause may be
looked for with much greater chance of success. The
prolonged existence of gum-boil in connection with a tem-
pomary tooth may produce the result, or the encroachment of
a neighbouring tooth upon the formative pulp may lead to
the formation of a dwarfed and misshapen tooth (Fig. 27).

Perhaps we shall not find a more fitting place for con-
sidering those deviations from the normal forms of the teeth
which are consequent upon interrupted development of the
dental tissues. The crowns of the affected teeth, instead of
presenting the beantiful smooth and glossy surface charac-
teristic of finely-developed enamel, are disfigured by the pre-
sence of an irregularly grooved or pitted surface, accompanied
by a considerable diminution in size. The incisors are
commonly very thin and compressed, while the canines and
the cusps of the molars are terminated by sharp points. By
the aid of the microscope we may learn that the tissues are
not only deficient in quantity, but that they are defective
also in quality. Neither the enamel nor dentine is perfectly
developed ; the elements ofthe former are imperfectly com-
Lined, hence the tissue is porous, yellow, opaque, and very

214 A SYSTEM .OF DENTAL SURGERY.

of the crowns of the central incisors may be altogether im-
perfect, while a small portion of the lateral teeth will be well
formed, In the canine, the good portion of the crown will
be larger than the bad, and the second molar will be
altogether without any visible defect, Tracing the teeth
from front to back, we may see that the defect crops out
at a definite point, and that there will be in this respect «
strict correspondence in the two sides of the mouth.

‘The defect of stracture will be limited to such portions of
the several teeth as were undergoing development at the
same time, and consequently under the same constitutional
state. If, for instance, we find the one-half of the crowns
of the central incisors and first permanent molars imperfect,
one-third of the lateral teeth will be in a corresponding con~
dition, while the defect will not extend over more than a
fourth of the crowns of the canines. Again, if the extent
of the defect be limited to the cutting edges of the central
incigors, the lateral incisors may be free from imperfections.

As yet, those cases only have been described in which the
dental tissue exhibits over a certain portion of a tooth ob-
vious signs of a defective organisation, But we sometimes
find teeth which are marked by grooves and ridges, very
regularly disposed. The grooves are the result of ‘imperfect,
and the ridges of perfect development of the enamel and
subjacent dentine, These transverse markings, resulting
from alternations in the developmental process, find an exact _
parallel in the striw produced by similar causes on the nails,
Owing to the more rapid and persistent growth of the latter,
it is often possible to see the mark left by a severe illness in
the form of a transverse groove across the nail, this being the
result of a temporary cessation of itsdevelopment. Although
in many, it is not in sll cases easy to trace this ridged, or
pitted, or honeycombed condition of the teeth to the presence
of serious indisposition of the patient during the period when
the defective portions of the teeth were being developed; it
can, however, be scarcely doubted that an imperfect onganisa-

216 A SYSTEM OF DENTAL SURGERY,

series are not liable to be affected, though they ray be lost
by exfoliation consequent on stomatitis and periostitis. On
the other hand, the occurrence of specific affections of the
mouth soon after birth may be readily supposed to affect
the permanent teeth which are at this time developing, and
certain characters are enumerated as indicative of such in-
terference with the growing teeth.

The incisors and canines are of small size, and peg-shaped ;
the crown is notched, the notch being in the main a concavity
from the one corner to the other, though there may be
secondary notches in this general concavity.

Pig, 105, C1)
A.

B

O-O-Oor

The existence of a “circumferential notch” encircling
the canines near their points, is also noted by Mr,
Hutchinson, but is by him attributed to a “ ciroumferential
wearing ” of the one tooth on its opponent. This explanation
is inadmissible ; the groove running round the crown of the
canine near its apex is simply the mark of a temporary arrest
of development (see page 214), and is precisely analogous to
the similar groove across a nail which sometimes is seen
after a serious illness, It is very possible that the arrest of
development may have been brought about by an attack of
stomatitia, and a similar circumferential groove would
probably be found encireling the incisors at a point lower

(2) “ Syphilitie™ inclaors ; copied from Mr, Hutchinsort's Paper (lec. ei).

218 A SYSTEM OF DENTAL SURGERY,

Hill (*), to ascertain with precision the extent to which cal-
cification has proceeded in the affected teeth at this period of
the child’s development. Unfortunately, the jaws te be
found in museums have almost invariably been macerated,
and the minute calcifying tips of the permanent teeth lost,
so that it is not-easy to acquire definite knowledge on the
subject ; moreover, the statements of various authors differ
in the times assigned to the commencement of calcification
in the permanent teeth,

In Gray's Anatomy (the authority for the periods not being
given) it is stated that calcification in the central incisors
takes place about the sixth or seventh month ; in the laterals
and the canines about the eighth or ninth month of foetal
life, Should these dates be correct, the theory that the
deformity is produced by stomatitis is placed in jeopardy,
seeing that the part most profoundly malformed is the ex-
treme tip of the incisor—that is, the part first formed—the
calcification of which is said to begin at the seventh month;
in other words, at least two months before the probable
occurrence of a specific stomatitis,

On the other hand, Kolliker(*), without giving definite
dates for the commencement of calcification, implies that it
is somewhat later; and Robin and Magitot (*) state that the
follicles of the permanent incisors and canines first appear
within « range of about fifteen days before or after birth, but
they do not say at what time caleification first commences
on the papilla.

One point, however, appears to have been overlooked by
Mr. Hutchinson, namely that the calcification of the tetnpo-
tary teeth is not so far advanced at the time of birth but
that we may expect them to be influenced by the oocarrence
of disturbing causes during the first month or two after birth.
On reference to Fig, 1 (page 6), it will be seen that only the

() Monthly Review of Dental Sctenea. June, 1472.

(2) Kalliker, Manual of Human Microscopic Anatomy, 1860,

(®) Robin et Magitot, Mémoire sur le genése et developpement des Follleules
Dentalres, 1860,

220 A SYSTEM OF DENTAL SURGERY.

‘The case from which the following illustration (Fig. 106)
is taken occurred in my own practice. A large nodule or
ousp projected from the neck of the tooth. It was perfectly
covered by the gum, so that its presence could not be sus-
pected, until, in passing the forceps up towards the neck of
the tooth, some unusual obstruction was felt.

’
Fig. 108, (2) Fig. 107. (2)

Supplemental cusps only have been spoken of, but we
sometimes see a tolerably perfect little tooth growing out, as
it were, from the side of another tooth. In Fig, 107 a small
twoth is shown connected with the distal side of the second
or third lower molar below the termination of the enamel.

Mr. Harrison placed at my disposal a molar, from the
lateral surface of the crown of which a minute but well-
formed supplemental tooth projects at a right angle.

Under the head of irregularities in the forms of teeth,
several physical peculiarities have yet to be considered, for
describing which it is difficult to find a more fitting place,

‘Those deviations from the normal number and arrange-
ment of the roots of teeth which influence dental operations,
will be treated of in connection with the operations them-
selves, But as the discussion of the subject of irregularities
of form generally would include such as are manifested in
the roots, as well as those which oceur in the crowns of the

(@) A permanent tooth, with a large nodule of enamel attached to the neck
below the point covered by the eden of the gum.
(®) A lower molar, with a small tooth projecting from ite side.

222 A SYSTEM OF DENTAL SURGERY.

to an ancestral type, there can be no doubt that the explana-~
tion of the occurrence of this abnormality in the fangs of the
bicuspids is to be found by a reference to the teachings of
comparative anatomy.

The bicuspids of the lower jaw, although their fangs may
be bent, but seldom terminate by two roots.

Among the molar teeth, the first permanent molars will be
found to be the most constant, and the third the least con-
stant, in the number, shape, and position of their roots. Three
may be reganied as the typical number of the roots of the
upper molar, and two as that of the lower molar teeth.
Now, although we find occasional exceptions to these rules in
the first permanent molars, they are very unusual. In the

Pig, 108. (9)

two teeth from the upper jaw which are figured, the three
roots are, by the confluence of two, reduced to two in mum-
ber; and I have seen one or two cases in which the two mots
of « first permanent lower molar were united so as to form
one conical mass.

On the other hand, in the place of a diminished, we may
have irregularity from an increased number of roots. The
lower molar may have three, or even four, roots, and the cor-
responding upper teeth four in the place of three roots, But,

(3) Shown two first permanent molars of the wpper Jaw. In the (eoth to
the right the two labial roots are united and reduced to ome, and In the left

hand figure the posterior labia and the palatal roots are walled $0 ax to form
ane broad and flattened root.

224 A SYSTEM OF DENTAL SURGERY.

their three fangs distinct(*), although, on looking over a large
number of skulls in various museums, I have found excep-
tions to this rule.

‘The great variability in the size and shape of the wisdom
tooth in civilized races, its occasional absence, and the irre-
gularity of the period at which it is erupted, may, when
contrasted with its large size and regular form in the lowest
savage races, be taken as an indication that the wisdom
tooth is slowly disappearing, and that there is a strong
probability that in future generations it will be normally
absent, Moreover, comparative anatomy lends a certain sup-

port to this conjecture, inasmuch as in the anthropomorphous
apes, where it is a proportionately larger tooth, it is erupted
at an earlier period, coming into place before the canine
tooth. Qn this matter Professor Huxley (*) says: “In the
Gibbons, the permanent canine emerges contemporaneously
with, or before, the last molar; but in the other anthropo-
morpha the last permanent canine is cut, ordinarily, only
after the appearance of the last molar.”

Tn connection with irregularities in the number and form
of the roots of the teeth, the unusual deviations in the
size may be mentioned, The corresponding teeth will vary
slightly in almost every instance where a comparison can be
made; but in a few cases the departure from the normal
length will be greatly in excess of what may be regarded as

O} Owen. Anatomy of Vertebrates, vol. lL. p. 320.
( Huxley. Anatomy of Vertebrate Animals, p. 486,

226 A SYSTEM OF DENTAL SURGERY.
sarily sacrificed, I have seen specimens in which the crown
of an incisor has been placed at a right angle with the root,
‘The instances of dilaceration which have fallen within my
own notice have been limited to incisors and bieuspid teeth.
‘Thore is no reason why the molar teeth should not be subject
to the deformity equally with the front tecth, excepting that
the situation in the mouth of the former renders them less
liable to accidental disturbance than the front teeth.
To the naked eye the displacement of the crown is suffi-
ciently apparent, but the coincident derangement of the tissues
can be seen only by the aid of the microscope, If, however,

Fig. 112, (1)

has

qwe tako a thin section from a tooth the crown of which has
been moved on its pulp during the period of calcification, we
shall find the dentinal tubes greatly bent or disturbed in
their course at the point of injury. The relations of the
enamel, the dentine, and of the cementum, are also interfered
with at a corresponding point.

There is one other deviation from the normal condition
which, as it affects the forms of individual teeth, must be
included under the present heading—viz., the union or gemi=
nation of contiguous teeth, This subject was entered upon

(1) Shows three instances of dilnceration. The figure to the left fs taken
from an tipper bicuspid, the crown of which had been moved on the pulp.
The contre figure i that of a central incisor removed from a bay In conse
quence of the eutting edge of the tooth being directed towards the tongue.
he dey has rexel¥ed @ blow upon the mouth. ‘The right-hand Sgure shows

appearance presented by a section of an incisor elmilarly deformed to
Dis penelope tithosgh us gota Sar Gos ie ea

230 A BYSTEM OF DENTAL SURGERY.

of the wisdom tooth is upon a higher level than that of the
second molar; but the difference is not greater than is often
seen to exist between the corresponding teeth in the mouths
of patients.

Tn examining a series of connate permanent tooth, it will
be found that where the crowns are involved, the union is
effected by a continuity both of the dentine and of the
enamel, the connecting portions of the tissues being common
to the two teeth, and by dentine and cementum, or by
cementum only, where the union is limited to the roots.

In the one case, both the dentinal and enamel pulps were
united, and thus produced a geminated tooth; in the other
case, the union must have been effected long after the crowns
of the teeth were developed, and at the time the roots
were forming. In cases of union occurring under the latter
circumstances, the medium of connection may be limited to
the cementum, much in the same manner as we see the con-
tiguous roots of a tooth bound together by the interposition
of cementum. Those examples in which, by the large deve-
lopment of cementum consequent upon disease, two con-
tiguous teeth become united, must not be classed with such
as may be regarded as cases of congenital union. The
cementum may be the uniting medium in either case; but
in the one the cementum will not exceed the normal amount,
in the other it will exist in excess, and constitute a disease,

Under the head of irregularity of the permanent teeth, ong
subject only remains for consideration—namely, Irregularity
in the period of their eruption; the premature or the retarded
appearance of members of the permanent set of teeth, and the
deviations from the natural order of eruption,

The molar teeth will vary in different individuals as to the
time of their eruption, but the amount of variation is seldom
suflicient in extent fairly to come under the head of pre-
mature eruption. But in those teeth which succeed to mem-
bers of the deciduous set, a considerable amount of devia-
tion in antecedence of the normal period may sometimes

232 A SYSTEM OF DENTAL SURGERY,

manent tecth would have been injured, and have appeared
prematurely throngh an inflamed gum,

Tn a practical point of view, the accelerated is leas inte-
resting than the retarded sruption of teeth. The premature
appearance of a tooth cannot be prevented, and when in
sight, the mischief it may occasion can be ascertained; but
when the eruption of a tooth is delayed, there is great diffi-
culty in learning its relations in respect to the other teoth,
its own conditions as regards size, shape, and stage of
development, and the amount of influence it may exert
either in the production or in the maintenance of neuralgie

pains.

‘The irregularities of position, and the results to which
they lead, have been already described; hence, in the present
section the inquiry may be limited tothe question of retarded
eruption of teeth which are not irregalarly placed dering
the period of growth; in other words, to teeth irregular only
in respect to the period of their eruption. It is by no means
uncommon. to find that certain members of the permanent do
not appear at the usual time, and even after the lapse of
some few years are still absent from the usual position ; and
it is not, porhaps, until long after their presence has been
called in question that they penetrate the gum. In a case
which has been described at page 158, the right central
incisor of the upper jaw appeared at the age of thirteen, that
is, six years ofter the fellow tooth, In o second case, an
upper canine pierced the gum at the age of two-and-thirty ;
and ina third, « similar tooth cut the gum after the patient
had passed the age of forty. Again, many cases have occur-
red in which teeth have been cut at a very advanced age.
The recognition of this wide range in respect to the time
of the occurrence of a process which is coincident with a
known epoch of general growth of the body, suggests an
inquiry into the condition of the teeth themselves at the
period of eruption, and also into the nature of the process of
eruption in these exceptional cases. In reference to the first

234 A SYSTEM OF DENTAL SURGERY.

defects does not prove that the production of the tooth was
delayed. Indeed, there is a want of decisive evidence in
support of the opinion that the actual development of the
teeth is delayed much beyond the usual period, although the
numerous eases of late eruption would at first sight favour
- the supposition. The period of eruption does not, however,
in these exceptional cases, bear any necessary relation with tho
time at which the development of the teeth was completed.
Tn some examples, the obstructing cause is sufficiently ob-

Fig. U8. 0)

vious, but in others, we fail to see why the tooth did not
take its place in the series at the usual time. In the case of
a female, the upper canine was absent, a space being left
between the first bicuspid and lateral incisor. At the age of
forty-five, the missing tooth slowly protruded itself.” Now,
in this instance the way was not prepared by the loss of a
tooth, neither were the gums receding; hence we are at a
loss to see why the eruption of the tooth was delayed, or
why it appeared at that age rather than at any other. The

@) Showing the first bisnspld retarded tn ite eruption by the presenor of
& tamporary tooth. The bicuspid is « perfectly well-developed tooth, but
the cuter wall of the alveolus is ateent. ‘The towporary tooth is marked by
the asterisk.

236 ‘A SYSTEM OF DENTAL SUROERY.

sive lengthening of root. The completed tooth has to change
its place without itself undergoing any change. The bone
which stands in its way must be absorbed, and the lower
portion of the socket from which the root of the tooth moves,
must be contracted by the deposition of bone. Indeed, in
the absence of a better hypothesis, it may be assumed that
the gradual contraction of the socket is the means nsed by
nature for bringing teeth to the surface when the process of
eruption has been delayed beyond the normal period, In
the one case, the movement is effected by the development
of bone within the alveolus; in the other, by the progressive
development and consequent lengthening of the tooth.

Tn many cases, however, the retarded teeth become ex-
posed to view by the absorption of the superjacent gum, the
teeth themselves being perfectly stationary. The pressure
on the gum caused by artificial teeth will not uncommonly
cause its absorption and the exposure of a hidden tooth,
and this tooth, once having been bared, will often descend
to a lower level than that which it had previously occupied.
The manner in which this takes place, and the effect produced,
may be seen on referring to the figures illustrating irre-
gularities in the position of the permanent teeth.

‘The cause which most commonly retards the cutting of a
permanent tooth is strictly a mechanical one. The space
which should afford a place for the missing tooth is already
oocupied either by a persistent deciduous tooth, or by the
crowding together of the contiguous permanent teeth. Under
these circumstances, the normal occupant of the spot is
either held back, as in Fig. 117, &., or takes some ex-
tremely irregular position, In the accompanying figure, the
second bicuspids of the upper jaw were retarded by the
presence of the temporary rnolars, The deciduous tooth on
the one side of the mouth had lost all its roots, and there
appears no reason why the bicuspid did not take its place at
the usual time ; but on the other side the temporary molar
has retained the greater portion of its palatal root, and was

288 A SYSTEM OF DENTAL SURGERY,

root on the part of the deciduous tooth, would have enabled
it to hold possession of the position, to the exclusion of the
second bicuspid, producing, perhaps, a similar result to that
shown in Vig. 117. But if we resolve upon removing deci-
duons teeth in all cases when the normal period arrives for
their replacement, the practice will now and then lead to
disappointment ; we may remove a temporary tooth which
is destitute of a successor, as shown in Fig. 98, or we may
make way for an imperfect tooth, inferior in every respect to
its predecessor, These exceptional cases are, however, of such
rare occurrence, that although they should not be entirely
disregarded, their influence upon our practice should be but
comparatively slight. Then, again, the temporary tooth may
not only retard the permanent tooth, but it may also lie ata
lower level than the adjoining teeth, and consequently if
allowed to remain, render little or no service in mastication,
as in Fig, 117,

Regarding, then, the persistence of temporary teeth as a
cause which commonly operates unfavourably, not only by
retarding the eruption of permanent teeth, but also by pro-
ducing irregularities in the dental series, their removal must,
as a general rule, be attended with advantage,

The wisdom tooth is sometimes prevented from assuming
its proper position by being situated immediately beneath
the second molar. Very recently a second upper molar was
extracted at the Dental Hospital, between the fangs of which
was a hemispherical cup of bone with a perfectly smooth
surface, which was at first sight imagined to be a portion of
the floor of the antrum. On examining the mouth, however,
the crown of the wisdom tooth was found to occupy the
space whence the tooth had boon extracted, so that the cup
of bone proved to be » portion of the bony cell in which it
had lain buried.

Whether the wisdom tooth will now descend into the
alveolar line (the patient being over thirty years of age)
remains to be seen.

=

TEETHING, 239

‘The consecutive changes in the teeth and jaws, which in
the healthy subject keep pace with the general growth of
the body, have to some extent been traced; and the results
whieh are entailed when the development of those parts is
interfered with have been pointed out; and this brings us
to the end of one division of our subject. ‘The section may

Fig. 121.

be concluded by the introduction of the preceding figure
(Pig. 121). The specimen delineated is, I think, unique; a

hippopotamus’s tusk, the cutting edge of which, from want
of antagonism, and the consequent absence of wearing away,

gradually advanced until it entered the pulp cavity, and thus

put an end to the further development of the tooth.

[ 20 ]

THE DENTAL TISSUES,

List of works referred to in the section relating to the
Dental Tissues -— (")

1. Koéutren.—“ Handbuch der Gewebelehre.” Ste Auflage.
1867.

2. WaLpever.—* Stricker’s Handbook of Human and Com-
parative Histology.” Sydenham Society Translation.
1870.

- Bown, F.—" Untersuchungen iiber dice Zabnpolpa.”
Archiv flir Mikros. Anat. Vol. iv, 1868.

. Heerz.—* Untersuchungen tiber den feineren Bau der

Zihne.” Virchow Archiv, 1866.

Beare, Da. L. S—‘On the Structure of the Simple
Tissues,” 1861; and, “ Lectures on the Structure and
Formation of the Teeth." (Reprint in “ Archives of
Dentistry,” vol. i.)

3, Horre-Serien,—“ Virchow's Archiv." Bd. vy. and bd,
xxiv.

Tomes, J.—* Transactions of the Royal Society.” 1850.

Satres, 8. J.—* Archives of Dentistry.” 1865,

Neumany.— Beitriige zur Kentniss des normalen Zahn-
und Knochengewebes.” 1863.

10. Ronis et Maarrot.— Sur la gendse et développement des

Follicules dentaires.” “Journal de la Physiologie.”
1860 and 1861.

a

San

(1) As reptated reference sill have to be made @ the views held by various
authuritien, it has wemed advlaable, in order to avold nevless repetition of the
titles of hooks, to give a list of works referred to tn « collected form,

242 A SYSTEM OF DENTAL SURGERY.

from which it was altogether protected prior to its eruption.
The teeth may, and very commonly do, present all the general
characters of well-developed ongans, and yet when examined
by the aid of the microscope, exhibit unmistakeable signs of
defective organization, rendering them highly susceptible to
disease when placed within the influence of the necessary
conditions.

On the other hand, those defects of structure which render
the tooth liable to early and rapid destruction, may be appa~
rent to the naked eye so soon as the crown of the tooth
becomes visible.

Before, however, the characteristics of the diseases, and of
their predisposing and exciting causes, are entered upon, it
will be desirable to give a short sketch of the histological
characters of the tissues in which they are situated. It will
not be necessary to enter at any great length, either into the
development or the structure of the tissues of the tecth, in a
work on dental surgery, though, inasmuch as an under~
standing of pathological conditions requires an accurate
knowledge of the characters which appertain to the normal
structure, it is desirable to give a brief account of the various
dental tissues in this place,

A tooth is composed of enamel, cementum, dentine, and
dental pulp.

The relative position of the several structures which col-
lectively form a tooth may be best seen by dividing one of
the front teeth longitudinally. Commencing the examination
from the surface, we shall find the crown is encrusted by a
layer of enamel, which is comparatively thick over the pro-
minent parts of the masticating surface, but becomes thinner
on the sides, and is eventually lost on the neck of the tooth.
At its terminal edge, the enamel is slightly overlapped by the
cementum, which holds to the fang and neck of the tooth
similar relations, in respect of position, to that which the
enamel does to the crown.

The cementum attains its maximum amount of thickness

244 A SYSTEM OF DENTAL SURGERY.

centre of which is found a cavity, bearing a general resem~
blance in form to that presented by the tooth itself. In the
central cavity the pulp of the tooth is contained. In the
roots of the teeth the cavity is small, and the pulp is at this
point principally composed of nerves and bloodyessels ; but
as the neck of the tooth is approached, the cavity attains its
maximum size, and afterwards diminishes as it assumes the
form presented by the outer surface of the tooth. ‘The pulp
cavity communicates with the surface of the tooth by a small
opening situated at the end of the root, and throngh this
opening the nerves and vessels enter. Ina few cases, canals
for the passage of vessels may be found entering the pulp
cavity through the side of the tooth, midway between the
neck and the apex of the root, while in a few others they
enter by several minute canals; but these must be regarded
as exceptional cases,

The Enamel.—tn a fully formed tooth the enamel contains
only from one to three per cent. of organic matter, though in
the opaque chalky-loolsing enamel of a tooth not yet com-
pleted the organic constituents amount to as much as fifteen
per cent. ‘This organic matter, said not to belong to the class
of gelatinous tissues, but to be closely similar to epithelium
in its chemical relations, is stated not to exist between, but
in the substance of the prisms (Hoppe-Seyler). The enamel
is made up of parallel fibres which lie in close contact with
one another, no intervening substance being demonstrable.
From their close mutual apposition they assume forms more
or less nearly approaching that of hexagonal prisms; 80 that
on transverse section a mosaic-like pattern of hexagonal areas
is seen; but some fibres will be found to be nearly square,
others nearly circular.

‘The inner ends of tho fibres rest upon and are united to
the surface of the dentine, while the outer extremities form
the surface of the crown of the tooth.

Tn tracing the course of the fibres, it will be found that
those situated on the prominent parts of the crown take a

246 A SYSTEM OF DENTAL SURGERY,

although they may be continuous over a considerable number
of fibres in certain parts of the preparation.

If sections taken from a number of teeth be examined, it
will be found that the strie are much more strongly marked
in some than in others, and that they are most strongly
pronounced in those parts of the specimens which, when seen
by transmitted light, have a brown colour, This, which is an
exceptional condition, and limited in extent in well-formed
teeth, will be found to pervade the whole of the enamel in
the teeth of certain nnhealthy subjects. The teeth, in place
of the brilliant white and almost translucent appearance, have
a dull opaque yellow colour. Enamel having this defect
presents structural characters which are much more strongly
marked than obtain in that which is more perfectly deve-
loped. The cause of this appearance of strintion is still a
doubtful question, none of the very various explanations
which have been offered proving wholly satisfactory.

It is explained by Waldeyer by a reference to the decussa-
tion of the prisms ; seeing that the prisms are united without
intermediate substance, and that contiguous layers do not
pass always in parallel directions, it follows as a necessary
consequence that the outlines of each enamel prism cannot
be perfectly straight and regular, and it is to this cause that
he ascribes the varicosities; while Hertz (4) accounts for
their presence by the assumption of intermittent calcification
of the prism.

‘The distinctness of the transverse striation can be greatly
increased by the use of dilute hydrochloric acid. The manner
of procedure is as follows: after reducing a section of enamel
sufficiently thin, place it for two or three seconds in the acid
(one part of hydrochloric acid to twelve parts of water),
Wash the section and examine it in water under a j objec-
tive, It will now be seen that the acid has acted upon the
different portions of the enamel fibres with varying effect,
attacking the central portions of the fibres with the greatest
vigour,

250 A SYSTEM OF DENTAL SURGERY.

are connected by one extremity with the cells of the stratum
intermedium, by the other with the surface of the deve-
loping enamel.

Such a section cannot well be made, on account of the
great hardness of the enamel; but these relations may be
well seen on sections of the tooth snes of young animals,
which have been hardened in chromic acid, and subsequently,
decalcified and cut, But most instructive preparations may
be made, by which the process of enamel development may be
traced, in fresh tooth sacs.

If, for example, a dental sac which has been removed from
the fortal jaw be carefully opened, it will be found that a
gelatinous semifluid substance is interposed between the inner
walls of the sac and the coronal surface of the young tooth,
Cylindrical columns, having near the extremity which lies
farthest from the formed enamel a large oval nucleus, together
with a large number of spherical or ovoid nucleated cells, will
be seen to make up this gelatinous matter,

The long cells are the formative cells or internal epithelium
of the enamel organ; and if the enamel itself be examined,
similar columns will be found adherent to its surface. Their
presence may also be demonstrated in the following manner.
After dividing the dental sac, and turning it back so as to
expose the forming tooth, place the preparation in a watch-
glass containing dilute hydrochloric acid. In a short time we
shall see & membrane-like substance detach itself from the
surface of the enamel, which, with a little careful manipu-
lation, may be removed to the microscope for examination,
and it will then be seen that one side of the membrane is
composed of columns of the enamel pulp, and the other of
decalcified enamel fibres, and that the columns and fibres are
joined end to end.

The columns are, however, very readily detached from the
peripheral ends of the enamel fibres, which are at this point
laterally united, presenting the appearance of a membrane
which not uncommonly assumes a deep brown colour, contrast~

252 © A SYSTEM OF DENTAL SURGERY. ~*

But in a series of investigations made in reference to the
elucidation of this point, the results did not coincide with
those recorded by Mr. Huxley (11), and subsequently by M.
Lent (16), The manner of proceeding was similar to that
pursned by the authors cited, which is described in the pre-
ceding page. No difficulty attended the production of the
membrane, but the columns of the enamel pulp were found
at many points adherent, and their continuity with the fibres
could in some cases be distinotly traced, as shown in the pre-
ceding figure (Fig. 125), Again, the detached columns ad-
hered in bundles to each other by the ends which approached
the enamel], and many of the columns were terminated by

Pig. 126.

delicate processes, which must at the time of separation have
been withdrawn from the interior of the partially calcified
fibres, and consequently must have passed through the mem-
brane which is supposed to separate the two tissues,
Immediately above the point from which the process starts,
each column has, when separated from its fellows, a slight
circumferential dilatation, as though the cylinder had been
everted at the edge when the separation was effected. On
closer examination, the columns appear to be made up of
tubular membranous sheaths, within which, at the end most
distant from the enamel, are large oval nuclei, the remainder
of the cell being filled with contents more or less granular.
At the end directed towards the enamel the investing mem-
‘rane appears to be absent, and it is often possible to see with

254 A SYSTEM OF DENTAL SURGERY,

are these. The columns of the enamel organ (enamel ceils,
internal epithelium of the enamel organ) are subservient te
the development of the enamel prisms, into which they by
calcification become actually converted. This conversion
goes on in the following method: the proximal end of the
cell undergoes some chemical change preparatory to calcifi-
cation, and is subsequently calcified; but this calcification
does not go on uniformly throughout its whole thickness, but
proceeds from its periphery towards its interior, the central
portion of the cell thus being calcified later than the external
portion which lies at the same level. At the same time that
calcification is proceeding inwards in each individual cell it has
united the contiguous cells to each other. At this point,
namely, at the extreme margin of calcification, the columns
(cells) vory readily separate from the calcified fibres, leaving
the surface of the latter having the appearance of a perforated
membrane; the perforations being due to the withdrawal of
the central uncalcified portions of the cells, which constitute
the processes of the enamel cells figured on a preceding page.
The calcification of the central portions of the enamel
fibres does not, as has been already stated, keep pace with
that of their exteriors; nor even in fully completed enamel
does it attain to precisely the same characters, or, as was
mentioned on page 246, the action of acids is more rapid on
the axial portion of the adult fibres than on their exteriors,
50 that by its use that appearance of fenestration which is
seen to normally exist in young developing enamel may be
restored. In the progress of calcification the nuclei of the
enamel cells disappear, and it is probable, as is believed by
Waldeyer (2), that the internal epithelium of the enamel is
recruited by the cells of the stratum intermedium as it
becomes itself used up by advancing caleification converting
it into enamel fibres,
But, although the balance of evidence seems to be in
of this view, it is not assented to by all observers.
Phas Wolliker (1) imagines that the enamel cells do not

256 A SYSTEM OF DENTAL SURGERY,

from the eoherent part? The solution of this question is
probably to be found in the chemical nature of the parts con~
cerned. It is probable that this, which intervenes between
the fully calcified and the uncalcified parts, has undergone
some chemical change preparatory to, or coincident with, the
first deposition of lime salts, by which it is rendered more
resistant to the action of reagents than that which lies on
either side of it, What the nature of this change may be, is
to some extent conjectural, though the researches of Professor
Harting, to be mentioned on a succeeding page (page 282),
throw much light on the question.

In fine, then, this membrane is to be regarded as the
youngest Inyer of enamel, as yet but slightly impregnated
with mineral constituents; and this view has lately received
full confirmation at the hands of Waldeyer (2).

Although the fibres of the enamel have attained their full
length some time before the tooth is cut, the development of
the tissue can scarcely be regarded os matured until after that
period; for at the time a tooth passes through the gum, the
enamel is comparatively soft and fragile, and it is only after
the lapse of some months, or even years, that it attains its
full degree of hardness.

Prior to the surface suffering any wear, a membrane can be
separated from the surface of the enamel by the employment
of anacid, Mr, Nasmyth was the first to draw attention to
this fact, and he described the membrane so separated as the
persistent dental capsule,

Mr. Husley considers it to be identical with the membrana
preformativa, that is to say, the membrane intervening be-
tween the cuamel cells and the enamel fibres; which must be
regarded as a mere artificial product, and as having no real
existence.

Waldeyer (2), who recognises the artificial nature of the
so-called “ membrana preformativa,” regards this Nasmyth’s
amembrane, or cuticula dentis, as formed from the external
epithelium of the enamel organ, which, after the disappearance

258 A SYSTEM OF DENTAL SURGERY.

by most recent writers, and this view as to its nature ignored,
a series of observations on a large number of specimens have
recently been made, which are in the fullest degree eon-
firmatory of the conclusions stated in the first edition of this
book. It would here be out of place to enter at any length
into the facts on which this statement is based, the more so
as they are to be found elsewhere(‘); butit may be mentioned
that it often seems to be continuous, not with the fully
formed cementum which forms a thin structureless layer round.
the neck of the tooth, but with something external to this.
And itis a very significant fact, that this membrane presents
all the characters of tissue prepared for calcification, which
we already know undergoes some chemical change preparatory”
to the actual deposition of salts, conferring upon it a remark-
able power of resisting reagents (see pages 256 and 282).

