Effect of parathyroid hormone on experimental tooth movement in rats.

INTRODUCTION The aim of this study was to investigate the effect of parathyroid hormone injection on experimental tooth movement in rats. METHODS Sixty male Wistar rats were randomly divided into 2 groups. Their maxillary right first molars were moved mesially with nickel-titanium closed-coil springs. The experimental group received daily subcutaneous injections of parathyroid hormone at a dose of 4 μg per 100 g of body weight for 12 days, and the control group received vehicle injections. The results were evaluated by intraoral measurements and by hematoxylin and eosin, tartrate-resistant acid phosphatase, and immunohistochemistry staining. RESULTS The tooth movement and osteoclast numbers were significantly increased in the parathyroid hormone group compared with the control group. The expressions of receptor activator of nuclear factor kappa B ligand and insulin-like growth factor-I were significantly stimulated in the parathyroid hormone group. CONCLUSIONS The data suggest that short-term parathyroid hormone injection might be a potential method for accelerating orthodontic tooth movement by increasing the alveolar bone turnover rate.