June 2011

Objective: The purpose of this study was to evaluate the relationship between bone fragility of the mandibular inferior cortex and tooth loss in older adults by accounting for periodontal disease and bone metabolism markers. Research Design: A total of 177 subjects aged 77 years participated in this study. We counted the number of remaining teeth. The mandibular cortex condition was examined using the mandibular inferior cortex classification (MICC) on dental panoramic radiographs. The mandibular inferior cortex was detected on both sides of the mandible, distally from the mental foramen (C1, normal; C2, mild/moderate erosion; C3, severe erosion). Multiple linear regression analysis was performed to assess the relationship between the mandibular cortex condition with the MICC and the number of remaining teeth after controlling for confounding factors such as gender, the percentage of sites with ≥4 mm clinical attachment levels, and serum osteocalcin levels. Results: The mean ± SD number of remaining teeth of MICC C1, C2 and C3 were 20.7±7.5, 14.6±8.1 and 4.0±0.0 for males, and MICC C1, C2, and C3 were 21.7±7.6, 17.2±8.0, and 16.2±10.4 for females. The MICC was significantly associated with the number of remaining teeth using multiple linear regression analysis (beta= -0.21, p=0.031). Conclusion: This study suggests that there is a relationship between bone fragility of the mandibular inferior cortex and tooth loss related to periodontal disease. Key words: Dental panoramic radiograph, elderly, epidemiology, mandibular inferior cortex, number of teeth