Abstract: Abstract：　Objective　To investigate that necroptosis has effects on distance and receptor activator of nuclear factor-κB ligand(RANKL), osteoprotegerin(OPG) expression changes in periodontal tissues during tooth movement in rats. Methods　The orthodontic model of maxillary tooth movement was established in rats, and according to the use of necroptosis inhibitor Necrostatin-1 (Nec-1), the rats were randomly divided into control group (group A), inhibitor group (group B), activation group (group C) and activation + inhibitor group (group D). The forward movement distance of the maxillary left first molar was measured with the vernier caliper, the hyalinization was observed by HE staining on the pressure side, the expression of RANKL and OPG in the periodontal tissue of the pressure side was detected by immunohistochemistry on the 1st, 3rd, 7th, 10th and 14th day. Results　In the group A and group B, the distances of teeth movement and the area of hyalinization did not change appeared, the expression of RANKL and OPG was less. In the group C and group D, the distances of tooth movement change appeared, there was significant difference between the two groups on the 3rd, 7th, 10th and 14th day(P<0.05); Moreover, the expression of RANKL reached the peak at 7 days, the large areas of hyalinization change appeared at the same time, and the expression of OPG reached the peak at 10 days in group C; The expression trend of RANKL and OPG in the group D was the same as that in the group C, but the expression level in group D was less than that in the group C on the 7th and 10th day, and the range of hyalinization change appeared on the 10th day. Conclusion　Necroptosis can promote tooth movement during orthodontic tooth movement. Nec-1 reduced the expression of RANKL and OPG, inhibited the differentiation and maturation of osteoclasts and hindered tooth movement.

Key words: Key words: tooth movement, hyalinization, necroptosis, Necrostatin-1