The related study of the effect of different orthodontic force on the rebuilding of periodontal tissue in rats

CHANG Yue; ZHANG Xiao-ping; WANG Ming-jie; Wang Yue; CUI Shu-xia

doi:10.15956/j.cnki.chin.j.conserv.dent.2015.09.004

Abstract：AIM:To investigate the effect of different orthodontic force on BMP-2 expression in the tension side of periodontal tissues of rat during orthodontic tooth movement. METHODS:60 healthy rats were randomly divided into 4 groups (n=15) and were subjected to different orthodontic forces:group A (0 g), group B (30 g), group C (50 g) and group D (80 g). The distance of orthodontic tooth movement was determined after adding the forces for 1, 3, 7, 14 and 21 d, respectively. Then the rats were executed and the periodontal tissue of the maxiallary first molars were ob-served by HE staining. The expression of BMP-2 in periodontal tissue in the tension side was determined by immunohis-tochemical method. RESULTS:The distances of orthodontic tooth movement were as in following order:group C>B>D>A. HE staining r showed that there were no significant changes in the periodontal tissue in group A. The periodontal tissue rebuilt in groups B and C was active and osteoblasts were more in the tension side of the periodontal tissue. While in group D, periodontal ligament fibers were in disorder and root resorption was observed . Immunohistochemical staining showed that BMP-2 was mainly distributed in periodontal ligament, especially in alveolar bone and cementum region, With the increase of orthodontic force, the expression of BMP-2 increased (P ﹤0. 05). No statistically significant difference was observed between group C and group D. CONCLUSION:The expression of BMP-2 is highly related with the orthodontic force strength. 50 g orthodontic force can promote periodontal tissue remodeling.