According to these researches, then, Nasmyth’s membrane
is to be regarded as cementum either imperfectly spp or
not yet calcified at all.

Apart, however, from this apparently Seance layer
described by Mr. Nasmyth, we may sometimes observe a
diminution in the fibrous character of the enamel at the ter~
minations of the fibres on the surface of the tooth, and also
at the terminal edge of the enamel on the neck of the tooth.
Tn each of these situations appearances may be found which
suggest'the idea that a fluid blastema became calcified, and
that the fibres had in the proceas become fused and more or
less lost in the mass so formed. Indeed, in the situation last
montioned, lumination of an indistinct charseter may take
the place of fibres; or both the laminated and fibrous ar-
rangement may be replaced by a structure exhibiting little
arrangement of parts. In well-developed teeth, however, this
deviation from the usual character of enamel is limited to the
terminal edge of the tissue.

The preceding observations for the most part relate to the

ae) ©. 8. Tomes. On the Nature of Nowmyth’s Membranes, Quarterly Journal
of Microscopical Selence, 1872,

THE DENTAL TISSUES. 259

enamel when perfectly formed. We have now to direct our
attention to defects in the structural character of the tissue,
Faulty organization very frequently leads indirectly to the
development of disease; it is therefore desirable that the
conditions which characterise the imperfections should be
Teognised, We may divide them into defects in the quantity
and ia the quality of the tissue.

The Dentine.—if a median longitudinal section of a tooth
be made, it will be seen that the surface of the central cavity
is everywhere pierced by an infinite number of extremely
minute openings. They are the orifices of the dentinal tubes,
the parietes of which, together with the matrix in which they
Nie, make up the walls of the pulp-cavity. The tubes take a
tadiste course from the central axis formed by the pulp-
cavity towards the surface of the tooth. In the crown, and
also to some extent, though in a less degree, in the root, in
addition to numerous secondary minute undulations, the
tubes describe several bold curves, which are commonly de-
Seribed as resembling the italic letter /. ‘Those situate in the
crown differ in some respects from those which occupy the
foot of the tooth. In each situation the branches which are
given off are very numerous, but in the crown there are com-
paratively few, until the tubes approach the surface encrusted
hy the enamel; while in the root branches are given off from
the tubes throughout the whole of their course, more ubun-
Aantly, however, as they near the surface of the dentine,
The dentinal tubes, by the anastomosis of their branches,
become connected with each other, and also establish rela-
tions with the external dental tissues; in the crown of the
tooth they terminate by forming loops, or become too minute
16 be traced, or pass into the enamel and become lost. In
teeth the dentine of which is imperfectly developed, the
terminal branches are lost amonz, or end in, the minnte
Gavities which aleyond in the layers at or near the peripheral
anrface of the dentine. In tho neck and root of the tooth,
the branches of the tubes anastornoge freely, and are lost

a . =

260 A SYSTEM OF DENTAL SURGERY,

near the surface of the tissue; near the neck they stop short
‘of the cementum, but towards the end of the root they not
uncommonly pass into the cementum, and connect them-
selves with the lacunm. By the extension of the dentinal
tubes into the enamel (*) and into the cementum, a connection
is formed more intimate than mere superposition and ad-
hesion of the one to the other would have established, and
the more so as the three tissues are developed from distinct
formative elements,

In a section which has been dried the tubes become yery
distinct, and it is often possible, by adding a coloured fluid
to the preparation whilst it is under the microscope, to ob-
serve its gradual passage into the tubes.

With respect to the contents of the tubes in the fresh state,
it was formerly supposed that they contained a clear fluid, and
were hence not casy to observe in a fresh wet preparation.

But the view that the eanals are hollow tubes conveying @
nutrient fluid has, for many years, been almost universally
abandoned; M. Killiker (1) and others, who were at first dis-
posed to call in question the existence of solid contents
in the tubes, having for some time past given expression
to their conviction that they do exist, and may readily be
dlemonstrated. (*)

Tf a portion of enamel be accidentally broken from the
crown of a tooth, so that the dentine becomes exposed, the

(@) In the marsupial animals the wniforia extension of the dentinal tubes,
hol ouly tuto but through the greater portion of the whale (hickness of that
Uissne, forms a character sofliclently marked to distinguisty the tects of that
from any other order of mammels,—On the Structare of tbo Dental Tissues of
the Marsuplata, Philosophical ‘Trammetions, Part [1., 1849. It may be inci-
dentally mentioned bere that this penetration ef Ue enamel by the dentinal
tubes hes been doubted by Waldeycr and Herts; nothing can pomibly be mere
clear than thelr passage across the boundary in any well-prepared section, anil
BKilliker remarks (1) that he cannot conceive how Waldeyer and Hertz can deny
its extatence,

(@) Mr, Salter (4) stands almost or quite alone in denying tho existence of
weft Sirile tn the dentinal tubes, but the grounds on which be does eo bein
Tully met by the statersents of vations writers, movably of M, Kallikker, do net
‘call for more than passing notloe here,

aes,

262 A SYSTEM OF DENTAL SURGERY.

or if the exposure be bronght about gmdually by the slow
wotring away of the enamel, that acute sensitiveness which
hos been described is not found to exist. Jn parts which
have been subject to the foregoing conditions, it will,
on examination, be found that the dentinal tubes, the per
pheral extremities of which have been exposed, are more or
less obliterated in some part of their course between the
surface and the pulp-cavity.

And it is possible to destroy the sensitiveness of dentine
by local applications, such as nitrate of silver, chloride of
sino, or arsenious acid, any one of which will have the effect
of rendering perfectly insensible the surface to which it may
be applied, though, unless its action be very prolonged, it will
not penetrate to any great depth. On removing the imme-
diate surface which has been acted on by these escharotics
the dentine beneath will be found to be as sensitive a8 ever;
thus unequivocally showing that their action has not been
upon the pulp, but upon the spot to which they have been
applied.

On reviewing the various circumstances under which den-
tine evinces sensibility, and those under which that sensibility
is lost, it is difficult to avoid the conelusion that the dentinal
tubes are in some way the medium through which sensation
is distributed through tho substance of the tissue. But if the
solo office of the tubes were conveyance of nutrient fluid
derived from the pulp, the difficulty of accounting for the
sensitiveness of the dentine remains, inasmuch as we have no
instance of sensation being manifested in a fluid. We might
endeavour to get out of the difficulty by assuming that the
dentinal tubes are constantly filled by fluid, and that pres-
sure made upon the fluid at the exposed ends of the tubes is
felt by the pulp at their inner extremities, This assumption
floes not, however, account for nearly all the ciroumstances
of the case, failing altogether to explain the greater sensi-
bility of the dentine at one part of the tooth than at another,
or the local effect of escharotics.

264 A SYSTEM OF DENTAL SURGERY.

the decalcification were intimately connected with the matrix
which they traverse.

‘They may be obtained after the tooth has been long mace-
rated so as to putrefy, or has been long boiled in caustic
alkalies so that any soft tissue would have been destroyed
(Kolliker, 1), Their precise chemical nature remains some-
what doubtful. Waldeyer (2) considers them allied to elastic
tissue; but Neumann (9) holds them to be calcified; whilst
Kiilliker (1) compares them to the internal sheaths limiting
old Haversian canals, and to the capsules around osteoblasts
which may sometimes be isolated in cementum.

Deferring for the present the further consideration of the
dentinal sheaths, we pass to their contents. In the interior
of each (in the fresh tooth) lies a soft homogeneous fibril (*),
by no means so indestructible as the sheath. Thus, if the
tooth be allowed to putrefy, or be boiled, or even treated in
the cold with caustic alkalies, it absolutely disappears; and
it is by no means difficult to destroy it by the nse of acids,

If a section be made of a recently extracted tooth in a
direction parallel with the tubes, placed in dilute hydrochlo~
ric acid till it is decalcified, and then torn in a direction
transverse to that of the tubes, the torn edges will be seen to
be fringed with transparent processes of varying length.

In repeating the experiment, it is desirable to place the
decalcified section upon the slide before tearing it, as if it be
lifted from the surface on which it has been torn, some of the
longer fibrils may get folded back upon the body of the
section, and thus become hidden from view.

Where the separation between the torn surfaces has been
but slight, we may often see an unbroken cord stretching
across the interval between the two halves of the dentine.

Tf section be taken in which the tubes are extended into
the enamel, and submitted to the action of acid, it will be
found that after the latter tissue has been dissolved, fibrils

() Kalliker, Watdeyer, Beale, Neumann, Lent, Boll, Santi Sirena (who has
demonstrated! thelr existence in aimphibla and in lizards), Wetsaal, ant oftrer,

266 A SYSTEM OF DENTAL SURGERY.

alkalies, or by pntrefaction, the soft fibril can no longer be
brought into view, although there is no difficulty whatever
in demonstrating the walls of the tubes (Kélliker, 1).

It is not necessary, however, to decalcify dentine in order
to show the fibrils. If a similar section to that already de
scribed be divided with the edge of a knife, many of these

Pig, 129, (1)

delicate organs will be seen, but they are usually broken off
much shorter, many of them scarcely projecting beyond the
orifices of the tubes. Again, if a minute portion of dentine
be cut with a sharp knife from the surface produced by frac-
turing a perfectly fresh tooth, the same appearances will be
seen, but not with the same certainty and distinctness, as in
the previous examples.

Tn order to demonstrate the connection of the fibrils with
the pulp, fine sections should be made with a sharp knife from
the edge of the pulp-cavity, In this manner I obtained the
specimen from which Mr. De Morgan has been kind enough

()) After Boll. In this section the dentinal sheaths project for a «bort

distance beyond the investing matrix, whilst the fibrils are seen issulng from
the termination of the sbeath.

270 A SYSTEM OF DENTAL SURGERY.

ment of dentine, that the one cannot be dealt with without
entering at some length into the other,

Various and irreconcilable opinions are held on this matter
of development, but on the one point, namely, that the
odontoblasts play some very important part in the process,
most authorities are agreed; though Professor Huxley main-
tained that the dentinal pulp had no very direct influence in
the formation of the dentine.

The tooth germ, or papilla dentis, corresponds in form to
the future tooth, or at least to that part of it which is at the
particular time about to be calcified. In its central portion
it is very rich in nerves and also in vessels, the latter forming
a dense plexus immediately beneath the outer layer of spe-
cialised cells, This layer, the membrana eboria, is not pene-
trated by vessels, but consists of a number of cells (odonto-
blasts) arranged perpendicularly on the surface, like an
epithelium, and pressed closely together so as to bein intimate
contact with one another.

‘The internal portions of the pulp consist of a fine fibrons
connective tissue containing great numbers of cells, at tirst
round but later becoming spindle-shaped (Kélliker). With
respect to the outer layers of the papilla, some little difference
of opinion exists; thus*Kulliker holds that it is bounded exter-
nally by a structureless membrane (membrana preformativa),
which, however, plays no part in the development of the den-
tine, while the existence of any membrane in this situation is
denied by many other observers. The explanation given by
Robin and Magitot (10) of this appearance of a membrane in
a place where none exists seems reasonable: they point out
that the gelatinous-looking intercellular substance which
abounds in anearly embryonic pulp projects outwards beyond
the odontoblast layer, so that it appears to form a sort of film
or varnish over these cells, Moreover it is stated by them
that this intercellular nature is more dense ab the periphery
of the pulp than in its interior, so that the resemblance to a
definite limiting membrane is yet further increased, This

272 A SYSTEM OF DENTAL SURGERY.

all, differ so very widely from that held by Kélliker and
Hertz.

On reference to the accompanying figure, or to the excellent
figures given by Boll (8), it will be seen that the odontoblasts
close up to the dentine are in actual contact with one another,
and that there is no room for an intercellular substance.

Big. 18. (1)

‘The preparation was made by breaking the tooth through
the centre immediately after its removal from the mouth, and
cutting with a sharp scalpel a very thin fragment from the
edge of the pulp-cavity, the pulp itself being present at the
time. We have in this example the dentinal cells adherent
to the developing dentine, and the continuity of the cal-
cified and uncalcified tissues clearly shown; and further,
that it is only necessary for the cells to become hardened,
and, a5 it were, fused together, by the reception of the salts

(*) Showing the appearance presented by a seetion cut with o sharp knife
from the edge of the pulp cavity of a tooth recently extmeted. The peri-
parral dentinal cells are retained in thelr natural position as resyocts the
developing dentine,

274 A SYSTEM OF DENTAL SURGERY,

some years ago, on the Dental Tissues of the order Rodentia
(Tomes, 17).

Tt was there stated, speaking of the incisor teeth of rodents,
that “the tubes which proceed from the pulp-eavity near the
base of phe tooth, are, in most cases, perceptibly larger than
those that are sitnated higher up; hence it follows that, as
the latter wore once near the tse of the tooth, the dentinal
tubes undergo # diminution of calibre after their formation.
Tn the teeth of the Sciuridm 1 have found a difference of size
amounting to a third or half between the tubes near the base
and those near the surface in wear.”

‘Then, again, there is the strongly-expressed opinion of Boll,
who states that the odontoblasts have certainly no limiting
membrane, but shade off insensibly from their innermost to
their outermost portion, and it is noticed by Wenzel (15)
that fresh odontoblasts have no membranous investments,
sharply-defined contours being seen only after the use of
re-agents, The recent valuable researches of Professor Hart-
ing (12) serve to throw considerable light on the question.
He appears to have followed in the line of inquiry first
porsued by Mr, Rainie (page 281), and was successful in
making a variety of structural forms by inducing the very
gradual precipitation of lime salts in solutions containing
albumen, or other organic constituents ; and not only did the
lime salts assume a definite structural arrangement, but the
albumen itself became profoundly modified.

Tt was found that on treating one of the “ calcospherites,”
or other forms thus artificially produced, with an acid, though
the lime was entircly removed, the mass retained its form and
structure; it bad, in fact, an organic matrix.

‘This matrix was composed, not of ordinary albumen, but
of a substance closely resembling chitine in its chemical
relations; that is to say, a body exceedingly insoluble and
exceedingly resistant to the action of re-agents.

Now, it is avery remarkable fact, that parts which are just
on the borders of calcification do present this very character,

276 A SYSTEM OF DENTAL SURGERY.

resists the disintegrating action, while the progress of the
disease gradually undoes the work of calcification,

In a certain stage of the disease the tubes appear to have
extromely thick walls, so that but little space is left for an
intertubular connecting tissue, whereas in healthy dentine
the diameter of the tubes is relatively small, and the amount
of intertubular tissue is comparatively large. he different
characters seen in the two cases may perhaps admit of
explanation on the following hypothesis, namely, that the
optical difference between the sheaths and the calcified
matrix is removed by the disease as it effects the work of
decaloifying the tissue; but in- the later stages the greater
power of resistance due to the peculiar chemical characters
of the sheaths lead to their remaining behind, isolated by the
total disintegration of the intervening tissue. It is quite
possible ta conceive that an equal degree of calcification would
afface the differences which were apparent in the soft tissue
prior to its induration, and that a higher or lower degree of
calcification in the part in immediate contact with dentinal
fibrila, would produce such a distinction of parts as that
which characterises the dentinal tubes; and that decalcifi-
cation might, under favourable circumstances, restore an
appearance which had been lost, and obliterate one which
had been produced by calcification.

It has already been pointed out that every odontoblast
communicates by means of its pulp process with the cells
which lie deeper in the pulp. Hence when one odontoblast
is fully used up in the process of calcification, another is ready
to take its place without any breach of continuity, and every
dental fibril may be regarded as the remnant of several con-
tinuous odontoblasts,

In respect to the parenchyma of the dentinal pulp, M.
Killiker speaks of its relation to connective tissue. Now, I
have seen instances, and not uncommonly, in which connec-
tive tissue very similar to the stellate areolar tissue, could
be traced in the substance of the pulp of a forming tooth,

278 A SYSTEM OF DENTAL SURGERY.

Kolliker—these canals would surely have gone with it. I
have made preparations in which several cells, nore or less
elongated in form, have been united end to end, not with
that uniformity, as regards size and position, which charac
terises the members of a linear series of cells in ossifying
temporary cartilage, but still their position and connection
with each other has been sufficiently distinct for positive
recognition, Again, if we examine the peripheral cells in a
pulp in which calcification is about to commence, and com-
pare them with similar cells in a pulp taken from a tooth the
development of which is approaching completion, it will be
seen that in the former they are much smaller in size and
more numerous than in the latter example.

Tt may be asked, whether one element of the pulp more than
another suffers absorption, in order to give space for the
dentinal cells to grow, seeing that after the cap of dentine
has been formed, it limits, by enclosing within its unyielding
caso, the general bulk of the pulp. Such a question can be
answered ouly hypothetically. Tbe pulp contains an infinite
number of nuclei, any or a certain number of which are pro-
bably capable of becoming developed into cells. I believe it
will ultimately be found that a growing cell, when placed in
organized matter which is not itself in « state of develop-
ment, is capable of growth at the expense of such matter,
whatever may be the degree of its organization. It is quite
clear that many of the nuclei, the vessels, and connective
iiterial, which constitute the dentinal pnlp, disappear in
favour of the dentinal cells prior to the calcification of the
latter, though the manner of their disappearance is not fully
made ont.

We have now reached a point when the fimetions of the
dentinal fibrils may be more profitably discussed. The con-
ditions under which sensation is manifested in the dentine
have already been stated, together with those under which
it is lost, and the difficulty felt in accounting for these
phenomena has been pointed out. The recognition of the

280 A SYSTEM OF DENTAL SURGERY,

#0 soon as the instrument reaches the healthy dentine, more
or Jess inconvenience is felt. If, on the other hand, there is
no consolidation of the fibrils, but the pulp is yet living, the
operation of removing the carious part is productive of pain,
even from the commencement; indeed, pressure upon the
surface of the softened tissue gives rise to discomfort. If in
such cases the softened dentine be examined, fibrils may here
and there be found but little altered from their natural
appearance.

‘The greater degree of sensitiveness observable in the den-
tine immediately below the enamel—that is, at the point of
ultimate distribution of the dentinal tubes, and consequently
of their contents—may be fully accounted for on the sup-
position that the latter are organs of sensation, and subject
to the same laws as nerves of sensation, the highest sensi-
bility of which is confined to their terminal branches,

The recognition of the dentinal fibrils must lead to a
modification of the opinions once entertained as regaris the
office of the tubes, namely, that they are for the cirenlation
of fluids only. The presence of soft tissue would not, how=
ever, hinder the slow passage of fluids; there are abundant
instances of nutritional changes taking places at a distance
from vessels, and the fact that calcification of the fibrils goes
on in old age shows clearly that finids can and do pass along
them. For when the fibrils become calcified near the surface
of the dentine, the hardening material must have been
derived from the pulp; at least, when the consolidation has
taken place in the crown of the tooth.

From what has been said, it will be obvious that some
nineertainty must at present rest on the functions of the
dentinal fibrils. That they, or some other soft contents of
the tubes, are the agents by which sensation is carried to the
pulp may be regarded as perfectly established ; and, inasmuch
as no other soft structures have been traced into the tifbes,
the inference is that the fibrils themselves possess this
function. At the sime time, in other parts of the body there

2382 A SYSTEM OF DENTAL SURGERY.

Dlending or fusion of the laminw which come in contact.
The globules themselves are stated to be produced by the
coalescence of smaller masses, which again are made up of
still smaller spherules of similar material; the individuality
of the constituent bodies being ultimately lostin the uniform
fusion of the whole into one compact mass. Globular masses
which at one time havea rongh and mulberry-like appearance,
gradually, by the coalescence and, as it were, fusing down of
the constituent sphernles, become perfectly smooth. The
lamination is supposed to result from the arrangement of the
Tasses in concentric layers, and their subsequent coalescence.
In the discovery of the substitution of the globular for the
crystalline form of these two salts of lime, Mr. Rainie con-
siders he has found an explanation of the process of calcifica-
tion, not only of bone and teeth, but also of the formation of
shells, and his results have been confirmed and extended by
the more recent researches of Professor Harting (12), who
has added to what was already known the important and
significant fact that the albumen itself becomes changed into
a remarkably insoluble and resistant substance, resembling
chitine in its behaviour with re-agents, to which he gives the
name of caleoglobulin.

If the thin edge of the forming cap of dentine be examined,
it will be found to have the appearance of being made up of
globules of varying size, this appearance being in great part
destroyed by treatment with a dilute acid.

‘This condition has been well figured by Messrs, Robin and
Mazitot, and is familiar to all who have watched the develop-
ment of dentine. The calcareous matter is in the first
instance deposited in the matrix in the form of isolated
globules, these increase in size and ultimately coalesce, their
outlines becoming obliterated by the deposition of calcareous
salts in their interstices.

Dentine in the globular form may be found in semi-
detached masses adberent to the surface of the pulp-cavity,
and in perfectly detached spherules in the substance of the

284 A SYSTEM OF DENTAL SURGERY.

made np of globules, and that its irregular form with pro-
cesses running ont from it is referable merely to the fact that
interspaces are left between a number of unyielding spherical
masses.

As has already been mentioned, in the fresh state these
cavities are not empty, but are occupied by formed structural
matrix which has not been as yet calcified. As might be
expected, therefore, the tubes and their contents pass across
the spaces without any interruption in their continuity.
The soft matrix which fills the interglobular space may be

Pig. 134.

slightly stained by prolonged soaking of a fresh tooth in Dr,
Beale's carmine finid, and it differs from the surrounding
matrix which has been impregnated with lime in salts, in
that it is more resistant to the action of acids. Like the
dentinal sheaths, the lining of Haversian canala, or the
encapsuled Iacune of cementum, the soft contents of the
spice may be isolated by maceration of the tooth in acids;
and they present us with another example of that remarkable
chemical transformation which tissue undergoes immediately
before the deposition of lime salts, conferring on the structures

286 A SYSTEM OF DENTAL BURGERY.

transparent, In less perfect teeth the clearness and trans-
parency are replaced by a granular condition of the tissue;
granules, or spherules, or minute globules, although united,
yet retain some traces of their individuality, and among these
the coronal dentinal tubes are lost. This condition, in a
wreater or less degree, is almost uniformly present in the
peripheral portion of the dentine of the root; but its.existence
in the crown of the tooth must be regarded as an indication
of faulty development. In seeking to explain the cause of
this granular condition, Mr. Rainie (if I have read his paper
correctly) would regard the phenomenon as resulting from an
arrest in the coalescence of the dentinal globules; and this is
probably the true explanation of the fact, the so-called
grmular layer, which underlies the cementum in the fangs,
being made up of a great number of minute interglobular
spaces,

Any change in the direction of greater porosity of the
dental tissues, my be regarded as favourable to the de-
struction of teeth, supposing them to be attacked by caries;
and it is only to such forms of departure from the normal
state of the tissne that attention need be directed. Under
ordinary circumstances, the dental tubes diminish slightly
in diameter as they approach the peripheral portion of the
crown of the tooth, but it will in some specimens be seen
that in passing an interglobular space they are considerably
dilated. Again, the terminal coronal branches, instead of
terminating by anastomosis, or by becoming imperceptibly
minute, may pass into small irregular cavities situated near
the surface of the dentine.

Tn a well-developed tooth a certain number of the dentinal
tubes will be seen to pass acroes the line which marks the
junction of the enamel and the dentine, without snfiering
any increase in size, and after proceeding a short distance in
the former tissue, become extremely minute and are lost,
But in teeth of less perfect organization the dentinal tubes,
after passing into the enamel, become suddenly dilated into

283 A SYSTEM OF DENTAL SURGERY.

portions of the enamel. If a seetion be made from a tooth
which presents these external characters, it will be seen that
the surface of the dentine doos not necessarily devjate from
the usual form, but that irregularity in thickness is confined
tw the enamel which lies upon it; at one point the dentine
will support oaly a thin and perhaps imperfectly developed
layer; at anothor, a considerable depth of well-formed
enamel.

Tu teeth which are grooved only while the natural colour
is maintained, it may be found that the deviation from the
normal condition is confined to alternations in the quantity
of the tissue, the natural charicters, as respects the structure
of the enamel, being preserved thronghout, But it is
frequently seen, that in the deeper portions of the grooves
the colour differs from that which obtains in the contiguous
healthy structure. In this, as in the case of the honey-
combed teeth, the abnormal colour indicates a defect in the
structure,

It has been stated, that irregularity in the surface of the
enamel does not imply a corresponding irregularity in the
surface of the dentine; under ordinary circumstances, the
elevations and the depressions on the surface of the crown,
have counterparts on the surface of the subjacent dentine,
differing only in the extent of the elevation. The enamel
attaining its maximum thickness over those parts of the
tooth which are most prominent, consequently breaks the
parallelism of the lines formed by the surfaces of the two
tissues. Although this is the general rule, many cases will
be seen in which the surface of the dentine presents the
usual form, while the enamel, from defect of quantity, fails
to coutribute its share in building up the crown of the tooth;
and the cusps of the molars are conseqriently stunted,

On the other hand, the surface of the dentine may deviate
from the natural conformation; the masticating surfaces of
the molar teeth may be flattened, or the cusps may be thin
and spear-shaped, as though pinched flat, aud the incisors

290 A SYSTEM OF DENTAL SURGERY.

‘The Sbrous character of the enamel, which in the perfect
tissue is lost by the blending or fusion of the sheaths of the
columns of the enamel-pulp in the process of calcification,
may be permanently maintained. Each fibre may to a
considerable extent preserve its individuality, a condition
which gives an opaque appearance to the tissne, and at the

Fig. 134.)

same time greatly impairs its strength. he fibrous cha-
racter may prevail in certain parts of a tooth, or it may
extend through the whole of the enamel. More commonly,
however, it will be seen in lines parallel, not with the
surface of the enamel or of the dentine, but with the line of
growth.

The fusion of the sheaths of the original fibres may,
however, be perfect, while the central portions or contents,

0) Shows a deep fissure in the enemel invisible to the naked eye, ‘The

section was taken from a fire permanent molar of the lower Jaw, removed soon
fuer its eruption,

‘THE DENTAL TISSUES. 291

She Macanpparir speeder ws para Tn the place

of faintly-marked striation, we may find either parallel series
of well-defined rounded masses, as shown in Fig. 124, or a
line of fine granules. Again, minute cavities arranged in
single lines may occupy the centres of the fibres, and in some
fow cases I have seen by the confluence of a series, a tube

‘The foregoing conditions may be sometimes found in
patches amongst the normal tissue of teeth which have the
general appearance of being perfectly developed ; but when
the enamel is obviously imperfect, and presents the honey-
combed character, the structural defects will be much more
generally diffused.

Not only may the fusion of the sheaths be imperfect, and
the central portions of the fibre fall short of the normal
conditions, but even the arrangement of the elements of the
tissue be lost. Both the longitudinal and transverse markings
mony be replaced by a general granular condition, as though
the tissue had been formed by the calcification of unarranged
spherical mnsses, about the size of bleod-globules, with
perhaps here and there a cavity of irregular form inter-

posed,

Inthe most perfectly developed enamel, the longitudinal
and the transverse markings are comparatively faint, and
under a high magnifying power with Phe sed Sy bod
appear, not as dark, but as light lines, enclosing spaces
+ cer igi beerler acne deeraghe ner tele
opaque than that which forms the lines. Any doparture
from this condition may be justly regarded as a predisposing
eanse of caries, the degree of predisposition being proportioned
seyisheorelatite amount of porosity in the tissue. In the

292 A SYSTEM OF DENTAL SURGERY.

Many other structural defects in the enamel might be
noticed here, but, inasmuch as they have no very practical
bearing, want of space forbids their introduction,

The close relation which exists between constitutional
conditions and imperfeet development of the teeth is often
exceedingly clearly indicated by the four first permanent
molars, which, being simultaneously developed, all present in
an extreme degree the character of honeycombed teeth,
whilst the other teeth in the same mouth are well formed.

( 293)

CARIES,

‘Tne enamel and the dentine are the tissues which are
more especially liable to be affected by caries. In them the
process of destruction commences. The disease may extend
to, or may even commence in, the cementum in teeth from the
necks of which the protecting gum has been removed. But
these are exceptional cases; we may therefore, for the pre-
sent, treat of the disease as an affection of the enamel and
dentine only, leaving for future consideration the results
which follow when the disease becomes complicated by ex-
tending so far into the tooth as to lay open the pulp-cavity,
and involve the pulp itself in rapid destruction or in chronic
disease,

Although dental caries has been investigated and described
by all who have written upon the subject of dental surgery,
from the earliest period when disorders of the teeth first
attracted attention down to the present time, yet it can
scarcely be said that the nature of the disease is porfectly
understood ; for even now two hypotheses prevail, In one,
the disease is assumed to be no disease whatever, but merely
the result of chemical solution of the dental tissues, and there-
fore dependent, both in its origin and its progress, on the
uncontrolled action of physical and chemical laws.

- According to the other hypothesis,.the fact that teeth are
part of a living organiam, if not essential to the origin of the
mischief, at all events profoundly modifies its progress.
‘Much has been written in favour of each of these views, and

a

yo

294 A SYSTEM OF DENTAL SURGERY.

yet the subject cannot by any means be held to be settled.
As it would be impossible to summarise and criticise the
views advanced by the numerous English and foreign autho-
rities who have contributed to the literature of the subject,
without unduly encumbering the text, and as, at the same
time, the present volume would be incomplete without such
a chapter, it is thought desirable to embody these theore-
tical considerations in the form of an Appendix, merely
giving here in the text a brief account of the appearances
actually observed.

The physical signs which mark the presence of caries are
first visible in or through the enamel. But they will vary
somewhat in accordance with the character of the surface
affected, If the disease arises in a fissure on the masticating
smrface, or in a depression on the crown of a tooth, a dark-
coloured spot will be the first indication of its presence; but
ifthe disease has attacked a surface free from any indentation
or fissure, the affected part will lose its translucency, and
become opaque and white: subsequently the white will be
sueceeded by an ash or slate, and finally by a brown colour,
more or lees deep. If the enamel be examined when in the
earlier stages of disease, it will he found that the presence of
opacity is accompanied, and no doubt occasioned, by an in-
creased porosity of the tissue, a condition which has succeeded
to one of the forms of imperfect development already de-
scribed, Either the union between the sheaths of the forma-
tive fibres has been imperfect, and the strictly fibrous
condition has been maintained until, under the influence of
disease, the union, at best but imperfect, becomes sufliciently
interrapted to give opacity to the parts; or the granular
condition previously alluded to has been continued, and thus
rendered the tissue susceptible to influences which would
have failed to prodace any injurious effects had the organi-
zation beon more perfect. ‘The predisposing causes to disease
have, however, been described in connection with the struc-
ture and the development of the enamel, and the description

CARIES, 295

need not be repeated. After recognising a distinction between
the central and the external portions of the so-called fibres,
and the more rapid action of @ mineral acid upon the
contained thin upon the containing part, it may reasonably
be expected that some such difference would be observed
io enamel when undergoing changes from the action of
disease. It would be most difficult to obtain a transverse
section of enamel which has been subject to the changes
produced by caries, but we may, by breaking down upon a
glass slide fragments of the brittle and chalk-like enamel
taken from a carious tooth, produce a sufliciently satisfactory
preparation for demonstrating the fact that the central
portion of the fibre is the first to suffer decomposition, much
in the same manner as when the destructive agent is inten-

tionally applied to a section prepared for experimental
‘The foregoing description applies to those cases where the

formity with the character of the surface attacked, but the
progress is somewhat varied, both in respect to the direction
in which the disease extends, and in the rate of destruction.
When the disease is established in a fissure, the indications
of its presence are not strongly pronounced, until a very con-
siderable amount of destruction has been prodaced. A con-
“< vecoahnnerlarantst tn the disease having extended into

the dentine, to a considerable depth in the direc-
tion of the tubes, and spreading laterally under the enamel,
without affecting its outer surface : with the softening of the
dentine, the inner surface of the enamel becomes softened
ETN celestial hae ts ca

296 A SYSTEM OF DENTAL SURGERY.

serving the terms, spreading caries, for the form previously
described.

