Accessory mental foramina: prevalence, position and diameter assessed by cone-beam computed tomography and digital panoramic radiographs.

Objective: To investigate the presentation of accessory mental foramina (AMF) on cone-beam computed tomography (CBCT) and digital panoramic examinations (PAN).

Study Design: Imaging examinations (i.e., CBCT and PAN) of 100 patients (200 hemi-mandibles) were assessed. AMF prevalence, diameter, and location related to adjacent teeth and to the mental foramen (MF) were analyzed.

Results: On CBCT images, the AMF was observed in 3% of the patients: two unilateral cases and one bilateral case, with mean diameter of 0.93 mm (±0.3); no AMF was identified on PAN. Most AMF were located between the premolars, either superiorly (two cases) or mesially (two cases) to the MF. The mean horizontal distance to the corresponding MF was 2.3 mm (±1.0) and the mean vertical distance was 4.0 mm (±0.7).

Conclusions: The results of this study suggest that CBCT is an effective tool for presurgical tridimensional assessment of the neurovascular structures, such as MF and its variations; On the other hand, PAN examinations were not able to show the AMF cases assessed on CBCT.