The Importance of Recognizing Pathology Associated with Retained Third Molars

“Clinical Showcase” is a series of pictorial essays that focus on the technical art of clinical dentistry. The section features step-by-step case demonstrations of clinical problems encountered in dental practice. If you would like to propose a case or recommend a clinician who could contribute to this section, contact editor-in-chief Dr. John O’Keefe at [email protected]. The presence of either partially erupted or fully impacted third molars often prompts a visit to the dental office. Patients may experience symptoms ranging from pain to mild or moderate trismus or even acute infection with purulence at the site of the involved tooth. In such instances, immediate treatment is often necessary to alleviate or resolve the patients’ presenting complaint. In the situation of completely impacted third molars, the clinician must make the patient aware of the presence of the impacted wisdom teeth and the presence or absence of any associated pathology. The prophylactic removal of impacted wisdom teeth is often suggested to prevent problems such as infection, carious lesions, destruction of adjacent teeth, periodontal defects involving adjacent teeth, cysts or tumours.1 Because a large number of wisdom teeth remain impacted or partially impacted (84%) rather than erupting completely (16%), it is important that retained wisdom teeth be carefully monitored for signs of pathology.2 As a result, it is important that patients undergo panoramic radiography as part of the initial evaluation when third molar symptoms are part of the chief complaint. Also, the need for proper referral if pathology is suspected, as well as appropriate radiographic follow-up, must be recognized. Figures 1 to 3 illustrate lesions associated with partially erupted or impacted third molars that might be missed if periapical radiographs alone are used for routine dental evaluation. Further radiographic assessment of some lesions (Fig. 2), including computed tomography or cone beam scanning may be indicated before surgical intervention. If some lesions are not detected early, they can continue to grow. In Fig. 3, for example, because the lesion appears distal to the crown of the tooth, it might not have been detected with periapical radiography, which would have allowed further enlargement of the cyst and increased morbidity. The presence of large pathologies such as ameloblastoma or odontogenic keratocyst can lead to destruction of a large portion of the mandible, and resection and reconstruction of the affected bone may be required. The Importance of Recognizing Pathology Associated with Retained Third Molars