The Effect of Thyroid Hormone, Prostaglandin E2, and Calcium Gluconate on Orthodontic Tooth Movement and Root Resorption in Rats

Statement of the problem: a major objective of investigators is to clarify the role of metabolites in achievement of maximum tooth movement with minimal root damage during orthodontic tooth movement (otm). purpose: the aim of this study was to determine the effect of administration of thyroid hormone, prostaglandin e2, and calcium on orthodontic tooth movement and root resorption in rats.materials and method: sixty four male wistar rats were randomly divided into 8 groups of eight rats each: 1- 20µg/kg thyroxine was injected in traperitoneally after installation of the orthodontic appliance. 2- 0.1 ml of 1 mg/ml prostaglandin e2 was injected submucosally. 3- 10% (200 mg/kg) calcium gluconate was injected. 4- prostaglandin e2 was injected submucosally and 10% calcium was injected intraperitoneally. 5- thyroxine was injected intraperitoneally and prostaglandin e2 was injected submucosally. 6- 20µg/kg thyroxine with calcium was injected. 7- prostaglandin e2 was injected submucosally with calcium and thyroxine. 8- distilled water was used in control group. the orthodontic appliances comprised of a niti closed coil were posteriorly con-nected to the right first molar and anteriorly to the upper right incisor. otm was measured with a feeler gauge. the mid-mesial root of the first molar and the adjacent tissues were histologically evaluated. the data were analyzed by one-way anova and student-newman-keuls test.results: the highest mean otm was observed in the thyroxine and prostaglan-din e2 group (mean±sd = 0.7375±0.1359 mm) that was significantly different (p < 0.05). a significant difference (p < 0.05) in root resorption was observed be-tween the prostaglandin e2 (0.0192±0.0198 mm2) and the other groups.conclusion: it seems that the combination of thyroxine and prostaglandin e2, with a synergistic effect, would decrease the root resorption and increase the rate of orthodontic tooth movement in rats.