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Full text of "Contemporary Oral and Maxillofacial Surgery,4th Ed Part II Principle of Exodontia"

Principles of Management of 
Impacted teeth 



Larry J. Peterson 




CHAPTER 



Chapter outline 




INDICATIONS FOR REMOVAL OF IMPACTED TEETH 

Prevention of Periodontal Disease 

Prevention of Dental Caries 

Prevention of Pericoronitis 

Prevention of Root Resorption 

Impacted Teeth under a Dental Prosthesis 

Prevention of Odontogenic Cysts and Tumors 

Treatment of Pain of Unexplained Origin 

Prevention of Fracture of the Jaw 

Facilitation of Orthodontic Treatment 

Optimal Periodontal Healing 
CONTRAINDICATIONS FOR REMOVAL OF IMPACTED 
TEETH 

Extremes of Age 

Compromised Medical Status 

Probable Excessive Damage to Adjacent Structures 

Summary 



CLASSIFICATION SYSTEMS OF IMPACTED TEETH 
Angulation 

Relationship to Anterior Border of Ramus 
Relationship to Occlusal Plane 
Summary ROOT 

MORPHOLOGY 

Size of Follicular Sac 

Density of Surrounding Bone 

Contact with Mandibular Second Molar 

Relationship to Inferior Alveolar Nerve 

Nature of Overlying Tissue MODIFICATION OF 

CLASSIFICATION SYSTEMS FOR 

MAXILLARY IMPACTED TEETH 

DIFFICULTY OF REMOVAL OF OTHER IMPACTED TEETH 

SURGICAL PROCEDURE PERIOPERATIVE PATIENT 

MANAGEMENT 




n impacted tooth is one that fails to erupt into the 
dental arch within the expected time. The tooth 
becomes impacted because adjacent 
teeth, dense overlying bone, or excessive soft tissue prevents 
eruption. Because impacted teeth do not erupt, they are 
retained for the patient's lifetime unless surgically removed. The 
term unerupted includes both impacted teeth and teeth that 
are in the process of erupting. The term embedded is 
occasionally used interchangeably with the term impacted. 



Teeth most often become impacted because of inadequate 
dental arch length and space in which to erupt; that is, the 
total length of the alveolar bone arch is smaller than the total 
length of the tooth arch. The most common impacted teeth 
are the maxillary and mandibular third molars, followed by 
the maxillary canines and mandibular premolars. The third 
molars are the most frequently impacted, because they are 
the last teeth to erupt; therefore they are the most likely to 
have inadequate space for eruption. 



184 



Principles of Management of Impacted Teeth 



CHAPTER 9 



In the anterior maxilla, the canine tooth is also com- 
monly prevented from erupting by crowding from other 
teeth. The canine tooth usually erupts after the 
maxillary lateral incisor and maxillary first premolar. If 
space is inadequate to allow eruption, the canine tooth 
becomes impacted. In the anterior mandible a similar 
situation affects the mandibular premolars, because 
they erupt after the mandibular first molar and 
mandibular canine. Therefore if room for eruption is 
inadequate, one of the premolars, usually the second 
premolar, remains un-erupted and becomes impacted. 

As a general rule, all impacted teeth should be re- 
moved unless removal is contraindicated. Extraction 
should be performed as soon as the dentist determines 
that the tooth is impacted. Removal of impacted teeth 
becomes more difficult with advancing age. The dentist 
should not recommend that impacted teeth be left in 
place until they cause difficulty. If the tooth is left in 
place until problems arise, the patient may experience an 
increased incidence of local tissue morbidity, loss of adja- 
cent teeth and bone, and potential injury to adjacent 
vital structures. Additionally, if removal of impacted 
teeth is deferred until they cause problems later in life, 
surgery is more likely to be complicated and hazardous, 
because the patient may have compromising systemic 
diseases. A fundamental precept of the philosophy of 
dentistry is that problems should be prevented. Preven- 
tive dentistry dictates that impacted teeth are to be 
removed before complications arise. 

This chapter discusses the management of impacted 
teeth, It is not a thorough or in-depth discussion of the 
technical aspects of surgical impaction removal. Instead 
its goal is to provide both the information necessary for 
proper management and a basis for determining the dif- 
ficulty of surgery. 

INDICATIONS FOR REMOVAL OF IMPACTED TEETH 

All impacted teeth should be considered for removal as 
soon as the diagnosis is made. The average age for com- 
pletion of the eruption of the third molar is age 20, 
although eruption may continue in some patients until 
age 25. During normal development the lower third 
molar begins its development in a horizontal angulation, 
and as the tooth develops and the jaw grows, the angula- 
tion changes from horizontal to mesioangular to vertical. 
Failure of rotation from the mesioangular to the vertical 
direction is the most common cause of the tooth 
remaining impacted. The second major factor is that 
the mesiodistal dimension of the teeth versus the 
length of the jaw is such that inadequate room exists in 
the alveolar process anterior to the anterior border of the 
ramus to allow the tooth to erupt into position. 

As noted earlier, some third molars will continue to 
erupt after age 20, coming into final position by age 25. 
Multiple factors are associated with continued eruption. 
When late eruption occurs, the unerupted tooth is usual- 
ly covered only with soft tissue or very slightly with 
bone. These teeth are almost always in a vertical 
position 



and are relatively superficially positioned with respect to 
the occlusal plane of the adjacent second molar. 

Finally and perhaps most importantly, sufficient space 
exists between the anterior border of the ramus and the 

1 9 

second molar tooth to allow eruption. - Likewise, if the 
tooth does not erupt after age 20, it is most likely covered 
with bone. In addition, the tooth is likely a mesioangular 
impaction and located lower in the alveolar process near 
the cervical level of the adjacent second molar. Finally, 
inadequate space exists to allow eruption. Therefore the 
dentist and surgeon can use these parameters to predict 
whether or not a tooth will erupt into the arch or remain 
impacted. 

Early removal reduces the postoperative morbidity and 
allows for the best healing. 3 " 6 Younger patients tolerate the 
procedure better and recover more quickly and with less 
interference to their daily lives. Periodontal healing is 
better in the younger patient, because of better and more 
complete regeneration of the periodontal tissues. More- 
over, the procedure is easier to perform in younger 
patients. The ideal time for removal of impacted third 
molars is when the roots of the teeth are one-third 
formed and before they are two-thirds formed, usually 
during the late teenage years, between ages 17 and 20. 

If impacted teeth are left in the alveolar process, it is 
highly probable that one or more of several problems will 
result. " 8 To prevent this, impacted teeth should be 
removed. 

Prevention of Periodontal Disease 

Erupted teeth adjacent to impacted teeth are predisposed 
to periodontal disease (Figs. 9-1 and 9-2). The mere pres- 
ence of an impacted mandibular third molar decreases 
the amount of bone on the distal aspect of an adjacent 
second molar (see Fig. 9-1). Because the most difficult 
tooth surface to keep clean is the distal aspect of the last 
tooth in the arch, the patient may have gingival inflam- 
mation with apical migration of the gingival attachment 
on the distal aspect of the second molar. With even 
minor gingivitis the causative bacteria have access to a 
large portion of the root surface, which results in the 
early formation of severe periodontitis (see Fig. 9-2). 
Patients with impacted mandibular third molars often 
have deep periodontal pockets on the distal aspect of the 
second molars but have normal sulcular depth in the 
remainder of the mouth. 

The accelerated periodontal problem resulting from an 
impacted third molar is especially serious in the maxilla. 
As a periodontal pocket expands apically, it becomes 
involved with the distal furcation of the maxillary second 
molar relatively early, which makes advancement of the 
periodontal disease more rapid and severe. In addition, 
treatment of the localized periodontal disease around the 
maxillary second molar is more difficult because of the 
distal furcation involvement. 

By removing the impacted third molars early, peri- 
odontal disease can be prevented and the likelihood of 
bony healing and bone fill into the area previously occu- 
pied by the crown of the third molar is increased. - 6 




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PART II 



Principles of Exodontia 










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FIG. 9-1 Radiograph of mandibular third molar impacted against second molar, with bone loss 
resulting from presence of third molar. 




FIG. 9-2 Radiographs show variations of mandibular third molar impacted against second molar, 
with severe bone loss secondary to periodontal disease and third molar. 



Prevention of Dental Caries 

When a third molar is impacted or partially impacted, the 
bacteria that cause dental caries can be exposed to the 
distal aspect of the second molar, as well as to the third 
molar. Even in situations in which no obvious 
communication between the mouth and the impacted third 
molar exists, there may be enough communication to 
allow for caries production (Figs. 9-3 through 9-5). 



Prevention of Pericoronitis 

When a tooth is partially impacted with a large amount of 
soft tissue over the axial and occlusal surfaces, the patient 
frequently has one or more episodes of pericoro-nitis. 
Pericoronitis is an infection of the soft tissue around the 
crown of a partially impacted tooth and is caused by the 
normal oral flora. For most patients the bacteria and host 
defenses maintain a delicate balance, but host defenses 
cannot eliminate the bacteria. 



l*rinciples of Management of Impacted Teeth 



CHAPTER 9 



187 













FIG. 9-3 Radiograph of caries in mandibuiar second molar secondary to presence of impacted 
third molar. 



If the host defenses are compromised (e.g., during minor 
illnesses, such as influenza or an upper respiratory infec- 
tion, or from severe fatigue), infection can occur. Thus 
although the impacted tooth has been present for some 
time without infection, if the patient experiences a mild, 
transient decrease in host defenses, pericoronitis may result. 

Pericoronitis can also arise secondary to minor trauma 
from a maxillary third molar. The soft tissue that covers the 
occlusal surface of the partially erupted mandibular third 
molar (known as the operculum) can be traumatized and 
become swollen. Often the maxillary third molar further 
traumatizes the already swollen operculum, which causes 
increased swelling that again can be traumatized more eas- 
ily. This spiraling cycle of trauma and swelling is often 
interrupted only by removal of the maxillary third molar. 

Another common cause of pericoronitis is entrapment 
of food under the operculum. During eating, a small 
amount of food may be packed into the pocket between 
the operculum and the impacted tooth. Because this 
pocket cannot be cleaned, bacteria invade it and peri- 
coronitis begins. 

