The aim of this study was to evaluate the diagnostic efficacy of the cone beam computed tomography (CBCT) - based mandibular indices and the CBCT mandibular bone density values and to determine whether they correlate with bone mineral density (BMD) of the lumbar spine (L1 - L4) and proximal left femur in patients with osteoporosis and diabetes mellitus, which were taken a treatment with strontium ranelate over a period of 6 months. The study included 20 osteoporosis patients and 40 diabetic patients (16 patients � type 1 diabetes mellitus and 24 patients � type 2 diabetes mellitus). In CBCT images, the radiomorphometric indices were measured in the right and left mandibles. The relationship between the CBCT measurements of the mandible and skeletal BMD was assessed. The present study showed that mandibular bone quality is closely correlated with the skeletal status of the patients with osteoporosis and diabetes mellitus which were in treatment with strontium ranelate for bone improving.