Evaluation of Correlation between Width and Morphology of Mandibular Inferior Cortex in Digital Panoramic Radiography and Postmenopausal Osteoporosis

Background: In osteoporotic patients, inferior mandibular cortex undergoes resorption which its manifestations can be detected on dental panoramic radiographs as a simple and available method. The aim of this study was to evaluate the correlation between width and morphology of mandibular inferior cortex in digital panoramic radiography and postmenopausal osteoporosis. Methods: Bone mineral density (BMD) of lumbar vertebrae and femural neck of 119 postmenopause women was assessed using DXA. Width [cortical index (CI)] and morphology [mandibular cortical index (MCI)] of inferior mandibular cortex were measured and the correlations between BMD and width and shape of the inferior mandibular cortex were evaluated. Results: The specificity and sensitivity in identifying women with low BMD of lumbar vertebrae by visual cortical estimation (normal or eroded) were 69.4% and 80.7% respectively. These results in identifying women with low BMD of femural neck were 67.7% and 81.5% respectively. For both sides, the threshold value that provided the highest validity (minimal false negative and false positive results) corresponded to cortical width of 4.29 mm. This threshold in lumbar vertebrae or femural neck provided a sensitivity of 81.4% (95% CI=69.1%-90.3%), specificity of 58.3% (95% CI=44.9%-70.9%), positive predictive value of 65.8% and likelihood ratio of 1.95. There were significant associations between BMD and CI and MCI. Conclusion: Postmenopausal women with thin or eroded mandibular inferior cortex may have an increased risk for low BMD or osteoporosis.