CBCT-Based Anatomical and Morphometric Analysis of the Accessory Mental Foramen: a Cross-Sectional Study

Background: One anatomical variation in the mental foramen area is the presence of an accessory mental foramen (AMF). This study aimed to investigate the position and anatomical features of the accessory mental foramen using CBCT imaging. Materials and methods: This cross-sectional descriptive study analyzed ۵۰۰ CBCT images (one per patient) to assess the prevalence and characteristics of the accessory mental foramen. Parameters recorded included the patient's gender, location of the accessory mental foramen to the main foramen, number, diameter, and distance between the main and accessory mental foramina. Data were analyzed using SPSS version ۲۷ at a significance level of ۰.۰۵, employing the Chi-square test, Fisher's exact test, and independent t-test. Results: AMF was observed in ۳.۴% (۱۷ patients). Among them, ۷۰.۶%  (۱۲ patients) had bilateral AMF, and ۱۷.۶% had unilateral right-sided, and ۱۱.۸% had unilateral left-sided AMF.most  accessory mental foramen were positioned apically (۸۶.۲%), distally (۷۲.۴%), and buccally (۸۹.۷%), with the apical-distal-buccal combination (۵۵.۲%) being the most common. The prevalence of accessory mental foramen was not significantly associated with gender, mandibular side, or age (p>۰.۰۵). However, the mean AMF diameter was significantly greater in men than in women (p=۰.۰۰۳). The mean distance between the main and accessory mental foramina showed no significant gender-related difference (p>۰.۰۵). Conclusion: Based on this study, given the anatomical variability and individual differences in AMF characteristics, CBCT is recommended for accurate identification before periapical or implant surgery to prevent complications such as nerve injury or inadequate anesthesia.