Effect of vitamin D deficiency on postorthodontic relapse: An animal study

OBJECTIVES: This study aims to evaluate the effect of vitamin D deficiency (VDD) on orthodontic tooth movement (OTM), retention, and relapse and to assess the effect of systemic administration of vitamin D (VD) in a rat model. MATERIALS AND METHODS: A total of 32 male Wistar rats were divided into two groups, a control group of 11 rats and an experimental group of 21 rats with VDD, after enhancement using a custom diet. Of the VDD group, 11 rats were supplemented with systemic vitamin D3 and categorized as vitamin (VD supplement [VDS]) groups. The VDS group received 40,000 IU/kg via intramuscular injection on Days 1 and 15 of the orthodontic treatment period. A modified orthodontic appliance was fitted to apply 0.5 N of force to move the maxillary right first molars mesially for 14 days, followed by retention and relapse periods for 7 days. Space created during OTM was measured and reassessed after the retention and relapse periods. The relapse ratio was estimated, and histomorphometric analysis was performed to assess the number of osteoblasts, osteoclast bone cells, and bone area. RESULTS: A significant increase in the relapse ratio and a reduction in osteoblast cells and bone area were observed in the VDD group. By contrast, the amount of tooth movement was significantly higher together with osteoblast cells and bone marrow in VDS with a significant reduction in relapse ratio. CONCLUSION: VDD was associated with a significant reduction in osteoblast cell count and total bone area in addition to a significant increase in relapse ratio. Routine screening of VD may be beneficial before commencing orthodontic treatment.