Streptococci and a large variety of anaerobic bacteria 
(the usual bacteria that inhabit the gingival sulcus) cause 
pericoronitis. It can be treated initially by mechanically 
debriding the large periodontal pocket that exists under 
the operculum by using hydrogen peroxide as an irrigat- 
ing solution. Hydrogen peroxide not only mechanically 
removes bacteria with its foaming action, it also reduces 
the number of anaerobic bacteria by releasing oxygen 
into the usually anaerobic environment of the oral cavi- 
ty. Other irrigates, such as chlorhexidine or iodophors, 
can reduce the bacterial population of the pocket. 

Pericoronitis can present as a very mild infection or 
as a severe infection that requires hospitalization of the 
patient. Just as the severity of the infection varies, 
the 




FIG. 9-4 Radiograph of caries in mandibular impacted molar. 



treatment and management of this problem vary from 
very mild to aggressive. 

In its mildest form, pericoronitis is a localized tissue 
swelling and soreness. For patients with a mild infection, 
irrigation and curettage by the dentist and home irriga- 
tions by the patient usually suffice. 

If the infection is slightly more severe with a large 
amount of local soft tissue swelling that is traumatized by a 
maxillary third molar, the dentist should consider extract- 
ing the maxillary third molar in addition to local irrigation. 



188 



PART II 



Principles of Exodontia 




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FIG. 9-5 Radiograph of caries in both impacted third molar and second molar. 



For patients who have (in addition to local swelling 
and pain) mild facial swelling, mild trismus secondary 
to inflammation extending into the muscles of 
mastication, and a low-grade fever, the dentist should 
consider administering an antibiotic along with 
irrigation and extraction. The antibiotic of choice is 
penicillin. 

Pericoronitis can lead to serious fascial space 
infections. Because the infection begins in the posterior 
mouth, it can spread rapidly into the fascial spaces of 
the mandibular ramus and the lateral neck. If a patient 
develops trismus (with an inability to open the mouth 
more than 20 mm), a temperature of greater than 101° F, 
facial swelling, pain, and malaise, the patient should be 
referred to an oral and maxillofacial surgeon, who may 
admit the patient to the hospital. 

Patients who have had one episode of pericoronitis, 
although managed successfully by these methods, will 
continue to have episodes of pericoronitis, unless the 
offending mandibular third molar is removed. The 
patient should be informed that the tooth should be 
removed at the earliest possible time to prevent 
recurrent infections. The mandibular third molar 
should not be removed until the signs and symptoms 
of pericoronitis have been completely resolved. The 
incidence of postoperative complications, specifically 
dry socket and postoperative infection, increases if the 
tooth is removed during the time of active infection. 

Prevention of pericoronitis can be achieved by 
removing the impacted third molars before they 
penetrate the oral mucosa and are visible. Although 
excision of the surrounding soft tissue, or 
operculectomy, has been advocated as a method for 
preventing pericoronitis without removal of the 
impacted tooth, it is very painful and usually does not 
work. The soft tissue excess tends to recur, because it 
drapes over the impacted tooth and causes regrowth of 
the operculum. The overwhelming majority of cases of 
pericoronitis can be prevented only by extraction of the 



tooth. 

Prevention of Root Resorption 

Occasionally, an impacted tooth causes sufficient pressure 
on the root of an adjacent tooth to cause root resorp-tion 
(Figs. 9-6 and 9-7). Although the process by which root 
resorption occurs is not well defined, it appears to be 
similar to the resorption process primary teeth undergo 
in the presence of the succedaneous teeth. Removal of 
the impacted tooth may result in salvage of the adjacent 
tooth by cemental repair. Endodontic therapy may be 
required to save these teeth. 

Impacted Teeth under a Dental Prosthesis 

When a patient has an edentulous area restored, there are 
several reasons that impacted teeth in the area should be 
removed before the prosthetic appliance is constructed. 
After teeth are extracted, the alveolar process slowly 
undergoes resorption. Thus the impacted tooth becomes 
closer to the surface of the bone, giving the appearance of 
erupting. The denture may compress the soft tissue on 
the impacted tooth, which is no longer covered with 
bone; the result is ulceration of the overlying soft tissue 
and initiation of an odontogenic infection (Fig. 9-8). 

Impacted teeth should be removed before prosthesis is 
constructed because, if the impacted tooth must be 
removed after construction, the alveolar ridge may be so 
altered by the extraction that the prosthesis becomes 
unattractive and less functional (Fig. 9-9). In addition, if 
removal of impacted teeth in edentulous areas is 
achieved before the prosthesis is made, the patient is 
probably in good physical condition. Waiting until the 
overlying bone has resorbed and ulceration with infection 
occurs does not produce a favorable situation for 
extraction. If extraction is postponed, the patient will be 
older and more likely to be in poorer health. Further- 
more, the mandible may have become atrophic, which 
increases the likelihood of fracture during tooth removal 
(Fig. 9-10). 



Principles of Management of impacted Teeth 



CHAFfER 9 





FIG. 9-6 Root resorption of second molar as result of impacted 
third molar. 



Prevention of Odontogenic Cysts and Tumors 

When impacted teeth are retained within the alveolar 
process, the associated follicular sac is also retained. 
Although in most patients the dental follicle maintains 
its original size, it may undergo cystic degeneration and 
become a dentigerous cyst or keratocyst. If the patient is 
closely followed, the dentist can diagnose the cyst 
before it reaches large proportions (Fig. 9-11). However, 
unmon-itored cysts can reach enormous sizes (Fig. 9-12). 
As a general guideline, if the follicular space around the 
crown of the tooth is greater than 3 mm, the diagnosis 
of a dentigerous cyst is a reasonable one. 

In the same way that odontogenic cysts can occur 
around impacted teeth, odontogenic tumors can arise 
from the epithelium contained within the dental 
follicle. The most common odontogenic tumor to 
occur in this region is the ameloblastoma. Usually, 
ameloblastomas in this area must be treated aggressively 
by excision of the overlying soft tissue and of at least a 
portion of the mandible. Occasionally, other 
odontogenic tumors may occur in conjunction with 
impacted teeth (Fig. 9-13). 

Although the overall incidence of odontogenic cysts 
and tumors around impacted teeth is not high, ° the over- 
whelming majority of pathologic conditions of the 
mandibular third molar are associated with unerupted 
teeth. It is therefore recommended that impacted teeth 
be removed to prevent the occurrence of cysts and 
tumors. 



Treatment of Pain of Unexplained Origin 

Occasionally, patients come to the dentist complaining 
of pain in the retromolar region of the mandible for no 
obvious reasons. If conditions such as myofascial pain 
dysfunction syndrome and temporomandibular joint 
(TMJ) disorder are excluded and if the patient has an 
unerupted tooth, removal of the tooth sometimes 
results in resolution of the pain. 




FIG. 9-7 Root resorption of maxillary lateral incisors as result of 
impacted canine. 



Prevention of Fracture of the Jaw 

An impacted third molar in the mandible occupies space 
that is usually filled with bone. This may weaken the 
mandible and render the jaw more susceptible to fracture 
(Fig. 9-14). If the jaw fractures through the area of an 
impacted third molar, the impacted third molar is fre- 
quently removed before the fracture is reduced and inter- 
maxillary fixation is applied. 

Facilitation of Orthodontic Treatment 

In patients who require retraction of first and second 
molars by orthodontic techniques, the presence of 
impacted third molars may interfere with the treatment. 
It is therefore recommended that impacted third molars 
be removed before orthodontic therapy is begun. 

Another consideration is that, after orthodontic treat- 
ment has been concluded, there may be crowding of the 
mandibular incisor teeth. This has been attributed to the 
mesial force transmitted to the molar and premolar teeth 
by impacted third molars, especially mesially inclined 

1110 

impactions. - Several other factors influence crowding. 
Growth of the maxilla stops before growth of the 
mandible. If the upper and lower incisors are in a proper 
overbite and overjet relationship, and if the mandible 
continues to grow after the maxilla stops growing, the 
mandibular incisors then become crowded to accommo- 
date the constriction imposed on them by the maxillary 
incisors. This explanation appears sound, because crowd- 



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FIG. 9-8 Impacted tooth retained under denture. Tooth is now at surface and is causing infection. 





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FIG. 9-9 Impacted tooth under fixed bridge. Tooth must be 
removed and therefore may jeopardize bridge. 



FIG. 9-10 Impaction in atrophic mandible, which may result in jaw 
fracture during extraction. 



ing occurs after the age at which the maxilla stops growing 
and the mandible continues forward growth. 

Many orthodontists still refer their patients to surgeons 
for removal of impacted third molars after orthodontic 
treatment is complete. Although the surgeon should explain 
the other reasons for surgery, the decision to remove 
impacted teeth to help prevent crowding should be 
supported. 

Optimal Periodontal Healing 

As noted earlier, one of the most important indications 
for removal of impacted third molars is to preserve the 
periodontal health. A great deal of attention has been 
given to the two primary parameters of 
periodontal 



health after third molar surgery; that is, bone height on the 
distal aspect of the second molar and attachment level 
on the distal aspect of the second molar. 

Recent studies have provided information on which to 
base the likelihood of optimum periodontal tissue heal- 
ing. 13 " 15 The two most important factors have been shown 
to be the extent of the preoperative infrabony defect on 
the distal aspect of the second molar and the patient's age 
at the time of surgery. If a large amount of distal bone is 
missing because of the presence of the impacted tooth and 
the associated follicle, it is less likely that the infrabony 
pocket can be decreased. Likewise, if the patient is older, 
then the likelihood of optimum bony healing is decreased. 
Patients whose third molars are removed before age 25 are 
more likely to have better bone 



Principles of Management of Impacted Teeth 



chajtl:r 9 



191 




FIG. 9-1 1 Small dentigerous cyst arising around impacted tooth. 



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FIG. 9-12 Large dentigerous cyst that extends from coronoid 
process to mental foramen. Cyst has displaced impacted third molar 
to inferior border of mandible. 









FIG. 9-13 Large ameloblastoma in mandible as result of impacted 
third molar. 



healing than those whose impacted teeth are removed 
after age 25. 14 In the younger patient, not only is the ini- 
tial periodontal healing better but the long-term contin- 
ued regeneration of the periodontium is clearly better. 14 
As mentioned previously, unerupted teeth may continue 
to erupt until age 25. Because the terminal portion of 
the eruption process occurs relatively slowly, the 
chances of developing pericoronitis increase, as do the 
amount of contact between the third molar and second 
molar. Both of these factors decrease the possibility for 
optimum periodontal healing. However, it should be 
noted that the completely bony impacted third molar 
in a patient older than age 30 should probably be left 
in place unless some specific pathology develops. 
Removal of such asymptomatic completely impacted 
third molars 



in older patients will clearly result in pocket depths and 
alveolar bone loss, which will be greater than if the tooth 
were left in place. 