As respects the dentine, the progress of decay does not
follow the same course as that which has been described in
reference to the enamel. It will be remembered that the
dentine is formed from cylindrical cells, or rods, of the
dentinal pulp, the individuality of which is lost in the
process of calcification, If we take @ thin section from a
carious tooth, it may be seen, in those parts of the preparation
where the tubes are divided transversely, that each tube is
surrounded by a very thick sheath—the diseased condition

has in a measure undone the work of development and
thrown light on the question how this was effected ; it may
almost be said to have restored the outline of the formative-
cells—the tissue is to a certain extent broken up into its
histological elements, Under the microscope the section
looks as though it might have been built up of multitudes of
tobacoo-pipe stems, united by an intervening substance,
Such is the condition when disorganization has advanced up
to a certain point ; at a later period short lengths of the walls
of the tubes (dentinal sheath, zahnscheiden of Neumann) are

(*) A tection from dentine roftensd by caries, showing the consolidated
dentinal Lnbes and fibrils cut transversely,

CARIES, 297

found isolated; and finally the whole tissue breaks down
into minute granular particles, which are by degrees washed
away in the saliva,

‘The first chemical change consists in the removal of the
lime-salts from the gelatine, leaving the dentine of a con-
sistence capable of being readily cut with a sharp knife, when
it will be found to exhibit the structural characters just de-
seribed. It might be supposed that similar results would be
produced from decaleifying a tooth by the aid of a dilute
mineral acid ; such, however, has not been the case in expe-
ftiments instituted with the view of determining the point.
Indeed, I know of no artificial means whereby the appear-
finees which have been described can be as fully brought out
as by the progress of disease. The question naturally
suggests itself, may not the appearance of dentinal rods be
nothing more than & certain stage in progressive decompo-
sition, due to a solvent fluid obtaining access to the tissue
through the tubes, and the outline pa ensl sonibe itieettve
only of the depth to which the fluid has

eet ace Sclskvaissnting mona aahctoos
the walls of the tubes tho last, to become disintegrated ; and
this, previous to the discovery by Neumann of the very in-
destructible nature of the dentinal sheaths, seemed to answer
the question :n the negative, Knowing, however, as we now

.
298 A SYSTEM OF DENTAL SURGERY.

sents pretty nearly its natural appearance, we then pass to a

point where the appearances depicted on the preceding page

are seen; still further on, this condition becomes yet more

strongly marked; and at the extreme edge, supposing the

section to have extended to the surface of the cavity, the
of disintegration may be seen,

If the dental tubes be isolated by the application of acids,
they will often be found to present varicosities and globular

If a tooth in which the disease is limited in extent be
divided, the relations of the diseased to the healthy parts may
be examined. The affected dentine will be cither opaque in
appearance, or it will have assumed » brown colour; and
these changes from the condition of health will be seen to
extend underneath the enamel beyond the limits which bound
the external indications of disease in that tissue. But it will
be in the direction of the dentinal tubes that the disease will
be found to have made the greatest progress. Supposing the
disease to have commenced upon the masticating surface of
@ molar tooth, it will commonly be found that the mass of
diseased tissue, when limited in amount, presents the shape
ofa cone, the apex of which is directed towards the pulp-
cavity, and the base towards the enamel.

‘The section will show that the destructive agent, having
gained access to the dentine through an opening in the
enamel, has spread, to a certain extent, upon the peripheral
surface of the tissue, through the terminal branches of the
tubes, and thus formed the base of the cone; but that it has
spread toa greater length in the course of the trunks of the
involved tubes following their convergent course towards the

(®) Excellent fizures are given of these beaded, elongated bodies in Helder
and Wodl’s Atlas eur Pathologie der Zahne, part tii., pp. 792, 08 und they are
further described in WedI's Pathologic der Zahne. In both places, however,
they are described as “Dentinsellenfortsiitze,” a word the exact meaning
attached to which T do not know, seeing that ite signifieance greatly depends
on the view held by the writer of the share taken by the odontoblasts in the

formation of dentine, and of the ultimate structure of dentine. Thus it might
yoran the dentinal fibril, the dentinal sheath, or both.

pulp-cavity, and thus produced the apex of the cone. But if
an example be taken in which the disease has assumed the
spreading character, the conical form of the disorganized part
will be less strongly, if at all, pronounced. Tn certain cases,
indeed, the whole of the masticating surface of a molar tooth
is lost before the disease has advanced to a sufficient depth
in the direction of the pulp-cavity to expose its vascular
contents. In the defective teeth described as “ honeycombed
teeth,” the disease, after the enamel has been destroyed and
the dentine reduced in thickness, becomes in certain cases
arrested, The exposed tissue assumes a polished surface, deep
‘brown colour, and acquires a density which enables the crown,
thongh deprived of enamel, to serve the purpose of masti-
«cation with scarcely less efficiency than an uninjured
tooth.

Coincident with structural changes in the dentine a certain
amount of uneasiness exists and marks the presence of the
disease ; and of this we have yet to speak.

I believe it rarely happens that the presence of caries in
its earlier stages is altogether unattended by some uneasiness
in the affected tooth. The amount is often very slight, so
alight, that the attention will be directed to the part in those

- only who are in the habit of devoting considerable care to
the preservation of the teeth: on the other hand, there are
many who immediately recognise the presence of discaso by
the discomfort it occasious; and in exceptional cases the
patients deacribe the affected teeth as giving them 4 con-
siderable amount of pain long before the disease has pro-
greased to an extent capable of directly involving the pulp,
Toothache of this description must be distinguished from
thaf which is consequent upon inflammation of the pulp,
whether resulting from exposure produced by caries, or
arising from any other enuse; and the distinctions may be
made by observing the characters of the pain, There is an
absence of throbbing, and a leas degree of intensity as com-
pared with that occasioned by inflammation of the yoy.

.
298 A SYSTEM OF DENTAL SURGERY.

sents pretty nearly its natural appearance, we then pass to
point where the appearances depicted on the preceding page
are seen ; still further on, this condition becomes yet more
strongly marked; and at the extreme edge, supposing the
section to have extended to the surface of the cavity, the
process of disintegration may be seen.

If the dental tubes be isolated by the application of acids,
they will often be found to present varicosities and globular
swellings. (1)

Tf a tooth in which tho disease is limited in extent be
divided, the relations of the diseased to the healthy parts may
be examined. The affected dentine will be either opaque in
appearance, or it will have assumed a brown colour; and
these changes from the condition of health will be seen to
extend underneath the enamel beyond the limits which bound
the external indications of disease in that tissue. But it will
be in the direction of the dentinal tubes that the disease will
be found to have made the greatest progress. Supposing the
disease to have commenced upon the masticating surface of
a molar tooth, it will commonly be found that the mass of
diseased tissue, when limited in amount, presents the shape
ofacone, the apex of which is directed towards the pulp-
cavity, and the base towards the enamel.

The section will show that the destructive agent, having
gained access to the dentine through an opening in the
enamel, has spread, to a certain extent, upon the peripheral
surface of the tissue, through the terminal branches of the
tubes, and thus formed the base of the cone; but that it has
spread to a greater length in the course of the tranks of the
involved tubes following their convergent course towards the

@) Excellent figures ure given of thesy beaded, longatet bodies in Helder
and Wedl’s Atlas zur Pathologie der Zahne, part lil,, pp. 792, 03 ; and they are
further described In Wedl’s Pathologie der Zahue, In both places, however,
they are described ax "Dentinaellenfortaitzs,” a word the exact meaning
attached to which Ido not know, seeing that Ite significance greatly depends
on the View held by the writer of the bare taken by the edavtoblasts in the

formation of dentine, and of the ultimate structure of dentine. Thus it might
‘mean the dentinal fibril, the dentinal sheath, or both.

800 A SYSTEM OF DENTAL SURGERY,

Contact with hot or cold fluids does not usually produce
any unpleasant effect,

I believe tho seat of pain to be mainly in the peripheral
portion of the dentine, and that after the destruction of
vitality in this part of the tooth has been completed, the
sensation of discomfort in great part passes away.
~ No doubt there are cases in which the presence of caries is
unattended with any feeling even of discomfort, for we find
those in whom the pulp becomes exposed and disappears
without a moment’s toothache, If a part endowed with
vessels and nerves, and a very high degree of sensibility,
ean be destroyed without pain, as it were unconsciously, it
would be unreasonable to suppose that the dentine cannot
undergo disintegration without manifesting sensation. Why~
in one person the destruction of a tooth should be attended
with so much, and in another with so little suffering, is «
question which we are as little able to answer, as we are to
account for the great difference in susceptibility to the action
of remedies, so frequently manifested in patients in whom
such constitutional peculiarities can be discovered by experi-
ment only.

‘The dentinal fibrils are subject to a change more or less
complete, the existence of which may be recognised even by
the naked eye. If we divido a sound tooth through its long
axis, the dentine exposed by the section will present a tole-
rably uniform degree of opacity ; but if the tooth has been
attacked by caries, in addition to the discoloration of the part
which has undergone chemical change, we shall find a com-
paratively transparent zone removed a short distance from,
and surrounding the disorganizing mass. If a thin section
be taken from the tooth, it may then be seen that the trans«
parency is produced by the air being thoroughly excluded
from the dentinal tubes in this part of the section, This
seems to be due to the consolidation of the dentinal fibrils
within the tubes, thereby obliterating the latter, and ren-
dering their outline obscure. The consolidated condition of

CARIES, 801

the fibrils may, however, be shown in a more satisfactory
manner by taking a tooth in which the progress of decay has
been slow, leaving the disorganizing dentine of a deep brown
colour, and comparatively firm in texture. If we cut with a
sharp knife s thin section in the direction taken by the den-
tinal tubes from the discoloured portion (if the tooth be well
selected), the consolidated fibrils will be seen within the
tubes broken abruptly into short lengths, Sometimes they
are present in great numbers, scattered over the specimens,
many lying within the tubes, others upon the surface, and

Fig. 198. 0)

occasionally they may be seen with one end projecting from

the edge of the section, and the other within the tube.
‘Chis consolidation of the fibrils necessarily exercises a con-

siderable influence in arresting the progress of disease, by

() A section in a plane with the tubes, from cariows dentine, showing
cpp ld a Ek celallag teeimetene dad ga
-“

of the while others faye bees broken @iubtn the

302 A SYSTEM OF DENTAL SURGERY.

rendering the dentine much more dense and impervious than
when in the normal state. The zone of consolidation outs off
and isolates the disease from the healthy portion of the
tooth, and its production must be regarded as an attempt on
the part of nature to circumsoribe and limit the mischief.
‘That this interpretation of the phenomenon is correct, will
be seen on examining teeth in which the rate of progressive
destruction has varied, and also by considering the conditions
presented in other tissues when they are attacked by local
disense.

In respect to teeth, it will be found that when the dentine
has been rapidly destroyed—when, in fact, the amount of
softening is great, and the external indication but compara-
tively slight—when that which at first sight would appear to
an unacoustomed eye a small cavity, is,on the removal of the
disorganized tissue found to be a very large one; that the
consolidation of the fibrils has been imperfect, or perhaps
altogether wanting, and that there is coincidently a high
degree of sensitiveness under operation. Again, compare the
foregoing case with one in which the destruction has been
comparatively slow, and the extent of the disease more
limited, and it will then be seen that the evidences of conso-
lidation are in the former very slight, in the latter very
abundant. It will, in fact, be found that the mate at which
the disease advances will accord with the amount of consoli-
dation. It must be borne in mind that the disease is, for the
present, regarded as strictly limited to the dentine and enanicl,
and that the teeth are assumed to be in an otherwise healthy
condition, When the pulp becomes exposed, or when the
gums have receded and exposed the necks of the teeth, other
conditions come into operation, and modify the symptoms,

‘Yo what extent this obliteration of the tubes is to be re-
garded as a vital action is a question the discussion of which
must be deferred to the Appendix on the nature and causes
of dental caries, +

Litmus paper applied within the cavity of a carious tooth

804 A SYSTEM OF DENTAL SURGERY.

held in constant apposition with the exposed dentine by the
saturated wood.

Experiments of this character lead to the conclusion that
within the mouth agents are present which, under favouring
circumstances, are capable of decomposing the dental tissues,
and the source of these agents becames the next question
which naturally suggests itself.

The secretion from the mucous membrane {s ordinarily
slightly acid, while the salivary fluid, when normal, is alkaline,
‘The result of the admixture of these, if equally proportioned,
would be a neutral fluid. Incertain conditions of health even
the saliva (") may be acid, and the mucus wonld then retain
its original character after the mixture of the two fluids,
Again, the degree of acidity of the mucus may be increased
beyond the normal amount, and its tenacity may enable it to
remain in certain situations unmixed, and consequently un-
influenced by the alkaline character of the salivary finid.
The quantity of the mucus may be excessive either from a
local or general cause, We not uncommonly find in mouths
tenanted by numerons carious teeth, the gums thickened and
vascular, and covered with a coating of thick adhesive mucus
capable of being drawn from the gums in long strings, A
case is fresh in my memory in which the teeth were rapidly
destroyed by caries, and coincident with the destructive
process the salivary fluid was scanty in amount. The mouth
owed its moisture to the secretion of the mucous membrane.
The patient complained of great discomfort from the dry
and clammy condition of the mouth and throat. The teeth
that wore first lost decayed in those situations in which we
usually expect caries to show itself; but at a later period the
whole of the remaining teeth were almost simultancously
attacked near the edge of the gum, producing round each
tooth an annular belt of softened tissue, The patient suffered
from long-standing dyspeptic symptoms; and among these
4 vitiated condition of mucus secreted from the surface of

4 See the chapter on the Saliva,

aie

806 A SYSTEM OF DENTAL SURGERY.

often follow when the filling introduced into a cavity is
allowed to project so as to keep up a state of irritation in the
gum. The patient after a time returns with toothache, and
on examination we find that the tooth has decayed above the
stopping in the immediate vicinity of the irritated gum,
‘The irritation, if continued, may lead to the secretion of pus,
But pus, when secreted by the mucous membrane, presents
the ordinary alkaline character of that finid, and does not
appear to exercise an influence upon the dentine.

The case as respects the lining membrane of the mouth isp
however, not without a parallel. The mucous membrane of
the bladder, when in a state of irritation, pours out a strongly
acid secretion.

A disordered state, local or general, of the mucous mem-
brane, must not, however, be regarded as the only source from
whence may be produced agents capable of decomposing
faulty enamel or dentine. For instance, examples present
themselves in which the teeth rapidly decay in mouths
free from any increased vascularity, local or general—free
from adherent mucus about the teeth, and also from any
sign of that fluid being either excessive in quantity or
vitinted in quality. If in such cases the oral fluid be care-
fully examined, I believe it will be found that the saliva
itself has at intervals lost its alkaline character and become
acid. Several patients (females) returning after a prolonged
residence in India, have presented the foregoing conditions of
the mouth. They have been pale, bloodless, and greatly de-
bilitated, though not necessarily greatly attenuated, subjects.

In speaking of the oral fluids as having constituents pos~
sessing sufficient activity to rob dentine of its phosphate of
lime, we must not lose sight of the fact, that where teeth
decay very slowly, and the disease arises in situations in
which defective organization is very often found, an abundant
supply of acid may be produced by fermentation of the food,
or may find its way from the stomach,

Without going into the consequences produced by caries,

ee

308 A SYSTEM OF DENTAL SURGERY.

'This secondary nodular dentine may or may not be
to the walls of the pulp-cavity; it is, however, n
quently free than attached, and in that caso fails to a
the useful purpose of protecting the pulp from exposu
“Mr. Salter speaks of the calcification of the pulp wi

tissue as dentine of repair. (')
~ Caries—Treatment,—The discase at present has been re~
garded as confined to the dentine and enamel only, and in
entering upon the treatment, the same limitation will be ob-
served. The exposure of the pulp and other complications:
will be subsequently considered,

In the treatment of simple caries two methods are emi

second method of treatment, In either case the diseased
part must be removed, or, at all events, such portions of it ax
“grote yer wag arigerinredagrteg
In selecting between these two operations, we must be
guided in the first place by the depth to which the disease
has penctrated, and by the situation in which it is esta-
blished. If the disorganization has not extended into the
dentine to a depth which greatly exceeds the thickness of the
enamel, and either the median or distal surface of a tooth (es-
pecially of a front tooth) be the part attacked, the operation
of excision may be performed with advantage. But if the
tooth are irregularly plaved, the advantages of this method
of treatment may be either increased or diminished by the
‘of the case. Teeth, when crowded together, will
‘be improved by the operation if they have been attacked

1 No el eel iaatnd ie bene llr e es
y of the Pulp.

TREATMENT OF CARIES. 809

with disease on the lateral surfaces, bnt when 4 separation
exists already, the widening of the aperture by the file will
produce an unsightly appearance, without offering any ad-

of the affected portion of a tooth by the file. Not
must the diseased part be cut away, but it must be re-
FSA sen apace ina arb gence td
will enable the operator to leave a perfectly

of a strip of linen or a piece of wood eut into a suitable

‘The median or distal side of « front tooth is the situation
‘in which the file is most commonly applied, andthe operation
will leave the

810 A SYSTEM OF DENTAL SURGERY. q

shall soon find the exposed dentine extremely sensitive, dis- —
coloured, and softened. Examples are sufficiently numerous 4|
in which a dividing file has been passed between two sound
front teeth for the purpose of relieving lateral pressure,
‘The division so produced has closed up, and the part placed
beyond the influence of friction. In the course of a com=
paratively short time, each tooth the enamel of which has
been cut through is attacked by decay; a cavity results, less
favourable for plugging than would have arisen had the
operation of filing been omitted.

Nature sometimes performs for herself an operation which
is analogous to filing when properly performed, both ax re~
gards its physical peculiarity and its results. The walls
of a broad but shallow cavity produced by caries break
down, the softened tissues are exposed to friction and
rubbed away, till at last the hard dentine is reached} this
becomes brightly polished, and endures for an indefinite
time unaltered,

The frequent occurrence of unfavourable results has led
many to regard with considerable distrust the operation of
filing, and the distrust is justified when that instrument is
used upon sound tecth for the purpose of relieving the
lateral pressure of one tooth upon another. But we may see
cases in which great advantages have resulted from the
operation, and it will not be difficult to discover the con-
ditions the observance of which ‘has led to those advantages,
Tn the majority of cases it will be found that, with the whole _
of the disorganized, a considerable portion of sound tissue
has been cut or filed away, and the surface resulting from
the operation placed within the influence of the food in
mastication, and of the tongue. In order to secure these
two conditions, it may be necessary to remove so much of &
tooth as will interfere with its appearance. It is better,
however, that the form should suffer slightly than that the
whole tooth should be lost,

‘The file only has been spoken of, but instruments known

——

312 A SYSTEM OF DENTAL SURGERY,

The results of cutting away superficial decay in such a
manner as to leave a polished and thoroughly exposed surface
are often exceedingly satisfactory; the difficulty, however,
lies in the sclection of cases, for it is at times attended with
the most disastrous results, It is often possible to recognise
cases of caries in which, although the diseased part might be
removed by the file, its use would be injudicions. At all
times the sensation produced by filing the teeth, to say the
least, is very disagreeable ; but in certain states of the teeth
the procedure is attended with great pain, so much so that
the operation cannot be properly performed. Again, when
we find associated with caries a thickened and vascular
condition of the gums generally, and more especially of those
parts whicli pass between the teeth, together with an
exudation of the thick ropy mucns to which I have already
referred, the operation of filing will be attended with very
doubtful success. Lf we filed out a small cavity, it is pro-
bable that in a short time another, equal to the oxtent of
dentine exposed, would take its place.

On the other hand, cases apparently most favourable for
this mode of treatment will now and then show results
equally unsatisfactory. It has recently been proposed by
Dr. Arthur (*) to very greatly extend the applicability of this
operation, and to use it not merely as a remedy, but as a
preventive against the attacks of caries. Starting with the
assumption that in certain individuals decay of the teeth is
perfectly certain to occur, and that these individuals may be,
with but little chance of error, recognised by the dentist, he
proposes to cut away sound teeth soon after their eruption,
in such a manner that they may be isolated from one another.
Where doubt exists as to the necessity of such a procedure,
he advocates s¢parating the incisors from one another as soon
as they take their places, and carefully examining their
prosimal surfaces; he states his conviction that if the

(®) Tevatiment and Prevention of Decay of the Teeth. R. Arthur, M.D.
Philedlelphin, 1571.

8l4 A SYSTEM OF DENTAL SURGERY,

nection with those cases which may be treated by operations
in the performance of which these instruments only are used,
But we shall have again to recur to them in connection with
the operation of filling, and as the manner of using such
instruments will then be described, it will be unnecessary to
enter upon the consideration here,

In the treatment of caries, filling must ever be regarded as
the great remedy by which the disease may be arrested, and
the defective tooth restored to a state of efficiency, The
operation consists in the removal of the disorganized tissues,
and replacing them by s material fitting perfectly the cavity
produced by their removal, and capable of resisting the
chemical influence of the oral fluids, and the mechanical
effects of the food during mastication.

The disorganized portion of the tooth is cut out, and the
lost part is made good by an inorganic material.

‘There is, perhaps, no other operation performed upon the
human body which is attended with the same unqualified
success as that of filling teeth, for we not only succeed, in
the great majority of cases, in arresting the further progress
of disease, but we also replace the part which has been lost
by an imperishable material, and render the organ as useful
as it was prior to its becoming the subject of caries, It is,
however, a great error to suppose that filling will, under all
circumstances, permanently save the tooth, even in cases
which at the time the operation is performed promise
favourably.

There are those who are disposed to regard the decay of
atooth which has been filled as the result of want of skill
or of care in the operator; such an opinion is perfectly
untenable, when the character of the operation is considered
in connection with the tissues which are involved, and the
various conditions under which disorganization may be
effected. The very fact that caries has appeared in a tooth
demonstrates its predisposition to disease. We can, for the
time being, arrest the disorder, but it may reappear in some

Ea

316 A SYSTEM OF DENTAL SURGERY.

have a tendency to produce in the minds of those whose field
of observation has been but limited.

The operation of plugging is divided into two distinet
stages—the first of which is confined to the removal of the

disorganized tissues and the production of a cavity of suit-

able shape; the second consisting in the introduction of the
material used for making the plug. For the present the
preparation of the cavity for the reception of the plag must
receive attention, upon the proper performance of which
the ultimate success of the operation will in great part
depend.

In the treatment of a case, the first point for decision will
be the extent to which the diseased dentine can be removed.
‘The general rule is to cut out the disorganized tissue, until
the walls of the cavity present the colour of healthy dentine ;
but there are exceptions to this rule. In the first place, the
dentine may have become to a certain extent discoloured, and
yet have retained its normal hardness. Again, the dis
coloration, and even softening, may have advanced eo fir
into the tooth that the removal of the whole would endanger
the exposure of the pulp. If the pulp be exposed during the
operation, the loss of the tooth is to some extent endangered ;
consequently it is better that a layer of discoloured dentine
should be allowed to remain for the protection of the pulp,
rather than run the risk of sacrificing the tooth. Supposing
that the walls near the orifice are strong and sound, it does
nob appear that the retention of a little slightly-softened
dentine at the bottom of the cavity interferes seriously with
the durability of the plug, The presence of any softened
tissue at or near the orifice of the cavity must, however, be
earefully guarded sgainst, for the neglect of this precaution
would be followed by the extension of the disease.

An exposed edge of disorganized dentine will allow solvent
fluids to pass through it to the sound tissue, rapidly or other-
wise, as the surface exposed is relatively great or small, and
spreading from a single point at the circumference of a plug,

$18 A SYSTEM OF DENTAL SURGERY.

removal of the softened tissue will often leave a large cavity,
the orifice of which is considerably contracted, owing to the
enamel, and perhaps a thin layer of the subjacent dentine,
having resisted the influence of the destructive agents more
successfully than the more deeply-seated tissue. It might be
thought that the overhanging of the sides of the orifice would
favour the retention of a plug, and the assumption would
perhaps be justified if it were practicable to introduce a
perfectly solid plug in a cavity so shaped. Unfortunately it
is extremely difficult to force a filling under a projecting
ledge so as to produce even a moderate degree of solidity in
the part which occupied the angle; and the consequent im-
perfection is still further increased when, in condensing the
surface, considerable pressure is directed in a line from the
top to the bottom of the plug, the effect of which is to
depress the gold and carry it away from the under surface of
the projecting margin of the cavity. The plug may have a

very satisfactory appearance when finished, but in a com-
eardy short time evidence of failure will be discovered.
That portion of the tooth which overhangs the plug being
but imperfectly supported from within, will break down,
moisture will find its way around the plug, decay will be
re-established, and if the operation is not repeated, the teoth
will be lost,

In order to avoid unfavourable results arising from the
foregoing cause, the overhanging edges must be cut away, if
not sufficiently to produce rectilinear walls, yet to reduce
the angles to moderately curved surfaces. The walls of a
cavity may bulge outwards or inwards, but anything ap-
proaching to receding angles or sharp corners must be
avoided. Jt may be necessary to repeat, that the pressure
applied by the filling instruments condenses the gold only in
the line in which the force is directed. The metal is con-
densed beneath the instrument, but it does not spread to any
appreciable extent in the lateral direction, unless a perforation
be made by the instrument, and the direction of the force

320 A SYSTEM OF DENTAL SURGERY.

ness to interfere with the appearance of a tooth not un-
commonly induces the operator to attempt the preservation
ofa part which eventually gives way, and necessitates the

of a second operation under circumstances leas
favourable than obtained on the first occasion, and the tooth
is left in a more unsightly condition than it would have been
had the fragile portion been freely cut away in the first
instance. The absolute strength required will vary with the
position which the tooth ocenpies in the mouth. In a molar
tooth, which has to sustain the full force of mastication, the
walls of the cavity must be composed of enamel and dentine,
with o considerable thickness of the latter; whereas, in front
teeth a much thinner layer will be found sufficient. Indeed,
in incisor teeth the enamel alone, if the extent be limited, is
sometimes sufficiently strong, when supported by a plug, to
endure for many years. The colour of the gold may show
throngh st the point where the dentine is entirely absent,
and yet there may be sufficient strength in the enamel for
the maintenance of the plug and of its own structure,

‘There is yet another point in the formation of a cavity to
which attention may be advantageously directed,

‘The character of the margin of the orifice is scarcely less
important than the shape of the cavity itself. Asa general
rule, the plugs which are surrounded by enamel are more
durable than those inserted in cavities the margins of which
are partly formed by dentine or cementum. It is conse-
quently desirable to preserve; if possible, the former tissue,
and te remove the dentine at the margin of the orifice in
such ® manner as to allow the gold to come in contact
with the enamel, so that the dentine may be wholly covered
over and protected. Where the cireumference of a plug is
bounded by strong enamel, as on the masticating surface of
a molar tooth, the undulating character of what we may call
the top of the wall, is unimportant; but should dentine
form a part of the whole of the boundary, as it will do when
the disease is situated on the mesial or distal side of a tooth,

‘

TREATMENT OF CARIES, 221

then it will be necessary to reduce the margin of the orifice
to a fiat and smooth surface.

Several forms of instruments are used in preparing cavities
for the reception of plags, but they come under one or other
of two heads, viz., cutters and drills, The one class will
include what are commonly called “ excavators” and enamel
cutters, while in the other will be ranged drills of varions
forms, and burr-heads, as they are called.

Fig. 137.)

4 . e DB © ¥

Jt will not be necessary to do more than make a few
general observations upon the manner of using the instru-
ments employed in removing the diseased tissnes, The
forms which have been figured may be taken as those most
commonly used, but the minute variation in size and shape

@) Figs. 157, 128, sow some uf tho most useful forms of excavarare.
¥

Ma to

=

822 A SYSTEM OF DENTAL SURGERY.

required from time to time generally leads to a great aceu-
mulation of this description of instruments. ‘The operator
should be able to make for himself excavators to suit any
peculiar case which may ariso. There is, however, one
preperty which should be possessed by all, whatever the
shape or size of the instrument. It should be made of good
steel, and kept perfectly sharp. A blunt instrument tends
to prolong an operation which is always disagreeable and

Fig. 138,

G a 1 4 ‘

sometimes very painful. With a perfectly sharp excavator
the diseased tissue is quickly removed, and with a com-
paratively slight amount of discomfort. A few rapid and
well-directed strokes of the blade, and the softened tissue is
ent away, and although a proper form has yet to be given to
the cavity, the subsequent steps of the operation are seldmo

B24 A SYSTEM OF DENTAL SURGERY.

holder will be found to present many advantages. The

crutch rests between the thumb and forefinger, or between

the latter and the second finger, leaving the tips of the

+9-141.@) thumb and finger free to rotate the shaft of the in-
strument, while pressure is made upon the crnteh,
(Pig. 189.)

For some years I have used this instrament with
the form of the cutter modified. Instead of pro-
ducing « spherical head, the steel has been allowed
to retain an uniform cylindrical figure, and teeth
have been cut, not only at the extremity, but for
some distance up the shaft. (Fig. 140.)

With this construction of cutter we secure all
the advantages of the rose-head, accompanied with
an udditional amount of strength in the part cor
responding to the neck of the latter; also the ca~
pability of enlarging an orifice through which the
point has entered by the entting surface of the
shaft.

‘The rotating file or rose-head is very serviceable
when the enamel requires removal, but for cutting
the dentine an ordinary drill presents many points
of superiority. It cuts more rapidly, can be more
easily made sharp, and its course can be more
readily directed than the rose-head, owing to the
greater amount of proasure required to bring the
latter into effective operation. Drills of various
size and shapes may be mounted in the crutch-
handled stock shown in a preceding figure, or the
drill ond shaft may constitute one continuous
length of steel (Fig. 141), The latter arrange-

ment possesses some advantages. The shaft is held, when
rotated, between the thumb and finger; and as but little
pressure is required to make the blade cut, the direction and

(2) Drill made from s cylindrical piece of steel, with the point chaptered
from each side.

$26 A SYSTEM OF DENTAL SURGERY.

been surmounted, but it has not been sufficiently long in tse
in this country to speak very positively as to its value,

Removal of Sensitive Dentine.—Cases are not infrequently
met with in which the carious dentine possesses such an
exalted degree of sensibility that its removal cannot be borne,
and the patient flinches from the slightest touch of any
instrument. A minute quantity of arsenic placed in the
cavity, and retained for a few hours, will render the part
absolutely insensible to pain. ‘The objection, however, to
such a course is the difficulty of limiting the action of the
arsenic to the surface on which it is applied, It may find
its way to the pulp, and occasion the death of that organ—a
condition speedily followed by discoloration of the while
crown of the tooth, and very probably by the supervention
of alveolar abscess. Thus Dr. Kingsbury, in a recent number
of the “‘ Dental Cosmos,” relates an instance in which arsenic
had been used for the purpose of obtunding the sensibility of
dentine, and had caused the ultimate death of the pulp in no
less than seven teeth in the mouth of one individual.

Hence the use of’ arsenic is perfectly inadmissible when
the cavity is deep, and can only be used with any degree of
safety for allaying tenderness of the layer of dentine im-
tnediately beneath the enamel. If it is to be used at all, it
should be applied dry, or very nearly so, to avoid the risk of
its reaching the deeper portions of the cavity, and the cavity
carefully sealed, preferably by a temporary filling of gutta
percha. But as there are other agents which are capable of
reducing the sensitiveness of dentine, its use is to be de-
precated; though it must be admitted that it is the most
efficient and most certain in its action of all the remedies
proposed for the purpose,

Next to arsenic, in point of efficacy, comes zinc chloride; a
small fragment of the partially deliquesced salt, or a piece of
wool dipped in the solution produced by allowing the salt to
deliquesce, will, if held in the cavity for a few minutes,
greatly reduce the sensitiveness of the dentine. The appli-

MATERIALS USED IN FILLING TEETH,

Temporary fillings.—There is a variety of h
as a doubtful exposure of the nerve, extreme
ness of the dentine, or the pouring ont of a certain amount
of discharge through or from the pulp cavity, which renders
it undesirable to insert a permanent filling. We may have
resort to some of the various temporary fillings, either for
the specific object of curing one of the conditions which
preclude the immediate use of a permanent filling, as, for
example, the use of gum mastic and creosote when the nerve.
is nearly exposed, or the insertion of a gutta percha filling in
8 tooth very sensitive to changes of temperature; or we may
employ them simply then as experimental fillings, to be
repluced by permanent plugs so soon as we are satisfied that
no mischief is going to be set up by the tooth being filled.

When from any cause it is inadvisable to place a perma-
nent filling in a tooth, we have recourse to various substances:
suitable for temporary purposes, Solutions of various gum
resins in ether or alcohol are exceedingly useful; gum
swndarac, animi, mastic, copal, or dammar, reduced by the
solvent to the finidity of thin treacle, may be introduced
into the cavity on a snitable piece of cotton-wool. By evapo-
tation of the solvent, and partly by its dilution by the saliva,
the gum is precipitated, and forms with the wool a tolerably
hard mass, capable of lasting for some days, or even a
few weeks, though, as a general rule, it should be renewed
every two or three days. The cavity should be dried out
with cotton-wool, or what is better, amadou, before the ine
troduction of the mass,

painfully sensitive to changes of temperature, that the pe

is in dread of either hot or cold beverages, or even of

cold air through the mouth. If the gutta percha be

tuted, the inconvenience passes off, the bath will ga |
end of a few meaty: Deer; the veiniodaesiea Sa
without any of the preceding discomfort.

