Utilization of cone beam computed tomography to determine the prevalence and anatomical characteristics of bifurcated inferior alveolar nerves.

The primary purpose of this study was to evaluate the prevalence of inferior alveolar nerve (IAN) bifurcations through the utilization of cone beam computed tomography (CBCT). The secondary purposes of this study were to analyze the average distance from the main trunk to its branch at the greatest point, to calculate the average distance of the bifid IAN from the apices of the teeth, and to determine the appropriate classification for each IAN bifid nerve according to the types described by Nortjé et al: type 1, 2 canals originating from a single foramen with a narrower inferior canal; type 2, 2 canals originating from a single foramen with a superior canal extending to the second or third molar; type 3, 2 canals of equal size that arise from 2 mental foramina that may link into a single canal near the molars. Examination of 194 CBCT scans revealed that IAN bifurcations were present in 13.4% (n = 26) of the study population. Bifurcation was bilateral in 4 individuals. For left bifurcated IANs, the average distance between the superior border of the main branch and inferior border of the bifurcated IAN (GDN) was 3.41 mm. The average distance from the superior border of the bifurcated IAN to the apex of the closest root (NAP) was 3.45 mm. For right bifurcated IANs, the average GDN was 4.01 mm, and the average NAP was 4.85 mm. Fourteen bifid nerves were type 1, and 16 were type 2. Preoperative CBCT studies can determine the presence of a bifurcated IAN, thereby reducing the chances of neurologic damage.