CONTRAINDICATIONS FOR REMOVAL 

OF IMPACTED TEETH 

All impacted teeth should be removed unless specific 
contraindications justify leaving them in position. When 
the potential benefits outweigh the potential complica- 
tions and risks, the procedure should be performed. Sim- 
ilarly, when the risks are greater than the potential bene- 
fits, the procedure should be deferred. 

Contraindications for the removal of impacted teeth 
primarily involve the patient's physical status. 



• 



192 PARTU * Principles of Exodmtia 




FIG. 9-14 Fracture of mandible that occurred through location 
of impacted third molar. 



Extremes of Age 

The third molar tooth bud can be radiographically 
visualized by age 6. Some surgeons think that removal 
of the tooth bud at age 7 to 9 can be accomplished 
with minimal surgical morbidity and therefore 
should be performed at this age. However, most 
surgeons believe that it is not possible to predict 
accurately if the forming third molar will be impacted. 
The consensus is that very early removal of third molars 
should be deferred until an accurate diagnosis of 
impaction can be made. 

The most common contraindication for the 
removal of impacted teeth is advanced age. As a patient 
ages the bone becomes highly calcified, therefore less 
flexible and less likely to bend under the forces of 
tooth extraction. The result is that more bone must be 
surgically removed to displace the tooth from its 
socket. 

Similarly, as patients age, they respond less 
favorably and with more postoperative sequelae. An 18- 
year-old patient may have 1 or 2 days of discomfort and 
swelling after the removal of an impacted tooth, 
whereas a similar procedure may result in a 4- or 5 -day 
recovery period for a 50-year-old patient. 

Finally, if a tooth has been retained in the alveolar 
process for many years without periodontal disease, 
caries, or cystic degeneration, it is unlikely that these 
unfavorable sequelae will occur. Therefore in an older 
patient (usually over age 35) with an impacted tooth 
that shows no signs of disease and that has a 
radiographically detectable layer of overlying bone, 
the tooth should not be removed (Fig. 9-15). The dentist 
caring for the patient should check the impacted tooth 
radiographically every 1 or 2 years to ensure that no 
adverse sequela occurs. 



If the impacted tooth shows signs of cystic formation or 
periodontal disease involving either the adjacent tooth 
or the impacted tooth, if it is a single impacted tooth 
underneath a prosthesis with thin overlying bone, or if it 
becomes symptomatic as the result of infection, the tooth 
must be removed. 



Compromised Medical Status 

Similar to extremes of age, compromised medical status 
may contraindicate the removal of an impacted tooth. 
Frequently, compromised medical status and advancing 
age go hand-in-hand. If the impacted tooth is asympto- 
matic, its surgical removal must be viewed as elective. If the 
patient's cardiovascular or respiratory function or host 
defenses for combating infection are compromised or the 
patient has a serious acquired or congenital coagu-lopathy, 
the surgeon must consider leaving the tooth in the alveolar 
process. On the other hand, if the tooth becomes 
symptomatic, the surgeon must work carefully with the 
patient's physician to remove the tooth with the least 
operative and postoperative medical sequelae. 

Probable Excessive Damage to Adjacent Structures 

If the impacted tooth lies in an area in which its removal 
may seriously jeopardize adjacent nerves, teeth, or previ- 
ously constructed bridges, it may be prudent to leave the 
tooth in place. When the dentist makes the decision not to 
remove a tooth, the reasons must be weighed against 
potential future complications. For younger patients who 
may suffer the sequelae of impacted teeth, it may be wise to 
remove the tooth while taking special measures to prevent 
damage to adjacent structures. However, for the older patient 
with no signs of impending complications and for whom 
the probability of such complications is low, the impacted 
tooth should not be removed. A classic example of such a 
case is the older patient with a potentially severe periodontal 
defect on the distal aspect of the second molar but in 
whom removal of the third molar would almost surely 
result in the loss of the second molar. In this situation the 
impacted tooth should not be removed. 

Summary 

The preceding discussion of indications and contraindi- 
cations for the removal of impacted third molars has 
been designed to point out that there are various risks and 
benefits for removing impacted teeth in patients. Patients 
who have one or more pathologic symptoms or problems 
should have their impacted teeth removed. Most of the 
symptomatic, pathologic problems that result from impacted 
third molars occur because of partially erupted teeth and 
occur less commonly with a complete bony impaction. 

It is less clear what should be done with impacted 
teeth before they cause symptoms or problems. In making 
a decision as to whether or not an impacted third molar 
should be removed, a variety of factors must be considered. 
First, the available room in the arch into which the tooth 
can erupt must be considered. If adequate room exists, 
then the clinician may choose to defer removal of the tooth 
until eruption is complete. A second consideration is the 
status of the impacted tooth and the 



Principles of Management of Impacted Teeth 



CHAFTKR 9 



193 







FIG. 9-15 Impacted maxillary right third molar in 63-year-old patient. This molar should not be extracted because it is 
deeply embedded and no signs of disease are present. 



age of the patient. It is critical to remember that the aver- 
age age of complete eruption is 20, but that eruption may 
continue to occur up to age 25. A tooth that appears to be 
a mesioangular impaction at age 17 may eventually be- 
come more vertical and erupt into the mouth. If insuffi- 
cient room exists to accommodate the tooth and a soft 
tissue operculum exists over the posterior aspect, then 
pathologic sequelae are likely to occur. 

Although there have been some attempts at making 
very early predictions of whether or not a tooth was 
going to be impacted, these efforts have not yet resulted 
in a reliable predictive model. However, by the time the 
patient reaches age 18, the dentist and surgeon can rea- 
sonably predict whether there will be adequate room into 
which the tooth can erupt with sufficient clearance of the 
anterior ramus to prevent soft tissue operculum forma- 
tion. At this time, if surgical removal is chosen, soft tissue 
and bone tissue healing will occur at its maximal level. At 
age 18 or 19, if the diagnosis for inadequate room for 
functional eruption can be made, then the asymptomatic 
third molar can be removed and the long-term periodon- 
tal health of the second molar will be maximized. 

CLASSIFICATION SYSTEMS 

OF IMPACTED TEETH 

Removal of impacted teeth can be either extremely diffi- 
cult or relatively straightforward and easy. To determine 
the degree of difficulty preoperatively, the surgeon 
should examine the patient methodically. The primary 
factor determining the difficulty of the removal is acces- 
sibility. Accessibility is determined by the ease of expos- 
ing the tooth, of preparing a pathway for its delivery, and 
of preparing a purchase point (or taking advantage of a 
natural purchase point). With careful classification of the 
impacted teeth using a variety of systems, the surgeon 
can approach the proposed surgery in an orderly fashion 
and predict whether any extraordinary surgical approach- 



es will be necessary or if the patient will encounter any 
postoperative problems. 

The majority of the classifying results from analysis of 
the radiograph. For most situations the periapical radio- 
graph provides adequate detail and should be the radio- 
graph most commonly used. The panoramic radiograph 
shows a more accurate picture of the total anatomy of the 
region and can be used as an adequate substitute. 

For each patient the dentist should carefully analyze 
the factors discussed in this section. By combining these 
factors, the dentist can assess the difficulty of the surgery 
and elect to extract the impacted teeth that are within his 
skill level. However, for the patient's sake the dentist 
should refer the patient to a specialist if a tooth presents 
a difficult surgical problem. 

Angulation 

The first classification system employs a description of 
the angulation of the long axis of the impacted third 
molar with respect to the long axis of the second molar. 
Because teeth at certain inclinations have ready-made 
pathways for withdrawal, whereas pathways for teeth of 
other inclinations require the removal of substantial 
amounts of bone, this classification system provides an 
initial evaluation of the difficulty of extractions. 

The mesioangular impaction is generally acknowl- 
edged as the least difficult impaction to remove (Fig. 9- 
16). The mesioangular- impacted tooth is tilted toward the 
second molar in a mesial direction. This type of 
impaction is also the most commonly seen and compris- 
es approximately 43% of all impacted teeth. 

In a severe mesial inclination the impacted tooth is 
horizontal (Fig. 9-17). This type of impaction is usually 
considered more difficult to remove than the mesioangu- 
lar impaction. Horizontal impactions occur less frequent- 
ly and are only seen in approximately 3% of all mandibu- 
lar impactions. 



194 



PART II 



Prim t pies ofExodontia 





FIG. 9-16 A, Mesioangular impaction — most common and easiest impaction to remove. B, Mesio- 
angular impaction is usually in close proximity to second molar. 




FIG. 9-17 A, Horizontal impaction — uncommon and more difficult to remove than mesioangular 
impaction. B, Occlusal surface of horizontal impacted third molar is usually immediately adjacent to 
root of second molar, which often produces early severe periodontal disease. 



In the vertical impaction the long axis of the 
impacted tooth runs in the same direction as the long 
axis of the second molar. This impaction occurs with 
the second greatest frequency, accounts for 
approximately 38% of all impactions, and is third in 
difficulty of removal (Fig. 9-18). 

Finally, the distoangular impaction is the tooth with 
the most difficult angulation for removal (Fig. 9-19). In 
the distoangular impaction the long axis of the third 
molar is distally or posteriorly angled away from the 
sec- 



ond molar. This impaction is the most difficult 
remove because the tooth has a withdrawal pathway that 
runs into the mandibular ramus, and its removal 
requires greater surgical intervention. Distoangular 
impactions occur uncommonly and account for 
approximately 6% of all impacted third molars. Erupted 
third molars may be in a distoangular position, this 
occurs, they are extremely difficult to remove tinely, 
compared with the removal of other teeth. 



Principles of Management of Impacted Tenth 



CHAPTER 9 




B 



FIG. 9-18 A, Vertical impaction — second most common impaction and second most difficult to 
remove. B, Vertical impaction is frequently covered on its posterior aspect with bone of anterior ramus 
of mandible. 





■:- 




FIG. 9-19 A, Distoangular impaction — uncommon and most difficult of the four types to remove. 
B, Occlusal surface of distoangular impaction is usually embedded in ramus of mandible and requires 
significant bone removal for extraction. 



In addition to the relationship between the angulation 
of the long axes of the second and third molars, the teeth 
can also be angled in a buccal or lingual direction. As is 
noted earlier, the linguocortical plate of the mandible 
becomes thinner as it progresses posteriorly. Therefore 
most mandibular third molars are angled toward the lin- 
gual direction or in lingual version. Occasionally, a tooth 
is angled toward the buccal aspect of the mandible or in 
buccal version. 

