MEASUREMENT OF MANDIBULAR BONE-MINERAL CONTENT USING THE DENTAL PANORAMIC TOMOGRAM

The aim of this study was to determine whether bone mineral content could be estimated densitometrically using dental panoramic tomograms. A nickel stepwedge was attached to the film cassette to give a reference image on the radiographs. Four mandibles were radiographed and the optical density of a number of sites on the bone images measured. The calcium and phosphate content of the mandibles at these sites was measured by chemical analysis, using 3 mm diameter full thickness cores. The radiographically derived equivalent nickel thickness of the mandibular test sites was significantly correlated with calcium content (r = 0.62, P = 0.013), phosphate content (r = 0.633, P = 0.011), and dry bone weight (r = 0.541, P = 0.036), provided correction for soft tissue thickness was made. A clinical study is justified to determine whether the technique has sufficient accuracy to provide sequential data on individual patients and whether it may be useful as a simple method of screening patients for mandibular osteoporosis.