Dento–Osseous Variability of the Mental Foramen: A Retrospective CT-Based Morphometric Study

Background and Objectives: This study aimed to identify osseous and dental mandibular landmarks that consistently indicate the location of the mental foramen, the primary reference for the mental–incisive trunk block. Materials and Methods: Computed Tomography (CT) scans of the mandibles of 100 patients from a Romanian population (N = 100) were retrospectively analyzed to measure the following: distances from the mental foramen to the basal border of the mandible, alveolar process/crest, and midline, as well as the position of the foramen relative to the lower premolars. These measurements were correlated with patients’ age (divided into three groups: 18–30 years, 30–60 years, >60 years) and gender. Results: The mental foramen was found to be closer to the alveolar crest (13.3 mm with SD = 3.3 in males and 10.7 mm with SD = 4.4 in females, overall mean = 12.3 mm, SD = 4.0) (p = 0.001) than to the inferior border of the mandible (14.3 mm with SD = 1.8 in males and 12.9 mm with SD = 1.6 in females, overall mean = 13.7 mm, SD = 1.9) (p < 0.001). In addition, the foramen was most frequently located adjacent to the second premolar (27.0%) rather than between the premolars (20.0%) and at a distance of ≃2.5 cm lateral to the midline (overall mean = 25.2 mm, SD = 3.5) (p = 0.034). Conclusions: Following the measurements performed, the mental foramen was identified as being closer to the alveolar crest in the vertical direction, at a distance of approximately 2.5 cm lateral to the midline, and most frequently located at the level of the second lower premolar.