Rarely a tooth is a transverse impaction, that is, in an 
absolutely horizontal position in a buccolingual direc- 
tion. The occlusal surface of the tooth can face either the 
buccal or lingual direction. To determine buccal or lin- 
gual version accurately, the dentist must take a perpen- 



dicular occlusal film. However, this determination is usu- 
ally not necessary, because the surgeon can make this 
identification early in the operation, and the buccal or 
lingual position of the tooth does not greatly influence 
the difficulty of the surgery. 

Relationship to Anterior Border of Ramus 

Another method for classifying impacted mandibular 
third molars is based on the amount of impacted tooth 
that is covered with the bone of the mandibular ramus. 
This classification is known as the Pell and Gregory classi- 
fication and is sometimes referred to as the Pelt and Grego- 
ry classes 1, 2, and 3. For this classification it is important 




196 PART II 



Principles of Exodontia 



that the surgeon carefully examine the relationship 
between the tooth and the anterior part of the ramus. If 
the mesiodistal diameter of the crown is completely ante- 
rior to the anterior border of the mandibular ramus, it is 
in a class 1 relationship. If the tooth is angled in a verti- 
cal direction, the chances for the tooth to erupt into a 
normal position are good (Fig. 9-20). 

If the tooth is positioned posteriorly so that approxi- 
mately one half is covered by the ramus, the tooth's rela- 
tionship with the ramus is class 2. In the class 2 situation 
the tooth cannot become completely free from bone, 
because a small shelf of bone overlies the distal portion of 
the tooth (Fig. 9-21). A class 3 relationship between the 
tooth and ramus occurs when the tooth is located com- 
pletely within the mandibular ramus (Fig. 9-22). It should 
be obvious that the class 1 relationship will provide the 
greatest accessibility to the impacted tooth and therefore 
will be easiest to remove. The class 3 relationship pro- 
vides the least accessibility and therefore presents the 
greatest difficulty. 



Relationship to Occlusal Plane 

The depth of the impacted tooth compared with the 
height of the adjacent second molar provides the next 
classification system for determining the difficulty of 
impaction removal. This classification system was also 
suggested by Pell and Gregory and is called Pell and Gre- 
gory A, B, and C classification. In this classification the 
degree of difficulty is measured by the thickness of the 
overlying bone; that is, the degree of difficulty increas- 
es as the depth of the impacted tooth increases. As the 
tooth becomes less accessible and it becomes more dif- 
ficult to section the tooth and to prepare purchase 
points, the overall difficulty of the operation increases 
substantially. 

A class A impaction is one in which the occlusal sur- 
face of the impacted tooth is level or nearly level with the 
occlusal plane of the second molar (Fig. 9-23). A class B 
impaction is an impacted tooth with an occlusal surface 
between the occlusal plane and the cervical line of the 
second molar (Fig. 9-24). Finally, the class C impaction is 




FIG. 9-20 Pell and Gregory class 1 impaction. Mandibular third 
molar has sufficient anteroposterior room (i.e., anterior-to-anterior 
border of ramus) to erupt. 




J 



FIG. 9-22 Pell and Gregory class 3 impaction. Impacted third 
molar is completely embedded in bone of ramus of mandible. 





fig. 9-21 Pell and Gregory class 2 impaction. 
Approximately half is covered by anterior portion of 
ramus of mandible. 



fig. 9-23 Pell and Gregory class A impaction. 
Occlusal plane of impacted tooth is at same level as 
occlusal plane of second molar. 






Principles of Management of Impacted Teeth 



CHAPTKK9 



197 



one in which the occlusal surface of the impacted tooth 
is below the cervical line of the second molar (Fig. 9-25). 

Summary 

The three classification systems discussed so far are used 
in conjunction to determine the difficulty of an extrac- 
tion. For example, a mesioangular impaction with a class 
1 ramus and a class A depth is easy to remove and is 
essentially the extraction of an erupted tooth (Fig. 9-26). 
However, as the ramus relationship changes to a class 2 
and the depth of the impaction increases to a class B, the 
degree of difficulty becomes greater. A horizontal 
impaction with a class 2 ramus relationship and a class B 
depth is a moderately difficult extraction and one that 
most general practitioners do not want to attempt (Fig. 
9-27). Finally, the most difficult of all impactions is a dis- 
toangular impaction with a class 3 ramus relationship at 
a class C depth. Even specialists view removing this tooth 
as a surgical challenge (Fig. 9-28). 




FIG. 9-26 Mesioangular impaction with class 1 ramus relationship 
and class A depth. All three classifications make it easiest type of 
impaction to remove. 




FIG. 9-24 Pell and Gregory class B impaction. Occlusal plane of 
impacted tooth is between occlusal plane and cervical line of second 
molar. 




FIG. 9-27 Horizontal impaction with class 2 ramus relationship 
and class B depth makes it moderately difficult to extract. 





FIG. 9-25 Pell and Gregory class C impaction. Impacted tooth is 
below cervical line of second molar. 



FIG. 9-28 Impaction with distoangular, class 3 ramus relationship 
and class C depth makes it extremely difficult to remove. 



1 . ■ . - 

-;:■■-?-- 



198 



PART II 



Pri f trip les of Exocfon tia 



ROOT MORPHOLOGY 



Just as the root morphology of the erupted tooth has a 
major influence on the degree of difficulty of a closed 
extraction, root morphology plays a major role in deter- 
mining the degree of difficulty of the impacted tooth's 
removal. Several factors must be considered when assess- 
ing the morphologic structure of the root. 

The first consideration is the length of the root. As dis- 
cussed earlier, the optimal time for removal of an impact- 
ed tooth is when the root is one third to two thirds 
formed. When this is the case, the ends of the roots are 
blunt and almost never fracture (Fig. 9-29). If the tooth is 
not removed during the formative stage and the entire 
length of the root develops, the possibility increases for 



abnormal root morphology and for fracture of the root 
tips during extraction. If the root development is insuffi- 
cient (i.e., less than one third complete), the tooth is more 
difficult to remove, because it tends to roll in its crypt like 
a ball in a socket, which prevents easy elevation (Fig. 9- 
30). The next factor to be assessed is whether the roots are 
fused into a single, conic root (Fig. 9-31), or if they are 
separate and distinct roots. The fused, conic roots are eas- 
ier to remove than widely separate roots (Fig. 9-32). 

The curvature of the tooth roots also plays a role in the 
difficulty of the extraction. Severely curved or dilacerated 
roots are more difficult to remove than straight or slight- 
ly curved roots (see Fig. 9-32). The surgeon should care- 
fully examine the apex area of the radiograph to assess 





FIG. 9-29 Roots that are two thirds formed, which are less difficult 
to remove. 



FIG. 9-30 Lack of root development. If extraction is attempted, 
crown will roll around in crypt, which makes it difficult to remove. 








FIG. 9-31 Fused roots with conic shape. 



Principles of Management of Impacted Teeth ■ CHAITKH 9 




the presence of small, abnormal, and sharply hooked 
roots that probably fracture if the surgeon does not give 
them special consideration. 

The direction of the tooth root curvature is also impor- 
tant to examine preoperatively. During removal of a 
mesioangular impaction, roots that are curved gently in the 
distal direction (following along the pathway of extraction) 
can be removed without the force that can cause fracture of 
the roots. However, if the roots of a mesioangular 
impaction are curved mesially, the roots almost always frac- 
ture or must be sectioned before the tooth can be delivered. 

The total width of the roots in the mesiodistal direction 
should be compared with the width of the tooth at the 
cervical line. If the tooth root width is greater, the extrac- 




FIG. 9-32 Divergent roots with severe curvature. Such roots are 
more difficult to remove. 



tion will be more difficult. More bone must be removed or 
the tooth must be sectioned before extraction. 

Finally, the surgeon should assess the periodontal liga- 
ment space. Although in most patients the periodontal 
ligament space is of normal dimensions, it sometimes is 
wider or narrower. The wider the periodontal ligament 
space, the easier the tooth is to remove (Fig. 9-33). A third 
molar that is in the proper stage of development for 
removal has a relatively broad periodontal ligament 
space, which eases extraction. However, older patients, 
especially those over age 40, tend to have a much nar- 
rower periodontal ligament space, which thereby increas- 
es the difficulty of the extraction. 

Size of Follicular Sac 

The size of the follicle around the impacted tooth can 
help determine the difficulty of the extraction. If the fol- 
licular sac is wide (almost cystic in size), much less bone 
must be removed, which makes the tooth easier to extract 
(Fig. 9-34). (Young patients are more likely to have large 
follicles, which is another factor that makes extractions 
easier in younger patients.) However, if the follicular 
space around the crown of the tooth is narrow or nonex- 
istent, the surgeon must create space around the entire 
crown, which increases both the difficulty of the proce- 
dure and the time required to remove the tooth. The sur- 
geon must carefully examine the follicle size when deter- 
mining the difficulty of an extraction. 

Density of Surrounding Bone 

The density of the bone surrounding the tooth plays a 
role in determining the difficulty of the extraction. 
Although some clues can be seen on the radiographs, 
variations in radiograph density and angulation render 
interpretations based on radiographs unreliable. Bone 
density is best determined by the patient's age. Patients 




FIG. 9-33 Wide periodontal ligament space. Such space makes extraction 
process less difficult. 



200 PART II 



Principles of Exodcmtia 



who are 1 8 years of age or younger have bone densities 
favorable for tooth removal. The bone is less dense, is 
more likely to be pliable, and expands and bends some- 
what, which allows the socket to be expanded by eleva- 
tors or by luxation forces applied to the tooth itself. Addi- 
tionally, the bone is easier to cut with a dental drill and 
can be removed more rapidly than denser bone. 

Conversely, patients who are older than age 35 have 
denser bone and thus decreased flexibility and ability to 
expand. In these patients the surgeon must remove all 
interfering bone, because it is not possible to expand the 
bony socket. In addition, as the bone increases in densi- 
ty, it becomes more difficult to remove with a dental drill, 
and the bone removal process takes longer. 








FIG. 9-34 Large follicular sac. When space of sac is large, amount 
of required bone removal is decreased. 



Contact with Mandibular Second Molar 

If space exists between the second molar and the impacted 
third molar, the extraction will be easier. However, if the 
tooth is a mesioangular or horizontal impaction, it is fre- 
quently in direct contact with the adjacent second molar. To 
remove the third molar safely without injuring the second 
molar, the surgeon must be cautious with pressure from ele- 
vators or with the bur when removing bone. If the second 
molar has caries or a large restoration or root canal, the sur- 
geon must take special care not to fracture the restoration 
or a portion of the carious crown (see Fig. 9-17, B). 

