Ultrasonographically locating the mental foramen and its soft tissue relations.

OBJECTIVES: This ultrasound-based cross-sectional study aimed to visualize, locate and compare the position of the mental foramen with regard to its relationship to various soft tissue landmarks.

METHODS: 100 Black and Caucasian subjects were included. An ultrasound transducer was used to locate the mental foramina. Distances to various landmarks were measured and compared.

RESULTS: All mental foramina were visualized. The mean soft tissue distance of the entire group from the mental foramen on the right and left sides, respectively, were as follows: (a) 3.4 mm [standard deviation (SD) 1.7 mm] and 3.4 mm (SD 1.5 mm) lateral to a vertical line passing through the chelion; (b) 20.1 mm (SD 2.6 mm) and 20.1 mm (SD 2.6 mm) distal to a horizontal line bisecting the chelions; (c) 15.1 mm (SD 2.4 mm) and 15.0 mm (SD 2.4 mm) proximal to the inferior border of the mandible. We found no statistically significant differences between race groups, between gender group and between age categories with regard to the horizontal soft tissue distance from a vertical line passing through the chelion to the mental foramen on the right or left sides. There were statistically significant (but not clinically significant) differences between race groups and between gender groups but not between age groups with regard to the vertical soft tissue distance from a horizontal line bisecting the chelions to the mental foramen as well as from the inferior border of the mandible to the mental foramen on both the right and left sides.

CONCLUSIONS: This study suggests that ultrasound is a feasible imaging modality that can be utilized to locate the mental foramen. Differences in the position of the mental foramen with regard to various soft tissue landmarks are minor and clinically insignificant.