Age- and Gender-related Differences in the Position of the Inferior Alveolar Nerve by Using Cone Beam Computed Tomography

Introduction: Surgical endodontic procedures require precise knowledge of anatomic structures that might be traumatized. The aim of this study was to evaluate whether differences in patient gender or age are predictive of differences in the relative location of the inferior alveolar nerve (IAN) compared with the roots of the mandibular first molar. Methods: We searched a database of 23,000 small-volume cone beam computed tomography scans and evaluated the first 200 patients that met the following inclusion criteria: (1) age between 30-69 years; (2) known gender (n = 25 males and 25 females for each 10-year age bin); and (3) scans containing the mandibular first molar and IAN. Exclusion criteria consisted of any pathosis that might alter the position of the IAN. Anatomic measurements were made by 2 observers with mutual agreement of any discordant measures. Fourteen measurements (in millimeters) were taken at the level of the IAN and mesial and distal root apices. Data were analyzed by 2-way (age, sex) analysis of variance with Bonferroni post hoc test at P <.05. Results: Regardless of age, females had significantly shorter vertical distances from the IAN to the mesial (P <.01) and distal apices (P <.01) and shorter horizontal distances for total width of mandibular bone at the mesial (P <.01) and distal apices (P <.01). In addition, the overall width of the mandibular bone decreased in both genders from the 3rd-6th decade of life (P <.01). Conclusions: Collectively, these data indicate that both gender and age are predictive of surgical endodontic anatomic relationships and should be considered in presurgical planning. (J Endod 2009;35:944-949)