Relationship to Inferior Alveolar Nerve 

Impacted mandibular third molars frequently have roots 
that are superimposed on the inferior alveolar canal on 
radiographs. Although the canal is usually on the buccal 
aspect of the tooth, it is in close proximity to the tooth, 
Therefore one of the potential sequelae of impacted third 
molar removal is damage to or bruising of the inferior 
alveolar nerve. This usually results in some altered sensa- 
tion (paresthesia or anesthesia) of the lower lip on the 
injured side. Although this altered sensation is usually 
brief (lasting only a few days), it may extend for weeks or 
months; on rare occasions it can be permanent. If the 
root ends of the tooth appear to be close to the inferior 
alveolar nerve, the surgeon must take special care to 
avoid injuring the nerve (Fig. 9-35), which makes the 
procedure more difficult. 

Nature of Overlying Tissue 

The preceding systems all classify factors that make third 
molar extraction easier or more difficult. The classifica- 
tion system discussed in this section does not fit into this 
category. However, it is the system used by most dental 
insurance companies and the one by which the surgeon 
charges for his services. 







■j-j- \- .■ 



• ■: » C-: -'j- ■'.■'. 





FIG. 9-35 A, Radiographic view of mandibular third molar suggests that it is surrounding or adjacent to inferior alveolar 
neurovascular canal. B, Hole and indentation in two roots of mandibular third molar indicate position of roots of this tooth 
to inferior alveolar canal. When this tooth was removed, inferior alveolar neurovascular bundle was severed (not same 
tooth as shown in A). 



Principles of Management of Impacted Teeth 



CHAPTER 9 



201 



According to this scheme, the, three types of im- 
pactions are (1) soft tissue impaction, (2) partial bony 
impaction, and (3) full bony impaction. An impaction is 
defined as a soft tissue impaction when the height of the 
tooth's contour is above the level of the alveolar bone, 
and the superficial portion of the tooth is covered only by 
soft tissue (Fig. 9-36). To remove the soft tissue 
impaction, the surgeon must incise the soft tissue and 
reflect a small soft tissue flap to obtain access to the tooth 
to elevate it from its socket. The soft tissue impaction is 
usually the easiest of the three extractions. 

The partial bone impaction occurs when the superfi- 
cial portion of the tooth is covered by soft tissue, but the 
height of the tooth's contour is below the level of the sur- 
rounding alveolar bone (Fig. 9-37). To remove the tooth, 
the surgeon must incise the soft tissue, reflect a soft tissue 
flap, and remove the bone above the height of the con- 
tour. The surgeon may need to divide the tooth in addi- 
tion to removing bone. 

The complete bone impaction is an impacted tooth 
that is completely encased in bone so that, when the 
surgeon reflects the soft tissue flap, no tooth is visible 
(Fig. 9-38). To remove the tooth, extensive amounts of 
bone must be removed and the tooth almost always 
must be sectioned. The complete bony impaction is 
often the most difficult to remove. 

Although this classification is extensively used, it fre- 
quently has no relationship to the difficulty of the 
extraction (Boxes 9-1 and 9-2). The parameters of 
angulation, 



BOX 9-1 



Factors that Make Impactior 


l Surgery Less Difficult 


1. Mesioangular 


7. 


Large follicle* 


position 


§. 


Elastic bone* 


2. Class 1 ramus 


9, 


Separated from second 


3. Class A depth 




molar 


4. Roots one third to 


10. 


Separated from inferior 


two thirds formed* 




aiveo/ar nerve* 


5h Fused conic roots 


11. 


Soft tissue impaction 


6. Wide periodontal 






ligament* 







Present In the young patient. 



^S&N 




BOX 9-2 



Factors that Make Impaction Surgery More Difficult 



1. Distoangular 


7. 


Thin follicle* 


2. Class 3 ramus 


8. 


Dense, inelastic bone* 


3. Class C depth 


9. 


Contact with second 


4. Long, thin roots* 




molar 


5. Divergent curved 


10. 


Close to inferior alveolar 


roots 




canal 


6. Narrow periodontal 


11. 


Complete bony impaction 


ligament* 








FIG. 9-36 Soft tissue impaction in which crown of tooth is 
covered by soft tissue only and can be removed without bone 
removal. 




FIG. 9-37 Partial bony impaction in which part of tooth, usually 
posterior aspect, is covered with bone and requires either bone 
removal or tooth sectioning for extraction. 




'Present in older patients. 



FIG. 9-38 Complete bony impaction in which tooth is 
completely covered with bone and requires extensive removal 
of bone for extraction. 



202 PART II ■ Principles of Exodantia 






FIG. 9-39 A, Vertical impaction of maxillary third molar. This angle accounts for 63% of impactions. 

B, Distoangular impaction of maxillary third molar. This angle accounts for 25% of impactions. 

C, Mesioangular impaction of maxillary third molar. This angle accounts for 12% of impactions. 



J 



ramus relationship, root morphology, and patient age 
are more important than this system. The surgeon 
should use all of the information available to determine 
the difficulty of the proposed surgery. 



OF 



CLASSIFICATION 



MODIFICATION 

SYSTEMS 

FOR MAXILLARY IMPACTED TEETH 

The classification systems for the maxillary impacted 
third molar are essentially the same as for the impacted 
mandibular third molar. However, several distinctions 
and additions must be made to assess more accurately 
the difficulty of removal during the treatment- 
planning phase of the procedure. 

Concerning angulation, the three types of maxillary 
third molars are (1) the vertical impaction (Fig. 9-39, A), 
(2) the distoangular impaction (Fig. 9-39, B), and (3) the 
mesioangular impaction (Fig. 9-39, C). The vertical 
impaction occurs approximately 63% of the time, the 
dis-toangular approximately 25%, and the 
mesioangular position approximately 12% of the time. 
Rarely other posi-tions, such as a transverse, inverted, or 
horizontal position, are encountered; these unusual 
positions account for less than 1% of impacted 
maxillary third molars. 

The same angulations in mandibular third molar 
extractions cause opposite degrees of difficulty for 
maxillary third molar extractions. Vertical and 
distoangular impactions are the easiest to remove, 
whereas mesioan-gular impactions are the most 
difficult (exactly the oppo-site of impacted mandibular 
third molars). Mesioangular impactions are more 
difficult to remove because the bone that overlies the 
impaction and that must be removed or expanded is on 
the posterior aspect of the tooth and is much heavier 
than in the vertical or distoangular im-paction. In 
addition, access to the mesioangularly positioned tooth 
is more difficult. 

The position of the maxillary third molar in a bucco- 
palatal direction is also important for determining the 
difficulty of the removal. Most maxillary third molars 
are angled toward the buccal aspect of the alveolar 
process, which makes the overlying bone in that area 
thin and therefore easy to remove or to expand. 
Occasionally, the impacted maxillary third molar is 
positioned toward the 



palatal aspect of the alveolar process. This makes the tooth 
much more difficult to extract, because greater amounts of 
bone must be removed to gain access to the underlying 
tooth. A combination of radiographic assessment and clin- 
ical digital palpation of the tuberosity area can determine 
if the maxillary third molar is in the buccopalatal position. 
If the tooth is positioned toward the buccal, a definite pal- 
pable bulge is found in the area; if the tooth is palatally 
positioned, a bony deficit is found in that region. When 
either is determined by clinical examination, the surgeon 
must anticipate a longer, more difficult procedure. 

The Pell and Gregory A, B, and C classification used to 
diagnose the depth of impaction in the mandible is also 
used in the maxilla (Fig. 9-40). Preoperative assessment of 
the remaining classifications is the same. The factors that 
influence the difficulty of mandibular impacted third 
molar removal are the same for maxillary third molar 
removal. For example, the individual impacted tooth root 
morphology plays a substantial role in determining the 
degree of extraction difficulty. The most common factor 
that causes difficulty with maxillary third molar removal 
is a thin, nonfused root with erratic curvature (Fig. 9-41). 
The majority of maxillary third molars have fused roots 
that are conic. However, the surgeon should examine the 
preoperative radiograph carefully to ensure that this is 
the situation with each individual impaction. The sur- 
geon should also check the periodontal ligament, because 
the wider the ligament space the less difficult the tooth is 
to remove. In addition, similar to mandibular third 
molars, the periodontal ligament space tends to decrease 
as the patient increases in age. 

The follicle surrounding the crown of the impacted 
tooth also has an influence on the difficulty of the 
extraction. If the follicular space is broad, the tooth will 
be easier to remove than if the follicular space is thin or 
nonexistent. 

Bone density is also an important factor in maxillary 
impaction removal and is related closely to the age of the 
patient. The younger the patient, the less dense and more 
elastic — and therefore more expandable — is the bone sur- 
rounding the impacted third molar. As the patient ages, 
the bone becomes denser and less elastic, and the tooth 
becomes more difficult to remove. 



_ 



Principles of Management of Impacted Teeth 



CHAPTER 9 






L 



FIG. 9-40 A, Pell and Gregory class A occlusal surface of third molar is at same level as that of sec- 
ond molar. B, Pell and Gregory class B occlusal surface of third molar is located between occlusal plane 
and cervical line of second molar. C, Pell and Gregory class C impacted maxillary third molar is deep 
to cervical line of second molar. 



The relationship to the adjacent second molar tooth 
also influences the difficulty of the extraction. It may 
require that additional bone be removed to displace 
the tooth from underneath the second molar. In 
addition, because the use of elevators is common in the 
removal of maxillary third molars, the surgeon must be 
aware of the existence of large restorations or caries in 
the adjacent second molar. Injudicious use of elevators 
can result in the fracture of restorations or carious 
teeth. 

The type of impaction, with respect to overlying tis- 
sue, must also be considered for maxillary third molars. 
The classification system used for mandibular teeth is 
the same as the system that is used for maxillary teeth: 
soft tissue impaction, partial bony impaction, and 
complete bony impaction. The definitions of these 
types of impactions are precisely the same as those 
used for the mandibular third molars. 

