Effects of vitamin D deficiency on bone and root resorption post-orthodontic retention in rats

Abstract

Background: Orthodontic therapy often causes external root resorption. Serum vitamin D (VD) level is important for tooth mineralization and bone remodeling. This study aimed to test the impact of vitamin D (VD) supplements on bone and root remodeling in a vitamin D (VD) deficient rat model following orthodontic retention. Methods and Material: 30 male Wistar rats were divided into three groups: a control group of 10 rats and two experimental groups of 10 rats, each with vitamin D deficiency (VDD) induced by a VD-free diet for 21 days. And a third group with VD supplement. All groups received active orthodontic treatment using a modified orthodontic appliance that applied 50 gm of force for 14 days to move the maxillary right first molar mesially, followed by seven days of retention and relapse. The VDD group received no intervention, while the VDS group received 40,000 IU/kg of systemic VD3 by intramuscular injection on the first and fifteenth day of orthodontic treatment. Histomorphometric analysis was performed to assess bone and cementum resorption and deposition. Results: The VDD group exhibited a significant increase in bone and root resorption and decreased bone deposition and cementum deposition ratio. In addition, bone deposition and the ratio of cementum deposition were substantially greater in the VDS group compared to the control group. Conclusion: VDD may increase bone and root cementum resorption and decrease deposition after orthodontic retention, which may play a significant role in relapse after retention. Before beginning orthodontic treatment, routine VD screening may be beneficial.