Radiographic features of lingual mandibular bone depression using dental cone beam computed tomography

To describe accurately the radiographic characteristics of lingual mandibular bone depression (LMBD) using CBCT images.

This study included 30 cases of LMBD with CBCT images from 29 patients. Age, sex, location, shape, size, and the relationships of the LMBDs to adjacent anatomical structures such as the mandibular inferior cortex and mandibular canal were recorded. The correlation between age and size was evaluated using Pearson's correlation coefficient.

The average age of the patients was 57 years. LMBDs occurred primarily in males (93%), occurrence in the right (n = 14) and left (n = 16) mandibles was approximately equal. The shapes were ovoid, round, peanut, triangular, or rectangular on panoramic radiographs. The occurrences in the molar, distal to the molar, and ramus regions were 63.3, 33.3, and 3.3% respectively. The mean size on CBCT was 15.4 mm in length, 11.2 mm in height, and 6.4 mm in depth. The relationship to the mandibular canal was categorized as separated (48.2%), contacted (31%), or go-through (20.7%). The relationship to the mandibular inferior cortex was classified as separated (20.7%), contacted (27.6%), or resorbed (51.7%). The Pearson's correlation coefficient showed a positive correlation between age and depth (r = 0.38; p = 0.038).

The typical features of a LMBD were ovoid, round or mutilobated radiolucent shape, well-defined sclerotic border, and position in the posterior area of the mandible between the mandibular canal and inferior mandibular cortex. The buccolingual depth of LMBD was deeper with increasing age.