“…Thus, it is important to evaluate the topographic relationship between the mandibular canal and impacted third molar preoperatively. There were reports [ 6 , 7 , 9 , 11 ] that showed the following 4 panoramic features were significantly associated with inferior alveolar nerve exposure following third molar extraction: interruption of mandibular canal, darkening of third molar root, diversion of mandibular canal and narrowing of third molar root. In addition, many studies reported that the interruption of mandibular canal was the most found panoramic feature that associated with direct contact between the two structures, which could be the risk of nerve injury and paraesthesia [ 2 , 6 , 8 , 12 ].…”