Two additional factors influence the difficulty of 
maxillary third molar removal but do not exist for the 
mandibular third molars. Both are related to the 
structure and position of the maxillary sinus. First, the 
maxillary sinus is in intimate contact with the roots of 
the molar teeth; and, frequently, the maxillary third 
molar actually forms a portion of the posterior sinus 
wall. If this is the case, removal of the maxillary third 
molar may result in maxillary sinus complications, such 
as sinusitis or an oroantral fistula. The presence of the 
maxillary sinus does not necessarily make the removal 
of the impacted tooth more difficult, but it increases the 
likelihood of postoperative complications and 
morbidity. 

Finally, in maxillary third molar removal, the 
tuberos-ity of the posterior maxilla can be fractured. 
Such fractures are possible, especially when dense and 
nonelastic bone exists, such as in older patients. In 
addition, a large maxillary sinus makes the 
surrounding alveolar bone thin and more susceptible 
to fracture when excessive force is applied. A root 
morphology that is not fused but has divergent roots 
requires greater force to remove and can make fracture 
more likely. In addition, mesioangular impactions 
increase the possibility of fractures (see Fig. 9-39, C). In 
these situations the overlying tuberosity is heavier, 
but the surrounding bone is usually thinner. When 
the surgeon prepares a purchase point at the 




FIG. 9-41 The maxillary third molar has the most erratic and 
bizarre root formation of all teeth. 



mesiocervical line, fracture of the tuberosity becomes a 
greater risk if: (1) the bone is nonelastic (as in older 
patients), (2) the tooth is multirooted with large 
bulbous roots (as in older patients), (3) the maxillary 
sinus is large and expanded to include the roots of the 
impacted third molar, or (4) the surgeon has to use 
excessive force to ele-vate the tooth. Management of 
the fractured tuberosity is discussed in Chapter 1 1 . 



204 PART II 



Principle of Exodotttia 





FIG. 9-42 A, Labially positioned impacted maxillary canine. Tooth should be uncovered 
with apical-ly positioned flap procedure to preserve attached gingiva. B, Muco peri osteal 
flap is outlined, allowing for repositioning of keratinized mucosa over exposed tooth. C, 
When flap is reflected, thin overlying bone is removed. D, Tissue is retracted and 
bonded to tooth with a wire or with a gold chain (E). 

F, Flap is apically sutured to tooth. 



Continued 



Principles of Management of Impacted Teeth 



CHAPTER 9 



205 




-cont'd C, After 6 months, exposed tooth is in desired 
position, with broad zone of attached gingiva. 

DIFFICULTY OF REMOVAL OF OTHER 
IMPACTED TEETH 

After the mandibular and maxillary third molars, the next 
most commonly impacted tooth is the maxillary canine. 
If the patient seeks orthodontic care, the orthodontist 
will frequently request that the maxillary canine simply 
have the overlying soft and hard tissue removed so 
that the tooth can be manipulated into its proper 
position by orthodontic appliances. When the tooth is 
positioned in such a way that orthodontic manipulation 
can assist the proper positioning of the impacted canine, 
the tooth is exposed and bracketed (Fig. 9-42, A). A four- 
corner flap is created to allow the soft tissue to be 
repositioned apically should this be required for 
maximum keratinized tissue management (Fig. 9-42, B). 
The overlying bone tissue is then removed with chisel or 
burs as is necessary (Fig. 9-42, C). Once the area is 
debrided, the surface of the tooth is prepared by the 
usual standard procedures of etching and applying 
primer. The bracket is then luted to the surface of the tooth 
(Fig. 9-42, D). A wire can be used to connect the bracket 
to the orthodontic appliance or more commonly a gold 
chain is attached from the orthodontic bracket to the 
orthodontic arch wire. The gold chain provides a greater 
degree of flexibility and the incidence of breakage of the 
chain is much less than breakage of a wire. The soft tissue 
is then sutured in such a way as to provide the maximum 
coverage of the exposed tissue with keratinized tissue (Fig. 
942, E). As the tooth is pulled into place with the ortho- 
dontic appliances, the soft tissue surrounding the newly 
positioned tooth should have adequate keratinized tissue 
and the tooth should be in an ideal position. 

If the tooth is positioned toward the palatal aspect, the 
tooth may be either repositioned or removed. If the tooth 
is repositioned, it is surgically exposed and moved into 
position orthodontically. In this procedure the overlying 
soft tissue is excised; flaps are not needed to gain attached 
tissue. Because the bone in the palate is thicker, a bur is 
usually necessary to remove the overlying bone. The 
exposed tooth then is managed in the same manner as is 
the labially positioned tooth. 

If the dentist decides the tooth should be removed, it 
must be determined if the tooth is positioned labially, 
toward the palate, or in the middle of the alveolar 
process. If the tooth is on the labial aspect, it is easy to 
reflect a soft tissue flap and to remove the underlying 
bone and the tooth. However, if the tooth is on the 



palatal aspect or in the intermediate buccolingual 
position, it is much more difficult to remove. Therefore 
when assessing the impacted maxillary canine for 
removal, the surgeon's most important assessment is of 
the buccolin-gual position of the tooth. 

Similar considerations are necessary for other im- 
pactions, such as mandibular premolars and 
supernumerary teeth. The supernumerary tooth in the 
midline of the maxilla, called a mesiodens, is almost 
always found on the palate and should be approached 
from a palatal direction when it is removed. 

SURGICAL PROCEDURE 

The principles and steps for removing impacted teeth 
are the same as for other surgical extractions. Five basic 
steps make up the technique: The first step is to have 
adequate exposure of the area of the impacted tooth. 
This means that the reflected soft tissue flap must be of 
an adequate dimension to allow the surgeon to retract 
the soft tissue and perform the necessary surgery. The 
second step is to assess the need for bone removal and 
to remove a sufficient amount of bone to expose the 
tooth for sectioning and delivery. The third step is to 
divide the tooth with a bur or chisel to allow the tooth 
to be extracted without removing excessive amounts of 
bone. In the fourth step the sectioned tooth is delivered 
from the alveolar process with the appropriate elevators. 
Finally, in the fifth step the wound is thoroughly 
cleansed with irrigation and mechanical debridement 
with a curette and is closed with simple interrupted 
sutures. The following discussion elaborates on these 
steps for the removal of impacted third molars. 

Although the surgical approach to the removal of 
impacted teeth is similar to other surgical tooth 
extractions, it is important to keep in mind several 
distinct differences. For instance, the typical surgical 
extraction of a tooth or tooth root requires the removal 
of a relatively small amount of bone. However, 
when an impacted tooth (especially a mandibular 
third molar) is extracted, the amount of bone that must 
be removed to deliver the tooth is substantially 
greater. This bone is also much denser than it is for 
typical surgical extractions, and its removal requires 
better instrumentation and a higher degree of surgical 
skill. 

Impacted teeth also frequently require sectioning, 
whereas other types of tooth extractions do not. 
Although erupted maxillary and mandibular molars 
are occasionally divided for removal, it is not a 
routine step in the extraction of these teeth. However, 
with impacted mandibular third molars, the surgeon 
is required to divide the tooth in a substantial majority 
of patients. The surgeon must therefore have the 
necessary equipment for such sectioning and the 
necessary skills and experience for dividing the tooth 
along the proper planes. 

Unlike most other types of surgical tooth 
extractions, for an impacted tooth removal the surgeon 
must be able to balance the degree of bone removal and 
sectioning. Essen- 



206 



part n 



Principles of Exodontia 



tially, all impacted teeth can be removed without 
sectioning if a large amount of bone is removed. 
However, the removal of excessive amounts of bone 
unnecessarily prolongs the healing period and may result 
in a weakened jaw. Therefore the surgeon should 
remove most mandibular third molars only after 
sectioning them. On the other hand, removal of a 
small amount of bone with multiple divisions of the 
tooth may cause the tooth sectioning process to take an 
excessively long time, thus unnecessarily prolonging the 
operation. The surgeon must remove an adequate 
amount of bone and section the tooth into a reasonable 
number of pieces, both to hasten healing and to 
minimize the time of the surgical procedure. 

Step 1: Reflecting adequate flaps for accessibility. The dif- 
ficulty of removing an impacted tooth depends on its 
accessibility. To gain access to the area and to 
visualize the overlying bone that must be removed, the 
surgeon must reflect an adequate mucoperiosteal flap. 
The reflection must be of a dimension adequate to 
allow the placement and stabilization of retractors and 
instruments for the removal of bone. 

In most situations the envelope flap is the preferred 
technique. The envelope flap is easier to close and heals 
better than the three-cornered flap. However, if the sur- 
geon requires greater access to the more apical areas of 
the tooth, which might stretch and tear the envelope 
flap, the surgeon should consider using a three-cornered 
flap. 

The preferred incision for the removal of an impacted 
mandibular third molar is an envelope incision that 
extends from the mesial papilla of the mandibular first 
molar, around the necks of the teeth to the distobuccal 
line angle of the second molar, and then posteriorly to 
and laterally up the anterior border of the mandible (Pig. 
9-43, A). 

The incision must not continue posteriorly in a 
straight line, because the mandible diverges laterally. 
An incision that extends straight posteriorly falls off 
the bone and into the sublingual space and may 
damage the lingual nerve, which is in close proximity 
to the mandible in the area of the third molar. If this 
nerve is traumatized, the patient will probably have a 
lingual nerve anesthesia, which may be distracting to 
the patient. The incision must always be on bone; 
therefore the surgeon should carefully palpate the 
retromolar area before beginning the incision. 

The flap is laterally reflected to approximately the 
external oblique ridge with a periosteal elevator (Fig. 9- 
43, B). The surgeon should not reflect beyond the 
external oblique ridge, because this results in increased 
morbidity and an increased number of complications 
after surgery. The retractor is placed on the buccal shelf, 
just at the external oblique ridge, and it is stabilized by 
applying pressure toward the bone, which results in a 
retractor that is stable and does not continually 
traumatize the soft tissue. 

The Austin and the Minnesota retractors are the 
most commonly used for flap reflection when 
removing mandibular third molars. 

If the impacted third molar is deeply embedded in 
bone and requires more extensive bone removal, a 
releasing incision may be useful (Fig. 9-43, C and D). 
The flap created by this incision can be reflected farther 
apically, without risk of tearing the tissue. The 



recommended incision for the maxillary third molar is 
also an envelope incision. It extends posteriorly from 
the distobuccal line angle of the second molar and 
anteriorly to the mesial aspect of the first molar {Fig. 
9-44, A and B). In situations in which greater access is 
required (e.g., in a deeply embedded impaction), a 
release incision extending from the mesial aspect of the 
second molar can be used (Fig. 9-44, C and D). 

