2018 年 17 巻 1 号 p. 18-26
Objectives: Relapse is a major clinical problem in orthodontic treatment, and long-term observation of treated cases often reveals relapse. Collagen metabolism in the periodontal ligament(PDL)is thought to be involved in relapse. Daidzein stimulates skin collagen synthesis in cultured skin fibroblasts in vitro. We investigated the inhibitory effects of daidzein on relapse after orthodontic tooth movement. Methods: After a force of 10 g induced tooth movement for 14 days, the appliance was removed, and the experimental group was injected with daidzein while the control group was injected with phosphatebuffered saline for 1 week. The distance of relapse was measured by micro-computed tomography. In addition, hematoxylin and eosin staining and the histopathological features were examined by immunohistochemistry using collagen type I (COL-I), matrix metalloproteinase(MMP)1, and proliferating cell nuclear antigen(PCNA). Results: The distances and ratio of relapse in the daidzein group were significantly lower than in the control group. Immunohistochemistry showed marked positive staining of COL-I and MMP1 in the daidzein group. The ratio of PCNA-positive cells in the daidzein group increased at day 7. Conclusion: These results indicated that daidzein activated the collagen metabolism in the stretched PDL and may inhibit relapse after orthodontic treatment.
