The relationship between panoramic radiomorphometric indices and the femoral bone mineral density of edentulous patients

ObjectivesTo determine the relative efficacy of panoramic radiomorphometric indices in detecting osteoporosis, and optimal thresholds for referral for osteoporosis investigation in edentulous patients.MethodsForty-nine edentulous patients, age 41–78 years, were divided into normal and osteopenic/osteoporotic groups according to femoral bone mineral density. Panoramic radiographs were obtained to determine the mandibular cortical index (C1, normal; C2, mild; and C3, severe erosion of mandibular cortex), mental index (cortical thickness in the mental foramen region), and panoramic mandibular index (ratio of thickness of the mandibular cortex to distance between the inferior margin of the mental foramen and the inferior mandibular cortex). Results were compared using a chi-squared test and Student’s t-test.ResultsCategories C1 and C3 were more frequent in the normal and osteopenic/osteoporotic groups, respectively (p = 0.007). The mean mental index and panoramic mandibular index values were significantly lower in the osteopenic/osteoporotic group than in the normal group (p = 0.002 for mental index, p = 0.019 for panoramic mandibular index). The sensitivity and specificity were 71.4% for the mandibular cortical index. The area under the receiver operating characteristic curve enabled moderately accurate identification of patients with osteoporosis using the mental index and less accurate identification using the panoramic mandibular index.ConclusionsThe mandibular cortical index and mental index are better than the panoramic mandibular index for identifying patients with osteoporosis. Within the limits of this study, edentulous male or female patients in category C3 with a mental index <3.5 mm should be referred for further osteoporosis investigation.