The Evaluation Of The Orthodontic Tooth Movement For The Rats And The Expression Of RANKL, OPG During Root Resorption Influenced By Alendronate Of Different Concentration

Object:To study the effects of lavage of different concentrations of alendronate(ALN) for the rats on orthodontic tooth movement by establishing root resorption model of rats. Dose-effect and time-effect between ALN and root Resorption was discussed by detecting expression of receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin(OPG) of peridentium of the test samples to provide experimental evidence for clinical application.Methods:24 healthy male SD rats were divided into five groups by the rats sacrificed time(4 in the 0d,3d,7d,lld group,while8 in the 14d group) to build root resorption model. The orthodontic loading device was installed in rat's maxillary between the incisor (as the anchorage teeth, and the anchorage loss was ignored) and first molar of one side randomly and fixed by bonder and retention groove. The loading side was applied 60g force and the other side as control, adjusted force once a week, measured the distance of maxillary first molar mesial movement on 0d,3d,7d,11d,14d through gastric lavage with Alendronate of 0mg/kg,2mg/kg,5mg/kg, 10mg/kg every other day from the Od, then obtained the samples of periodontium experimental teeth by sacrificing the rats, evaluated the degree of root resorption by the changes of RANKL and OPG through PCR.Results:1.The osteoclasts was expressed on the pathological section from the 7th day after installing the loading device on the maxillary of the SD rats, which implied that root resorption began.2.There was no statistical difference (P> 0.05) of the distance of experiment maxillary first molar mesial movement in the group of Omg/kg and 2mg/kg, compared with them, the distance in the group of 5mg/kg on 11d,14d and the group of 1 Omg/kg on 7d, 11d,14d was smaller, and had great statistically significant difference (P≤0.01).3.There were no obvious changes of the expression of OPG and RANKL on the day of 0,3,7day. The expression of the OPG increased from the 11d and was proportional to the concentration of Alendronate, while the expression of the RANKL was in inverse proportion to the concentration of ALN.Conclusion:1.Alendronate of high concentration can inhibit the tooth movement in the orthodontic treatment long term.2. Root resorption caused by mechanical force can be inhibited effectively by gastric lavage with Alendronate of high concentration long term.