Diagnostic Efficacy of Panoramic Radiography in Detection of Osteoporosis in Post-Menopausal Women with Low Bone Mineral Density

OBJECTIVE: The aim of the study was to evaluate panoramic radiograph, a commonly taken dental radiograph as a screening tool to detect early osseous changes (normal, mildly or severely eroded) of the mandibular inferior cortex and measure the mandibular cortical width (CW) in post-menopausal women and correlate it with the bone mineral density (BMD) measured by the ultrasound bone sonometer at the mid-shaft tibia region. MATERIALS AND METHODS: The study included females between 45 years and 65 years of age in their post-menopausal stage (no menstruation for at least 6-12 months). Mandibular indices (mandibular CW and mandibular cortical shape) were evaluated from panoramic radiographs. The BMD assessment was carried out at the mid-shaft tibia region, exactly half-way between the heel and the knee joint perpendicular to the direction of the bone, using an ultrasound bone sonometer. It is a non-invasive device designed for quantitative measurement of the velocity of ultrasound waves as speed of sound in m/s, capable of measuring bone density at one or more skeletal sites. Using 1994 WHO criteria the study subjects were categorized as Group 1: Normal, Group 2: Osteopenia, Group 3: Osteoporosis. (WHO T score for tibia BMD can be used as a standard). RESULTS: The diagnostic efficacy of the panoramic radiograph in detecting osseous changes in post-menopausal women with low BMD was shown to have 96% specificity and 60% sensitivity with mandibular cortical shape and 58% specificity and 73% sensitivity with mandibular CW measurement. Factorial ANOVA analysis carried out indicated a significant correlation of BMD classification with mandibular cortical shape (F = 29.0, P < 0.001, partial eta squared [η(2)] =0.85), a non-significant correlation with mandibular CW, (F = 1.6, P = 0.23, η(2) = 0.86), and a more significant correlation with combined cortical shape and width (F = 3.3, P < 0.05, η(2) = 0.70). CONCLUSION: The study concludes that the combined mandibular cortical findings (P < 0.05) and mandibular cortical shape erosion alone (P < 0.001) on panoramic radiograph are effective indicators of osteoporosis in post-menopausal women.