Association between number of teeth present and mandibular cortical erosion in Japanese men and women aged 40 years and older: A cross-sectional study

Mandibular cortical erosion detected on dental panoramic radiographs is associated with increased risk of osteoporosis in older adults. Additionally, many reports have demonstrated an association between decreased number of teeth present and osteoporosis. However, whether mandibular cortical erosion is associated with a decreased number of teeth remains unclear. The purpose of this study, therefore, was to clarify the association between mandibular cortical erosion and number of teeth present in Japanese men and women aged 40 years and older. Among patients who visited our university hospital and underwent dental panoramic radiography for the diagnosis of dental diseases, 839 patients (293 men and 546 women) aged 40-89 years (mean [SD], 63.7 [10.6] years) participated in this study. Multiple regression analysis revealed that mildly to moderately eroded cortex (p = 0.007) and severe eroded cortex (p < 0.001) were significantly associated with a decreased number of teeth present. Analysis of covariance adjusted for covariates revealed a significant association between mandibular cortical erosion category and number of teeth present (p < 0.001). Subjects with a severely eroded cortex had significantly fewer teeth present than those with a normal cortex (mean [SE], 20.7 [0.5] vs. 23.4 [0.3], p < 0.001) or mildly to moderately eroded cortex (22.2 [0.4], p = 0.04). Subjects with a mildly to moderately eroded cortex had significantly fewer teeth present than those with a normal cortex (p = 0.033). Our results suggest the significant association between mandibular cortical erosion and number of teeth present in Japanese men and women aged 40 years and older.