Category Archives: Principles of Management of Impacted Teeth

Facilitation of Orthodontic Treatment

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 vith the treatment. It is therefore recommended that impacted third molars be removed before orthodontic therapy is begun.
Another consideration is that, after orthodontic treatment 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 impactions. 11,12 Several other factors influence crowding. Growth of the maxilla stops before growth of tile mandible, If the upper and lower incisors are in a proper overbite and overjet relationship,-and if tile mandible continues to grow’ after the maxilla stops growing, tile mandibular incisors then become crowded to 3rCOJllIl1Odate the constriction imposed on them by the maxillary incisors: This explanation appears sound, because CfOW. FIG: 9-8

FIG: 9-8

Impacted tooth retained under denture. Tooth is now at surface and is causing infection.

FIG. 9-9

FIG. 9-9

FIG. 9-9 Impacted tooth under fixed bridge. Tooth must be removed and  therefore may jeopardize bridge ..ing Occurs after the age at which the  axilla 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  emove impacted teeth to help prevent crowding should be supported.

 

 

 

 

 

 

 

Prevention of Fracture of the Jaw

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 frequently removed  before the fracture is reduced and inter maxillary fixation is applied.

Treatment of Pain of Unexplained Origin

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 [oint
(TM]) disorder are excluded and if the patient has an unerupted tooth, removal of the tooth sometimes results in resolution of the pain.

Prevention of Odontogenic .Cystsand Tumors

Prevention of Odontogenic .Cystsand 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, unrnonitored 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, 10 the overwhelming 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.

Impacted Teeth under a Dental Prosthesis

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 one; 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 situatio-n for extraction. If extraction is postponed, the patient will be older and more likely to be in poorer health. Furthermore, “the mandible mayhave become atrophic, which increases the likelihood of fracture during tooth removal (Fig. 9-10). ‘ -.

HG. 9·6

HG. 9·6

HG. 9·6 Root resorption of second molar as result of impacted third molar.

FIG. 9-7

FIG. 9-7

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

 

 

Prevention of Root Resorption

Prevention of Root Resorption

Occasionally, an impacted tooth causes sufficient pressure on the root of an adjacent tooth to cause root resorption (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 cementa I repair. Endodontic therapy !!lay be  equired to save these teeth

Prevention of Pericoronitis

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 pericoronitis.” Pericoronitis is an infection of the soft tissuearound 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.

FIG. 9-3

FIG. 9-3

FIG. 9-4

FIG. 9-4

If the host defenses-are compromised (e.g., during minor illnesses, such as influenza or an upper respiratory infection, or from severe fatigue), infection can occur. Thus although the impacted tooth has been present for some time without infectlon, 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 operculums can be traumatized and become swollen. Often the maxillary third molar further traumatizes the already swollen operculum, which causes increased swelling that again cap be traumatized more easily. 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 pericoronitis 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 irrigating
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 cavity.
Other irrigates, such as chlorhexidine ‘or iodophors, can reduce the bacterial population of the pocket. Pcricoronitls can present as a very mild infection or as a severe infection that requires hospitalization (\1’ the
patient. Just as the severity of the infection varies. the FIG. 9-4 Radiograph of caries in mandibular impacted molar btreatment 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 extracting the maxillary third molar in addition to local irrigation.

fiG. 9-5

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 mrn), a temperature of greater than 1010 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 stoperative complications; specifically dry socket an~ postop erative 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 pericoronltts 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 pence ronitis can be prevented only by extraction of the tooth.

 

 

 

 

Prevention of Pericoronitis

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 pericoronitis.” Pericoronitis is an infection of the soft tissuearound 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.

Prevention of Dental Caries

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 IX’ enough communication to allow for caries production (Figs. 9-s through

Prevention of Periodontal Disease

Prevention of Periodontal Disease

Erupted teeth adjacent to impacted teeth are predisposed to periodontal disease (Figs. 9-1 and 9-2). The mere presence of an impacted mandibular third molar decreases the amount of bone on the distal aspect ofan 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 inflammation with apical migration of the gingival attachment on the distal aspect of the second molar. Wjth 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 secondmolars but have normal sulcular depth in the remainder of themouth. The accelerated periodontal problem resulting from an impacted third molar is especially serious in the maxilla. As a periodontal pocket expands apically, i~ becomes involved with the distalfurcation 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, periodontal
disease can be prevented and the likelihood of bonv bealing and bone fill into the area previously occu

FIG. 9-1