Evaluation of the Mental Foramen and Accessory Mental Foramen with Cone Beam Computed Tomography

Abstract Background The mental foramen (MF) is the opening through which the mental nerve leaves the mandible and is usually located between the roots of the first and second mandibular premolars. Some anatomical variations, such as accessory mental foramen (AMF), have been reported and must be considered to prevent clinical complications. Various AMF studies have been presented in the literature. However, the MF and AMF remain to be evaluated in detail. This study aimed to assess the AMF via cone beam computed tomography (CBCT) and evaluate its relationship with the MF. Methods Two hundred forty-four CBCT images that met the inclusion criteria were evaluated. The AMF and MF diameter, AMF number, MF–crest distance, MF–mandibular basis distance, AMF–crest distance, and AMF–mandibular basis distance were measured. Results The prevalence of AMF was 9.4%, with a total of 46 (26 on the right and 20 on the left) observed. The diameters of the first and second AMFs were 0.67 ± 0.28 mm and 0.56 ± 0.11 mm on the right and 0.68 ± 0.23 mm and 0.46 ± 0.11 mm on the left, respectively. Regarding the MF, the right and left sides measured 2.06 ± 1.37 mm and 1.91 ± 0.45 mm, respectively. The first and second AMF–crest distances and first and second AMF–mandibular basis distances were 15.18 ± 2.77 mm, 13.5 ± 2.0 mm, 16.63 ± 2.64 mm, and 14.13 ± 4.36 mm (right side) and 13.90 ± 3.01 mm, 12.23 ± 0.9 mm, 13.14 ± 2.4 mm, and 14.40 ± 3.21 mm (left side), respectively. Regarding the diameter of the left MF, the distance between the right and left MF crest and the distance between the MF and mandibular basis were greater in males (p