Prevalence and Length of Anterior Loop of Inferior Alveolar Nerve

Background: Interforaminal region of mandible is often related to neurovascular complications during surgical procedures such as implant placement and during harvesting bone graft. This is due to anatomic variations such as the anterior looping of inferior alveolar nerve and the lingual vessels. Cone Beam Computed tomography (CBCT) is an imaging modality with which such anatomical variants can be visualized and necessary modifications can be made during pre-surgical phase of implant placement. This study aims at identifying the prevalence and the length of anterior loop of inferior alveolar nerve using CBCT.

Materials and Method: 50 patients scanned using Sirona Orthophos XG device for the purpose of implant placement were included in this retrospective study. Using the device’s software, the inferior alveolar nerve was traced and marked in each included CBCT volume. The length of the anterior loop was measured with AutoCAD 2018 software using the reconstructed 3D model of the scan.

Results: Of the 50 selected CBCT volumes, 33 volumes had anterior looping of inferior alveolar nerve. The mean length of the loop observed in the selected patients was 0.42 ± 0.40 mm on the left side and 0.42 ± 0.31 mm on the right side. For males, the mean length of the loop was 0.42 mm on the left side and 0.42 mm on the right side. For females, the mean length was 0.40mm on the left side and 0.45mm on the right side.

Conclusion: The anterior loop of inferior alveolar nerve is quite common in south Indian population. The looping has to be assessed before implant placement in the anterior mandibular region so as to identify and prevent neurovascular complications.