Gutta percha is also very useful as an experimental
where there is some doubt whether the nerve can be
alive, as in the case of the tooth sahing, tt con aaa
removed, even by the patients themselves, should the neoes-
sity for their so doing arise.

For temporary fillings, the varions preperitions of alu tae
chloride are exceedingly useful. Zinc oxide is mixed with a
strong solution of zinc chloride into a thick paste, which, after
the lapse of a short time, becomes perfectly hard. Different
makers introduce different substances which in some degree
modify the rapidity with which it sets, and possibly alter
the resultant compound to some slight extent. ‘Thus borax
is often introduced into the fluid; and powdered glass, or
actual silica, into the powder, for the purpose of m:
conferring greater hardness on the mass when it has set,
But the various osteoplastic fillings which I have examined
differ only in slight and immaterial points, and the objec-
tions which can be urged against one, apply, I believe,
almost equally to all.

The zinc oxychlorides are a class of bodies for the most
part. readily decomposed by the action of acids and alkalies ;
moreover, the manner in which the mixture is made pre-
cludes the possibility of a definite chemical compound, with-
out excess of either constituent, being formed. As a matter
of fact, there is always free zine chloride to be found in the
finished filling, and the filling is consequently hygroscopic,

332 A SYSTEM OF DENTAL SURGERY.

point below that of the constituent metals; thus, the addi-
tion of cadmium to certain other alloys confers this property
in a marked degree,

Several formulw have been proposed (of which the best
known is Dr, Wood's) for forming alloys which melt at a
sufficiently low temperature to be applied to a tooth by the
aid of hot instruments; but such preparations have found
little favour in this country, and I have but little experience
in their use.

It may, I think, be assumed as a settled point, that for
dental purposes a pure metal, such as gold, or even tin, is in
all respects preferable to any mixtures of metals at present
known. But there are cases in which the one can be used
while the other cannot, The American writers on dental
surgery have urged every possible argument against the mse
of amalgams, and have gone so far as to pass rules for the
expulsion from dental societies of members who would not
pledge themselves to discontinue the use of mercurial fillings,
. Yet there are teeth the condition of which is such that gold
fillings cannot be inserted with any chance of success, but
which, if plugged with a good amalgam, will last for years,
and be perfectly effective for a long period.

Common sense will, I think; decide the question whether
it is better to have a tooth filled with amalgam, or to lose
it at once, It has been urged that the mercury used in
making the alloy will salivate the patient, I have never
seen a case in which this result was produced, nor do T know
of a well authenticated instance, and J think we may fairly
conclude that the instances are so extremely rare that they
need not influence our practice,

It must, however, be borne in mind that I am not
advocating the use of amalgams where pure metals can be
used, but I do contend that the former are extremely useful
where the employment of the latter is prohibited. Take, as
an example, a tooth the crown of which has been hollowed
out to such an extent that the introduction of a foil filling

——s

E

884 A SYSTEM OF DENTAL SURGERY.

crust of bread, and felt as though they would ache before —
many weeks had passed. I removed as well as I could the

carious portions, of course very imperfectly, and filled them
with amalgam. Those teeth have since that time given me

no discomfort : hence I have a right to consider that the use
of amalgam has enabled me to retain two teeth
would otherwise have been removed or have fallen into
disuse three years ago. 7

Till within « comparatively recent period it was custotpary
to reduce into filings the ordinary silver coin, mercury was
added, and the compound worked up in a mortar or in the
palm of the hand until the whole became reduced to a stiff
paste. The superfluous mercury was then squeezed out,
either by pressing the mass between the thumb and finger or
in a fold of. chamois leather. After this manipulation the
compound is placed in the tooth, and in the course of a few
hours becomes quite hard. Although this form of amalgam
is bright when introduced, yet in a short time the surface
becomes black and the whole body of the tooth by degrees
assumes a dark grey colour.

A series of amalgams have been long known as Sullivan's
cements, which are in the inain composed of copper, but the
composition of the several qualities offered for sale has not
been. described. They are sold in large pill-shaped masses,
and the operator is directed to crush in a mortar a sufficient
quantity for the case under treatment; and to place the
mass in an iron spoon, which is to be held over the flame of
a spirit-lamp until globules of mercury appear upon the
surface of the fragments. In the heated condition the
compound is returned to the mortar, and rubbed until
reduced to a paste, It is afterwards squeezed in chamois
leather, to separate the excess of mercury, and is then ready
for use, These amalgams possess the same objectionable
qualities as the one already noticed, but in a less degree, and
are therefore preferable.

Precipitated palladium, when rubbed up with mercury,

336 A SYSTEM OF DENTAL SURGERY.

Mr. Arnold Rogers published, in 1850, an account of an
amalgam which he had used for several years with success (7),
Tt was composed of one part of gold, one part of silver, and
seven parts of mercury, and required heating before use,
much in the same manner as Sullivan’s cements, This pre- _
paration was not subject to discoloration, but I am told by
Mr, Rogers there was some difficulty in obtaining uniform
results as regards the degree of hardness of the plugs, and ~
the time required for the hardening when used in the mouth,
‘These difficulties led him to discontinue its use in favour of
other formulas which have since been introduced.

Messrs. Ash, of Broad-street, vend an alloy, supposed to
be composed of silver, and tin, and asmall percentage of gold,
to which mercury is added when required for use. And
Mr. Robertson, of Birmingham, at about the same date,
published a formula, containing similar ingredients. Tt is
composed of “gold, one part; silver, three parts; and tin,
two parts.” The metals, which must be perfectly free from
impurities, are melted together, and run into an ingot, and
afterwards reduced into filings (*), To these mercury is
added at the time of using, and the quantity required is
equal in weight to the filings.

But, although the tissues of the teeth are not discoloured,
yet even these preparations become a little dark in hue after
they have been some weeks in the mouth. Moreover, they
are hard and brittle; hence a preparation capable of retaining
the physical properties which Dr. Evans's amalgam possessed
at the onset, would be an improvement upon those sold by
Messrs, Ash and others.

When required for immediate use, the requisite amount of
filings is placed in & mortar, or in the palm of the band ;
mercury is added, and the two are rubbed together until a
stiff paste is formed. This should be washed, either with
alcohol, or (according to Mr. Rogers) with compound spirits

(©) Pharmaceutical Journal, vol.tx,, p. 402, L860,
@) Thid,, vol. xf, No.12, 1852.

388 A SYSTEM OF DENTAL SURGERY.

ments with the view of determining the real
failure, and waa led to the conclusion that oh

on the alloy had little or nothing to do with
amalgams at no time form perfect plugs. Every o
whieh were submitted to experiment contracted as
hard; some very greatly, others less, but still all
to an extent that must imperil the preservation of
round the circumference of the plag. But this M
takes place with the greatest rapidity in the first few |
after the amalgam has been mixed up, and subseq
is slight in amount, though it is often not completed
twelve hours. Hence we may partly get over the di
by employing an amalgam which sets with great
such as palladium, In using this metal as an
the greater part of the shrinkage is cree bees ng
is completed. !

General experience had already shown that of all amalgams
in use, palladium was decidedly the best, and that next to
this came copper ; and it was exeeedingly satisfactory to find,
in my experiments on this matter, that these two displayed
Jess shrinkage than any of the others. But of the numerous
amalgams submitted to experiment there was not one which
did not contract markedly as it hardened ; so that they must,
one and all, & prioré be pronounced ynreliable. It was found
that the addition of platinum to silver and tin amalgams
greatly hastened their setting, whilst the addition of gold
lessened their contraction ; there is, however, a limit to the
quantity of gold which can be advantageously added, inas-
much as it eventually interferes with the complete setting
of the compound.

So far as I am aware, no serviceable amalgam which does
not contract as if hanlens has as yet been produced;
Mr. Fletcher has, however, by the addition of both gold and
platinum to a silyer and tin alloy, succeeded in producing an
amalgam in which the total shrinkage is not great, whilst the
rapidity with which it sets allows some part of the contrac

_ A ©

842 A SYSTEM OF DENTAL SURGERY.

cently annealed, in order thnt the adhesive property shall he
fully pronounced. The plugs must be built np of small frag=
ments, each one being perfectly consolidated before another
is added. The metal must be preserved from the contact
of moisture until the plug is formed. And appropriate
instruments must be nsed in performing the operation, The
neglect of either of these conditions will be followed by an
unfavourable result.

Sponge gold on exposure to the atmosphere soon loses its
peculiar adhesive quality, and becomes quite nnmanageable ;
instead of welding together under the stopping instrument,
it falls to pieces, and all attempts to make additions to that
which is already consolidated are unsuccessful; on this
account it is desirable to anneal the metal where any doubt
exists as to its condition. By the process of heating, the
adhesive property is restored, even though the temperature
to which the gold is exposed falls short of a red heat, But
to whatever extent the welding property is produced, the
presence of moisture will at once render it unavailable. The
metal, from its porous condition, absorbs like a sponge, and
instead of consolidating under the pressure of the instrament,
works up into powder. We must therefore guard against
the admission of the saliva, and also protect the tooth under
operation from the expired breath, which being charged with
moisture will, if the metal be of a lower temperature than
itself, deposit upon it a sufficient amount of fluid to interfere
with the adhesive property of the gold.

The instruments fitted for operating with crystal gold
differ from such as are required for the introduction of non-
adhesive foil, but in most respects resemble those best
adapted for adhesive foil.

The working end, instead of terminating like a wedge, is
more or less flattened, and cut up into a series of small
points or ridges, in the formation of which it is necessary to
exercise some little care. The more perfectly formed are
the ridges or quadrilateral cones, the more easy will be the

BM A SYSTEM OF DENTAL SURGERY.

introduced, the solidity of the plug is ensured, and
favourable for the addition of still more gold is pr

‘The character of the surface to which further
gold are required is of considerable importance, h
place, it must be perfectly clean, and free from mo
any kind; and in the second, it must be rough, |
from the impressions of the one or the many-pointed
ment,

Let the surface be made wet by the tongue, or smooth:
the burnisher, and no more gold will adhere until it is @
rendered perfectly clean and reduced to the rough
previously mentioned.

Fick tae i lo re re ee
readiness with which the lost half, or even
rearrpothtag brani tobe
absent part. When out of the mouth the half or the
of the crown of a tooth may be reproduced in sponge
but in the mouth the operation of restoration is by no means
#0 easy: itis not impossible, but it is generally impracticable,
‘There are few patients who could keep the mouth open for a
sufficient length of time, and when they can, the tooth
gradually cools down to a lower temperature than the expired
breath, and precipitation of moisture upon the metal is the
result. ‘The operation may be suspended for a short time,
if on recommencing it the gold be wiped dry, and the
surface scraped or filed, so as to ensure a clean surface. Tt
is seldom, however, that the result is perfectly satisfactory
when the procednre is interrupted; indeed, the restoration
of any considerable amount of the crown of a tooth is rarely
attended with lasting success. A few show-casos may be
produced, but the operation is too tedious, and the ultimate
result is too uncertain, to admit of general application.

In instituting © comparison between gold foil and crystal
gold, the microscope may be called into requisition with
advantage. If plugs be made in perforated picces of ivory
(in the manner already alluded to) with the various forms of

346 A SYSTEM OP DENTAL SURGERY.

examining very closoly into the results, I have con
conclusion that it is inferior to foil for the construy
that portion of the plug which rests against Gl

of gold, plugs may be produced, the density and
ability of which comot be surpassed.

Sponge gold when long kept, appears to undergo some
molecular change, greatly iuterfering with its welding pro
perties, which are only in a measure restored by annealing. —

Gold foil is prepared by beating, or sometimes, in the ease
of very heavy foils, rolling, into thin sheets a perfectly pure
metal. The sheet when prepared for dental purposes is
usually four inches sqnare, and is numbered in accordance
with its weight, Thus the Nos, 4,5, 6, 7,8 indicate the
number of grains contained in each four-inch sheet, and
recently very much heavier foils have been employed,
reaching as high as two hundred and forty grains per
sheet,

The gold leaf of commerce is an altogether different article,
Tn order to produce a leaf sufficiently thin for gilding pur
poses, it is necessary to introduce a certain amount of co}
as otherwise the metal whon greatly reduced in thickness
will not leave the vellum, between sheets of which it is
beaten,

Considerable care is necessary in the preparation of the
gold leaf, as it is absolutely essential that it shall possess
certain physical characteristics as well as chemical purity,
Thos it must be tough and soft, and must possess either a
high degree of adhesiveness, or else must be completely non=
adhesive. In the one case, if several strips bo placed in a
pill-box and well shaken, they should become inseparably
united, whilst in the other they should not adhere when
firmly pressed together,

Moch fight has been thrown on this matter of adhesive-

348 A SYSTEM OF DENTAL SUNGERY.

molecular change when kept for a length of time, le
its assuming a hard, harsh texture,
Before describing the manner of introducing the g
will be well to devote a little space to the consid
the instraments employed, and the methods of ke
cavity free from moisture.
Methods of keeping the eavity dry—The most cial
applicable appliance for this purpose is a small
twisted into the form of a rope; the roll being passed
over the crowns of the teeth behind the tooth to be operated
on, and held down on either side of it by the operator's
fingers, Though it is easy to demonstrate the various
ways in which the napkin may bo applied, it would be an
endless task to attempt to desorie them. In employing the
napkin in the lower jaw it is generally possible to make
pressure over the mouth of the salivary duct, so as to
prevent or retard the exit of saliva; when operating on
the left side of the jaw, the first and second fingers of the
operator's left hand may be most conveniently used to hold
the napkin down, whilst in operating on the right side of
the lower jaw, it will generally be more convenient to stand
behind the patient, and employ the thumb of the left hand
on the inside and the first finger on the outside of the teeth.
Tt is often, however, excessively fatiguing to hold the napkin
in its place, und this may be done by a Hawes's tongue com-
pressor applied over the inner portion of napkin, whilst
single finger of the operator's hand holds down the outer
fold. Dr. P. Smith has modified and greatly improved
Hawes's duct compressor, and the instrament so altered is
extremely useful. ‘The figure which is here given will
explain itself; in applying it the napkin is first adjusted,
and then hold down by the introduction of the horizontal
arm with its horse-shoe end, which has been
detached from the rest of the instrument, Whilst this is
held in its place, its free end ig slipped through the hole at
the top of the upright (which has been previously raised to

850 A SYSTEM OF DENTAL SURGERY.

view of the cavity would be obscured, Hence it ix
passed over the tooth in front and that behind the on
operated on; but, of course, no general rule can be
on this point, If the teeth stand close to one anot]
about the eighth of an inch should intervene b
holes in the rubber, but if there is an interval
tooth a larger space must be left, so that the in
gum may be covered,

In applying the rubber the sheet is put on the
between the forefingers of the right and left hands, placed on
either side of the first hole: it is thus forced over the front
tooth, then over the next, and soon from before backwards,
till all the teeth which are intended to. be included are
through their respective openings in the sheet.

The rubber is then slightly pulled away from each tooth,
and the free edge lying against the neck of the tooth, which,
from the manner in which the rubber has been applied, will
look upwards, is tucked in by the side of the neck of the
tooth so tlt it is directed downwards; this may easily be
effected by the use of a burnisher, or other blunt instrument,
When the shape of the teeth is favourable to its retention,
no further measures are required to keep it in its place; but
should it tend to slip upwards, pieces of waxed silk may be
passed down between each tooth, and their ends tied together,
In other cases wooden wedges may be employed to retain it
in its place, or ligatures of waxed silk tied around the neck
of the tooth previously to the application of the rubber, so
as to form artificial ledges.

Tt is seldom necessary to apply the rabber dam in order to:
fill cavities in the grinding surfaces of upper teeth; a fold of
napkin placed between the cheek and the alveolar ridge will
generally answer the purpose in such cases.

There are, however, many cases in which the application
is exceedingly difficult, and in which the labour and possible
failure, after every precaution has been taken, render its use
hardly worth the trouble of its adjustment. Minor diffi-

The required space may be gained by #
Se ree ,
‘teeth.
‘I'he separation may be effectod at once, or tt]

‘The method of “ quick wedging,” as it is
ever, a good many advocates, and may be first
For this purpose twa wedges of orange wood an
one is forced between the necka of the teeth, and the sec
which is more tapering, is foreed between the point
teeth. Gentle taps of a mallet are given to the latter, an
the space thus gained is secured by a tap on the first wes

apart, snd when an adequate interval has been gai
second wedge is withdrawn. The force which — Pa
exerted in this way is very great, and many u near
accidents have been reported from an incautious use of the
mallet.

‘This method can only be reccrntoena in the ca:
incisor teeth, which require to be moved ‘
short distance; and it must not be resorted to where there
is any unhealthy condition of the gums or alveoli. On the
whole, the method of slow wedging is safer, and is the one
generally adopted in this country, If wood be employed, only
moderate degree of force should be used in inserting the
wedge, which may require to be replaced by a larger one
after the lapse of a few days. But the most convenient
material is india-rubber; this should he employed only im
very thin pieces, which may be cut from the solid lump. It
should not be left many days without renewal, and in no case
should a thick piece be introduced at once, as this would
exert a degree of force which might prove injurious, a

Tn many cases the separation may be very conveniently
effected by the use of cotton-wool, firmly pressed between the
tweth r this should be frequently renewed. ‘The time required.

|

the other ‘ill be found: to’ sxipesad asks
Gold Foil, non-adhesive —The maeee

cut up into more or less square pieces; or th
loosely twisted into ropes (Fig. 145).

Fig. 145.

—__

Or, again, the leaf may be cut into four or more
Salar cedioh Agreed hh SOSA ES
means of the instrument sold for the he
of two sheets of metal, une edge ct’ vaxkaot whial
up 6 as to form a ledge about one-fourth of an inch 4
‘The riband or rope is eut into lengths somewhat more
twice the depth of the cavity, and the pieces introduced b
means of an instrument with a tolerably large ext
the middle of each is carried down to the bottom
cavity, 80 that the two ends project from its orifice. When
the cavity is nearly full, an instrument with a smaller point
is used, and one end of each strip carried down to the bottom,
When we are unable to introduce any more foil, a sharp
wedge-shaped or trocar point is forced into the centre of the
plug, so that in the act of perforation the gold is very forcibly
pressed from the centre towards the circumference of the
cavity. ‘The hole thus made is filled by folding in strips
until no more can be introduced. ‘lhe operation of
aud filling the perforations, is repeated until itis no longer — |
possible to make the instrument enter. The success of the
proceeding will depend upon the character of the foil em= |
ployed, that which is destitute of adhesive properties being
alone suitable when the foregoing manner of operating is
adopted. Had the operation been conducted with adhesive —

\)
=

856 A SYSTEM OF DENTAL, SURGERY.

has been pressed is condensed into a hard
which lies next fo the cavity bas been relatively
acted upon, and probably, instead of adapting itse
turned away from the tooth at several poiats h
inatrument, and become loose in the cavity. -

With the non-adhesive foil, a mass after introduction is
readily applied to the walls of the cavity, which becomes
contracted to an amount corresponding to that of the metal
added, until at last the whole space is occupied by gold.
But each mass so alded, although closely adapted to that
already introduced, will preserve its own identity, and on
the tooth being broken up, may be separated from those with
which it has lain in contact. On breaking up the plug, it
will become apparent that the component masses have béen
held together by a system*of packing within a cirocumseribed
space, not by the adhesion to each other of the several por-
tions of which the plug has been built, It is very mecessary
that this point should be fully understood.

If the operator proposes using the non-adhesive foil, he
must proceed upon the principle of packing, and the layers
of foil must pass in a direction from the bottom to the orifice
of the cavity. The foil may, however, be introduced in other
forms than that of a loosely-twisted rope: it may be rolled
into a ball 6f sufficient size to loosely fill the cavity before it
is compressed, and when in position perforated with sharp=
pointed conical instrument, of sufficient size to foree the foil
against the circumference of the cavity. In filling up the
central aperture thus produced, the sides of tho filling should”
be forced down, At this stage of the operation we shall have
4 dense plug immovably fixed upon the floor of the cavity,
and rising up the sides to within a limited distance of its
orifice. ‘To complete the filling, the careful superposition of
layers of adhesive foil is alone necessary. Jn this manner a
plug may be built up in a cavity, two sides of which have
been lost, supposing the two remaining walls are strong,
For example, a large fissure running across the masticating

358 A SYSTEM OF DENTAL SURGERY.

are ent off; the other, by closely folding it into a fi
and rolling the riband round a fine broach, or, wi
an instrument made for the purpose. The oylind
Pig.14t, Fig.144.00) dnoed by the first method are soft
compressible; those by the last much
@ so, the respective advantages of th
forms being dependent on the nature ‘
cavity. i

‘The cylinders are made a little long
than the depth of the cavity which they are
intended to fill, and are introduced by plugs
Bing forceps. (See Fig. 154.)

Every cylinder is placed in such a po-
sition that one end rests on the bottom
whilst the other projects from the orifice of
the cavity; thus, if the cavity be on the
grinding surface, each cylinder will stand
vertically, but if it be interstitial, every
cylinder will lie horizontally. As it has
been happily expressed, the cylinders are
placed in the cavity like cigars in a
tumbler,

Two methods may be pursued in their
introduction into the cavity : a number of the tightly-rofled
cylinders may be set upright in the cavity till it is loosely
filled by them; a wedge or trocar-shaped instrument is then
forced in between them at any point where it can be made
to enter, and the holes thus produced filled by fresh oylin=
ders. At the last, when only small perforations can be
made, it will be found easier to fill these up by the -use of

() Metrement for rolling the foll Into cylinders. The shoet is cat Into two,
fied folded on itself (Hl the resulting riband is »omewhat wider than the cavity
{x dewp; it Is pelzed close to one end between the thin points of the tnstrament,
Wh are closed by pustiing up the eliding ring. When o eufficiont length bas
twon rolled op, the riband is cut off, and the cylinder released by very slightly
frawiog tack the sliding ring, Jt ls convenicot to make a stock of cylinders
of ouavenient #aes, keeping them ina bvttle until required for use,

be left for a compressor applied b
on @ properly inserted plug, it will have but little
effect. ‘
Difficulties in the use of adhesive foil nay iso
gold already in the cavity having been insufficiently eon=
solidated, and so yielding before the instrament and the

superadded layer, instead of affording an unyielding surface

against which the latter may be welded; or the failure’
arise from the surface of the gold being soiled, or wetted b
saliva, the condensation of the breath, or condensation from
the atmosphere. If the gold does not adhere readily it
should be annealed, either in the sheet, or by passing each
fragment through the flame of a spirit-lamp; with the heayy
foils the latter course is preferable. These heavy foils, which
may be rolled in the place of being beaten out, are remarkably
adhesive; the manner of using them does not differ in any
material particular from that just described, eave that they
should be cut into picoes nearly the size of the cavity, as it
is difficult to fold them : by having picocs of a suitable size,
each piece is laid on flat, and forms « complete layer in itself
The very heavy numbers, such as 140, are not easily
condensed without the use of some form of mallet; still
with care, and in a suitable position, very dense plugs may
be made by hand pressure alone.

Although the very heavy foils will probably never bave
more than a limited applicability, such numbers as 20 are
exceedingly useful, and in large cavities, where it is necessary

364 A SYSTEM OF DENTAL SURGERY.

been submitted to heat after the final beating. ‘The condition
was therefore that of unannealed foil.

Several sheets were folded and cut up into short strips for
the purpose of using in the stellate manner. In working it
was found to be adhesive, but at the same time very brittle,
and consequently required unusual care in introducing it
between the teeth, otherwise portions broke off and fell inte
the mouth. Another sheet was torn in six or eight pieces,
and rolled up between the fingers into as many small balls.
‘These were introduced, one after the other, into a lateral
cavity, with a small instrament having a slight spiral curve
near the point. The centre of the ball was first
lightly into the cavity, and the edges subsequently turned
in, and then the whole was thoroughly compressed. During
the operation the gold went down before the instrument inte.
a very solid condition, but there was not the slightest
tendency to turn up on one side when the other was pressed
down, or to roll in the cavity. The gold filed freely, and
when completed the plug presented a most satisfactory
Appearance,

From the same book a leaf was taken and rolled into
rather firm balls, which were subsequently annealed. Under
this treatment, although the adhesive quality was brought
out more strongly, each ball, instead of going down dead
before the instrument, had a tendency to tarn up and clog
the orifice of the cavity. Another leaf was annealed first,
and then rolled into balls, which on trial proved superior to
the annealed, but inferior to the unannealed balls,

From the same book two leaves were taken; one was
annealed, and after division into thirds, twisted into three
loose ropes; the other leaf was divided, and rolled without
annealing. The Intter showed a tendency to break to pieces
and waste, while the former packed and adhered, the one
fold to the other, with great readiness, and produced an
extremely good plug.

‘The foregoing results have been brought forward to show

366 A SYSTEM OF DENTAL SURGERY,

respectively used. The degree of heat to which the m
submitted in annealing will also exert a
finence in determining the manner in which it ean be
effectively manipulated. It would, however, be

t% enumerate every circumstance that may i
nection with the use of the different forms of gold
description |

in plugging teeth, and to give a detailed
methods of overcoming every difficulty that may |
itself to the operator. The task would be almost
and if accomplished, would not even then relieve the
from the necessity of making himself practically,
with the subject by means of carefully-conduoted experi=
ments, both in respect to the materials used in the formation
of plugs, and the instruments employed in conducting the

operations.

The cavity by one method or another having been filled,
and the gold allowed to project slightly from the orifice, the
next step towards the completion of the operation will be to
reduce the surface of the plug and the margins of the cavity
to the same general level, allowing a slight degree of fulness
to the central portion of the plug.

This part of the operation will readily be effected by a
suitable file, after which the plug may be carefully examined
with a sharp-pointed instrument, and should any part he
found sufficiently soft to allow of penetration, the aperture
must be enlarged and additional foil introduced, after which
the file must be again used to reduce any inequalities, and to
remove the impressions left by the instrument. We have
now to remove, by means of pumice powder or fine silica,
applied upon a strip of soft wood, or by a corundum tape,
the marks left by the file, and subsequently the surface may
‘be burnished with a little sonp, It will be found that the
burnisher will facilitate the steps of the operation, if it be
used after the file has been abandoned, and again after the
application of the pumice powder. Indeed, in many cases
the firm application of a burnisher will assist in the con-

368 4 SYSTEM OF DENTAL BURGERY. —

use the instruments constructed for use with
hand-pluggors (see Fig. 151); Butler's set of | ic
especial favourites in this country. -

For large condensing instruments, or for

ing, the preferable form ; it is large enough to be very
grasped in the palm of the hand, while the point of
strament is not far from the thumb and fingers, a i
some importance where considerable force must be used, as it
enables the operator to guard against the point slipping and
injuring the soft parts around. ‘Thus, in using a burnisher
the thumb may generally be rested on the tooth operated on,
or on one of its neighbours, and foree exerted in a direction
towards the thumb; in this way there is no risk of slipping,
and the force applied is both steadier and strongerthan when
the point of the instrument reaches far beyond the fingers.

In the more simple forms of plugger the shaft is perfectly
straight, but there are some cavities which can only be
reached by curved instruments, A very useful form is that
in which the shaft is bent in a spiral direction to the extent
of an eighth ora quarter of a turn, the coil being more or less
open or irregular to suit the requirements of particular eases.

For filling the lower teeth, and more especially for reach~
ing distal cavities in the lower jaw, the shaft of the instra=
ment may advantageously be bent at a right angle. For
reaching cavities far back in the mouth, the double bend
represented in Fig. 149 is serviceable.

There are some few operators who work with perfectly
smooth-pointed instruments, but the great majority prefer to
use points more or less deeply serrated. ‘These serrations,
which should consist of sharp-pointed pyramids, may be
cut with a sharp dividing file, and finished with a small
three-sided file; but it can be more readily accomplished
by a special tool. Such a tool is readily constructed by
taking an ordinary receded scalper, softening it, and convert~
ing its longitudinal ridges into teeth by making transverse

870

A SYSTEM OF DENTAL 80

an instrument with a sharp point, cham

Fig, 161.0)

(2) Mallet plugger

the plog when finished, ‘but fot) rt
each piece as it is introduced. It
officient means of thoroughly co
gold, and is adopted by a great number
rators; and it is productive of

priori.

The mallet should be constructed
heavy material, a very good form

« bent of led icloee! a a open LODE
silver, to Which is attached a handle about eight
inches long. Tut the use of the actual
is, to say the least, very inconvenient in
absence of an assistant; and a variety of auto-
matic mallets have been devised, the majority
of which simply repeat, in the form of a blow,
that same amount of force which has been
already expended on the filling in the form of
steady pressure, Inasmuch as the same force
is more effective in the form of a tap than in
the form of steady pressure, these automatic
mallets are advantageous ; but the force is gene-
tally insufficient, and those which give a blow
that is independent of previous pressure are to
be preferred,

‘To meet. this difficulty, the form of automatic

|

pattern,
enna Oe Meceie, No fey Riel Bete 9

SO Bl, fy aiieting 1 ‘a Won es iseeney Wat ‘handle of
am) afternarte with & mallet,

A SYSTEM OF DENTAL SURGERY,

the spring, so that the plugging point is actually:
from the gold, and is driven down upon it againuby
of the spring when the rod is released. In addition t

thero isa fixed leg, the point of which sie ert, nod

which is sufficiently long and thin to. enable the
spring it away from the striking point, In using

sa Un pll hha ne Sony pee a
Pig. 183.)

leg upon it, while blows are

hammered.

progress of an operation.

used by grasping the tooth, and squeezing the plug by

the handles: caution is, of course, required in its use, but in
(@) Mr, Tomos’s modification of condensing plugging forceps.

the second or striking leg at a

tance from the first varying at the
will of the operator, Itis exceedingly
useful in cavities in which the gold
is disposed to roll, as one side can be
securely held down while the other is

The points are changeable, but it
adds greatly to the convenience of the
operater to haye more than one spring
mallet, so a8 to obviate the necessity
for changing the point during the

After a very little practice no diffi-
culty will be found in varying at will
the force of the blow; the lightest
possible tap may be given, or, by
drawing up the spring to the utmost
possible extent, a blow might be given
which would be perfectly unbearable,

The gold having been introduced, the surface is next con-
densed by the use of instruments of gradated sizes; in
jnterstitial cavities, not very accessible, this is sometimes
rather difficult. A most usefal instrament, which is far too
little appreciated, is the condensing plugging forceps; it is

876 A SYSTEM OF DENTAL SURGERY.

As the tecth are usually in close apposition, it b i

necessury to resort to means capable of
amount of separation to allow of the introduction of fnsten=
ments, The end may be gained either Fide eo
of strips of caoutchouc or of compressed wood

Pig. 161. (2) coin oe oy ot
tooth. ‘The selection of means must
depend upon the state of the tooth to
be operated upon. If the decay has a
considerable superficial extent, it will be
well to cut away the lingual surface of
the tooth with the chisel (Fig. 157),
in such a manner as shall leave a V~
shaped division between the teeth, with
out interfering with their external ap-
pearance. If the superficial extent of
the disease be limited, it will be well to
avoid cutting into the tooth, as we
should be sacrificing sound tissue. ‘The
requisite separation may be obtained by
the insertion of india-rabber between
the affected and the contiguous tooth.
In some cases a sufficient interval will
be produced in twenty-four hours, while
in others a much longer time may be
reqnired,

‘The next step isthe removal of the
disorganised dentine ; but before proceed=
ing to remove the decayed tissue, the
condition of the gum with respect to the
diseased tooth should be considered. In many cases we
shall find the free edge vascular, and descending below the
upper margin of the cavity, and perhaps curled intoit. When
in this state it will be next to impossible to operate withont-
wounding the gum; blood will then flow for some time, and

(2) Straight enamel-cutter,

=|

878 A SYSTEM OF DENTAL

must ever be borne in mind that the pulp
fize, corresponds very closely in shape to the
althongh it may be, and often is, altered is

will be better to leave a little discoloured ti
bottom of the cavity. From the walls and fro
the cavity, on its labial and lingual sides, »

proceeding behind or in front of it, 2 |
Having shaped tho cavity in accordance with thé i

given when treating upon the subject generally,
mil be cls fall seinen shi
it a stream of warm water, by means of a

cavity should now be wiped dry with cotten-wool or tise
paper, and its shape very carefully examined. Should any
doubt exist as to a proper form having been produced, a
little warm wax or gutta-percha may be pressed into it, and
a cast obtained, By this simple procedure we shall often
discover that had a plug been introduced, the chance of its
preserving the tooth for any length of time would have been
but slight. Supposing it be found that the walls of the
cavity are generally divergent from within outwards, the
defect must be remedied. Small hoe-shaped instruments
will be found suitable for reducing to parallelism the labial
and lingual walls; and a drill, carefully directed so that it
hall not approach too closely upon the pulp in the neck of
the tooth, will reduce to a proper figure the upper wall of the
cavity. The excavator, figured on page 388, will be found
very serviceable in preparing the cervical portion of the
cavity. After feeling assured that the cavity has acquired
a form favourable for the retention of a plug, it must be
thoroughly washed out, and subsequently made perfectly dry.

