A Limited Field Cone-beam Computed Tomography-based Evaluation of the Mental Foramen, Accessory Mental Foramina, Anterior Loop, Lateral Lingual Foramen, and Lateral Lingual Canal

Abstract

Introduction: The aim of this retrospective observational study was to evaluate the cone-beam computed tomographic (CBCT)-based characteristics of the mental foramen (MF), accessory mental foramen (AMF), anterior loop (AL), lateral lingual foramen (LLF), lateral lingual canal (LLC) and to explore any relationships between their characteristics.

Methods: The location and dimension of the MF; the incidence, location, and dimension of the AMF along with its distance to the MF; the presence and dimension of the AL; and the presence, location, angle of entry of the LLF and LLC, and its relation with the mandibular canal (MC) were evaluated in 109 CBCT scans. The data were analyzed descriptively, and associations were tested using the chi-square and analysis of variance tests.

Results: The MF was most frequently located between the first and second mandibular premolar teeth (43.5%) or below the second premolar (34.3%). The mean horizontal dimension of the MF was 3.1 mm, the vertical dimension was 2.8 mm, and the mean vertical distance from the alveolar crest was 14.2 mm. An AMF was observed in 12.8% of cases with a mean distance of 4.1 mm from the MF. An AL was present in 47.2% of cases with a mean loop length of 3.38 mm. An LLF was present in 20.4% of cases, predominantly below the first premolar (27.3%) with a mean angle of entry of 148°. The LLC always communicated with the MC and generally not with the tooth apex. A statistically significant association existed between the presence of the LLF and AMF.

Conclusions: The anatomic complexity of the MF region was confirmed; hence, CBCT-based evaluation is essential before surgical exploration of this region.

Keywords: Accessory mental foramen; anterior loop; cone-beam computed tomography; lateral lingual canal; lateral lingual foramen; mental foramen.