Anatomical variations of the mental foramen in prognathic, retrognathic and orthognathic mandibles: a cone-beam computed tomography based analysis

Introduction The mental foramen is a key anatomical landmark that transmits the mental nerve and vessels. Its position varies across individuals and skeletal patterns, making accurate localization essential during surgical procedures such as local anesthesia, implant placement, and dental extractions. The objective of this study was to assess the horizontal position of the mental foramen, the distance from the mental foramen to the adjacent tooth apex and the distance from the superior border of the mental foramen to the inferior border of the mandible in individuals with prognathic, retrognathic, and orthognathic mandibles using cone-beam computed tomography (CBCT). Material and methods CBCT-derived lateral cephalograms of 39 subjects were used to identify cephalometric landmarks and classify subjects into three skeletal groups. Mental foramen position was assessed using standard references, with group differences analyzed by Fisher-Freeman-Halton exact test and one-way ANOVA ( p  < 0.05). Results The position of the mental foramen was classified from P1-P5 based on their relationship to the mandibular teeth: P1, anterior to first premolar; P2, in line with the first premolar; P3, between first and second premolar; P4, in line with the second premolar; P5, between second premolar and first molar. The predominant position in the retrognathic mandible was P5–46.2% (right) and 38.5% (left). In the prognathic mandible, P4 was the most common position—53.8% (right), while P3 (46.2%) predominated in the left. In orthognathic mandibles, P3 (69.2%) was the most common position on both sides. Significant differences were observed in the position of the mental foramen between the groups only on the right side. Significant sex differences were seen when the distance from the superior border of the mental foramen to the inferior border of the mandible was compared. Conclusions Significant differences in the horizontal position of the mental foramen among skeletal patterns was observed on the right side. The distance between mental foramen and adjacent root apex demonstrated a significant right-left difference in the retrognathic group. CBCT may aid in the preoperative localization of the mental foramen for mandibular surgical planning.