380 A SYSTEM OF DENTAL SURGERY,

Tvs vonpunl" te mane te tab

Having recognised the manner in which a

arise, we have to consider how its occurrence may be

or, if present, how it may be overcome, The

condition may be avoided by passing the instrament over

the whole. weston of the gid with + AgHOREENE

the operation with gradually increased foree until

is equally consolidated. But should the pape

sition to roll, we shall do well to remove it and recommence

the operation, or to take an instrument in the left hand and

hold down one part of the circumference while the other i
compressed. The use of two instr

Pig. 160. (1) ments in the manner already alladed ta

# is not unusual whero adhesive foil in
employed.

After thoroughly condensing the foil

in the upper part of the cavity, the
completion of the plug is comparatively
easy. If the adhesive foil be used, the
operation may be pretty rapidly per
fected by adding short strips one after
the other, compressing each consecutive
piece upon the gold already introduced,
taking care that in making the folds
the duplicatures do not fall short of the
walls of the cavity, otherwise the plug
will be hard in the centre and soft in
the circumference.
Should non-cohesive foil be preferred,
the same method with respect to filling
the upper part of the cavity first, may be adopted; but in the
subsequent proceeding it is necessary that the folds of the
rope or riband should pass from the bottom to the orifice

(*) A palr of instramonte, right and left, adapted for compreming plags in

the méestal or distal surface of front teeth, or for adding adhesive foll or sponge
gold to the eurface of an unfinished plug.

eC |

METHODS OF INTRODUCING THE GOLD. 881
of the cavity, To effect this,‘an instrament #¥g. 160.(1)
the

HET
ak
let

ee
Ate

i

from the surface of the plug, when chalk may tak
of the pumice. This amount of care in fini

rioration. Bat on « cle exatzination fal the b
the cases it will be found that the disposi od

versed, it is probable that, in place of finding the p
should have heard that front teeth had been™p
years ago, but that the fillings fell out in a short |
that these, with other teeth which were then di
gradually decayed away down t8 the level of the gum.
‘The immediate object in filling a tooth is to perfectly ex-
clude from the cavity all extraneous matter, fluid or otherwise,
and at the same time to leave a surface upon which mucus:
or minute particles of food cannot readily adhere, If the
surface of the gold be left rough, these indications are not
fulfilled; food and other matter will collect, and necessitate:
the frequent use of the toothpick, which falling from time to
time into the inequalities of the gold, eventually disturbs the
filling. There is another advantage resulting from
with care the surface of a plug, and itis this: after the
and harder part has been filed away, and the surface of the
plug and the contiguous surface of the tuoth reduced to the:
same level, we not uncommonly find that the plug is soft at
some point, aod admits of being perforated. ‘The discovery ~
of a defect having been made, a remedy must be found, even
though its application may necessitate the removal of the
gold and the recommencement of the operation. For to leave
the plug pervious to moisture will be to endanger, if not to
ensure, the further injury of the tooth. Unfortunately, the
fault is very commonly in the worst possible position, both as
regards its effect in exposing the tooth to further disease,
and its capabilities of amendment, That part of rien

—| 4

duced from the front, leaving the whole of the ba

the tooth standing. By the adoption of this plan, m

of the front of the tooth may be retained than the

firm, strong lingual wall of the cavity had been For

mi a am so eg ee |
preserved, although too weak to stand unsupported |

plug, the firmness and the retention of which will |

ciently secured by the upper, the lower, an he gal le

of the cavity. In condueting the operation, however, g

care must be taken to avoid injuring the weak part;

will be found expedient to introduce the foil in small portions,

making each piece firm before the succeeding one is added;

for should an attempt be made to consolidate the

by perforating the central part of the mass, the

of the cavity will give way, and thus frustrate the objectof

the operation.

Cases not infrequently arise in which the walls are all
much weakened, excepting only at the upper part of the
cavity. If this part can be so shaped as to very firmly
retain the gold packed into it, the rest of the cavity may be
filled by gold packed adhesively on to that first introduced,
very little pressure being made upon the weak walls, Thus
it is often possible so to form the upper half of the cavity,
that it will firmly retain a ball of non-adhesive gold pressed
into it and malleted till it is perfectly hard; sponge gold
may then be built on to this till the cavity is full, and thus
4 satisfactory filling introduced where the walls, towards the
lower end, are little else than enamel.

A useful contrivance for making up pellets of non-adhesive
gold, consisting of two sheets of zinc, has already been de-
scribed, By means of this all handling of the gold is avoided,
and the adhesive gold will more readily stick to the pellet |
first introduced.

Cases will arise in which the disease has so far injured the
tooth, that instead of finding one, all the walls excepting the

oe a

886 A SYSTEM OF DENTAL SURGERY,
ment, Natural depressions are not uncommonly fi

not require any special description.

When the development of the enamel has been d
cavities may be produced by disease in those |
the natural defect is most strongly pronounced, whether it |
be situated on the lingual or labial surfaces of the teeth. —
submitted to treatment at a tolerably early period, the hole
is usually characterised “by greater breadth than depth, and
its shallow walls slope outwards, om

The cavity, after the mere removal of the discase, ]
compared to a sancer—a form incapable of
with any dogrve of certainty. ‘The first step in the proceed~
ing must be the reduction of the walls to a vertical position
by the use of a small, sharp excavator, and it will be well,
when the cavity is very shallow, to produce « slight degree
of undereut. In selecting the materials for forming a plug,
foil and crystal gold may be taken with advantage. Three
or four thicknesses of foil, sufficient to line in an even layer
the sarface of the cavity, should be first introduced; small
fragments of sponge gold may then he added, and
conipressed, one after the other, until the resulting plug stands:
higher than the general levol of the tooth, Or if a groove
be cut at the upper and lower portions, or at its two sides, as
may happen to be most convenient, foil may be packed so
ctrely into each of these places, and the plug completed by
filling up the central space between the portions first intro-
duced by some form of ndhesive gold, the latter acting like
the keystone of an arch,

After removing the superfluous gold with a file, the surface
of the plug should be examined with a sharp-pointed insteu-
ment, and any defect made good. ‘This having been done,
woud the instrament marks filed out, the surface may be
further improved by rubbing it with Water of Ayr ora slip

li =

388 A SYSTEM OF DENTAL SURGERY.

borne in mind, otherwise the removal of that tissue will be
attended with greater difficulty and greater inconvenience
to the patient than necessary. The most suitable instrn-
Fig.1er, Ment is the flat chisel-shaped enumel-cutter, the
edge of which, on commencing the operation, should
be applied in a direction parallel to the course of
the alveolar line, and gradoally changed to a rect-
angular position with the disappearance of the part
undergaing removal. The excision of the carious
tissue will now be effected without difficulty; and
having advanced thus far, it will be advisable to
introduce the wooden wedge between the teeth im
the manner described at page 377. ‘The gum
having been pressed up against the alveolus, the
cavity may be redaced into the required form
without fear of embarrassment from a wounded
vessel, Oare must be taken to remove all the af-
fected tissue from the upper part of the cavity.
This may be accomplished with a drill, but the
position of the pulp must be borne in mind, for in-
struments of this character, when in good order,
cut rapidly, and if a proper direction be not ob-
served, the pulp-cavity will be opened. In pro
ducing parallelism of the sides of the cavity, the
hoe-shaped excavator will be found very useful, as
will, also, the round-ended excavator here figured;
and several sizes and forms of these should be at
hand, some of which are constructed to ent by a
drawing, others by a pushing motion. If this part
of the operation has been conducted with success,
an oval cavity will have been produced, the walls
of which converge slightly from within outwards,
more especially the wpper wall, the margin of which will
be covered by the wedge, thus producing « shallow cavity,
a temporary side being formed by the wood. The head
of the patient should be thrown back into the position

390 A SYSTEM OF DENTAL SURGERY.

each is thoroughly adherent to, and condensed upon, ite
predecessor, and that each is laid on with some degree of
evenness. If the latter caution is neglected, on conrpleting
the operation it will be found that the plug is perfectly
solid in the centre and porous at the sides—a faulty con-

ig. 182, (1)
Figs, 163 and 16,

\

dition which it is difficult to remedy without commencing
the operation anew. In order to guard against the occur-
rence of this error, it will be well to test the plug from time
to time with a square-pointed or a wedge-shaped perforat-
ing instrument. It may be neceasary, when the lowér wall
is approached, to change the instrument in favour of one
the blade of which is more bent upon the shaft (Fig. 164),
in order to ensure the gold being carried to the bottom of the

\!) Figs. 162-34 show instruments having the same general character, the

frst being adapted for introducing the gold, whether foil or sponge; the secon
and third for the condensation of the plug.

Se

the point where the enamel :
beyond it, so as to get rid of this fragile pico n
obtain a cavity the cervical wall of which is:

that the cervical wall had better be composed of cemé

than of enamel,

it onen matter of @ifeuy to itradace the gal
beneath the enamel and dentine which bound

towards the masticating surface of the ou an
not perfectly solid at this part, the tooth will give it
it during mastication. A method which is often very sem
viceable, consists in altogether cutting away this wall of the
cavity with an enamel-cutter. In this way a cavity is formed

above downwards and from without inwards, the
portion boing, of course, at the cervical ‘wall and at the floor
of the cavity—or, at least, what would lige |
had not the masticating wall of the cavity been temoy
The whole cavity is thus easily accessible to straight instrn-
ments; and by commencing with a piece of non-adhesive,
apt eunpietitg the. Slog ‘by’ ploone f eicsiny aa
results may be obtained,

satisfactory 7
American dentists have lately introduced « plan of filling

= =—

METHODS OF INTRODUCING THE GOLD. 893

‘these interstitial cavities by the aid of “ matrices ;” these

consist of polished plates of metal introduced between the

teeth, soas to serve as a temporary fourth wall to the cervical

portion of the cavity; they are removed either when this

part of the cavity is filled, or are allowed to remain until
whole plug is

Treatment of Simple Cavities in the Upper Molar Teeth,—It
will not be necessary to enter minutely into all the details
connected with plugging the molar teeth, as the account
would be but a repetition of that which has already been
described

thrown back, and placed at a height to "#70
operator.

-used, and the tooth cut away until, on
the lips being drawn tack by the frst

894 A SYSTEM OF DENTAL SURGERY. —

and second finger of the loft hand, the cavity omn be
‘The operation of plugging is far too diffieult tos

successfully performed in s cavity which is out of sight. It
will consequently be sometimes found necessary to reduce
the tooth to a greater extent than would have been needed,
had the disease been situated on the mesial surface of

extent of injury it has produced.

The preparation of the cavity must be pro-
ceeded with upon the same general plan as that
already described, and the instruments used in
plugging the bicuspid will be equally suitable
for the molar teeth. In consolidating the
surface of the plug, the sccompanying form

| will be found suitable.
il For cavities situated on the labial surface
of the upper molars, a pair of instruments,
right and left, somewhat of the forms given in the figure
(Fig. 168), will be found serviceable. With the head thrown
back, and the face turned to the right or left to suit the
case, and the commissure of the lips draten back, the cavity
can be readily reached with the instrument, and a twist
(@) Showing an instrument suitable for the Introduction of exystal gold, or
for Ginally condensing the surface of w foll-flling altaated In the distal surface

of ai Upper molar or bicuspid tooth.

METHODS OF INTRODUCING THE GOLD, 395

given to the blade will enable the operator to force the foil
opwards and backwards, without allowing the shaft of the
instrument to interfere with the teeth and lips of either jaw.

Pig. 164. (F)

No one will be found to question the superiority of gold
over other filings, but there are cases in which the crown is
#0 hollowed ont that the tooth is reduced to a mere shell,
quite incapable of withstanding the force necessarily em-

@) Higtt and feft instramente for introducing felt Into cavities stinated upon
Ge labial eurfaces of the upper molar teeth.

396

ployed in the introduction of foil or sponge gold.

treatment of a case of this kind, we shall d
amalgam. The tooth may not last for any
timo, bat should it be rendered serviceable but fo

Pig. 188. (4)

the
former material. The slight dis-

ance, Gutta percha might be used,
but it does not render the

—lIn operating upon the lower tecth the proceeding will be
varied as respects the position of the patient, the form of the
instruments used, and the precautions necessary to exclude
the intrusion of the saliva from the part under treatment.
‘The ename)-cutter will be called into requisition, but the
straight chisel-shaped instrament so useful in the npper, fails

() Right and left asbre-bladed chumel-cutters, sultable for pen
‘the mesial or distal purthce of whe bicusplds or first molars of the lower Jaw.

=

595

linen, 4. corepcading 44. cur cod
the lip and gums, the two being retained in positi

napkin, twisted into a rope-like form, and
crown of the teeth.
‘The cavity having been rendered perfectly dry,
may be introduced with instruments similar to those used
rig.imt,q@) conducting the like operations on the corre
sponding upper teeth. Cavities in the cay
may perhaps in some cases prove
and require similar management to that
which will be subsequently described as ap-
plicable to the treatment of the contiguous
bicuspids,

In filling cavities situated on the mesian or
distal surface of the last-named teeth, the
spiral-bladed instrument may be employed
with advantage, the gold being introduced from
the labial side of the tooth. When the distal
surface of the right teeth is under treatment,
the operator should staud to the right, and a
little behind his patient ; and on the side, but
slightly in front, when the corresponding part
of the left bicuspids is operated upon—the
patient in the former case leaning his fice to

the left, in the latter towards the right side. Those in-
stances in which the crowns of the teeth are reduced to a
considerable extent on the lingual side, in consequence of
the disease having encroached upon the muasticating surface,
as woll as upon the neck, will allow the foil or sponge to be
introduced from above more advantazeously than from the
side, ‘The plugging instrument should have a short blade,

(® An tastrament ueed for condensing the surface of the guid inserted either
on the distal mde of the right, or the mesial side of the left bleuspht. An
instrument resembling the one shown in the figure Is well adapted for con-
Genming the purface of the gold.

400 A SYSTEM OF DENTAL SURGERY,

porarily close it. With a little management, we shall suc-
ceed in keeping the tooth under operation dry for a sufficient
length of time to enable the gold to be introduced. When

Figt. 172 and 173 (1)

the operation is on the
left side of the patient's
mouth, the

will differ only in the
position of the left
hand, which will then
be in front; the thumb
will rest on the labial,
and the second finger
on the lingual side of
the teeth. By using the
second finger for the
retention of the napkin,
the first is loft free for
assisting in the guidance
of the instrament, or the
adjustment of the nap-
kin, should it become
displaced: and the use
of such an instrumentas
Hawes's ductand tongue
compressor will save the
Operator's fingers much
fatigue. If the flow of
saliva be excessive, «
small fold of linen may
be placed hehind the in-
cisor teeth, and when

saturated, renewed with the right hand, while the left keeps
the napkin which surrounds the faulty tooth undisturbed.

(1) Instruments constructed with a double curve for filling cavitts in the
masticating surface of the lower molar teeth; the former being suited for
ordinary foll, the latter fur edbesive foll or sponge sold.

402 A SYSTEM OF DENTAL SUNGERY.

in which the disease is situated on the distal surface of the
lower molars, more especially when the cavity is small-and
confined to the neck of the tooth, The free use of the

Pigs. 17S amd 196, (1)

enamel-cutter is required, and it is often with great difficulty
that the crown of the tooth is sufficiently cut away to enable

qty A right and a left double-curved Instrument, for introdecing fol] Into
avities on the labial surfaces of the lower molars.

== :

after the lapse of a few months, have found
itself had become calcified at the point corres;
disorganized dentine. The presence of a pli
further progress of the disease, and prevents the
the mouth from penetrating through the d
the pulp-cavity, while the softened tissue re
covering to the pulp saves the latter from
sudden changes of temperature, which would have
directly conveyed through a metal plug but for the i
vention of the dentine. When, however, the expos
produced during an operation the pulp is usually wounded,
and bleeds freely. The pain is commonly scute, but soon
subsides ; but sometimes no pain is experienced. After the
bleeding has ceased the cavity should be syringed out with
tepid water, and carefully dried with cotton-wool. The
actual state of the walls of the cavity, the size of

foration into the pulp-cavity, and the condition of
immediately around the hole, can then be examined. If it
be found that the whole of the softened dentine had been
removed, that the aperture into the pulp-cavity is very
minute and surrounded by sound tissue, we may proceed to
plug the tooth in the usual manner, adopting the precaution
of laying a small piece of foil, folded six or eight times npon
itself, over the sperture. But should it appear that the
opening into the cavity is of considerable size, or that,
though small, it is surrounded by softened tissue, the removal
of which would increase its size, a different mode of proceed-
ing must be adopted.

As much as possible of the disorganized tissue, short of
enlarging the aperture, should be carefully cut away, taking
care that the walls of the cavity are reduced to a suitable
form ; an artificial substitute for the missing portion of the
wall must be provided, in the preparation of which two
conditions should be observed. Like the dentine, it should
be a non-conduoctor, and also, like it, be capable of
the pulp from pressure. To possess the latter quality th

4

406 A SYSTEM OF DENTAL SURGERY, —

determined whether the plug is to be regarded as a tem-
porary or a permanent one, Should the treatment prove
successful, the exposed portion of the pulp will, in the course
of s few months, become calcified, and the aperture in the
cavity stopped from within by a layer of secondary dentine,
Assuming this process to have been effected by nature in a
teoth that has been permanently plugged over a cap, it &
quite possible that the filling will presorre the tooth for an
unlimited period, but it is far more probable that a plug
introduced under such circumstances will, after a time, fail,
and the failure perhaps may not be discovered until the
crown of the tooth is all but lost, Had the filling been
regarded as temporary, the tooth would have been examined
after the lapse of six or eight months, the temporary plug
removed, aud a gold filling introduced under circumstances
far more favourable than obtained when the operation was
complicated by the presence of a cap and general tenderness
in the tooth,

So much uncertainty, however, was found to follow on the
capping of exposed nerves, that the practice fell Into some
disfayour, but it has again been revived in a somewhat
modified form, and meets with fairly successful results, In
the place of using a protective cap of quill, or other hard,
unyielding substance, it is now usual to lay over the point of
exposure a very small picce of cotton-wool soaked in thymol
or carbolic acid, or a drop of collodion containing carbolic
acid, Over this a filling of gutta-percha, or, I think,
preferably, zine oxychloride, is inserted and allowed to
remain for some months, Some writers advocate the direct
application of the zine oxychloride to the exposed surface of
the pulp; but I prefer to protect the point of exposure by
one or other of the substances mentioned. Jn many instances
where the exposure of the pulp is very small, or where some
softencd dentine remains, forming an insufficient
to it, a layer of zinc oxychloride may be put over it and
allowed to harden; this is cut away on the next day,

Vim

408 A SYSTEM OF DENTAL SURGERY. —

if the pulp were capped, the introduction of a plug would be
attended with risk of breaking down the shell. ‘The patient
may be unable to return to you, or to obtain the assistance
of a dentist for some years to come. On the ocourrence of
circumstances such as those enumerated, the protective
system of treatment mnst be abandoned. Instead of striving
to save the pulp, means must be adopted to bring about its
destraction. ‘I'he most effectual, and at the same time
safest, manner of accomplishing this end, ee
a very fine and flexible broach through the Rers ‘in the
pulp-cavity up the fang of the tooth, When the further
progress of the instrument is arrested by the diminished size
of the cavity, a rotatory motion should be given to the
broach. The effect will be to ont off the pulp in the root of
the tooth at the most constricted part of the canal, and, con-
sequently, of the pulp itself, This treatment is applicable
to single-rooted teeth only, and even in these the

is sometimes attended with great pain, owing to the difficulty
of passing the broach to its proper destination, Whatever
instrument be used, it should be at once boldly thrust home:
little or no more pain is given by such @ procedure than by
& mere touch, and indecision on the part of the operator
involves prolonged suffering to the patient,

By destroying the pulp, we convert the once simple into a
compound cavity, the one part being formed by the pulp
cavity, the other by the cavity produced by the silent
disease.

The two cavities have now to be regarded as one, and
steps must be taken to reduce it to a suitable form for the
reception of a plug. The canal in the reot, after the with-
drawal of the pulp by a spirally-twisted broach, or preferably
by one of the barbed instruments constructed for the pur
pose (7), should be enlarged with a drill, and the distinction

Brot Tor. destroy ant witha oft the pulp ioc vue fi

elastic, and flexible, otherwise the capability of fullowlng the curved
necessary for the effective performance of the operation will not be obtained,

410 A SYSTEM OF DENTAL SURGERY. —

tissue will, ceteris paribus, generally be
amount of surface injured. In the case of a
sectional area of the pulp near the end of the "

small, that its division in a healthy subject will not be fol-
lowed by inflammation, unless the injured part is subse-
quently exposed to irritation. But should the saliva find
access, or a large coagulum collect in the vacant cavity or
in the interstices of the wool, and decompose, the lacerated
surface will become inflamed, and the disease will extend
from the remnant of pulp to the periosteum of the root and
socket,

Thore are other, methods than that just described. of de
stroying the pulp; and in cases where the use of the broach
is attended with difficulty, owing to the position of the
opening in the pulp-cavity, or to the tooth having more
than one root, they are to be preferred. The use of escharo-
tics for destroying the pulp can no longer be looked upon as
a novel mode of treatment, The practice has stood the test
of time, and may be regarded as one of many great improve-
ments in dental surgery matured during the present genera-
tion. Ruspini, in a pamphlet published in 1797 (*), mentions
destroying the pulp, and subsequently filling the eavity, but
the operation was not generally adopted, and its details and
results worked out, until within the last twenty years. It

() Respini, in bis "Treatise on the Teeth," the eighth edition, published:
2797, makes the following statement: “Whenever caries appears it must be
opened with » masterly hand t» ihe very bottem, If tm doing so the chord of
the tooth is discovered, the operation will prove painful; but stfll it must be
dosteoyed, either with an panbemmtihin ied
caustic Liquor.

We ought to be very attentive in the operation; for if we do met

destroy the tald chord, but only prick It, the most raging palns will
together with an inflammation, and the Inevitable necessity of drawing the
tooth,

© When a tooth by Ube loss of Its chord |¢ become tnsensible, ft must be Sitesd
with lead or gold, In order to prevent any acid or galing particles from petting
through the hole where the chonl went Into the socket, to burt dts dolicate
membrane; for then there wvnld be no means of redress but by drawing the
tooth ; bene all the care that bad been taken, and oll the pain that had beer
avlured to render the tooth invensible, would then b: of no avai."

ee e |

412 A SYSTEM OF DENTAL SURGERY,

for a long time in the tooth, it may permeate the dentine
and affect the peridental membrane; whereas, if the body of
the pulp be dead, the degree of sensibility of that which
remains in the roots is so much lowered that it may be with=
drawn without occasioning any considerable amount of pain.
By observing this precaution we ensure the removal of the
caustic, and leave the pulp st the point of rupture in a much
more favourable condition for healing than if it had been
saturated by the escharotic,

‘Yhe fourth rule is, that escharotics should not be applied
to a tooth, with the view of destroying the pulp, unless the
fang is fully developed, and the aperture through the ex-
tremity of the root reduced to its ultimate size. In young
subjects the canal in the root of a tooth is very large gene~
rally, but more especially at the terminal portion, and the
pulp maintains a corresponding size,

‘The expediency of destroying the pulp by means of an
escharotic having been determined on, the substance best
fitted to produce the effect must be selected. The mineral
acids, nitrate of silver, chloride of zinc, and many other sub-
stances possessing canstic properties, have each in turn been
used, Arsenions acid has, without giving rise toa
amount of pain, been found to act with more certal:
in less time, than any other agent, The
operation 18 80 great a recommendation that
invariably employed in preference to any ©
caustic. The extremely active cha
as 4 poison led me some years since to
which, although less certain
employ in the mouth. At
of arsenic capable of c

414 A SYSTEM OF DENTAL SURGERY.

must be directed to avoid masticating upon the tooth, or
disturbing the application by any other means, even though
the pain it occasions should be severe. Both the intensity
and the duration of the pain produced by the destrective
action of arsenic upon the dental pulp are inconstant te a
degree for which the recognisable differences in the cases fails
to account. Qne patient will tell you that the application
produced no pain, another that the toothache was most
severe, and lasted for ten or twelve hours, while a third will
describe the pain as moderate in degree, and of a very
bearable kind.

It is remarkable that the application of arsenious acid to a
tooth which has previously been aching severely
*9-17-() ig seldom followed by much pain; perhaps this
may be due toa pulp in a state of inflammation
being more readily destroyed than one in a com=
paratively healthy condition. The more free the
exposure of the pulp, the less pain will, as a mile,
be experienced : there is no condition productive
of such severe suffering as a mere pin-hole ox-
posure of the pulp through which the arseni¢
passes only in sufficient quantity to act as an
irritant; the result is that the pulp swells, a
hernial protrusion is forced through the constricted.
orifice, and the aching and throbbing are almost
unbearable, It isin a complete exposure of the
pulp, and an effectual application of the escharotic,
and not in the admixture of drugs such as morphia
with the arsenic, that we must seek to obviate

suffering during the destruction of the pulp.
A small opening into the pulp-cavity may be
advantageously enlarged by the use of the instru-
ment here figured: from its shape it has the advantage
of not slipping abruptly into the pulp, as would be the case
were # rose-headed drill or a broach employed to enlarge the

(1) Drill for opening the pulp-cavity.

416 A SYSTEM OF DENTAL SURGERY,

fangs, that their withdrawal occupies some little time, the
pulp becoming broken down by the operation. In such
eases the contents of each fang must be drawn out separately.
Although the body of the pulp has become insensible, more
or less pain will be felt when the pulp situated in the roots
of the tooth is broken across at or near the orifice by which
it passes into the alveolus; but the pain subsides immediately.
Should slight hemorrhage follow, the operation may be sus-
pended for a few minutes, by which time the bleeding will
have ceased.

Ifthe treatment has been successful, the pulp-cavity of the
body and of the roots 6f the tooth will have been cleared of
their natural contents, The further treatment will consist in
filling first the roota (when practicable) with gold, then the
pulp-cavity, and lastly the external cavity. The necessity
of filling the roots has been strongly insisted on by the
American writers, and there can be no doubt of the adyan-
tage which resnlts, supposing the canals to have attained a
certain magnitude. But when the root is small and its cavity
too minute to admit a fine broach, it may be left without
the fear that avy evil consequence will ensue, In a first
molar of the upper jaw, for example, the anterior and palatal
roots should be filled, but the posterior root is commonly
traversed hy a canal too small to render filling necessary.

Some doubt has been expressed as to the practicability of
filling the roots of teeth, and no doubt the operation is
tedious; but when sufficient time is given very little difi-
culty isoxperienced. In front teeth it is simple enough, and
in the back teeth it mnst be rendered simple, otherwise the
result will be imperfect. The crown of the tooth must, in
fact, be cut away until the pulp-cavity is fully exposed and
its continuation in the roots bronght within the reach of an
instrument, It will in most cases be found desirable to
enlarge the canal with a broach. ‘The question constantly
suggests itself as to what extent the enlargement shall be
carried, and to what depth. The determination of these

418 A SYSTEM OF DENTAL SURGERY,

broach, and consolidated. Ora piece of soft annealed gold
wire may be inserted into the fang.

Some little attention must be given to the instruments
employed for this delicate operation. If an ordinary four
sided broach is used, the temper must be reduced to that of
4 spring, otherwise it will snap off during the operation, a
portion probably remaining in the cavity. 1 have known this
accident happen in several cases, and a portion of steel has
unavoidably been allowed to remain iu the tooth, without
any evil consequence becoming immediately developed.

A preferable instrument may be made either from a piece
of steel wire, or by grinding into a cylindrical shape a strip
taken from a clock spring. ‘The extremity, if left flat, will
carry the gold to the bottom of the cavity more readily than
it would do were anu edge or point produced, ‘The curved
course which the broach is required to tale renders elasticity
absolutely essential, and in no way can this be obtained more
readily and more certainly than by adapting te our purpose a
piece of watch or clock spring,

‘The root or roots being plugged, the sobsequent part of
the operation does not vary from that of making an ordinary
plug, excepting that the eavity in the tooth is umusnally
large, and will therefore occupy a greater length of time
than would be consumed in filling a simple cavity, If a
large molar, either of the upper or lower jaw, be the subject
of treatment, the compound cavity, even after the roots of
the tooth are filled, may be so deep that difficulty will be
encountered in packing non-adhesive gold so as to form a
single plug. In such cases it is well to first fill perfectly the
pulp-cavity, and then to proceed to make the more external
part of the plug. It is a convenient practice to fill the roots
with gold, and the crown of the tooth with some temporary
filling, postponing the completion of the operation for a
fortnight or more, so that should any alfeolar irritation
arise, the removal of the plug may be readily effected.

.
420 A SYSTEM OF DENTAL SURGERY.

and face aro unpromising subjects, and we can soareoly
expect a very favourable result where the gums are in an
unhealthy condition.

The ocourrence of « small and unimportant chronic gum-
wil, coming and going with little or no inconvenience, must
be placed amongst the results which may follow the destruc
tion of the pulp and the subsequent filling of the palp-
cavity. In respect to the root itself, changes, T believa,
commence from the time of the operation, aud proceed,
more or less slowly, until the tooth is lost. In pivoted teeth
the root sometimes becomes enlarged, but mure commonly
suffers a diminution of bulk. In a case which came under
my notice, the pivot had -been exposed by absorption on one
side of the root; in another a sufficient amount to ensheath
the gold pin only remained. Again, if we take the roots of
teeth which, after the loss of the crown, have had the pulp-
cavity sealed up by secondary dentine, we shall find that
vither additions of cementum have been made to the surfhee,
or that the surface has been gradually wasted by absorption.
In many cases there will be ample evidence to show that the
two actions have alternated. Ultimately the waste exceeds
the repair, the root is shortened, loses its implantation, the
socket disappears, and the tooth, after the lapse perhaps of
some years, falls out.

In the place of filling the fangs with gold, cotton-wool
saturated with carbolic acid may be used ; the results are, for
a time, at all events, very satisfactory, though eventually
the carbolic acid seems to disappear, and in some cases the
wool becomes saturated with discharge, and then a gumboil
is the inevitable result. f

Other methods of treating an exposed pulp than those
already described have been proposed, and for a time found
fayour. Mr. Hullihen described an operation which has
since received his name. Ht consists in drilling o small hole
‘through the neck of the tooth into the pulp-cavity. The
‘perforation is made either under the free edge or through

Sa F |

METHODS OF INTRODUCING THE GOLD. 421

the gum, a short distance above its terminal margin. The
cavity produced by caries is then filled permanently, leaving
the artificial perforation open. But as this operation relates
to the treatment of diseased pulp, its further consideration
may be postponed. :

Some few years since it was proposed to char the exposed
surface of the pulp by electric cautery, with a view of
destroying the exposed portion preparatory to the introduc-
tion of a plug. In my own practice the advantages derived
from this mode of treatment were’ very questionable, and
the operation was therefore abandoned.

¢ 422°)

DENTAL EXOSTOSIS.

Tae implanted portions of the teeth, like other parts of the
skeleton, are liable to local hypertrophy. In the bones the
stritcture is uniform throaghout their substance, and the new
tissue does not materially differ from that to which it is
added. The routs of the teeth present this point of differ-
ence: they are composed of dentine clothed with an external
layer of cementum, a tissue which offers no striking eha-
racter by which it can be distinguished from ordinary bone.
In exostosis this layer becomes thickened either loeally or
nip. 800) generally, the dentine in no case participating
“ in the enlargement. The disease may be defined
as an addition of tissue, more or less normal
in character, but abnormal in amount, to a pre-
existing tissue of the same structural character.
li, for example, we male a section from a tooth
the root of which has been increased in size
beyond the natural dimensions, an unnaturally
thick layer of cementum will be found, but it will in many
instances be difficult to point out a sharp line of demarca-
tion dividing the pre-existing from the recently-added tissue.
Tn respect to the structure of cementum, it scarcely falls
within the scope of the present work to enter minutely into
its histological characters. For a full description of these
the student is referred to Mr. Shelley’s paper in the “'Trans-
actions of the Odontological Society,"(*) to works on His-
tology, and to the previous publication of the author, But
{(*) An upper bicuspid tooth, with exovtosis of the cementum of the root.

(*) *On Dental Exestosis." By Herbert Sheltey, Esq. MB, Lond, MAECS,
© Transactions of the Odontologteal Society of Loudon.” 1854-87.

