Radiological analysis of lingual mandibular bone depression: morphological classification and anatomical relationships in large sample study

This study aims to comprehensively characterize the clinical and radiographic features of lingual mandibular bone depression (LMBD), a frequently misdiagnosed yet benign mandibular entity. Particular emphasis is placed on atypical presentations that deviate from classical descriptions and challenge conventional diagnostic assumptions. We analyzed panoramic radiographs and three-dimensional images from 223 cases diagnosed with LMBD. On panoramic radiographs, we evaluated the anatomical location and the relationship with adjacent teeth and the mandibular canal. Three-dimensional imaging was used to evaluate the relationships with adjacent teeth and the mandibular canal, as well as buccal cortical bone involvement. Chi-square goodness-of-fit tests were used to assess differences in the distributions of sex and lesion side, with statistical significance set at p < 0.05. LMBDs were more frequently observed in male patients (79.37%) and in patients aged 50 years or older (60.54%), with a significant difference in sex distribution. The lesions were observed on the left side in 113 cases (50.67%) and on the right side in 110 cases (49.33%), with no statistically significant difference. The angle area was the most common location (53.36%). Contact with adjacent teeth was identified in 8.07% of cases on panoramic radiographs and in 6.73% on three-dimensional imaging, and 48.88% of cases were in contact with the mandibular canal. Class 2 buccal cortical involvement was frequently observed (48.88%). Three cases were radiographically absent in earlier imaging but became apparent in adulthood, and five cases showed progressive enlargement over several years. This study demonstrates that LMBDs exhibit a broader anatomical spectrum than previously recognized in terms of lesion location, anatomical relationships, and buccal cortical bone involvement. It particularly demonstrates that atypical LMBD cases with a high potential for misdiagnosis are not uncommon. These findings emphasize the clinical importance of recognizing atypical LMBDs and assessing their anatomical relationships through 3D imaging to achieve accurate differential diagnosis. Not applicable.