Abstract:Objective:To study the feasibility and regulation mechanism of recombinant human parathyroid hormone(rhPTH) to promote orthodontic tooth movement after maxillary anterior osteotomy. Methods: Forty-eight rabbits were used to a model of anterior maxillary osteotomy and the orthodontical movement of right maxillary first molars. They were randomly divided into experimental group and control group. The group received subcutaneous injection of rhPTH 20 μg/kg or normal saline every other day. On the 5th, 7th, 14th, and 21th days, the animals were sacrificed respectively. Then the mesial movement distance of the right maxillary first molars was measured. The TRAP staining, immunohistochemistry and fluorescence quantitative PCR were performed on the proximal periodontal tissues of the moving tooth. Results: At the same stage, 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 counts of the experimental group was significantly larger than that of the control group (P<0.05). Through immunohistochemistry and fluorescence quantitative PCR Testing, In the mesial periodontal tissue of right maxillary first molars, the expression of Sclerostin (SOST) mRNA and protein in the experimental group was significantly higher than those in the control group (P<0.05), while the bone morphogenetic protein-2(BMP-2) mRNA and protein in the experimental group were lower than that of the control group (P<0.05). Conclusion: In the proximal pressure side of the orthodontic tooth after maxillary anterior osteotomy, subcutaneous injection of rhPTH may increase the alveolar bone remodeling to accelerate the movement speed of orthodontic tooth by up-regulating the expression of SOST and reducing the expression of BMP-2.
