Study of recombinant human parathyroid hormone to accelerate orthodontic tooth movement after anterior maxillary osteotomy

Abstract:

Objective：To study the feasibility and regulation mechanism of recombinant human parathyroid hormone（rhPTH） for pro－moting orthodontic tooth movement after the maxillary anterior osteotomy. Methods：Forty-eight rabbits were used to establish the model of anterior maxillary osteotomy and orthodontical movement of right maxillary first molars. They were randomly divided into the experimental group and the control group. The experimental group received subcutaneous injection of rhPTH 20 μg/kg，while the control group received the normal saline every other day. The mesial movement distance of the right maxillary first molars was measured on the 5th，7th，14th and 21th day. The mesio-periodontium of moving teeth were taken and tartrate resistant acid phosphatase（TRAP） staining of osteoclast count，immunohistochemistry and fluorescence quantitative polymerase chain reaction（qPCR） of sclerostin（SOST） and bone morphogenetic protein-2（BMP-2） were performed. Results：During the same period，the moving distance and speed of the first molars in the experimental group were faster than those in the control group（P<0.05）. In the mesial periodontal tissue of right maxillary first molars，the osteoclast count in the experimental group was significantly larger than that in the control group（P<0.05）. According to the immunohistochemistry and qPCR，the expression of SOST mRNA and protein of the mesial periodontal tissue of right maxillary first molars in the experimental group was significantly higher than that in the control group（P<0.05），while the expression of BMP-2 mRNA and protein in the experimental group was lower than that in the control group（P<0.05）. Conclusion：In the proximal pressure side of the orthodontic tooth after maxillary anterior osteotomy，subcutaneous injection of rhPTH on every other day may in－crease the alveolar bone remodeling to accelerate the movement speed of orthodontic tooth by upregulating the expression of SOST，downregulating the expression of BMP-2 and increasing the re－construction of alveolar bone.