Studies on bone mineral density and fracture risk in diabetic patients have attracted interest in the last few years. This study was aimed at comparing mandibular osteoporotic changes assessed by qualitative and quantitative radiographic methods in the mandibles of type 2 diabetes mellitus patients with those of non-diabetic subjects using cone beam computed tomographic images. This quantitative and qualitative study of mandibular bone in diabetic patients included 23 type 2 diabetes mellitus patients and an equal number of healthy subjects. Radiomorphometric measurements were performed for each subject using cone beam computed tomography images. Changes in cortical bone thickness were determined by measuring bone area. Fractal dimension analysis was applied to evaluate the trabecular structure of the bone. No statistically significant difference could be established between the type 2 diabetes mellitus group and the control group in regard to either radiomorphometric measurements or fractal dimension analysis. Quantitative assessment of mandibular bone indicated a thinning of the cortical bone, with a statistically significant difference between the type 2 diabetes mellitus patients and the healthy controls. Bone condition related to diabetes involves complex pathophysiological mechanisms; thus, radiographic imaging parameters may be useful as an adjunct to clinical parameters.