424 A SYSTEM OF DENTAL SURGERY. 7

centric arrangement of the laminw. In the former case the
lacune partake in the concentric disposition, and direct ©
large portion of their canaliculi towards the Haversian canal :
in the latter their arrangement is less definite, and the cana-
liculi are directed with less regard to the position of the eon-
tiguous vascular canal, In the one instance the characters
indicate the presence of secondary bone, or bone whieh has
been developed to supply the place of pre-existing bone
removed by absorption; in the other, the presence of primary
bone, or that which has been developed in temporary car
tilage, or upon the surface of an existing bone. It being to
bone developed under the latter circumstances that cemen-
tum is most closely allied, the process of its formation may
be considered with advantage. In young subjects the shafts
of long bones are gradually increased in diameter by ad-
ditions to the surface. The flat and other bones are increased
in thickness by @ similar process, and with the femur or
humerus, will be found equally convenient for examination
and description. If we take either of the latter in a per
fectly fresh state, and make transverse sections, either by
eutting small fragments with a sharp knife, or even by
grinding, taking care to preserve as much of the

as possible, the following appearance will, by means of the
microscope, be recognised. Sturting up from the general
surface of the bone will be seen a series of processes, disposed
at more or less regular intervals, producing ridges and
furrows, which, for the most part, follow in the length of
the bone. Each process is terminated either by a rounded
or adiluted extremity. By the increase of the dilatations
of contiguous processes, and their ultimate contact and
union, the grooves aré converted into cannls, which are
occupied by portions of the cellular layer of the periosteum,
which are undergoing conversion into “ medulla,” and are
ultimately permeated by blood-vessels. ‘The new bone has,
in fact, been moulded around the portions of the periosteum
—n process by the repetition of which the shaft of the bane

io , al

426 A SYSTEM OF DENTAL SURGERY. :

decalcify and ent it transversely through the fang, we mett
with the following stractures from without inwards, On
the outside is the outer part of the periosteum, consisting of
decussating fisciouli of connective tissues internal to this is
a layer to which the name of “cambium” has been some
times given, consisting of roundish cells with processes,
‘These lie in a reticulum made up of cells which give out
@ small number of homogeneous transparent processes; by
the inosculation of these processes a network is formed,
which has beon well figured by Dr. Lionel Beale. @)

Between the reticulum and the fully-forined cementum
lies the osteoblast layer, consisting of much larger cells,
which are often provided with fine processes. The trans
parent homogeneous processes already spoken of as forming
the reticulum may be eeen fn sey oe
the osteoblast Iayer, and may be traced passing withont
interruption into the matrix of the cementum, As the
osteoblasts form a continnons layer, and are very numerous,
it is obvious that only a small pereentage of them ever
form lacunse, or otherwise retain their individuality, As the
process of calcification goes on the outlines of individual
cells and of the trabeoule of the reticulum become lost in
the general transparency of the matrix, only a cell here and
there remaining as a lacuna,

‘The explanation of the formation of bone lacunm from the
osteoblasts given by Henle and Dr. Lionel Beale, which has
been substantially accepted by Waldeyer and Rollet, seems
to accord best with the appearances observed.

The deposition of calcareous matter, and that ehange
which immediately precedes it (so as to produce the “ formed:
material” of Beale), takes place from without inwards,
Thus we might picture to ourselves each caleifying osteo~
blast as enclosed by hard structure, like an egg-shell, con-
tinuous deposition taking place on the inside till the central
cavity was obliterated. At the same time, the contiguotis

@) "On the Structure of the Simple Tissues."

a |

428 A SYSTEM OF DENTAL SURGERY.

‘as in the Instance of the pore cellé of plants." "It rather apperre te
the lacunm and canalicull were litte varieties IeR in the Cy
deposition of the reticular fibres, a+ open Gigures are lef owt In
Prplimermipriitareie pen apart hary
the apposition of the minute apertures existing between
‘the lamella: gives rise to the canaliculi.” “At the same the 1

* unlikely that « cell or a cell nucleus may originally Lie tn the lacuna or
cavity, and may perhaps determine the place of Its furmation.”*
agrené with Schwann, while Gerter (3) and Bruns (%) appeur to bold the
‘of Tedd and Mowrman, With the exception of Dr, Shanpey, the

ver 2

‘The appearances would at first view seem to justify the opinion expressed, |
Dr, Sharpey ; but a careful examination of the tissve duriag 4 lope

the unquestionable fact that In the development from cartilage the

cil becomes converted into a lacuns, togrther with |
Iscunal cells are frequently found in the Haversian canals and exprellated |

strvoture, especially in the bones of old subjects, and at times inmbedited ts thee
structure of the bone, have lef no room for doubt tm che wuthorw’ enlnds that
‘the lacune are formed from aprclal nucieated cell, Iu the manner Gtverited In
the text.

Further details of the appearances observed in ossification
may be found in the following extract from a paper in the
Royal Society's l'ransactions (*); the osteal cells there spoken
of are equivalent to the osteoblasts of later
the differentiation between osteal and “ lacanal” cells exists
only in so far as they are the same clements in a different
stage of calcification (see page 427).

wif the advancing Senghrdet mide amend tes a

Jura mater be
removed from their Tespective wurfares, we shill #ned-tihegrovtiagp Sasa
Leary elma raf persia end cee e

E

thaue will show differences 06 dianaster fn different
distance from tbe bone at which the observations are made,

}
ii
2
:

tissue, Dr. Sharpry has olserved that the membrane Into which the bone

extends is Hike fibrous tissue in an earty stage of development, and thie obser

(8) * Microscopic em ha Human Body,” p. 310,

(2) * Allgemeine Anatorn:

(@) * Observations me eneiien and Development of bemotts
‘Tomes, FBS, Surgeon-Dentist to the Middlesex Hospital; and
De Morgan, Surgeon to the Middiesex Huspital,

484 A SYSTEM OF DENTAL SURGERY.

of this new development are to be seen on the inner, or tooth=
surface of the periosteum of the socket, and not of its outer
‘or bone surface ; and this may in a measure serve to explain
why bony union does not take place,

When a disease consists in the mere increase of a tissue,
the presence and position of which are normal, the transition
from health to disease is imperceptible, and is usually desti-
tute of symptoms. It is only when the amount of new tissue
bas attained a considerable thickness, that distinct symptoms
are developed, and even then they are in many cases absent.
In dental exostosis, a distinction must be drawn between
those cases in which the disease is consequent upon pre
existing disease in the tooth, followed by marked irritation
of the alveolar membrane, and those in which it is developed
independently of any other disease.

Fig. 190.2) When the disease arises in connection with
> caries, it is attended bya thickening of the

*, gums, which assume a deep dull colour, and a
disposition to bleed when subject to friction
either from the tooth-brush or food. Bat
when the crown of a tooth is free from disease,
exostosis of the root may be unattended with

ir any recognisable change in the condition of

the contignons gum. ‘The occurrence of sym~

pathetic pains in the head, face, or neck, may be, and often
is, the only indication of disease. In the presence of such
pains it is often extremely difficult to determine whother
the teeth are in fault, and if so, which tooth or teeth have
occasioned the suffering. Sooner or later local symptoms
tay arise by which the offender can be recognised. Tho
tooth will become tender on pressure, or sensitive to the
effect of hot or cold fluids, or the gam may become absorbed,
and leave exposed the neck of the tooth, which eventually
becomes loose. Such obvious symptoms, however, commonly

@) A molar tooth of the upper jaw, the roots of which are thickenal by the
addition of cementum, the crown being free from disease.

486 A SYSTEM OF DENTAL SURGERY,

water or air not only produced pain in the two teeth, but also
brought on an attack of pain in the face. The terth were
extracted, and for several months the patient was com-
paratively free from pain. Other teeth became similarly
affected, and were removed with similar results; but it was
only after the whole of the teeth of the upper jaw had been
extracted that the patient became perfectly free from the
recurrence of the disease. In another ease the patient had
suffered for several years from intermittent pain in the head
and face. For a long time the cause of the disease appearsd
to have a constitutional rather than a local cause, but the
usual remedies failed to afford relief, After a time a feeling
of uneasiness attracted attention to the only remaining molar
tooth, the second molar of the upper jaw, situated on the
side in which the pain was felt. On removal the crown was
found to be sound, but the roots of the tooth were enlarged.
Tn this, as in the preceding case, the liability to pain m the
face ceased after the operation,

in the two cases cited the relief was complete, although by
no means instantaneous. ‘The pain became gradually less
severe, and the attacks less frequent, and shortly ceased to
recur,

It may be stated generally, that the removal of a tooth
which has been the cause of sympathetic pain, usually
produces a severe attack, the paroxysm bearing some Tela
tion in its duration and in intensity to the previous attacks,
and to the length of time during which the disease has
existed.

‘he sympathetic affection may, however, in a few. rare
examples, extend to a derangement of the whole nervous
system, Two cases have occurred ander my own observa-
tion, in which epilepsy was consequent upon diseased teeth,
the test prominent feature being exostosis of the roots,
which will be described at a future page,

The abnormal growth of the cementum is, as compared to
exostosis of bones, confined within very narrow limits. ‘The

438 A SYSTEM OF DENTAL SURGERY.

often attended with difficulty, we should be able te point out
why their separation in the presence of disease is always
preserved when contiguous bones placed under similar cir
cumstances become so readily united.

If we examine a case of local disease in a bone—a phalanx,
for example, in which the vitality is at one point lost—we
shall find an opening throngh the integuments from which
pus is discharged; extending from this point, the skin and
periosteum will be inflamed to a certain distance, the diseased
gradually merging into the healthy tissues. If an oppor~
tunity of a careful examination be afforded, it will be found
that where the dead joins the living bone, the latter is under
going absorption, and that beyond this point mew osseous
tissue is becoming developed upon the surface of the pre
existing bone, the latter part corresponding to the junction
of the healthy and the diseased soft tissues, and the former
to the part where the skin exhibited all the indication of
chronic inflammation, In a tooth the periosteal investment
of which has become inflamed, conditions in many respects
similar to those which take place in bone may be observed.
‘Thus the end of the tooth will be denuded of periosteum, and
in some cases diminished in bulk by absorption. Higher up
the membrane will be adherent and thickened, and beneath
this the cementum also will be increased by recent additions
of new tissue, In order to allow of the increased bulk, the
alveolus is necessarily enlarged. Still, the interval which
separates the wall of the socket from the contained root is
small, and might readily become the seat of bone uniting the
toath to the jaw, but for the existence of some cause which
prevents the union of the tooth to the jaw while it allows
two bones, when similarly placed, to become connected by
ossification.

Tt is not unusual to see microscopic evidence of an alter-
nation of absorption and deposition of cementum, and this is
especially apt to be found where a stump has for a Jong time
been a source of slight irritation.

‘The absorption which takes place later may go so far as to

Am

( 440 )

NECROSIS OF THE TEETH.

Waerx a part or the whole of a tooth has lost its vitality,
the condition is expressed by the term necrosis. The disease
involves the death, but not necessarily the decomposition, of
the dead part, the tissues of which become discoloured, but
are seldom softened.

The term is no doubt associated in the minds of many
practitioners with that state which is attended with dis
coloration of the whole of the crown of the affected tooth.
But the discoloration of a dead tooth is, strictly spgaking,
an accidental and by no means necessary coincidence. It
depends, in the first, place, upon the pulp losing its vitality
when its vessels are filled with blood, and wpon the ultimate
decomposition of the blood-globules, and the solution of the
colouring matter in the fluids present. These permeate the
dentine, and impart to it a permanent stain, the diseovery of
which is looked upon as an infallible indication that the
tooth is dead. he loss of the normal colour is obviously a
mere consequence of the death of the pulp under certain cir
cumstances, and a consequence which takes some time to
develop.

The depth of the stain will also be varied, the variation
depending upon the age of the patient. The younger the

+ subject, the larger and more vascular will be the pulp, and
the deeper the stain produced by its decomposition. In old
people, on the contrary, the pulp is relatively small, and the
discoloration of the tooth cousequent upon its death is but
slight, and may, in fact, be altogether wanting, The dis-

—

Add A SYSTEM OF DENTAL SURGERY.

reduced by absorption, and even the dentine in many cases
suffers also.

I remember a case in which seven front teeth lost their
attachment to the socket, excepting where the nerves and
blood-vessels entered the root, without the vitality of the
pulp having been sacrificed or the gums absorbed.

There is yet another form of partial necrosis, One root of
the double-rooted teeth, or one or two of the treble-moted
teeth, may become dead and perfectly detached from the
lining membrane of the alveolus, while the remaining root
or roots preserve their vitality. Teeth when in this con-
dition are apt to be at times very troublesome. When they
are used in mastication pain is experienced from the dead
root being pressed into the socket, the lining membrane of
which is injured by the rough surface usually presented by
the dead root. The continued irritation arising from this
cause is productive of thickening of the alveolar covering,
accompanied by the development of a high degree of sen-
sitiveness in the hypertrophied parts, the susceptibility to
pain in which is consequently increased. Hot or cold fluids
taken into the mouth also excite pain in the tooth itself, or
in tho irritated alveolus (it is very difficult to say in which).
The alveolus and gum of the dead root may or may not
become absorbed.

In one case we may see the whole of the root, even to its
extreme point, laid bare by the removal of the investing parts,
and in another case the gum will maintain its normal height,
Of the two, the former condition is preferable, on account of
the greater degree of irritation and pain which usually attend
the latter,

The thickened periosteum, if adherent at any point to the
cementiim, may be, and sometimes is, withdrawn from the
socket on the tooth being extracted. It is usually light in
colour, of considerable thickness, and almost as dense as
fibro-cartilage. :

In respect to the treatment of either partial or complete

te

NEOROSIS OF THE TEETH. 445

necrosis of a tooth but little can be said, further than that
so soon as the diseased organ becomes a source of serious
annoyance, it should be removed.

Any attempt to restore the vitality of the part would be
useless, The gum and periosteal covering of the neck and
roots of a tooth having lost their attachment, never become
reunited.

( 446 )

ABSORPTION OF THE ROOTS OF PERMANENT
TEETH.

Tue removal by absorption of tore or less of the root in
teeth the crowns of which have been injured by disease, has
been already mentioned; but cases from time to time arise
in which, while the crown of a tooth is perfectly sound, the
root is attacked by absorption. It is to absorption, when it
occurs under the latter circumstances, that attention will be
directed.

Although the processes of absorption will be the same
under whatever circumstances they may be set in action, yet
we may arrange the cases under two divisions, in accordance
with the character of the exciting cause. In the first may
be placed those examples in which the whole or part of the
root of a sound permanent tooth is absorbed without reference
to the growth of an adjoining tooth ; and in the seoond, those
cases where a portion of a permanent tooth is absorbed to
make way for the eruption of # neighbouring tooth.

7.28.0) I have seen many cases of absorption in per-

F manent teeth, where the waste has so far re

; duced the root that they became loose and

a painful; but I am indebted to Mr, Canton
= and to Mr. Brooklouse for specimens showing
complete absorption of the root. In the one

case the central incisors, one after another,

became loose, and fell out, on the younger side of forty,

(1) Permanent central incisor, the reot of whieh has been absorbed: from a
Apecimen placed at my disposal hy Mr, Alfred Canyon,

=

448 A SYSTEM OF DENTAL SURGERY.

‘The cases which fall under the second heading are usually
dependent upon the malposition, and consequent retarded
eruption, of a permanent tooth, The extent to which the
absorption of tissue is carried is usually limited to the pro
duction of a slight depression in the neck or root of the
tooth, but in a few cases the process is continued until the
pulp-cavity is laid open and the pulp exposed,

The canines of the upper jaw being more frequently mal-
placed and retarded in their eruption than any other teeth,
we should expect to find instances of absorption in the lateral
incisors and first bicuspid teeth, But in these we seldom
see more than a simple depression, towards which the ad-
vancing crown of the coming tooth has been directed. Tt is
upon the second molars that the greatest extent of injury is
inflicted. When the crown of a wisdom tooth is directed
forwards, it leads to absorption in the neck of the
tooth ; and the process, though generally arrested before the
second molar id permanently injured, will, in some cases, lay
open its polp-cavity, 1 have seen several cases in which the
injury has been followed by inflammation of the pulp, neces
sitating the immediate removal of the tooth. In a case
which occurred recently, the patient complained of severe
pain ina second molar of the upper jaw. ‘The tooth appeared
in every respect sound ; directions were therefore given that
a leech should be applied to the gum. On the following day
the patient returned, complaining that the abstraction of
blood bad failed to produce relief, and strongly urged that
the tooth should be removed. The tooth had become slightly
movable, and the crown had lost a little of the natural
brilliancy of colour. After removal, the cause of the snffer-
ing was manifest. The pulp-cavity had been laid open, the
pulp became inflamed, lost its vitality, and at the time of
the operation was in a state of decomposition. In this
instance there was not the slightest evidence of caries; but
in others which have come under my notice, the cavity pro~
dnced by absorption subsequently became the seat of caries,

<= -

ABSORPTION OF THE ROOTS OF PERMANENT TEETH. 449

The manner in which the latter result is brought about
requires some explanation.

It has already been stated that absorption is effected by a
vascular papilla, which advances in front of the moving tooth.
In those cases in which decay arises in a cavity so produced,
the papilla has been situated but a short distance within the
margin of the gum, and the cavity consequently becomes ex-
posed to the fluids of the mouth when the latter parts shrink
down to a lower level.

( 450 )

EROSION OF THE TEETH.

Ir occasionally happens that the enamel and the subjacent
dentine become eaten away, without any of the ordinary
appearances of dental caries being manifest. The cavities, if
such they may be called, are in general regular in form, and
sauioer-shaped, the removal of the enamel having taken place
more widely than that of the dentine, The surface is per-
fectly hard and polished, and often absolutely free from
discoloration.

This affection, which was described by Hunter under the
name of “decay by denudation,” most commonly attacks the
necks of the teeth, forming a smooth horizontal groove close
to the edge of the gum: it is more frequently met with in
the upper than in the lower jaw, and closely simulates the
appearance produced by mechanical abrasion caused by the
frit {0 tooth-brush.
and then, however, teeth are attacked in positions
, inaccessible to the tooth-brash; thus, in the

canine tooth here figured, the groove was not only

upon the anterior surface, but extended lack on
both sides of the neck of the tooth; moreover,
it was distinctly undercut.

‘This erosion may go on till the pulp-cavity is
opened, and even passed, so the tooth is fairly
cut through by it, An instance of a lower blens-

srown thus undermined, has recently
elf, which, from its position, was

Fig. 187. (

(1) Canine, of which the front and sides of the neck are deeply grooved.

452 A SYSTEM OF DENTAL SURGERY.

abrasion, is furnished by an observation of Dr, Murie(*),
who found that the teeth of a sea lion (Otaria jubata) bad
been thus wasted. The excellent figure given (Joc. cit.) is
too large for reproduction in these pages, but it is at once
evident, on inspection of the drawing, that the cireum-
ferential grooving of these tecth cannot be aceounted for by
friction, as in most instances, and notably in the great
vanines, the places most affected are situated on the sides of
the teeth most protected from wear, and the crowns are
merely worn down in the ordinary way,

This condition, at least in this extreme degres, is not
common among the seals, but { have seen an approach to it
in the teeth of other specimens of otaria, and in the pro-
boscis seal,

In the museum of the Royal College of Snngeons there
is a skeleton of otaria stelleri, in which this form of wasting
of the teeth is well exemplified. In it the teeth are much
worn down by mastication, but in addition to this, some of
them are deeply grooved in positions not at all exposed to
wear, The third left upper incisor is thus deeply notched
on its outerand anterior aspect, close to the edge of the gum,
whilst other teeth present a similar condition, though less
markedly.

‘There is yet another form of wasting of the teeth, which
is more rare than those already deseribed, In it, not
isoluted spots, but the whole exposed portion of the tooth is
attacked ; as the morbid action goes on the enamel is slowly
removed from the crown, 40 that the teeth become shorter
and thinner, and assume a peculiar yellowish, translucent
appearance, the position of the pulp-cavity being strongly
marked by a difference of colour. In the only case which has
come under my own observation, the wasting of the teeth was
established beyond all doubt by taking models from time to
time, The patient, an anwmic girl, was reduced ton state of
great prostration by acute dyspepsia, and was for @ con-

(@) Tramactions of the Qontological Seclety, June, 1870.

= |

454 A SYSTEM OF DENTAL SURGERY.

Dr. Magitot (’) regards the grooving of the necks of the
teeth as the result of caries, which has tendel to spon-
taneous cure by the obliteration of the dentinal tubes; but
this view does not differ from that which nscribes it to
chemical solution, as Dr. Magitot holds that caries itself is
the result of a chemical solvent.

When the cavities produced are of suitable form, the
further progress of the malady may be arrested by filling
them ; and for this purpose gutta-percha is often found x=
eoedingly efficient. But where the surfaces attacked do not
admit of protection by a filling, treatment does not yield
satisfnetory results. The use of soft tooth-brushes should be
enjoined, and alkaline dentifrices prescribed, as being the most
likely to prevent solvent action on the teeth,

The cavities produced by erosion of the teeth are often ex-
cessively sensitive to the touch of an instrument, or to alter=
nations of temperature, ‘I’his sensitiveness may be cured by
applications of nitrate of silver, or, where a black stain would
be objectionable, by chloride of zine.

(1) Mecherches suri Carle des Dents. Paris, 1871, p. 613:>—* La cavité office
alors Vaspoct stngulior qui la fait comparor A wn tralt de sete transversal &
psrols lisses, polis, dures ct résistantes. Ce sont cos cavités que Duvalet divers
aulres auteurs déslgnaient sous le nem do ‘caries slinulant jusare,’ et dent be
tnode de production n'dtalt pas expiiqué. Elles ont, en effet, toutes Tas
apparences de l'usure veritable, mals nos obeervationa sur la paceman des
diverses périodes de la maladie nous ont démon/ré que ces alllons nets et polls
ve Gont sutre chose que des caries du collet pansies a l'état de guérisom:
fpontanée ou caries seches,"*

456 A SYSTEM OF DENTAL SURGERY,

somewhat vague, a8 in the group which is about to be con-
sidered, that the attention is called to the general condition
of the body.

Irritation of the Dentinal Pulp.—A diseased condition of
the pulp, whatever may be the nature of the disease, is, in
the majority of instances, consequent upon the pulp-cavity
being laid open, either by the destruction of its walls by
caries, or by injury of the crown of the tooth from mechanical
violence. But a few cases will be met with in which the
tooth becomes painful, and highly sensitive to the effects of
sudden changes of temperature induced by the contact of
hot or cold fluids, and even to slight pressure upon the erown
or upon the neck of the tooth, while the walls of the pulp-
cavity are free drom injury. Tn such cases the patients will
complain that the tooth is incapable of bearing with comfort
the pressure exercised in mastication. Careful examination
usually leads to the detection of caries, or to loss of a portion
of the crown of the tooth, cither from wear or fracture. A
certain degree of pain is produced by pressing a steel instrn-
ment upon the injured spots, but the degree of pain will not
correspond to the amount of force exercised; indeed, slight
contact seems to give quite as much pain as firm pressnre,

But we may fail in detecting any indication of structural
change in the sensitive teeth. The disordered state may
depend upon some other tooth, which, althongh itself free
from pain, may produce sympathetic irritability in other
teeth; thus pain really due to the wisdom tecth is often
referred to the bicuspids; or it may depend upon @ cause
which has a constitutional or general origin, The earlier
stages of cold, rheumatism of the jaw, or the presence of
mercury in the system, are frequently accompanied by an
irritable state of the teeth,

When the foregoing local symptoms are present, it is very
difficult to determine whether the sense of pain in the tooth
is confined to the dentinal fibrils, or whether it is situated in
the pulp, the susceptibility of which has become abnormally

458 A SYSTEM OF DENTAL SURGERY,

for whom it is next to impossible to successfully perform the
operation of filling.

No doubt the pulp of a tooth may pass into a state of
irritation, independent of injury sustained by the hard and
protecting tissues, just as in certain states of the system the
susceptibility to disease of any other organ of the body may
be increased, But in those cases in which the crown of the
tooth has suffered, there appears good reason for supposing
that the abnormal state bogins in the dentinal fibrils, and
extends through them to the pulp. This view is, I think,
supported by the results which follow careful treatment. If,
in a tooth the crown of which has been injured by caries toa
slight depth only, but in which the dentine is highly sensi-
tive, nitrate of silver be applied to the affected part, the
suaceptibility to pain will in a few minutes be greatly te-
duced. A similar result will follow the application of other
forms of escharotics, unless the walls of the pulp-cavity are
sufficiently reduced in thickness to allow the application to
pass through to the pulp. The effects with these active
agents are rapid, but their use is not free from danger; for it
is not always easy to discover how much or how little sound
tissue may intervene between the pulp and the sensitive
surface. Excepting as a matter of experiment, or when a
sufficient length of time cannot be allowed for the applica-
tion of less active remedies, it will be well to employ vegetable
astringents, such as tannin, or solutions of gum-resins in al-
eohol, and to continue the treatment till the tooth regains its.
normal state, :

In a previous page it was stated that the dentine loses
sensation on the pulp being destroyed, and it is now shown
that a sensitive surface of dentine loses its power of feeling
or transmitting pain after treatment with nitrate of silver,
The results thus obtained indicate pretty clearly that we
shall not be wrong in attributing a considerable share of the
hyper-wsthesia to the dentinal fibrils, and the conclusion is
still further justitied by the fact that if we excise the surface

|

460 A SYSTEM OF DENTAL SURGERY.

patch of dentine added to the wall of the pulp-<cavity
(Fig. 190, and Fig. 191).
In neither of the preceding cases can the calcification have
been effected during the day or two
IMBC), POG OD. oF earth suffering in the tooth, con-
sequently it may be inferred that
the production of secondary dentine
took place when the irritable con-
dition prevailed. It must not on
this account be assumed that cal-
cification of the pulp invariably
follows upon irritable conditions of
the tooth, for cases will be found in
which the presence of secondary dentine cannot be recognised,
and others in which # large portion of the pulp has undergone
calcification without the precedence of irritability in the
tooth, Moreover, it seems probable that the mere presence of
these isolated nodules in the pulp is capable of exciting great
irritation, instead of being a result of previous excitation of
the pulp. It must also be remembered that small ixolated
caleareons globules are to be found in perfectly healthy
developing teeth (see page 283),

Treatment.—W hen the irritability of the tooth is conse-
quent upon the presence of simple caries, our aim must be to
introduce a permanent plug; some little caution mist, how-
ever, be used, otherwise the remedy will but serve to increase
the disease, The patient may have sufficient enderance to
allow the excision of the whole of the affected’ dentine, and
the subsequent introduction of a gold or other metallic filling,
but the presence of metal, from the rapidity with which it
transmits changes of temperature, serves, when the tooth is
highly sensitive, to increase rather than mitigate the evil.

@) Section of a tooth, showing Ube Local thickening Of the wall of the pul ~
eavity, consequent Opon Irritation produced by advancing curios,
(2) Bicuspid in which « formation of secondary dentine lees felled to ebylate
perforation st he palpsavty Brea ‘Tomes's " Lecture on Dental Physiology
and Surgery." “s

_—

162 A SYSTEM OF DENTAL SURGERY.
necks, were kept from further deterioration for five or six
years.

It may be said that the foregoing treatment bears rather
upon an abnormal condition of the dentine than upon an
irritable condition of the pulp; and the objection may, in
some cases, be valid, but it will be almost impossible to
distinguish between pain felt in the dentinal fibrils and in
the pulp, and the distinetion in respect to the treatment i#
unimportant, unless the ailment has a constitutional origin,
when it must of course be treated by remedies which operate
throngh the general system.

Acute Inflammation of the Dentinal Pulp.—The ocourrence
of inflammation of the pulp is usually consequent upon ite
exposure, brought about either by caries or the accidental
fracture of the tooth. Not that the pulp is more exempt
from the occurrence of inflammation than some other soft
tissues, but still the cases of idiopathic disease are not very
frequent. In ninety-nine cases out of a hundred the dis
eased action is consequent upon the perforation of the pulp-
cavity. ‘Yhe following is the usual course of events:—A
hole is discovered in a tooth, food and other matters collect
in it, and are from time to time removed. The presence of
foreign bodies at firet produces no inconvenience, but after
awhile certain substances, such as stignr, of salt, or acid
mutters, when lodged in the tooth, occasion considerable
uneasiness, which is, after awhile, exchanged for positive
fain. ‘The removal of the irritating matter is soon followed
by the restoration of comfort. This state of things may go
on for some time, but, sooner or later, the pain, ibstead of
passing off, steadily increases, assumes a throbbing character,
becomes still more acute, extends from the faulty tooth to
the neighbouring teeth, and to the side of the face, the tooth
forming the centre of its intensity. After the lapse of sume
hours the pain usually anbsides, to return again on the
slightest provocation, or ou the patient assuming the hori-
zoutal position. Ifa tooth be examined subsequent te two

—— ail

464 A SYSTEM OF DENTAL SURGERY,

will also tend to modify the severity of the symptoms. Geno-
rally, the smaller the amount of vascular tissue involved in
the disease, the milder will be the symptoms; it is, conse
quently, seen that in young people in whom the pulp is
relatively lange, and the amount of secondary dentine within
its substance comparatively small, the suffering is greater,
and the inflammation more extended than in older subjects,
The size of the aperture by which the pulp is exposed, will
also influence the amount of suffering which attends inflam-
mation of that organ. Local constriction of an inflamed
part, under all circumstances, greatly aggravates the pain.
Ina tooth the pulp is uniformly confined, excepting at the
point where the wall of the cavity has been perforated;
when the vessels become distended, and the more finid
portions of the blood are effused, the pulp will enlarge at
any point where enlargement is possible, and it is conse
quently protruded through the aperture in the walls of the
pulpeavity. The hole in the substance of the tooth ix
always much larger than the opening into the pulp-cavity,
consequently that part of the pulp which has been pro-
traded through the narrow opening into the larger space
may there become enlarged, while the part which connects
it with the pulp is constricted.

There are but few of o8 who do not know something of the
pain which results from drawing the air from a carious and
aching tooth—or, in other words, sucking it—whereby the
atmospheric pressure is taken off the exposed portion of the
pulp, leaving the vessels unsupported to withstand the force
of the circulation. The immediate result is, that the pulp
is forced against or through the opening, and in some cnses
its vessels ore ruptured. ‘The bleeding so produced not un-
commonly relieves the distended vessels, and the inflam-
mation ia for the time checked. That which we ean
produce at will occurs, in a greater or less degree, without
our intervention; and the amount to which the pulp is
protruded, aud the degree of strangulation which is induced

a = |

466 A SYSTEM OF DENTAL SURGERY.

If the gums are in a thickened and unhealthy state, or if
the patient be liable to nearalgic pain about the face and
jaws, or should there be reason to suppose that the roots are
not fully developed, and the aperture at the extremity of each
root contracted’ to’ its ultimate size, it will be well to remove
the tooth. In the absence of any disqualifying condition,
we may adopt a plan of treatment for the preservation of the
tooth, That plon will consist in the application of an e+
charotic for the mpid destruction of the pulp, with the
view of filling the pnlp-cavity, and making good the injured
portion of the tooth by means of gold, or some other ma-
terial. Arsenic, when applied in the manner already de-
scribed, will be found to-be the best agent for bringing
about the result, The pain produced by the disease is
seldom increased by the arsenic; indeed, it is not unusual
for the violent throbbing to be almost immediately ex-
changed fora dull aching sensation, which passes away in
the course of four or five hours,

Chronie Inflammation of the Dental Pulp may arise inde-
pendently of caries, or of the mechanical injury of a tooth,
but practically its occurrence may be assumed to be conse-
quent upon, and almost invariably coincident with, the
presence of an opening into the pulp-cavity, It differs from
the acute form of the disease in the less active character of
the symptoms, and also in the results to which it leads,
'Yhe pain is seldom long continued, or very intense when
present. Jt generally comes on at irregular intervals, a
periodical character being observed in exceptional cases only,
although these partial inflammations of the dental pulp am
specially prone to set up wandering neuralgic pains, the true
origin of which may be obscured by the complete absence of
local toothache. A sudden change of temperature, the appli-
cation of an irritating substance, such as salt or sugar, will
gonerally bring on a paroxysm of pain, which may endure
but for a few minutes, or may last for several hours.

On carefully examining a tooth which gives rise to the

ee

468 A SYSTEM OF DENTAL SURGERY,

escapes from its surface; and it is, moreover, a sufficient
warning to abstain from the immediate introduotion of a
permanent plug,

A second result of chronic inflammation is the formation
of an ulcer, of a very painful and irritable kind, upon the
exposed surface; and a third consequence is the development
of granulations, which may grow until a mass is formed ex-
eoeding the size of the pulp itself, and, in some cases, com-
pletely filling up the cavity produced by the destruction of
the enamel and dentine. This condition is usually de-
scribed as polypus of the dental pulp. The morbid growth
is not necessarily very sensitive. It bleeds readily, and
emits a very offensive secretion.

