Clinical efficacy of computed tomography and coronectomy for prevention of postoperative inferior alveolar nerve injury occurring after impacted mandibular third molar surgery *
Our aim was to evaluate the clinical efficacy of computed tomography and coronectomy for preventing postoperative inferior alveolar nerve injury after impacted mandibular third molar surgery. Among the patients who visited Kawasaki Medical School Hospital between January 2009 and December 2010, 12 patients with high-risk signs of inferior alveolar nerve injury on panoramic imaging were examined for the extraction of impacted mandibular third molar by computed tomography (CT). CT examinations were performed in order to examine the relationship between the root apex of impacted mandibular third molar and inferior alveolar canal for 16 teeth. Based on the imaging findings，the patients were informed about treatment methods and their consent was obtained. We compared the CT and panoramic findings and discussed the relationship between the impacted third molar and the inferior alveolar nerve. Medical records were also examined for the presence of abnormal postoperative complications. 1) Interruption of the cortical white line of the inferior alveolar canal was identified in 13 panoramic radiographs, and bending of the inferior alveolar canal was observed in 2 panoramic radiographs. 2) CT findings indicated type 2 inferior alveolar nerve proximity in 13 teeth, and there was no proximity in 3 teeth. 3) The observation was selected in 10 teeth showing nerve proximity in CT findings. Traditional third molar removal was performed for the 3 teeth with no nerve proximity. Coronectomy was performed in 3 teeth with nerve proximity. 4) The clinical course was uneventful. To prevent inferior alveolar nerve injury, coronectomy may be a better means of removing the crown of an impacted third molar while leaving the roots intact, in cases where teeth might be in proximity with the inferior alveolar nerve. (Accepted on January 25, 2012)
