Anatomical and CBCT-Based Evaluation of the Mental Foramen in Korean Adults: Clinical Implications for Implant Surgery and Mental Nerve Block.

Background

Precise localization of the mental foramen (MF) is essential to avoid mental nerve injury during implant placement, osteotomy, periapical surgery, and regional anesthesia. However, MF morphology and canal orientation show population-specific variability, and comprehensive morphometric data combining cadaveric dissection and CBCT analysis remain limited in Koreans. This study aimed to provide clinically applicable MF reference values for Korean adults.

Methods

Thirty-two hemimandibles from 16 dentate Korean cadavers were examined through direct anatomical dissection. MF position relative to teeth, shape, vertical and horizontal diameters, and distances to the gingival margin, inferior border, and mandibular midline were measured. CBCT imaging of 12 hemimandibles was used to assess the internal trajectory and opening direction of the mental canal.

Results

The MF was most frequently located below the second premolar (75%), followed by the P2-M1 region (15.6%). Round foramina (62.5%) were more common than oval forms. Mean distances from the MF to the gingival margin, inferior border, and midline were 16.6 mm, 15.5 mm, and 26.5 mm, respectively. The mean horizontal diameter of the MF was 3.0 mm, and the mean vertical diameter was 2.2 mm. CBCT analysis revealed two emergence patterns-posterolateral (50%) and lateral (50%).

Conclusions

This study identified the positional characteristics, diameters, and canal emergence patterns of the MF in a cadaveric sample using dissection and CBCT. The findings regarding MF location, dimensions, and the opening direction of the mental canal provide practical anatomical information that may support safer implant placement, mental nerve blocks, and anterior mandibular surgery.