In the removal of third molars it is vital that the flap 
be large enough for adequate access and visibility of the 
surgical site. The flap must have a broad base if a 
releasing incision is used. The incision must be made 
with a smooth stroke of the scalpel, which is kept in 
contact with bone throughout the entire incision so that 
the mucosa and periosteum are completely incised. This 
allows a full-thickness mucoperiosteal flap to be 
reflected. The incision should be designed so that it can 
be closed over solid bone (rather than over a bony 
defect). This is achieved by extending the incision at 
least one tooth anterior to the surgical site when a 
vertical releasing incision is used. The incision should 
avoid vital anatomic structures. Only a single releasing 
incision should be used. 

Step 2: Removal of overlying bone. Once the soft tissue is 
elevated and retracted so that the surgical field can be 
visualized, the surgeon must make a judgment concern- 
ing the amount of bone to be removed. In some situa- 
tions the tooth can be sectioned with a chisel and deliv- 
ered without bone removal. In most cases, however, 
some bone removal is required. 

Although chisels can be used to remove bone overlying 
impacted teeth, most surgeons and patients prefer that 
bone be removed with a drill. The preferred instrument is 
a handpiece with adequate speed, high torque, and the 
ability to be sterilized completely, usually in a steam 
autoclave. 

The bone on the occlusal aspect and on the buccal 
and distal aspects down to the cervical line of the 
impacted tooth should be removed initially. The 
amount of bone that must be removed varies with the 
depth of the impaction, the morphology of the roots, 
and the angula-tion of the tooth. Bone should not be 
removed from the lingual aspect of the mandible 
because of the likelihood of damaging the lingual 
nerve. 

The burs that are used to remove the bone overlying 
the impacted tooth vary with surgeons' preferences. A 
large round bur, such as a no. 8, is desirable, because it is 
an end-cutting bur and can be effectively used for 
drilling with a pushing motion. The tip of a fissure bur, 
such as a no. 703 bur, does not cut well, but the edge 
rapidly removes bone and quickly sections teeth when 
used in a lateral direction, 

The typical bone removal for the extraction of an 
impacted mandibular tooth is illustrated in Fig. 9-45. 
The bone on the occlusal aspect of the tooth is 
removed first to expose the crown of the tooth. Then 
the cortical bone on the buccal aspect of the tooth is 
removed down to the cervical line. Next, the bur can be 
used to remove bone between the tooth and the cortical 
bone in the cancellous area of the bone with a maneuver 
called ditching. This provides access for elevators to 
gain purchase points and a pathway for delivery of the 
tooth. No bone is removed from the lingual aspect so as 
to protect the lingual nerve from injury. 



('rind pies of Management of Impacted Teeth 



CHAPTER 9 



207 









FIG. 9-43 A, Envelope incision is most commonly used to reflect soft tissue for removal of impacted 
third molar. Posterior extension of incision should laterally diverge to avoid injury to lingual nerve. 
B, Envelope incision is laterally reflected to expose bone overlying impacted tooth. C, When three- 
cornered flap is made, a releasing incision is made at mesial aspect of second molar. D, When soft tis- 
sue flap is reflected by means of a releasing incision, greater visibility is possible, especially at apical 
aspect of surgical field. 







FIG. 9-44 A, Envelope flap is most commonly used flap 
for removal of maxillary impacted teeth. B, When soft 
tissue is reflected, bone overlying third molar is easily 
visualized. C, If tooth is deeply impacted, a releasing 
incision can be used to gain greater access. D, When 
three-cornered flap is reflected, the bone's more apical 
portions become more visible. 



2< )8 PA RT II Principles of Exodon tia 



.- 





B 




FIG. 9-45 A, After soft tissue has been reflected, bone overlying 
occlusal surface of tooth is removed with a fissure bur. B, Bone on 
buccodistal aspect of impacted tooth is then removed with bur. 



For maxillary teeth, bone is removed primarily on the 
buccal aspect of the tooth, down to the cervical line to 
expose the entire clinical crown. Additional bone must be 
removed on the mesial aspect of the tooth to allow an 
elevator an adequate purchase point to deliver the tooth. 
Because the bone overlying maxillary teeth is usually 
thin, it can be easily removed with a unibevel chisel with 
only hand pressure. 

Step 3: Sectioning the tooth. Once sufficient amounts 
of bone have been removed from around the 
impacted tooth, the surgeon should assess the need to 
section the tooth. Sectioning allows portions of the 
tooth to be removed separately with elevators through 
the opening provided by bone removal. 

The direction in which the impacted tooth should be 
divided depends primarily on the angulation of the 
impacted tooth. Although minor modifications are nec- 
essary for teeth with divergent roots or for teeth that are 
more or less deeply impacted, the most important deter- 
minant is the tooth's angulation. 

Tooth sectioning can be performed with either a bur 
or chisel; however, the bur is used by most surgeons. If 
a chisel is used, it must be extremely sharp, and the 
blows delivered to it by the mallet must be sharp and 




FIG. 9-46 A, When removing mesioangular impaction, buccodistal bone is removed to expose crown of tooth to cervical 
line. B, Distal aspect of crown is then sectioned from tooth. Occasionally, it is necessary to section entire tooth into two 
portions rather than to section distal portion of crown only. C, After distal portion of crown has been delivered, small 
straight elevator is inserted into purchase point on mesial aspect of third molar, and tooth is delivered with rotational and 
lever motion of the elevator. 



Principles of Management of impacted Teeth 



CHAPTER 9 



209 



forceful enough to split the tooth. For the conscious 
patient the sound of the chisel striking the tooth may be 
bothersome. 

When the bur is used, the tooth is sectioned three 
fourths of the way toward the lingual aspect. A straight ele- 
vator is inserted into the slot made by the bur and rotated 
to split the tooth. The bur should not be used to section 
the tooth completely through in the lingual direction, 
because this is more likely to injure the lingual nerve. 

The mesioangular impaction is usually the least difficult 
to remove of the four basic angulation types. After sufficient 
bone has been removed, the distal half of the crown is sec- 
tioned off at the buccal groove to just below the cervical line 
on the distal aspect. This portion is delivered. The remainder 
of the tooth is removed with a no. 301 elevator placed at the 
mesial aspect of the cervical line. A mesioangular impaction 
can also be removed by preparing a purchase point in the 
tooth with the drill and using a Crane pick elevator to ele- 
vate the tooth from the socket (Fig. 9-46). 

The next most difficult impaction to remove is the 
horizontal impaction. After sufficient bone has been 



removed down to the cervical line to expose the superi- 
or aspect of the distal root and the majority of the buc- 
cal surface of the crown, the tooth is sectioned by divid- 
ing the crown of the tooth from the roots at the cervical 
line. The crown of the tooth is removed, and the roots 
are displaced with a Cryer elevator into the space previ- 
ously occupied by the crown. If the roots of an impacted 
third molar are divergent, they may require sectioning 
into two separate portions to be delivered individually 
(Fig. 9-47). 

The vertical impaction is one of the two most difficult 
impactions to remove. The procedure of bone removal 
and sectioning is similar to the mesioangular impaction; 
that is, the occlusal buccal and distal bone is removed. 
The distal half of the crown is sectioned and removed, 
and the tooth is elevated by applying an elevator at the 
mesial aspect of the cervical line of the tooth. This is 
more difficult than a mesioangular removal, because 
access around the mandibular second molar is difficult to 
obtain and requires the removal of substantially more 
bone on the buccal and distal sides (Fig. 9-48). 








FIG. 9-47 A, During removal of horizontal impaction, bone overlying tooth (i.e., bone on distal 
and buccal aspect of tooth) is removed with bur. B, Crown is then sectioned from roots of tooth 
and delivered from socket. C, Roots are then delivered together or independently by Cryer 
elevator used with rotational motion. Roots may require separation into two parts; occasionally, 
purchase point is made in root to allow Cryer elevator to engage it. D, Mesial root of tooth is 
elevated in similar fashion. 




210 PART 11 



1 Yin i~ip!v$ of Exoifon tia 




FIG. 9-48 A, When removing vertical impaction, the bone on the occlusal, buccal, and distal aspects 
of crown is removed, and the tooth is sectioned into mesial and distal sections, if the tooth has a 
single-fused root, the distal portion of crown is sectioned off in a manner similar to that depicted for 
mesioangular impaction. B, Posterior aspect of the crown is elevated first with Cryer elevator inserted 
into small purchase point in distal portion of the tooth. C, Small straight elevator no. 301 is then used 
to elevate the mesial aspect of the tooth by rota ry-and -lever type of motion. 



The most difficult tooth to remove is the 
distoangular impaction. After sufficient bone is 
removed from the buc-coocclusal and the distal sides of 
the tooth, the crown is sectioned from the roots just 
above the cervical line. The entire crown is usually 
removed, because it interferes with visibility and 
access to the root structure of the tooth. If the roots 
are fused, a Cryer or straight elevator can be used to 
elevate the tooth into the space previously occupied by 
the crown. If the roots are divergent, they are usually 
sectioned into two pieces and individually delivered. 
Extracting this impaction is difficult, because much 
distal bone must be removed and the tooth tends to 
be elevated distally and into the ramus portion of the 
mandible (Fig. 9-49). 



Impacted maxillary teeth are rarely sectioned, because 
the overlying bone is usually thin and relatively elastic. 
In situations in which the bone is thicker or the patient 
is older (and therefore the bone not so elastic), tooth 
extraction is usually accomplished by bone removal 
rather than tooth sectioning. Under no circumstances 
should a chisel be used to section maxillary teeth, 
because displacement of the tooth into the maxillary 
sinus is highly likely. 

In general, impacted teeth elsewhere in the mouth are 
usually sectioned only at the cervical line. This permits 
removal of the crown portion of the tooth, displacement 
of the root portion into the space previously occupied by 
the crown, and removal of the root portion. 



Principles of Management of Impacted Teeth 



CHAPTER 9 



211 







FIG. 9-49 A, For distoangular impaction, occlusal, buccal, and distal bone is removed with bur. It is 
important to remember that more distal bone must be taken off than for vertical or mesioangular 
impaction. B, Crown of tooth is sectioned off with bur, and crown is delivered with straight elevator. 
C, Purchase point is put into remaining root portion of tooth, and roots are delivered by Cryer elevator 
with wheel-and-axle type of motion. If roots diverge, it may be necessary in some cases to split 
them into independent portions. 



Step 4: Delivery of the sectioned tooth with elevator. Once 
adequate bone has been removed to expose the tooth and 
the tooth has been sectioned in the appropriate fashion, 
the tooth is delivered from the alveolar process with den- 
tal elevators. In the mandible the most frequently used 
elevators are the straight elevator, the paired Cryer eleva- 
tor, and the Crane pick. 

