Clinical and panoramic predictors of femur bone mineral density

Dentists are a potentially valuable resource for initial patient screening for signs of osteoporosis, as individuals with osteoporosis have altered architecture of the inferior border of the mandible as seen on panoramic radiographs. Our aim was to evaluate the efficacy of combining clinical and dental panoramic radiographic risk factors for identifying individuals with low femoral bone mass. Bone mineral density was measured at the femoral neck and classified as normal, osteopenic or osteoporotic using WHO criteria in 227 Japanese postmenopausal women (33-84 years). Panoramic radiographs were made of all subjects. Mandibular cortical shape and width was determined and trabecular features were measured in each ramus. Mean subject age, height, and weight were significantly different in the three bone-density groups (P<0.0001). A classification and regression trees (CART) analysis using just clinical risk factors identified 136 (87%) of the 157 individuals with femoral osteopenia or osteoporosis. Mean mandible cortical width (P<0.0001), cortical index (P<0.0001) and trabecular features (P=0.02) were also significantly different in the three bone density groups. A CART analysis considering only radiographic features found 130 (83%) of the 157 individuals with femoral osteopenia or osteoporosis, although none of the subjects with osteoporosis was correctly identified. A CART analysis using both clinical and radiographic features found that the most useful risk factors were thickness of inferior border of the mandible and age. This algorithm identified 130 (83%) of the 157 individuals with femoral osteopenia or osteoporosis. The results of this study suggest that 1) clinical information is as useful as panoramic radiographic information for identifying subjects having low bone mass, and 2) dentists have sufficient clinical and radiographic information to play a useful role in screening for individuals with osteoporosis.