Osteoporosis is common in the elderly and the dentist is often the only healthcare professional that they visit regularly. Since dental panoramic radiographs (DPRs) are widely used for routine examinations when planning treatment, this study evaluated whether the presence of osteoporosis might be apparent in a population of patients who underwent DPR. The mandibular cortical index (MCI) and a new method of measuring the mandibular radiographic density (m-RD), which used DPR that incorporated an aluminium step-wedge, were compared with the total vertebral bone mineral density (v-BMD) of the lumbar vertebrae measured using dual energy X-ray absorptiometry (DXA) in 25 osteoporotic women. Although there was only a weak correlation between m-RD and v-BMD, significant correlation was found between MCI and v-BMD. Since both m-RD and MCI were related to v-BMD, dental radiographic density and MCI may be useful in clinical dental practice to identify osteoporotic women with previously undetected low BMD.