Preoperative assessment of the relationship between the mandibular third molar and the mandibular canal by axial computed tomography with coronal and sagittal reconstruction

Objective. We sought to evaluate the relationship between the mandibular third molar and the mandibular canal by using axial computed tomography with coronal and sagittal reconstruction for third molar surgery. Study design. Forty-seven impacted third molars in 41 patients were found in close association with the mandibular canal during a panoramic radiographic assessment. The relationship between the mandibular third molar and the mandibular canal was evaluated by using computed tomography and compared in terms of operative exposure of the inferior alveolar nerve and postoperative labial dysesthesia. Results. Twenty-four (51%) mandibular canals were buccal relative to the third molar, 12 were lingual, 9 were inferior, and 2 were between roots. At the time of the surgical procedure, the inferior alveolar nerve was visible in 7 patients. Postoperative lower lip dysesthesia occurred in 1 patient whose mandibular canal was in the lingual position. Conclusions. Axial computed tomography with coronal and sagittal reconstruction provides useful information to surgeons regarding the relationship between the mandibular third molar and the mandibular canal.