‘There are other results which attend chronic inflammation
of the pulp. One consists in the gradual disappearance of the
pulp without pain, and consequently without any symptom
which attracts the attention of the patient, The practitioner
finds the pnip-cavity empty.

The results of inflammation hitherto mentioned are de-
structive in their tendencies, but the presence of disease is
usually attended by reparative efforts. ‘I'he development of
nodules of dentine in the pulp is almost invariably coin-
cident with the occurrence of caries; and there is no reason
for assuming that the process of formation is arrested in the
comparatively healthy portion, although the exposed surface
of the pulp be inflamed. Lut there seemed some reason to
doubt whether the exposed surface could undergo caleifica-
tion. Mr. Amold Rogers has recently placed at my dis-
posal a preparation which, 1 think, sets the question at rest.
A patient applied to have the roots of a first molar removed,
the crown having been broken off many months previously,
when, for the relief of pain consequent upon caries, the ex-
traction of the tooth was attempted. The pain ceased after
the fracture, and the roots of the tooth were allowed to
remain. After the lapse of some months, the remains of
the broken tooth cavscd annoyance, and Uney were removed,

en 2

470 A SYSTEM OF DENTAL SURGERY,

ganized tissue. Had it been otherwise, the pulp would
probably have been injured and ultimately destroyed by
mastication.

Tam not acquainted with any case which can be regarded

Fein @ strictly parallel to the foregoing, but we ~

- may find instances—if a number of teeth ure
divided—showing that the bulk of the soft
tissue had been calcified, although at the
point of exposure the conversion remained
incomplete. 1 believe it not uncommonly
happens, that the calcification keeps in al-
vance of the progress of caries, and thus pro-
tects the pulp from exposure. But such teeth

are hot removed, and therefore do not come into onr hands
for examination.

Allusion has already been made to the fact that chronic
inflammation of the pulp may not be accompanied by pain
in the tooth itself, yet that it may cause severe sympathetic
pains in the head and face, and that the pain may extend
down the neck as far as the shoulder, 1 remember a case
in which the patient suffered severe pain on one side of the
head and face at tolerably regular intervals. ‘The pain came
on in the evening, and lasted for six or eight hours. It was
for some weeks regarded as a case of tic, or hemicratiia,
After internal remedies had failed, a decayed but painless
wisdom tooth of the upper jaw was removed, and from that
time the facial pain disappeared. Tho pulp of the tooth
was exposed and inflamed at a point a to an
aperture in the pulp-cavity.

Treatment.—The same general principles that een stated
in respect to the treatment of acute must be acted upon in
the management of chronic inflammation of the pulp, Re-
medial measures offer but a very small chance of success if
the disease has extended beyond the limits of the pulp, and

1) A first permanent molar tooth of Uwe upper ‘on Sen alg Mae WR
calsine, calaified, excepting at Wts upper part wud at the <span we,

472 A SYSTEM OF DENTAL SURGERY.

effective, and in my hands more satisfactory, as it requires
a less expenditure of time and less frequent renewala of
the remedial agent, consists in the application of a soft
mass, composed of tannin, mixed with gutta-percha re~
duced to a gelatinous consistence, with chloroform. The
astringent properties of the tannin act in arresting the dis
charge, while the gutta-percha holds it together, and en=
sures its contact with the pulp. Although the soft plug
will last for some days, it by degrecs wastes away; still
the renewals are required less frequently than when the
cotton and spirit are used.

But the agents of most value are pure carbolic acid and
thymol; they should be applied on a small pledget of
wool, and sealed up in the tooth Ws ee
in a solution of some one of the resins used for the par

pose,

The treatment having been commenced, the remedial
agents, whatever they may be, must be applied uninter-
ruptedly, otherwise the chances of a successful result will

be but poor. It is useless to apply an astringent eno
day, and on the next leave the cavity open and the pulp

unprotected.

It will be apparent that where the aperture in the pulp-
eavity is large, any kind of soft plug would, under very
moderate compression, adapt itself to and bear painfully
upon the exposed surface of the pulp. To this cireumstance,

ful issue may be obtained, we shall have great difficulty
in foretelling the time that the case will be under treat-
ment. I have known instances in which all signs of
discharge from the pulp ceased within a fortnight; but
TI have also met with many examples which
uncontrollable either by sledhslic whaton ot

[em :

i
a

474 A SYSTEM OF DENTAL SURGERY.

advantage; but it is difficult to recognise them, and in
the absence of precise knowledge, the operator is forced to
abandou the use of an agent the indirect result of which he
is unable to predict, and this practice has gradually fallen
into complete disuse,

When the exposed pulp has ceased to discharge, the
sooner the cavity in the tooth is sealed up the better. In
conducting the operation, care must be taken both to avoid
compressing the pulp and subjecting the tooth to an un
necessary amount of manipulation. The force
employed in producing a gold plug, and the rapid conduct-
ing power of an amalgam plug, render each objectionable.
The disadvantage which attends the use of the latter may
be overcome by capping the pulp with a non-condueting -
substance. A better result will, however, follow the intro-
duction of a gutta-percha plug. In this material, as pre
pared for dental purposes, we have a perfect non-conductor
of changes of temperature; it is readily applied, perfectly
excludes fbi and saliva, and is easily removed should symp=
toms of inflammation of the pulp come on. A plug s
formed must be regarded as temporary in its effect, It
will last for many months, or even one or two years; but
so severe a test of its durability should not be tried, Ibis
in some cases easier, and indeed better, to use zine oxy-
chloride as a temporary filling; it is less durable, but that
is no objection, and it can be inserted with less disturbance
of the covering of the pulp; but this latter must be carefully
guarded agninst contact with the zino salt. If, after the lapse
of three or four months, the tooth is free from all signs of
abnormal susceptibility, the gutta-percha should be removed
for the purpose of substituting a permanent plug. Tt is
well not to hurry the final operation, but rather to re-intro-
duce gutta-percha when there is tenderness or any other
indication which would throw a doubt upon the capability
of the tooth to bear the insertion or the presence of a metal
plug. :

ed a

( 476 )

INFLAMMATION OF THE ALVEOLAR
PERIOSTEUM.

Tse inflammatory affections to which the lining mom-
brane of the sockets, or the intra-alveolar periosteum (7),
of the teeth is liable, admit of division into the following
groups -—

‘The first will include general inflammation of the alve-
olar membrane affecting the socket of each tooth, or, at
all events, the majority of the teeth equally, and dependent
for its origin upon a constitutional condition, such as rhen-
mmatism, the presence of mercury or some other agent in the
system, dc. &o,

Local inflammation involving the sockets of one or two
teeth, and dependent upon a local cause, will come under
the second division.

‘The causes of periostitis about the jaw are various; thus *
it may be set up by the inhalation of phosphorus fumes,
and ultimately give rise to phosphorus necrosis, Or it may
arise in 4 scrofulons person ; or, again, as a result of syphilis
or rheumatism. In any case effusion of serum takes place
between the bone and the periosteum ; this may be absorbed,
or soften down into pus, or become organised into fibrin,
and this fibrin again into true bone. It is pointed out by
Mr. Wood that the hardening is more common in a rheu-
matic than in a strumous or syphilitic node, on account of
the greater readiness of the fibrin to organise in the former

@) This term fs used to distinguish the periosteum which Unes the sockets
of the teeth from that which covers the outer walls of the alveoli,

(cc

478 A SYSTEM OF DENTAL SURGERY. ‘

the inflammation seldom advances heyond a congested state
of the vessels, with effusion into the surrounding tissues. It
is only in extremely severe cases that suppurative action is
established, ani in them the secrotion of pus is limited to
that portion of the alveolar membrane which merges into the
mucous membrane at the necks of the teeth. The purnlent
discharge oozes up between the gums and the teeth, and
may generally be rendered visible by making pressure upon
the former, he state is altogether different from that of
alveolar abscess or gum~boil. In the former the pus is pro-
duced at the neck of the tooth, and finds reaily escape ; in
the latter, it is formed about the root of the tooth, is enclosed
within the socket, and bas to find its way either by the side
of the tooth or through the alveolar wall to the surface of the

gum,

Prolonged inflammation of the alveolar membrane may
lead only to the absorption of the alveoli, and.this, with the
consequent loosening and loss of the teeth, is the more com~
mon result; but examples are not wanting to show that the
suppurative state may, in enfeebled and strumous subjects,
be succeeded by ulceration of the soft parts, and necrosis
of the alveolar margin, involving, perhaps, the loss of s con-
siderable portion of the jaw.

I have seen a few cases in which the inflammatory action
has ultimately led to the production of large florid granula-
tions. They have sprung up close to the teath, the crowns
of which have been, in great part, overrun and obscured by
the morbid growth, The patients complained of pain and
tenderness in the teeth, and perfect inability to use them im
the mastication of food.

When inflammation of the alveolar periosteum is con-
nected with a rheumatic slate of the system, the prineipal
indication of the presence of that diseaso may at times
confined to the state of the teeth and gums, but the abnor
mal condition of these parts, when so affected, can scarcely
be said to present a specific character. The patient will

=

—— |

480 A SYSTEM OF DENTAL SURGERY.

but the idiosynerasy of the patient will exercise a still
greater influence. There are those in whom a single dose
of calomel, or even of blue pill, will produce salivation, and
the second or third indnee the formation of large sloughs,
with necrosis of more or less of the alveolar processes,
There are others, again, in whom it is extremely difficult
to produce ptyalism.

‘The destruction from sloughing of the soft parts in the
alveolar region of the month, consequent upon inflammation
commencing in the gums and intra-alveolar periosteum, is
sometimes so extensive that the cicatrices which follow drag
down and fix the cheeks firmly to the masillm, and limit
the motion of the jaw, depriving the patient of the ability
to open the mouth sufficiently for the ready introduction of
solid food.

‘The treatment in general inflammation of the alveolar
periosteum must, in cases dependent upon « bad state of the
aystem, be addressed to the improvement of the general
health, If the local disorder depends upon rheumatism, the
usual remedies for the relief of that disease should be ad-
ministered, such a8 alkalies, abstinence from malt liquors,
and fomentations or steaming of the mouth; in some cases
iodide of potassium in large doses will have a most marked
effect in cutting the disease short; if the malady assumes a
strumous type, the remedies best suited for the treatment
of stroma should be prescribed. If the disease be depen-
dent on an enfeebled state of the body, a generons diet,
with quinine, or some other equally active tonic, will prove
advantageous.

Cases which partake of the latter character and yield
mupidly to generous treatment, prevail towards the end of
the London season among those who have applied them-
selves too closely to business.

In aiding the general treatment, local remedies will be
found useful. During the stage of congestion, finely-
powdered tannin may be robbed upon the gains night and

a

482 A SYSTEM OF DENTAL SURGERY.

rently from any other morbid condition; these cases are
probably referable to one or other of the canses of general
periostitis which have just heen enumerated,

be the exciting cause, the symptoms of the disease

but little variety, excepting as respects their intensity, the
rapidity with which the different phases of inflammation.
succeed each other, and the extent to which the neighbouring:
parts become involved.

‘The inflaramatory action usually sets in with feelings of
slight uneasiness and tension, sensations which excite a strong
desire to press by the opposing teeth, or to shake with the
fingers, the affected tooth in its socket. Slight, steady pressure
of the fang into the jaw gives relief, but the uneasiness
returns on the pressure being withdrawn, The sense of
uneasiness is soon followed by a dull, heavy pain, and the
tooth feels to be longer than its fellows. The dasire to move
the tooth in its socket continues, till disease has rendered the
parts so tender that pressure can no longer be borne, and even
the mouth cannot be firmly closed without pain,

The existence of disease within the socket is soon shown
in the gum, which becomes swollen and tender opposite the
fangs of the tooth whose periosteum is affected. In addition
to this ‘latter symptom, and often prior to its appearance,
the free edge of the gum assumes a deep red colour, unne~
companied by pain, tenderness, or noticeable
The neck of the tooth appears encircled with a well-defined
red ring, This symptom is usually present in the earlier
stage; but as the disease advances the distinction is lost in
the general inflammation of the gum. The pain becomes
more severe, but still preserves its heavy, wearing character,
and thongh not always constant, is seldom absent for many
successive hours,

Tf the progress of the disease be unarrested, the periosteum:
becomes detached from the cementum, and the point of sépa-
ration usually commences at, and extends from, the foramen
in the root of the tooth. Into the interval thus formed pus

484 A SYSTEM OF DENTAL SURGERY.

stance of the gum. At this stage of the disease we have &
kind of double abscess—an abscess with a constriction, one
division of which is situated in the gum{ and the other within
the alveolus, the two being connected by a small opening
through the alveolar plate. If the disease be left to run its
own course, the contents of the abscess will sooner or later
find their way to the surface and escape. But the time
ocenpied in the process will depend upon the situation of the
disease, upon the condition of the parts prior to the advent
of disease, and upon the general condition of the patient. Tn
those who are in strong health, the formation of an alveolar
abscess is soon succeeded by swelling of the gum and the
escape of the pus, But in patients who are in a debilitated
condition the disease advances more slowly; the products of
suppuration accumulate, and a large abscess is formed, at the
expense, perhaps, of the sockets of several adjoining teeth,
Considerable mischief may have been produced before the
natural relief by the spontaneous bursting of the abscess is
obtained. The pus, instead of escaping into the mouth, may
find its way to the surface of the face, or into the antrum.
‘The latter result is, of course, only likely to occur when the
disease has originated in the bicnspid or molar teeth of the
upper jaw; a case, however, came under my notice in which,
on the extraction of a central incisor in consequence of
alveolar abscess, a perforation into the antrum was found to
exist. The previous symptoms of abscess of the antrum had
been but little marked. ‘There is no tooth from the socket
of which an abscess may not extend to the surface of the face,
Instances are sometimes met with of an absccss connected
with the root of a lower incisor tooth opening under the ¢hin,
and moro rarely, opening in front of the chin.

Abscesses resulting from difficult eruption, or caries of the
wisdom teeth, occasionally pass forwards inside the mouth,
and open near the canines or bicuspids; or they may pass
backwards and buret into the fances(); they are not

(1) Transactions of the Odontological Soclety, 1808, p. 8.

al

486 A SYSTEM OF DENTAL SURGERY. ¥
of alveolar abscess, and is especially prone to happen in
strumous subjects,

A collection of pus formed in the socket of an upper in-
cisor, will sometimes burrow along between the bone and
periosteum of the hard palate, and open upon the surface of
the soft palate: in other cases, the periosteum is separated
from the one side of the hard palste, and forced downwards
to & lovel with the crowns of the teeth by the accumulated
pus. The pressure caused by the abscess, which often be
comes chronic, may cause absorption of a portion of the
palatine process of the superior maxilla, as oceurred in a Gise
recently under observation. For some reason not very ap~
parent, abscess on the palate almost invariably proceeds fromi
n lateral incisor. A case bas lately been recorded in whieh
pus dripped down behind the velum; it was found to
proceed from an alveolar abscess about the fang of a Interal
incisor.

The opening of the abscess, whether effected by nature or
by the hand of the surgeon, forms an epoch in the complaint:
The symptoms from that time gradually subside, the pain dies
away, and the awelling rapidly diminishes, leaving a small
opening through which pus will continue to be discharged.
The coats of the abscess gradually contract, and close upon
the root fram which they had become separated, The sépara-
tion of the two parts is, however, permanently maintained.
While the inner surface approaches the root of the tooth, the
outer surface of the coats of the abscess becomes thickened,
and occupies the space whieh would otherwise be left between
the expanded alveolus and the collapsed abscess, In extract=
ing teeth which have been the cause of alveolar abscess, the
coats of the abscess are sometimes withdrawn entire, and
an opportunity of observing ‘the preceding conditions is
afforded.

Such, then, are the events which, in the ordinary course of
the disease, mark the progress of alveolar abscess. Excep-
tional cases now and then ocour, in which the local are acoom=

490 A SYSTEM OF DENTAL SURGERY. bd

to rheumatism, to struma, or to syphilis; or again, the
patient may have already suffered from syphilitic necroses
elsewhere, and slight wounds be prone to take on ulcerative
action. If the disease can be traced to rheumatism, the teeth
should not be extracted, even though they are very loose, as
the probability of a favourable termination is great. But if
the disease appears to be connected with strums or syphilis,
no hesitation need be felt in removing any carious teeth, ax
they are far more likely to cause extension of the mischief
by remaining as sources of irritation, than the operation is
likely to do mischief. And even though the involved teeth
be sound, when once syphilitic or stramous periostitis has ran
on to a considerable length, the destruction of the involved
teeth by the death of their socket is probable, and the ex-
traction of greatly loosened teeth may become the best
course.

The removal of the involved tooth, however skilfully per-
formed, is not always followed by a cessation of pain; on the
contrary, the degree of suffering is sometimes for awhile in-
creased, arising, no doubt, from the laceration of the inflamed
tissues. The duration of the after pain will genormlly be
proportioned to the extent of the inflammation, and to the
amount of sympathetic pain previously excited.

In all cases of pain after the operation of extraction, the
vacant socket should be sponged out with a loosely-rolled
pedget of cotton steeped in phénol sodique, or in the fol+
lowing substitute for that preparation—

R. Acidi carbolici glacialis, 3).

Liquoris potassm, §j,

Aqua, ad, 5viij.
‘This will usually give very great relief, and the wool may
be suffered to remain for a day or two, if the pain tends to
return on its removal. But it will often be found that one
or two applications of the fluid will dispel the severe pain,
and that the wool need not be left in the socket. Should

(ie | |

492 A SYSTEM OF DENTAL SURGERY,
manifested ; the more so as the susceptibility of different

persons to its action is very various.

When the more active symptoms have subsided, a small
fistulous opening will remain for the exit of the pus, unless
the fluid finds its way to the surface through the fang, It
is quite possible that the coats of an abscess situated in the
dilated alveolus may embrace the necrosed extremity of the
fang, and cease to secrete; in which case the gum would
heal perfectly, leaving the end of the tooth in a similar posi-
tion to that of an encysted foreign body, But I do not think
this event is common, neither would its occurrence be ex-
pected, when it is considered that the fangs of teeth admit,
under pressure, of a slight degree of motion,

Chronic Inflammation of the Dental Periosteum, limited to
the alveolar membrane of one or two teeth, excepting in its
extent, and dependence upon a local cause, resembles in
character that form of disease which has been described under
the head of general inflammation of the alveolar periosteum.

After a case has passed throngh its earlier stages, there is
some difficulty in determining whether the malady originated
in the gum or in the periosteum, At the outset the margin
of the gum exhibits increased vascularity, becomes slightly
thickened, and bleeds readily. If allowed to run its course
uninterruptedly, the inflammation passes from the tissues about
the neck of the tooth tewards those which surround the root
‘The tooth becomes loose, the edge of the alveolus disappears,
and the gum sinks down. By slow degrees the tooth loses
ite implantation and falls out. Generally the disease is
attended with but little pain, excepting such as is produced
by force applied to the loosened tooth,

Tooth after tooth may be, and in uld people frequently is,
lost, till the mouth becomes edentulous.

‘The inflammation may, however, take a more active form.
We shall then have pus secreted from the surface of the
diseased, tissue, and granulations may spring up from the
Margin or from within the socket,

494 A SYSTEM OF DENTAL SURGERY.

‘The edge of the alveolus seldom becomes absorbed, 0 that
the fang is held firmly in its place,

When there are three crownless fangs in a row, and the
periosteum of one only the subject of chronic inflammation
about the end, it is extremely dificult, if not impossible, to
detect the offender, unless revealed by tenderness on pressure;
or the margin of the gum being encircled with a red line,
neither of which symptoms is constant.

This bulbous state of the dental membrane (often termed
fungous) is cceasionally found in connection with dental
exostosis, and sometimes with necrosis, but in the latter
case the disease is disposed to become active, and to end in
alveolar abscess.

There is but one method of treatment—the affected tooth
should be removed.

When a patient suffering pain in the jaw, or face, or ear,
is unable to state the exact.seat of pain, but is disposed te
ascribe it to the teeth, itpwill be well to remove any stumps
that are found in the mouth; for the periosteum of one or
of all of them may: be thickened and diseased, and this
will not be known with certainty till they are removed. Very
generally the diseased tissue is more firmly connected to the
tooth than to the alveolus, and is therefore drawn out with
the tooth.

A disease having established itself in the soft tissues sub-
sorvient to the maintenance of the teeth, the revoguition of
its origin is at all times attended with difficulty, for no
sooner is the periosteum attacked than the contiguous gum
becomes affected, and wice vered. This remark applies even
to tumours arising in this part of the body. A tumour may
originate in the gum, or spring from within the socket of a
tooth, or it may commence in the periosteum investing the
outer surface of the alveoli; but in either case the growth is
usually described under the head of tumours of the gums, am
arrangement which, for the sake of convenience, will be

adhered to in the present instance.

496 A SYSTEM OF DENTAL SURGERY.

surface. This was found to be a part of the floor of the nose,
into which air passed freely; and fluids poured throngh the
nose in drinking.

Since the removal of the tooth some years have elapsed,
the aperture being covered by a process from the artificial
teeth which are worn by the patient. ‘This remedies the
inconveniences of a communication existing between the
nose and the mouth; but, although the aperture has greatly
contracted, it shows no disposition to entirely close up.

‘The most remarkable feature of this case is the entire
absence of any assignable cause for the mischief; the patient
was a healthy man of middle age, with no history of syphilis;
the tooth had been only in a very slight degree decayed, and
had been successfully filled with gold years previeusly. No
blow had been received ; in short, nothing whatever could be
discovered to account for the lesion.

Another case lately came under my care, at the Dental
Hospital, of necrosis occurring without any assignable cause,
Tn this case the sequestrum was much larger, extending from
the second lower molar of the right side to the lateral incisor
of the same side, and included the mental foramen end
portion of the inferior dental canal. ‘The teeth involved Ih
the dead bone were all sound, and the patient, whose stute-
ments appeared perfectly reliable, could not throw any light
on the origin of the disease, No history of syphilis conld he
elicited.

"The immediate cause of necrosis is périoatitis, resulting in
purulent effusion between the bone and the periosteum, and
ina large majority of cases the more remote cause of the
disease can be traced out.

‘Thus, in children of stramous dinthesis, large portiens ~
often necrose, and the disease may be, and, I think, very
commonly is, set up by a decayed tooth, The twoth-pulp
inflames, the inflammation extends to the periosteal lining
of the socket, and from thence spreads to the body of
the jaw.

_— ;

498 A SYSTEM OF DENTAL SURGERY.

The detached piece, however, did not reunite; abscesses
formed under the chin, and finally it was removed, in con-
sequence of its becoming necrosed.

Necrosis of a portion of the bone may follow wpon the
extraction of a tooth, however skilfully this has been per
formed; and it must not be supposed that the operstion ix
always, or even commonly, to blame for the advent of
necrosis after the extraction of tooth. The conditions lead~
ing to necrosis are, in the great majority of cases, developed
previously to the removal of the tooth, and are quite inde-
pendent of its removal; the necrosis would generally have
been quite as sure, and perhaps even more extensive, had
the tooth been left in, There is not the smallest reason for
believing that the removal of a tooth should be deferred
because the tissues around it are in a state of acute inflam—
mation or suppuration ; if the tooth be the exciting canse of
the mischief, there is no excuse for delaying its extraction
for a single moment; and the opinion to the contrary, held
though it be by a number of medical men, is in no degree
shared by dentists, and being based on no evidence whatever,
must take rank in the category of popular errors,

Fatal consequences have, in several instances, been known
to follow upon necrosis after tooth extraction. Thus, in
Wedl’s “ Pathologie de Ziihne” (page 178), a case is quoted
from M. Leynseele, in which a portion of the lower jaw was
splintered in the removal of a tooth ; pus burrowed along
the side of the jaw, ascending by the ramus to the base of the
skull; and gaining access to the cranial cavity by the foramen
ovale, rotundum, and spinosum, caused the patient's death
from meningitis.

Another case resulted from an unsuccessful attempt to
extract an upper molar tooth; suppurative periostitis around.
the tooth ensued, and rapidly spread to the body of the jaw¢
after « fortnight the necrosed bone was readily removed, but
severe rigors ensued, and the patient died, at the end of a

500 A SYSTEM OF DENTAL SURGERY.
and lic loose in the substance of the thickened gum, bathed

in pus.

Pain is complained of early in the disease, and is eom-
monly supposed to be toothache; later in the course of the
necrosis the face becomes swollen, especially in cases of
Phosphorus Necrosis, which disease, being in some respects
peculiar, requires a short special description,

If the pus, which is very profusely poured out around the
sequestrum, does not find a ready exit into the mouth, it will
often point below the chin, or even pass down the neck be-
neath the fascia, thus sometimes teaching as low as the
clavicle. In the case of the upper jaw the pus usually makes
its way into the mouth.

Phosphorus Necrosis,—A peculiar form of necrosis affecting
the jaws has been repeatedly observed in persons whose
duties expose them to the vapours of phosphorus. So
numerons are the cases, and so clearly is their
traceable, that no doubt can be entertained that the phos-
phorus is the actual cause of the disense. ‘There is a
prevalent idea that the lower more frequently suffers
from the disease than the upper jaw, but this is nob
borne ont by statistics, as ont of fifty-one cases collected
by Von Bibra, both jaws were affected in five instances,
the upper alone in twenty-one, and the lower alone in
twenty-five.

One fact connected with the origin of this disease gives it
{ special intorest in the eyes of the dental surgeon ; there is
a considerable amount of evidence in favour of the view that
the poison acts locally, but that in the first instance it cannot
attack an unbroken*surface. Hence, it usually gains access
to the bone through the socket of an extracted tooth, or
through the cavity of a carious tooth, exposure of the pulp
being, according to Mr. Salter ("), the only manner in which
it gains necuss,

(*) Holmos's * Dictionary of Surgery,” rol. iv., p a9.

508 A SYSTEM OF DENTAL SURGERY.

dead bone the treatment of the case may be said to terminate
‘The inflammatory action in the gums and contiuons sro
tures, in the absence of a source of irritation, mepidiy
subsides, and the mouth is speedily restored to a state of
health,

lt is important, however, that the sequestrum should te
picked out as soon as it has become loose: if thia te
neglected, burrowing abscesses may be formed. Thus Mr
Cattlin relates a case in which a piece of dead bone from the
jaw passed down in abscess cavities, and was finally remored
below the clavicle; and Mr. Wood has forcibly pointed ont
that it is quite possible to wait too long before removing the
dead bone, It has already been mentioned that developing
permanent teeth are often lost in the sequestrum thrown of
in the so-called “ exanthematons necrosis,”

Not only, however, may the permanent teeth be exfolinted,
but the whole jaw has been known to be cast off,
Mr. Pollock figured and described such a case(*); there was
not a vestige of a lower jaw, which, according to the state
ment of the patient's friends, had been thrown off when ale
was two years of age. The deformity was leas than would
have been expected.

lowe

@) Art, © Diseases of the Mouth.” Holmes's “ Dictionary of, Surgery”
Yd exitioe

510 A SYSTEM OF DENTAL SURGERY.

the phenomena are seen in those who have passed the middle
period of life, and also in certain other cases ; but a question
may be raised as to its validity on the ground of want of
conformity to those cases in which the crowns of the teeth
are lost, and the roots thereby deprived to a great extent of
their life, and yet the absorption of sockets and gums does
not follow. I believe, however, the difference of result is due
toa variation of the conditions, In cases of absorption of
the alveoli, the roots of the teeth are almost destitute of
cementum, whereas in the roots of teeth around which the
sockets and gums are preserved, the cementum is also Te~
tained. Examples illustrating this condition will be found in
young or middle-aged patients whose teeth have decayed and
broken off close to the edge of the gum, the level of which
is for a certain time preserved. Sooner or later, however,
the edge of the alveolus recedes, and is followed by the gam.

There are other conditions than those already enumerated
under which the teeth may lose their sockets. A case re-
cently came to my notice in which, without any appreciable
wasting of the gums, the whole of the upper front teeth
becarne excessively loose and fell out. The alveoli were
altogether absorbed, or were greatly enlarged, but the pre-
sence of any manifest disease, cither in the teeth themselves
or in the surrounding parts, could not be detected. ‘The
gums were not more vascular than would be considered
consistent with health, and in the teeth there was a total
absence of that horn-like appearance previously described ;
indeed, the cause of the malady was too obscure to admit of
recognition,

Absorption of the alveolar processes may be more partial
than in the cases previously considered. The outer or the
inner plate only may disappear. ‘The accompanying illus
tration is taken from a preparation in which the labial plate
corresponding to the upper front teeth has been removed.

Indications of a similar change in other parts of the jaws
fire shown, but the amount of loss is comparatively trifling,

oo a

612 A SYSTEM OF DENTAL SURGERY.

parts, This fact is shown in the case figured. ‘The rig
upper canine has lost the whole of the anterior wall of its
socket, while the contiguous lateral incisor, which lies bacle,
has retained the corresponding part of the alveolar invest-
ment. The canine teeth being the last of the front teeth to
take their position, are subject in a contracted jaw to stand
in advance of the dental arch, The course taken by the root
can be readily traced, and the small amount of bone and
giun by which its anterior surface is clothed is recognised.
It. is from the roots of a tooth so placed that the anterior and
projecting wall of the socket most frequently disappears.
The labial surface of the root becomes exposed
the greater part of its length, leaving the tooth dependent
upon the posterior or lingual wall of the socket for its
retention in the jaw. A prominent and comparatively
unsupported position would seem to offer an explanation of
the early disappearance of the outer plate of the alveolus,
but cases are now and then seen to which this explanation
could not be satisfactorily applied. A specimen in my own
collection exhibits the full complement of teeth in the upper
jaw, sound and well arranged, but from a bicuspid tooth the
whole of the labial plate of the alveolus has been absorbed.

It is in many cases very difficult to discover a
cause for the premature disappearance of the alveolar pro-
cesses, The presence of inflammation of the gums, or of the
alveolar periosteum, or of collections of tartar about the
necks of the teeth, and the consequent irritation of the edges
of the gums, are followed as 4 secondary consequence
absorption ; but it is to the occurrence of alveolar absorption,
without the precedence or accompaniment of obvious disease
in the soft tissues which clothe the socket, that attention has
eon directed. The frequent use of a hard tooth-brush will
hasten the wasting of an outstanding socket, the corre-
sponding gum of which has the appearance of being stretched
ina thin layer over the neck of the tooth.

When the alveolar loss is genera Yoroughont the mouth,

_. =|

54 A SYSTEM OF DENTAL SURGERY.

The hard, dense tartar which encircles the neck of the
tooth beneath or at the level of the edge of the gum should
be carefully removed ; not because it is, a8 has'been supposed
by some, cause of the disease—it is a secondary deposit,
and could never have got there without pre-existent disease
—but because it is a source of irritation,

If there is much discharge, the sulcus between the tooth
and the gum should be touched with a fragment of solid
zinc chloride, and the patient directed to wipe it out with a
camel-hair brush at least once a day, the brush being charged
with a solution of zinc chloride gr. y. ad §j., or with phénol
sodique, a convenient substitute for which is subjoined—

R, Acidi carbolici, 3).
Lig. potassm, 3).
Aqum ad Jj.
Or, if an astringent scem desirable, the following will be
found very efficient—
R. Glycerini acidi carbolici,
Glycerini acidi tannici, 44 Fs. my

If there be much congestion of the gums, they may he
freely lanced, and frequently painted with tincture of iodine
(double strength).

In some few cases much good may be done, but as rnle
the results of treatment are very unsatisfactory.

In the absence of an obvious cause of mischief, we can
but direct that the patient should use @ soft tooth-brosh,
employ a moderately astringent dentifrice, take care that
the teeth are well cleaned, and, at the same time, avoid frri-
tating the edges of the gums by unnecessary friction.

The use of a piece of stiff twine will be found very service-
able in deciding whether or not # loosened tooth should be
extracted ; if it can be passed up nearly to the apex of the
fang, on half or more than half the circumference of the
tooth, the chance of its again beooming firm is very small.

La A

518 A SYSTEM OF DENTAL SURGERY.

Reverses f the alton ve Sat a
A fairly characteristic case which occurred in the practice
Mr. Syme, and was seen more than once by my father, waa
met with in an adult, and affected both jaws alike ‘The
increase was slow, and no operation was resorted to; the
‘the

musourn of the Odontological Society.

Fig. 201. (2)

Another case, in which the growth was much larger, and
caused more distortion of the features, was successfully
operated upon by Mr. Pollock.

The following notes of Mr. Pollock's case are abridged
from Mr. Salter’s(*) article. At the fifth week after birth,
ix teeth had appeared, and it was noticed that the gums
were thick and puffy. At the age of two years, all the tem~-
porary teeth were extracted, and the gums cauterised.

