The goal of this study was to assess the effect of the intermittent combination of an antiresorptive agent (calcitonin) and an anabolic agent (vitamin D3) on treating the detrimental effects of Type 1 diabetes mellitus (DM) on mandibular bone formation and growth. Forty 3-week-old male Wistar rats were divided into four groups: the control group (normal rats), the control C1D group (normal rats injected with calcitonin and vitamin D3), the diabetic C1D group (diabetic rats injected with calcitonin and vitamin D3) and the diabetic group (uncontrolled diabetic rats). An experimental DM condition was induced in the male Wistar rats in the diabetic and diabetic C1D groups using a single dose of 60 mg?kg–1 body weight of streptozotocin. Calcitonin and vitamin D3 were simultaneously injected in the rats of the control C1D and diabetic C1D groups. All rats were killed after 4 weeks, and the right mandibles were evaluated by micro-computed tomography and histomorphometric analysis. Diabetic rats showed a significant deterioration in bone quality and bone formation (diabetic group). By contrast, with the injection of calcitonin and vitamin D3, both bone parameters and bone formation significantly improved (diabetic C1D group) (P < 0.05). These findings suggest that these two hormones might potentially improve various bone properties.