An important difference between the removal of an 
impacted mandibular third molar and of a tooth else- 
where in the mouth is that almost no luxation of the 
tooth occurs for the purpose of expansion of the buccal 
or linguocortical plate. Instead bone is removed and teeth 
are sectioned to prepare an unimpeded pathway for deliv- 
ery of the tooth. 



Application of excessive force may result in unfavor- 
able fracturing of the tooth, of excessive buccal bone, of 
the adjacent second molar, or possibly of the entire 
mandible. 

Elevators are designed not to deliver excessive force but 
to engage the tooth or tooth root and to apply force in the 
proper direction. Some highly skilled surgeons use the peri- 
apical curette to remove sectioned roots from their sockets. 
Because the impacted tooth has never sustained occlusal 
forces, the periodontal ligament is weak and permits the 
easy displacement of the tooth root if appropriate bone is 
removed and force is delivered in the proper direction. 

Delivery of maxillary third molars is accomplished 
with small straight elevators such as the no. 301 elevator, 



212 PART II 



Pr'waptes ofExodottthi 



A 



B 




)-50 Delivery of impacted maxillary third molar. A, Once soft 
tissue has been reflected, small amount of buccal bone is removed 
with bur or hand chisel. B, Tooth is then delivered by small 
straight elevator, with rotational and lever types of motion. Tooth 
is delivered in distobuccal and occlusal direction. 



which distobuccally luxates the tooth. Some surgeons 
prefer angled elevators, such as the Potts or Miller eleva- 
tors, which aid in gaining access to the impacted tooth. 
The elevator tip is inserted into the area at the mesial 
cervical line, and force is applied to displace the tooth in 
the distobuccal direction (Fig. 9-50). The surgeon 
should be cautious about applying excessive pressure 
anteriorly to avoid damage to the root of the maxillary 
second molar. In addition, as pressure is applied to 
displace the tooth posteriorly, the surgeon should have 
a finger on the tuberosity of the maxilla (especially if 
the impaction is mesioangular) so that if a fracture does 
occur, steps can be taken to salvage the tuberosity of the 
maxilla. 

Step 5: Debridement of wound and wound closure. Once 
the impacted tooth is removed from the alveolar process, 
the surgeon must direct attention to debriding the 
wound of all particulate bone chips and debris. The sur- 
geon should irrigate the wound with sterile saline, taking 
special care to irrigate thoroughly under the reflected 
soft tissue flap. The periapical curette is used to 
mechanically debride both the superior aspect of the 
socket and the inferior edge of the reflected soft tissue 
to remove any particulate material that might have 
accumulated during surgery. The bone file is used to 
smooth any sharp, rough edges of bone. A mosquito 
hemostat can be used to remove any remnants of the 
dental follicle. Once the follicle is grasped, it is lifted 
with a slow, steady pressure and 



will pull free from the surrounding hard and soft tissue. 
A final irrigation and a thorough inspection should be 
performed before the wound is closed. 

The surgeon should check for adequate hemostasis. 
Bleeding can occur from a vessel in the flap, from the 
bone marrow that has been cut with a bur, or the inferior 
alveolar nerve. Specific bleeding points should be con- 
trolled if they exist. If brisk generalized ooze is seen, after 
the sutures are placed the surgeon should apply firm pres- 
sure with a small, moistened gauze pack. Postoperative 
bleeding occurs relatively frequently after third molar 
extraction, and therefore adequate hemostasis at the time 
of the operation is important. 

Usually the closure of the incision should be a primary 
closure. If the flap was well designed and not traumatized 
during the surgical procedure, it will fit into its original 
position. The initial suture should be placed through the 
attached tissue on the posterior aspect of the second 
molar. Additional sutures are placed posteriorly from that 
position and anteriorly through the papilla on the mesial 
side of the second molar. Usually three or four sutures are 
necessary to close an envelope incision. If a releasing inci- 
sion was used, attention must be directed to closing that 
portion of the incision as well. 

PERIOPERATIVE PATIENT MANAGEMENT 

The removal of impacted third molars is a surgical proce- 
dure that is associated with a large amount of patient 
anxiety. In addition, this surgical procedure can involve 
unpleasant noises and sensations. As a result, surgeons 
who routinely perform surgical removal of impacted 
third molars commonly recommend to their patients 
some type of profound anxiety control such as a general 
anesthetic or deep intravenous (IV) sedation. 

The choice of technique is based on the surgeon's pref- 
erence. However, the goals are to achieve a level of 
patient comfort that allows the surgeon to work effi- 
ciently and that limits the patient's experience to the 
minimal number of unpleasant effects. 

Whether a deep IV sedative or a light general anesthetic 
is used, most surgeons intend their patients to have little, if 
any, unpleasant memory of the surgical experience. 

In addition to the increased need for anxiety control, 
a variety of medications are required to control the seque- 
lae of third molar extraction surgery. The use of long- 
acting local anesthetics should be considered in the 
mandible. They will provide the patient with a pain-free 
period of 4 to 6 hours during which prescriptions can be 
filled and analgesics taken. The surgeon should consider 
writing a prescription for a potent oral analgesic for every 
patient who undergoes surgical removal of an impacted 
third molar. Enough tablets should be prescribed to last 
for 3 or 4 days. Combinations of codeine or codeine con- 
geners with aspirin or acetaminophen are commonly 
used. Nonsteroidal antiinflammatory drugs (NSAlDs) 
may be of some value for certain patients. 

To minimize the swelling common after the surgical 
removal of impacted third molars, some surgeons prefer 
to give parenteral steroids. IV administration of a modest 



Principles of Management of Impacted Teeth 



CHAPTER 9 



213 



amount of a glucocorticoid steroid provides sufficient 
antiinfiammatory activity to give relief to swelling. 
Although many different regimens and protocols for 
steroids exist, a relatively common one is the single 
administration of 8 mg of dexamethasone before surgery. 
This is a relatively long-acting steroid, and its efficacy in 
controlling third molar postsurgical swelling is docu- 
mented. Although steroids given in this manner have few 
side effects or contraindications, the general philosophy 
of weighing the risks and benefits of drug administration 
must be carefully followed before the decision is made to 
give these drugs routinely. 

Many surgeons recommend the use of ice packs on the 
face to help prevent postoperative swelling. Although it is 
unlikely that the ice has much effect on preventing 
swelling, patients frequently report that the ice made 
them feel more comfortable. Something cool applied to 
the face often makes patients more comfortable. It also 
provides them the opportunity to participate in their 
postoperative care, which is important for many patients. 
The intraoral use of ice may have additional benefit. Gent- 
ly sucking on small pieces of ice or even on commercial 
Popsicles may be of some value in helping patients feel 
more comfortable, although any measurable decrease in 
swelling in patients who use this technique is unlikely. 

Another medication that is sometimes used is an antibi- 
otic. If a patient has had a preexisting pericoronitis, it is 
common to prescribe antibiotics for a few days after sur- 
gery. However, if the patient is healthy and the clinician 
finds no systemic indication for antibiotics or a preexisting 
local infection, antibiotics are usually not indicated. 

The normal postoperative experience of a patient after 
surgical removal of an impacted third molar is more 
involved than after a routine extraction. The patient can 
expect a modest amount of swelling in the area of the sur- 
gery for 3 to 4 days, with the swelling completely dissi- 
pating by about 5 to 7 days. A modest amount of dis- 
comfort usually follows the procedure. This discomfort 
can be effectively controlled with potent oral analgesics. 
Patients usually require analgesics for 2 or 3 days on a 
routine basis and intermittently for several more days. 
The patient may have some mild soreness in the region 
for 2 to 3 weeks after the surgery. 

Patients who have had mandibular third molars surgi- 
cally removed frequently have mild-to-moderate trismus. 
This inability to open the mouth interferes with the 
patient's normal oral hygiene and eating habits. Patients 
should be warned that they will be unable to open their 
mouths normally after surgery. The trismus gradually 
resolves, and the ability to open the mouth should return 
to normal by 10 to 14 days after surgery. 

All of the sequelae of the surgical removal of impacted 
teeth are of less intensity in the young, healthy patient 
and of far greater intensity in the older, more debilitated 
patient. Even healthy adult patients between the ages of 
35 to 40 years have a significantly more difficult time 
after the extraction of impacted third molars than do 
healthy 17-year-old patients. 

See Chapter 10 for a more detailed description of post- 
operative care. 



REFERENCES 

1. Venta I et al: Assessing the eruption of lower third molars on 
the basis of radiographic features, Br J Oral Maxillofac Surg 
29:259, 1991. 

2. Venta I et al: Clinical follow-up study of third molar erup 
tion from ages 20 to 26 years, Oral Surg Oral Med Oral Pathol 
72:150, 1991. 

3. Bruce RA, Frederickson GC, Small GS: Age of patients and 
morbidity associated with mandibular third molar surgery, J 
Am Dent Assoc 101:240, 1980. 

4. Marmary J et al: Alveolar bone repair following extraction of 
impacted mandibular third molars, Oral Surg Oral Med Oral 
Pathol 61:324, 1986. 

5. Meister F Jr et al: Periodontal assessment following surgical 
removal of mandibular third molars, Gen Dentistry 14:120, 
1986. 

6. Osborne WH, Snyder AJ, Tempel TR: Attachment levels and 
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odontot 53:93, 1982. 

7. Lysell L, Rohlin M: A study of indications used for removal 
of the mandibular third molar, Int J Oral Maxillofac Surg 
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8. Nordenram A et al: Indications for surgical removal of the 
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10. Stanley HR et al: Pathological sequelae of "neglected" 
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11. Richardson JE, Dent M: The effect of mandibular first pre- 
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12. Richardson ME: The role of the third molar in the cause of 
late lower arch crowding: a review, Am J Orthod Dentofac 
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13. Kugelberg CF: Periodontal healing two and four years after 
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14. Kugelberg CF et al: The influence of anatomical, pathophysi- 
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15. Kugelberg CF et al: Periodontal healing after impacted lower 
third molar surgery in adolescents and adults, Int J Oral Max- 
illofac Surg 20:18, 1991. 

BIBLIOGRAPHY 

Bean LR, King DR: Pericoronitis: its nature and etiology, J Am 
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ChinQuec TA et al: Surgical removal of the fully impacted 
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Laskin DM: Indications and contraindications for removal of 
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