Evaluation of the Linear Relationship of the Inferior Alveolar Nerve Canal to the Lateral Cortex and the Alveolar Crest in the Posterior Mandible: A Computed Tomographic Study.

BACKGROUND AND OBJECTIVE: A cross-sectional study was conducted to evaluate a clinically relevant position of the inferior alveolar nerve and canal with respect to the lateral cortex, alveolar crest, and first and second molar root apices in adult dentate patients.

METHODS: The study was conducted in the patients who reported various oral and maxillofacial surgical procedures at the Department of Oral and Maxillofacial Surgery for whom preoperative computed tomography (CT) scan was taken for the required surgical procedures. CTs were selected based on the selection criteria, and a total of 50 CTs were evaluated. Predictor variables were gender and side. Outcome variables were the average linear buccal measurements from the lateral cortex to the outer cortical margin of the inferior alveolar canal from below the mandibular foramen till the mental foramen, linear vertical measurements from the alveolar crest to the superior crest of the inferior alveolar canal in the third, second and first molar regions, and linear vertical distance from the superior aspect of inferior alveolar canal till the apices of second and third molars. Descriptive statistics were analysed with t test and paired t test. P value < 0.05 was taken as significant.

RESULTS: The study sample was composed of 27 male and 23 female patients with a mean age of 29 ± 4.6 years. The mean value of linear measurements of IAN to the right lateral cortex at the mandibular foramen was 4.96 ± 1.13, and for the left side, it was 4.79 ± 1.33. The mean values of linear measurements from the superior aspect of IAN canal to the alveolar crest at third, second and first molar regions obtained in this study were 18.5 ± 3.79, 19 + 3.83 and 19.5 + 3.48 for the right side and 17.8 + 3.86, 18.8 + 3.54 and 19.143.31 for the left side, respectively. The average linear measurements of IAN to the root apex of first molar were 10.8 3.89 for the right side and 10.868 + 3.85 for the left side; for second molars, they were 10.5 + 3.62 for the right side and 10.52 + 3.62 for the left side. Gender and side influenced the outcome with varying statistical significance.

CONCLUSION: The study has identified the average linear measurements of the buccal cortical bone along the path of IAN in the mandible, average height of alveolar bone above the IAN and average distance between the IAN with the first and second molar root apices. This will be useful guide while planning and performing various mandibular surgical procedures close to the IAN nerve and procedures that can disturb the IAN. The implications of these findings will influence the course of surgery.