Computer-assisted evaluation of Mandibular Cortical Width (MCW) index as an indicator of osteoporosis

Background: To assess the diagnostic accuracy of mandibular cortical width (MCW) as an indicator of the presence of osteoporosis. Materials and methods: The study included 343 women between 45-75 years of age. After informed consent, all subjects underwent dual energy X-ray absorptiometry (DXA) of the hip and the lumbar spine (L1 to L4) in order to establish a gold standard diagnosis of osteoporosis and an orthopantomogram (OPG). From the initial subjects, 28 (8.2%) did not meet the inclusion criteria. In the final sample 315 patients were included, of whom 293 were postmenopausal (93.3%) and 22 perimenopausal (6.7%). Based on the DXA examination the sample was divided into three groups: a) normal controls (n=106), b) osteopenics (n=103) and c) osteoporotics (n=106). The MCW index was calculated by three different observers using the Emago image processing software. Inter-rater agreement was considered important since MCW was being tested as a possible screening tool for osteoporosis. Results: Comparisons of MCW values between normal controls, osteopenic and osteoporotic women in our sample showed that these values clearly differentiate between the three groups, especially between normal and osteoporotic subjects. Furthermore, the receiver operator characteristic curve (ROC) analysis showed this to hold true in real diagnostic terms, giving a threshold value of 3.24 for differentiating between normal and osteoporotic women. Conclusions: With ROC values ranging between 0.80 and 0.87 we can reasonably assume that the MCW index is a reliable indication of the presence of osteoporosis in a patient