At the time of admission into St. George's Hospital the
child was eight years old ; it was remarkable for an abnormal

(*) Other cases may be found in—" System of Surgery,” by 8. D. Gross, M.D.

: Surgical
Journal.” April, 1869, two cases; “Injuries and Diseases of the Jaws,” by
©. Heath, 2nd edition, 1872, p. 294. 4
(@) From a worel of the upper jaw of Mr. Syme’s case,
@) “A System of Surgery,” by Timothy Holmes, M.A. 20 edition, 2870.
Att, " Dineases of the Teeth,” vol. Iv, p. 342.

a

522 A SYSTEM OF DENTAL SURGERY.

by its rising up round them: in Mr. Pollock’s case, related
by Mr. Salter, it is noticed that the teeth were of unusually
large size, and were developed somewhat before their normal
time.

It does not appear possible to certainly connect this disease
with any constitutional taint; for though in Mr. Canton’s,
Dr. Gross’s, and Mr. Pollock's cases the children were stra-
mous and of defective intellect, in Mr. MaoGillivray’s case
the patient was otherwise perfectly healthy.

524 A SYSTEM OF DENTAL SURGERY,

increased till the boy reached the age of twelve, when the
left upper maxilla was removed by Mr. Heath; the intega-

ment having, however, shared in the hypertrophy, great
deformity still remains.
A model of the mouth (Fig. 205), taken before the opera-

tion, shows that on the right or healthy side the permanent
incisors, canine and bicuspids, are in place; while on the

@) Haif of the left upper maxtila (Mr. Heath's cuxe); the section has been
carried through the permanent teeth, which had not as yet been erupted: same
of the teeth are In the other half of the bone, so that they ure not abown in
this Agure,

a

DISEASES OF THE GUMS, Ero,

Sromatit1s—Inflammation affecting the mucons membrane
of the mouth is far more common during early childhood
than at any later period.

Dr. West, in treating upon inflammation of the mouth
(stomatitis), says: “ Inflammation of the mouth is an occur
rence by no means confined to the period of teething, hut it
comes on in children of all ages, assumes very different forma,
and leads to very different results in one ease from those
which characterise it in another, The mucous follicles of the
mouth are the chief seat of the disease in one case; the suly
stance of the gum in another, and that of the check in #
third. In the first (follicular or aphthous stomatitis), the
affection issues in the formation of several small ulcers, which
heal eventually of their own accord; in the second (uleera-
tive stomatitis), an unhealthy process of ulceration destroys
the gums and denudes the teeth, but it is tardy in its ad-
vance, and tends to a spontaneous cure; while in the last
gangrenous stomatitis), mortification involves all the tissues
of the cheek, and spreads with a rapidity which remedies fail
to check, and which is arrested at last only by the patients
death." (*) Although esch of the foregoing forms of disease
has a constitutional origin, and for the most part fall under
the treatment of the surgeon, yet they sometimes come under
the notice of the dentist.

Simple Stomatitis (Erythematus Stomatitis) is charac

(1) “ Lectores on the Diseates of Infancy and Childhood.” By Charles West,
M.D, Third edition.

g —_

584 A SYSTEM OF DENTAL SURGERY.

rence of the metallic taste, and to the feetor of the breath,
and ulso to the soreness and discomfort of the mouth which
mark the influence of mercury on the system, the gums show
indications that these conditions aro about to appear—that
the pationt will in a few hours be salivated. The state of
gum I am about to describe is, in fact, a premonitory sign
of ptyalism, for should it appear, and the mereury be inmme=
diately discontinued, yet solivation will come on, ‘The sign
is this:—the adherent portion of the mucous membrane of
the gums assumes an opaque white colour, contrasting
strongly with the non-adherent portion, which preserves its
natura! hue or becomes more red. ‘The free edge of the gums
is moveable, but that part which lies over the edge of the
alveoli is firmly tied down to the periosteum; and as the
edges of the alveoli present a festooned line, so the whitened
mucous membrane presents corresponding undolations. Again,
where the mucous membrane is loosely reflected from the
gum to the cheek, the natural colour is preserved. Whe
whiteness of gum is produced by an increased secretion of
epithelium, which, from being thicker and more opaque than
in the healthy state, renders the colour given by the veasela
to the subjacent tissne less apparent,

The surface of the mucous membrane, when deprived of
epithelium, is studded over with innumerable small conical
elevations or papillm. The thickened opithelium is readily
rubbed ‘off the toyis of the papille, while it retains its full
thickness in the intervening depressions; hence, if closely
inspected, the gums will not be seen to present a uniform
white hue, but a mottled aspect.

With the increased thickness there isa decrease of tenacity
between the scales that form the epithelium, for the surfane
may be much more readily rubbed off than when in its
natural state,

This curious and useful premonitory sign of coming
ptyalism was, I believe, first noticed, and its value pointed
out, by Mr, Corfe; at all events, he was the first to draw

: =|

540 A SYSTEM OF DENTAL SURGERY.- -

local. But in certain states of the system attended with an
altered condition of the cireulating fluid—in blood diseases, as
they are.often called—the whole of the gums become similarly
affected, and in maladies partaking of the nature of sea
scurvy end purpura, this peculiar condition of the vascular
tissues about the teeth forms a characteristic feature.

Fig. 8.0)

In scurvy the gums are greatly affected; the appearance
of the mouth is very peculiar, as the lips and tongue are
jallid, and contrast strongly with the blotchy, dusky purple
gums rising up between and even over the teoth, and bleeding
on the smallest touch.

In severe cases blood continually oozes from the gun
and these may even slongh and lay bare the necks of the
teeth and alveoli. The teeth become rapidly loos, and
finally fall out,

A somewhat similar appearance is met with in purpura;
in it the contrast between the gums and the lips is not 20
marked, and the severer lesions do not often occur,

G2) Shows the Injected vessels of grime inflame’ and sniiciently to
cover over and obscure the greater portion of the labial surface of

teeth. ‘The proparation was ottained from the mouth of a deceased r.
by Dr. Roberta, to whom 1 am indebted for this iftastration. ‘

~s

—

550 A SYSTEM OF DENTAL SURGERY.

be embedded and entangled in, rather than adherent to, the
fibrous tissue which composed the mass. After it had been
dislodged from the tumour, and submitted to microscopic
examination, the following characters were clearly mani
fested :—the whole of the surface bore the marks of absorp
tion, while the substance of the bone presented the structural
characters of normally-developed tissue,

The presence of these characters, and the size of the
fragment of bone, fully justified the assumption thet it at
one time formed a portion of the subjacent alveolus, andl that
its detachment had been effected by absorption; and further,
that when so detached, it had proved a source of irritation,
and thus led to the development of the epulis. Ina case
previously published, the stump of a tooth, the crown of
which had been broken off five years before, was found in the
centre of an epulis (Fig. 207),

Pig, 201. (8)

But true bone may be developed in the fibrous tissne of an
epulis, just as bone may occur as 8 new development in
yarions other situations; two examples of this are given by
Mr. Heath (*).

12). Sips nh han Deon: Dak open te ene te Soe

Surgery.”

Jay fn its centre. Prom Totes“ Lectures om Dental Anatomy and.
@) *Injurtes and Diseancs of he Sawn, tnd wtiton, yw.

560 A SYSTEM OF DENTAL SURGERY.

depends on the thoroughness of the operation; for if small
fragments are left, they form nuclei for the deposition of
fresh salts, In order to secure the smoothness of the scaled
surface, they should be polished with pumice-powder on a
piece of wood, after the tartar has been removed by suitable
steel instruments.

‘Tooth-powder that will dissolye the tartar will also dis-
solve the teeth, and therefore may not be used.

In young people the permanent teeth soon after their
appearance through the gum may become disfigured by the
deposition of dark green pigment upon the surface of the
enamel near its terminal edge. If tartar were present it
would project from the general level of the tooth, but in the
cases of green discoloration the surface of the enamel 7s mot
raised.

The habitual nse of the tooth-brush and the act of mastica-
tion gradually rub off the pigment, and the teeth are restored
to their proper colour, If, however, the disfigurement remains
after the teeth are fully developed and the enamel has
density, the unsightly appearance may be removed by rubbing
the part with a piece of soft wood loaded with fine pumice-
powder.

As to the nature of this green discoloration, the most
diverse views ure held: in the tenth edition of Harriss
“Principles and Practice of Dentistry,” it is said to erode
the enamel with great rapidity ; but this does not aceond
with the experience of most writers, who have found it to be
perfectly innocuous. It is sometimes met with
the lower animals, both domesticated and wild, in whom
caries is very rarely seen; and the colour, which is
of vegetable origin, probably occupies the substance of the
enamel cuticle.

566 A SYSTEM OF DENTAL SURGERY.

Pain caused by difficult eruption of wisdom teeth will
seldom be cured by any other measure than the extraction
of the tooth; but relief may be temporarily given by free
incisions, cutting away, if possible, the tough overlying gum;
and the excessive tenderness of the ulcerated surfaces may
be very greatly relieved by very lightly touching them with
nitric acid, and afterwards using repeated applications of
phénol sodique.

other—with the exception, hov
I have called epileptiform. 1
cause of the neuralzia most fr:
influence on the recurrence, th
invasion of the paroxysms of

of the pain; but the pain itself.
characters.”

To take a recent definition
described as, “a disease of the
itself by pains which, in the gre
lateral, and which appear to fol
particular nerves, and ramify, s
times into all the terminal branc
pains are usually sudden in the
stabbing, boring, or burning cha
attended with any local change, ¢
ment. They are always mark
rate, at first; the intermissions
sometimes irregular; the attacks
in severity on each successive occe
distinguished by complete, or alt
suffering. and in ronnet --

~~ “U0 a8 indica;
is most Severe in
the temple, the aff
and far back in th
Which ig Tather ra:
the upper Jaw,
Pain Teferred to
maxillary articulati:

o-wasia may ;
to be'soughe,

about from time to ¢
Varies though thig
Talgia,

gi
Wedl (loc, cit.
saigia th-exty
the nery, ming @

in amputation stumps;
diathesis, Mav tok. +

ODONTOMES. 601

dentine from the calcification of the odontoblasts, and per-
haps also enamel, the enamel organ having followed, as it
tends to do, the wanderings of the dentine germ; but as no
part of a tooth has as yet been formed, the mass may boa
confnsed heap of dental tissnes, not bearing the most remote
external resemblance to a tooth,

Tt will be well to note, before proceeding further, that the
product of the calcification of a dentine pulp is by no means
always true dentine: so long as the layer of odontoblasts
costs its surface, true dentine is produced; but this layer is
easily displaced and destroyed, and, once destroyed, is pro-
bably never formed afresh. Any calcification which may
take place after the destruction of the odontoblasts will
assume the form of secondary dentine, or of confused bone-
like tissue, but no more true dentine can be furmed. The
foregoing description may serve to explain the manner in
which the mass here figured arose,

Pig, 213.01)

appearance presented ‘vertical section through portion
Heine eg cane rg at of Sal

ODONTOMES. 603

case having been reganied as one of disease of the bone, which
was likely to proceed from had to worse, the portion of jaw
figured was excised by Sir W. Fergusson.

Dr, Forget records a somewhat similar case: the mass in
this instance occupied the whole space between the first
er eae en Oe Jew, ond wee by

him regarded as the representative of the second and third
molars of that side, the crown of one molar and the second
bicuspid having been found held down beneath it, For the
use of this figure, which is copied from Dr. Forget’s memoir,
“Des Anomalies Dentaires ct de leur Influence sur les
Maladies dex Os Maxillaires,” | am indebted to the kindness
of Mr. Christopher Heath.

Pig. 214. (2)

‘The patient in whom) this odontome occurred was aged
twenty, but disease of the jaw had first been remarked at the

_ sieetistine A
af which j bone.

ODONTOMES. 605

similar odontome, and will serve to exemplify the usual
structural characteristics of these growths. It is traversed

Fig. 115.0)

hy pirallel vascular tracts (a), which here and there dilate
into pouches, or branch out into several divisions ; from these
vascular tracts the dentinal tubes radiate with considerable
regularity.

Pig. 116. (*)

neg
detached fro
nount of tr:
interval su fe
¢Xplanation of
buried teeth a
Conceive ¢

the cname| an
the Contiguous
hone being cone
In the case of 5
leing cut, it ig
bursts ; but whe;
may be the Tesuli
Tf the foregoin

how an cncysted t.

in M, Maisonney
the bottom Of a ca
Now, as neither th,
of their ¢j

th in an

Wondered at, see
molars often nin.

Cording to Otto WwW
Place in two aitrea.:

a
should he, w
Ohne, Temove i
mind of the 1
injudicioug in

30 operation for
he enlarged by 1

654 A SYSTEM OF DENTAL SURGERY.

place; indeed, it is not to be wondered at that this should
sometimes happen, for when displacement takes place during
the development period, a very complete union is formed, as
is exemplified in the accompanying figure; and it is no

Fig. 235.

uncommon occurrence for the pulp to resume its formative
functions long after the cessatiun of regular calcification.

And that an injured pulp may be stimulated into under-
going calcification is well seen in the specimen which haa
been figured on page 469.

658 A SYSTEM OF DENTAL SURGERY.

to time been made at “replantation of teeth.” It should
have been mentioned in the section relating to alveolar
periostitis that experiments have lately been performed by
Mr. Coleman, following in the steps of Mitscherlich and
others, in which carious teeth were extracted and replaced,
after scraping off the thickened and diseased periosteum.

The results, however, are not such as to render it an
advisable operation; and Mr. Sercombe has lately placed in
the museum of the Odontological Society a pivoted tooth,
which had been extracted on account of prolonged irritation
in the socket, and afterwards replaced. It became toleratly
firm, but alter some little time became so loose that it had
to be removed, when the fang was found to have almost
disappeared, Such seems to be the usual termination of
cases of replantation,

me OS 26.11.

PIVOTING TEETH. 669

mation, if taken at the onset, may be controlled, and the
tooth saved by local bleeding and the administration of an
aperient.

Should there be reason to suppose that unfavourable symp-
toms may arise, it will be advisable to fix the pivot in a
manner that will admit of its ready withdrawal, and refix it
when all chance of mischief has passed away.

THE OPERATION OF EXTRACTION,

it must be forced outwards, the movement accompanied

with the slightest possible degree of
rotation, and, when it is felt to yield,
draw it upwards and outwards.

The cuspidati of the upper and lower
jaws require for each a pair of forceps
made upon the same plan as those for
the removal of the incisors, except that
they must be larger and rather stronger.
Those for the cuspidati of the lower
maxilla should, like forceps for the in-
cisors of the lower jaw, have the handles
slightly bent, Sometimes these teeth
are very small, in which case forceps
adapted to the adjoining teeth may serve
for their removal. The canine teeth,
whether in the upper or the lower jaw,
may be detached from their membranous
connection with the jaw by a rotatory
movement, and will then leave the
socket readily.

The bicuspids will be extracted with
instruments similar to those already des-
cribed, exoupt that there will be a little
difference in the jaws, which must be
accurately fitted to the neck of the
tooth, These teeth are not very fre-
quently liable to much variety in size,
go that an instrument which is well
adapted to an ordinary bicuspid tooth
will apply itself to almost all. I have
forceps in which the jaws are bent at
right angles with the handles, and open

laterally, for the extraction of bicuspids of the inferior maxilla.

(5 Forceps adapted for the removal of the lower incktor teeth, with the
handle curved to enable the operator to avoid the teeth of the npper Jaw.

700 A SYSTEM OF DENTAL SURGERY.

divergent roots, would be removed by force employed in the
usual direction. In the one case the operation would result
in the fmeture of one or both roots, or the withdrawal of the
portion of the alveolus enclosed by their convergence ; im the
other, in the fracture of one or more roots, or perhaps in the
removal of a portion of the labial or lingual wall of the alve~
olus. But if a similar course were pursued with the wisdom
tooth, it would break off at the neck, or the tooth would
effectually resist the efforts of the operator, With the

it would be very difficnlt to extract such a tooth, bat hy
adopting the elevator, the tooth could be gradually pried out
of its socket withont difficulty.

In operating upon teeth in the upper jaw, similar diffieul-
wig. 8.0 ties may arise. An unusnal size of the one, ar the

“"""" occurrence of several roots, even in a bicuspid
tooth, will sometimes embarrass the operator, by
raising & igpringrstrditgrnp ties
way under the fore’ he is employing. Similar
difticulties, consequent upon similar canses, will
arise with respect to the molar teeth of
jaw. ‘The application of the usual force is not
attended with the usual result,

The remedy will consist in steadily incrensing~
the force and varying its direction, feeling our
way, ag it were, nutil the tooth is separated from its socket,

The wisdom teeth of the upper jaw, though frequently the '
subjects of irregularity, being implanted in com;
porous bone, very seldom resist the efforts of the

‘The irregularities of form to which the teeth are Hable,
having been described in a preceding part of the vol
not be again particularised. |

Owing toan unusual thickness and strength in
the removal of a tooth is sometimes attended with
difficulty, and the operator is still further embarrassed
the crown of the tooth so cireumstanced is broken off on

(7) Shows « first bicuspid of the upper Jaw, with three distinct uote

ON EXTRACTION OF THE ROOTS OF TEETH. 705

extraction of a bicuspid tooth ; these symptoms disappeared
on extract of opium being placed in the vacated socket. A
ery common sequela of tooth extraction is exfoiiation of the
edges of the alveolar process ; this is always liable to happen
where there has been much suppuration preceding the ex-
traction of the tooth, and it is particularly liable to happen
where unusual force or protracted attempts have been made
use of to dislodge the tooth. Hence it is very common atter
the removal of impacted wisdom teeth, and it can in no way
be attributed to want of skill on the part of the operator.

( 716 )

APPENDIX.

THE PATHOLOGY AND ETIOLOGY OF DENTAL CARIES.

THE literature of this subject is now so profuse, and the opinions
advocated are so diverse, that has seemed inadvisable to burden
the text with asummary of them; whilst, at the same time, so much
of the dental surgeon’s time is occupied in combating caries and its
effects, that a manual of dental surgery which passed over this
branch of the subject in silence would be manifestly incomplete.

The actual appearances observed have been already described
(p. 294, e¢ seq.), and it will suffice to allude to certain additional
characters in connection with the theories which they influence.
The views held as to the nature of dental caries may be, for the
sake of convenience, grouped under the three following heads :—

These which regard it as a real “disease,” a vital phenomenon,
strictly comparable to morbid conditions of other more highly
organised parts of the body.

Those which regard it, inthe main, as the effect of mere chemical
action, but also consider that some very constant appearances are
only explicable on the hypothesis of vital action.

Those which regard it as wholly and entirely the effect of
chemical action, in no degree modified by the connection of the
tooth with a living organism.

It was at one time very generally supposed that dental caries
was an inflammatory affection, a true “ disease ” of the dentine, and
the name “ Odontitis” was given to this supposed disease : amongst
the older writers, Hunter, Cuvier, Fox, T. Bell, and others held this
spitien: and it has of late years been revived by Neumann and

lertz,

Tn support of this idea, the occurrence of so-called caries interna

734 A SYSTEM OF DENTAL SURGERY.

predisposes to the occurrence of caries, though as yet it is aneeriats
in what way it does so,

Caries is of very rare occurrence in animals, but when tt dew
arise it is usually in domesticated beasts (4): thus it has been at
with in the horse. It has, however, been met with, according te
Dr. Magitot, among the anthropoid apes whilst in the feral state,

One link in the chain of evidence is as yet wanting; mo one haw
hitherto succeeded in artificially producing all the histelogicl
characters of caries in teeth which have been submitted to the
action of reagents out of the mouth ; nevertheless, sufficient dats
exists for arriving at a tolerably accurate estimate of the nature uf
dental caries,

‘The following conclusions weem to be most nearly in scoordanm
with the preceding facts, viz >—

That caries is an effect of external causes, in which so-calla
“ vital” forces play no part,

That it is due to the solvent action of acids which have bets
generated by fermentation going on in the mouth, the buccal mucet,
probably, having no small share in the matter; and when once the
disintegrating process is established at some congenitally defective
point, the accumulation of food and secretions in the cavity will
intensify the mischief by furnishing fresh supplies of acid.

(*) The fact that stall-fed onimals are liable to & swollen, spongy coulitie
of the gunat has already been neted (page S37).

INDEX.

MENORMALITIES, in the form of | Absorption, Mr. Spence Bate upon,
teeth— 82

Incisors and canines, 200 » . of alveoli, 25, 508
Wisdom teeth, 211, 224 Abscess, nlveolar, 463, 482, 486
Honeycombed teeth, 213 | » following application of
Syphilitic teeth, 215 arsenions acid, 326

Supplemental cusps, 220 » of antrum, 634
Dilaceration, 226 » fital result from, 485

Gemination, Acids, action of, on the teeth, 723
Union of teeth, 220 Alveolar portions of jaw, growth of,
Total irregularity in develop- 18, 98, 101, e¢ passin
ment, 598 of deheiencies af, 67
Abnormalities, in the position of +» Abserption of, 508
teeth— hypertrophy of, 515
Hereditary character of, 114, | Alloy, fusible, 332
148 Amalgams,
Of incisors, 127, 153, 156 » —ifeeta. of, om dentine,
OF canines, 168, 179 333, 837
Of bicuspids, 145, 148, 185 Cases suitable for, 399
Of molars, 174 a various formule for,
Of wisdom teeth, 186 | 834
Of temporary teeth, 37 a contraction of, 388
Abnormal development of maxille, | » durability of, 833, 898
108 Amaurosis caused by dental irrita-
Abrasion of the tecth, 647 | tion, 571, 595
Absence of temporary teeth, 38 | » from pressure of antral
» permanent teeth, 115, abseass, 639
206 nm (Galenzowski’s case),
Absorption, process of, 71, 80,459. | 640
» of roots of temporary | Anmsthesia, 711
teeth, 70 | Anchylosis of jaws, 644
” of reots of permanent ... of teeth to jaws, 433
teeth, 80, 446 Anstie, Dr., on nenralgia, 569, 573
in suspensions of peecase | * on extraction of teeth

of, 77 in neuralgia, 583

—

736 INDEX.
Astrum, abscess jn, » cause of | Bone, development of, 425
th deen into, 643, 655 bslagmane Me deatal caries, Pi
» tee ven into, on
» diseases of, B+ Broca, Prof., on odoatomes, 58
» dontigerous cyst ae B24 ry on relative liability af
” various races todem
wit oe esa inevwn iaeord De pi (et
+ aD yD.
” tect ia relation with, 634 | Broach, use of, S34 :
» perforation by abscess, 635 | Buccal aaah m& source of caries,

» -Maalignant disease of, 637

» —- agnosia, 637
Arthur, Dr., on trentment of caries,
312

Arrested growth of jaw, 107
Arsenious acid, forallaying sensitive-
nessaf dentine, 262,

326
° for destrnetion of the
p, 418
Articular cartilage, influence on
growth of jaw, 24, 108
Artificial teeth, caries in, 719
Ash, Messrs., amalgam of, 356

Brats, Dr. L.S., on dentine develop-
ment, 271, 279
= on dentinal fibrils, 268
" on development of In
canm, 426
Bernard, M., on saliva, 555
Bicuspids, irregularities of, 145
* malformations, 291
” insertions of fillings in,
387
“ displacement of, 185
Bickersteth, Mr. case of hyperes-
tosis, 525
Bleaching discoloured teeth, 441
Blows, effect of, on teeth, 442
Boll, M.,on dentinal fibrils, 265
» 00 serves of tooth pulp,
279

“a ondentinedewelopment, 271
Bone, deficiencies af, 67
absorption of, 116

S04, 728
Buried ear ied 188, 617
Buruishers, 57

CaLorricatios, process of, 281
* of enamel,
» of dentine, 273
” = bee, at
” pulp,
Calooglobulin, 282
Cal rites, 274
Cambium layer of 4a
Canine tecth, irregularities im pale
tion of, 16%
® total dis af
197,
” ° ” oo
insertion tag
in, 387
~ extraction of, #77

738 INDEX,
Compressol wood, nse of, as | Sees

wedging, 352 sensitivoness of, 261, 02%
Condensing instruments, 394, ef »— Berve supply of, 269
peesia ” peril i}
Congenital abnormalities, 114 # velopment of, 271
ie syphilis, effect of, 215 » Changes in advamoed life,
Contour fillings, 867 268, 273, 722
Convalsions during first dentition, ” > 282
3ae a os Lea spaces ts,
® during second denti- 28:
tion, 589 » ~— aréolar, 255.
Copper, amalgam of, 334 » defects in structure, 235
Sromnies of the teeth, effects of, « _ eondary, 407
166 Dentinal tubes, 259, 263, 268
Crystal yold, method of employing, a » —_- termination of, 260,
853 | 296
Cusps, supplemental, 220 ‘= a into enamel,
Cuticola dentis, 245, 257
Cylinder fillings, 058 . » obliteration of, 272,
” ” instrument for 268, 721
rolling, 358 * v walls of
Cyst, serous, formed from abscess 263, 275
gan, 485 s » isolation of, 264,
» dentigerous, 616 278
+» At roots of teeth, 628 Lhe » Swelling of, in
}, involving lower jaw, 629 caries, 717
» diagnosis, 630 | ig Waite 264
origin of, 628 ae, n demonstration af,
treatment, 632 = 265 ood
e Ssormak, M., interglobul spaces | * » «Battire fanetion
of 283 b of, 28, 278
SS a » Sbliteration in old
Draru from pywmin after tooth | age, 268, 722
extraction, 485, 498 | <= © palp (sce Pulp)
» from tetanus, 591 ee cd = ar
» from meningitis, 498 = 3
» from antral abscess, 639 " » — Caleifiention of, 263,

Deafness from dental irritation, 591 268, 721
Decussation of enamel fibres, 245 | Dentigerous eysts, _e of, G16,
Defective enamel, 288

Deficiencies in number of teeth, 37,

5, 208
” in ‘drvslopusaa of | Dentition, temporary, 1
maxillm, 107 » permanent,
Delirium from mee eruption ofl » «=: @ cause of constitutional
wisdom teeth, 59 Aravartummen, MA, AOL

742
Instruments for inserting sponge
gold, 343

” forceps for condensing
a plug, S72

3 spring mallet, 371

” =r oe of toeth,

Interglobular spaces, 283
fnversion of all anterior teeth, 128
»_ of central incisors, 155,
Irregularities in pesitions of tem-
porary teeth, 97
" in uumber of tempo-
rary tecth, 87
” in form of temporary
teeth, 40
- in position of perma-
nent teeth before
their eruption, 63
in the position of
manent teeth al
ing the whole jaw,
117, 127, 139, 144
= causes of, 86, 140
9 hereditary character
of, 114, 148
” of contral incisors, |
127, 153
. of lateral Incisons,
156
* of canines, 108, 179
of bicuspids, 145,
148, 185
” of first and
molars, 174

second

» of wisdom toeth, 186 |
4 treatment of, 131, et |

passim

= in the number of |
permanent teeth,
115, 198, 206

” in the time of erup-
tion, 51, 98

” in the form of per-
manent teeth, 209

(see Nonormalities)

Irregularities, involving root a
well ax crown, 6

” f growth of, 22, 104
* chaagy form at different

ages, 34
» Cdentulons, 105
» Closure of, 644
aememieabi rob a
vel
, me eS ee
» on odontoblaste, 281
on articolar

a
Lacusa, sature of, 425, 427
7" evelopment of, 426
= “ encapsuled ” 243, 427

724
bers the gums, advisability of,

P.. incisors, irregularities of,
1

Leber and Rottenstein, on dental
caries, 719, 723, 725
Lent, M., om enamel development,
252

2 bmn

Leptothrix rece, 725

Leucorrbea, attributed to dental
disorder, 592

Loynseele, M., case of meningitis,
498

Lower jaw, method of operating
rayon, SOS

INDEX.

MaoGrutrvnay, Mr., case of alveolar
hypertrophy, 520.
Magitet, Dr., ou nature of imem-
brane proformativa,
270
” on dentine devel
mont, 282 ae
” on the saliva, 555
" mated caries, 722,

on erosion of teeth, 453

Making, Mr., on amalgams, 339

n on sponge gold, 340

on welding of gold, 347
Mallet, forms of, 370
» Spring, 371

Malposition of teeth (total)

" of incisors, 176

” of canines, 177

” of bicuspids, 185

> of wisdom teeth, 186
Matrices, use of, iu filling, 393
Maxillu, development of, 3, 17, 33,

101
» abnormal development, 138
» arrested development, 107
» of S-months’ fntus, 3
» of 2-months’ child, 9
of 3-months’ child, 13
» of 6-months’ child, 14
«» of B-monthe’ child, 15
« of Q-months’ child, 17
» of 12-months’ child, 27
» of 18-months’ child, 29
of 21-months’ child, 31
yw of 28-months’ child, 51
» of 40-months’ child, 32
» of 4-years’ child, 35
» of G-years’ child, 59
* e Seow child, 87
” 2-years’ child, 4
”
”

mitoen child, 98
Cewitret of daring first den-
eition, 18
second

dentition, 101

7438
Maxilln, Ga age of fatal with
adalt, 22

Veshay lit
” ,
* ry occurring with
vaneing ago, 104
Mechanical petiesre to the teeth,
O47, 649, 655
” ” to jaws, 659
Mombraua eboris, 268
» —-Preformativa, 251, 255,
270
» Nasmyth's, 243, 257
Meningitis, set up ay pus from
alveolar abscem, 493
eniel Sesiees changes in position
of, 1
Neots effects of, apon the mouth,

Metallic fillings, 331
Microscopical character of dental

tissues, $41
ial 4 of enamel, 245
wi n of dentine, 259,
284
" » of carious den-
tine, 296
" » of cementum,
423
Moisture, necessity of excluding, S44
* methods of * 4B
Molar tooth, erupted in middle of
ite, 553.
Py operation of filling, 393.
7s » ofextracting,
679
Cie Mr., case of dentigerous cyst,
7

Mucus, influence of, on caries, 728
Mummery, Mr., on dental caries, 733

Napxes, methods of app!
Nasmyth’s menses
Necrosis, of the teeth, pri

» of the jaw, 495

nm —_ phosphorts, 500

» exanthematous, 503

746 INDEX,
Second dentition, | Supplemental cusps, 290
rs constitutional dis~ Sympathetic pain, 567, 592,
turbances from, | perssiin
588 Syphilis, effects of, on form of tenth,
Sensibility of dentine, 261, 526 215
Separation of teeth, Sh1 n & cause of necrosis, 182,
Sercombe, Mr., case of replantation, 47
658 » of ulceration of mosth,
case of seeondary 345, HE

uterine pain, 592
Sequestrum, detachment of, 500
Shedding of temporary teeth, 70
Silver, an ingredient in amalgams,
ou
Sinuses opening upon the cheek,
154, 195

on chin, 482
«(nthe neck, 485
below the clavicle, 435,
508
Sockets, relation of teeth to, 98, 110
>. estoration of, 124
Speculum, for mouth, 711
Sponge gold, 340
Spasmodic closure of jaws, 485, 645

- wry neck, 593
Stomatitis, 526
* simple erythematous,
526

» _ aphthous, $27
oa ulocrative, 529
s gangrenov
~ general, 5
syphilitic, 535, 541
Stratum intermedium of enamel
argan, 254
Striation of enamel, 246
Strumous diathesis, influence on
dentition, SL
“ a cause of né-
erosis, 477
Stumps, removal of, 639
Sullivan's amalgam, 334
Sopernumerary teeth, 198
number of,
116, 199

ee

” "

of uleerstion of tongue,
oS

Taran, nature of, 657
» Varieties of, 558
green variety of, 560, T22
| Teeth, abrasion of, 647
n» eresion of, 450
» fracture of, 649
i diskncation wf 855
» Teanion efter fracture, 652
" pay pe on
+ development of, 4, ¢f emia
y Romenclature of surfaces of,
36
» positlonef permanent, durtne
development, ST
» transposition of, 197
» transplantation, 656
» getnination of, 227
mn eruption of ae
* irrgdarity at pase position of

is iregalariy of nomber af

~ cepa of form of, 208,
219, 295
- permumie: 1s
ns hemeyeoeabed, 13
» syphilitic, 216
Absence of, te
» Telative Liability to ceaurley
729
Teething, 1

K divoriers consequent ape

INDEX.

Wisdom teeth, misplaced, 18Y Wood, Mr., on early removal of +-
deficient ‘space for,| — questra, 508
186 Wry neck, case of, 503

in sigmoid notch, 189
piercing the cheek, | Zinc oxychloride, as temporar
f filling, 331

: inversion of, 196 3 » — Oavities — guitabl
variability of, 211, for, 385
2 ik + applicative t
” orm of, in apes and sensitivedentine
savage races, 224 326

Wood, De., fasible alloy of, 33: Zone of transparency, in caries, 720

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