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Full text of "Medical Jurisprudence And Toxicology"

AGE                                                                    29

Tooth                                                               Years

Central Incisor

Lateral Incisor

Canine

First Bicuspid

Second Bicuspid

First Molar

Second Molar

7.10

7.8S

10.87

10.50

11.57

6.48

11.79

General Characteristics of Teeth.—In some rare cases the temporary
teeth may either appear abnormally early or be present at birth, a condition
probably due to hereditary syphilis. P. S. Khosla13 reports the case of a Hindu
male child in whom he found the lower central incisor coming out of gums,
when he saw him the next day after his birth. S. N. Chatterjiu also reports
the case of a male child who was born with two well-marked incisor teeth
in the lower jaw. On the other hand, eruption of the temporary" teeth may
be delayed for a considerable time owing to rickets and other nutritional
diseases.

The temporary teeth commence to be shed about the sixth or seventh
year after the eruption of the permanent first molar teeth. Hence in a child
of six or seven years there will be twenty-four teeth, viz. twenty temporary
teeth and four permanent first molar teeth.

The permanent teeth erupt at first in the lower jaw and after short
intervals in the upper jaw, but are not always regular in their appearance.
In a few cases they may appear earlier than the average period. rPhe time
of eruption of the third molar teeth or wisdom teeth is more uncertain. After
the eruption of the second molar teeth the body of the jaw grows pos-
teriorly and the ramus is elongated to make room- for the appearance of the
third molar teeth. Hence, during the examination of a minor for determin-
ing his age, a note should always be made as to whether there was a space
in the jaw behind the second molar teeth, if the third molars were absent.
These teeth are usually cut between 17 and 25 years of age, but I have seen
the left lower third molar tooth in a Mohamedan boy and a Mohamedan
girl, aged 14 years respectively, and in a Hindu boy of 15 years. I have
also found the lower third molar teeth in a Hindu boy of 16 years. Sahay
found three third molar teeth in a Bawari boy, aged between 15 and 16
years. Lall and Townsend15 found one third molar tooth between the ages
of 15 and 16 years, two third molar teeth between the ages of 16 and 17
years and three third molar teeth between 17 and 18 years of age in a
majority of 125 girls examined in Lucknow. On the other hand, in some
rare cases the third molar teeth may not appear till adult age is advanced.
I have seen a man of 40 and another of 48 who had not cut their third molar
teeth. K. Venkat Rao16 reports the case of a man, who, at the age of 54
years, cut his third molar tooth in the right upper jaw, while it was still
absent in the left upper jaw. Both the third molar teeth were present in
the lower jaw.

The notched and stunted upper central incisors of inherited syphilis^
known ^ as Hutchinson's teeth, are always permanent. In old age the teeth
have either fallen off or the crowns are worn away to the sockets. So
times a smooth rounded surface is to be seen in place of alveolar cavities.

13.   Indian Med. Gaz., Feb. 1927, p. 68.

14   Indian Medical Gazette, January 1932, p. 57.

15.    Ind. Med. Gaz^ Get 1939, p. 614.

16.    Indian Medical Gazette, March 1932, p. 127.