Measurements in Mandibular Pantomographic X-rays and Relation to Skeletal Mineral Densitometric Values

The gold standard diagnostic modality for osteoporosis is dual-energy X-ray absorptiometry (DXA). But it is expensive and often unavailable. Studies have demonstrated that decreased bone mineral density (BMD) may affect mandibular bone morphometrically on radiographs. Such studies are rare in the Indian population. This study was conducted to evaluate correlation between radiomorphometric markers on digital orthopantomograms (OPGs) and BMD measurements done by DXA in an Indian population. A total of 344 subjects aged 45 years or above, who visited a dental outpatient department over a period of 6 years were included in the study after obtaining ethical committee approval and informed consent. Digital OPG and DXA BMD measurements were obtained. Subjects' T-scores were obtained, on the basis of which they were divided into osteoporotic, osteopenic, and normal. OPGs were evaluated to obtain the mandibular cortical index (MCI) and the panoramic mandibular index (PMI). Correlations of MCI and PMI with BMD were analyzed statistically with SPSS (version 16.0; SPSS, Chicago, IL). In the osteoporotic group, there was no subject with MCI finding of C1, and 77.42% prevalence of C3 finding was found. C2 finding was in highest proportion in the osteopenic group (p<0.05). Normal BMD group was associated with the C1 finding of 76.47%. Almost 48% of the osteoporotic group had a PMI score of <0.40, whereas 50% of osteopenic subjects had a PMI score of 0.4-0.44. Normal subjects having a PMI score of >0.44 constituted 49.1% of the population. Mean BMD scores decreased significantly with increasing MCI stage and increased significantly with increasing PMI (p<0.05). Significant correlations between PMI and MCI were obtained with DXA BMD. Digital OPGs may provide an economical and reliable diagnostic tool to rule out osteoporosis or osteopenia in undiagnosed patients, where DXA screening may not be available or is financially nonviable.