伊班膦酸钠对正畸源性牙根吸收面积的影响

目的:通过牙齿移动距离的差异、牙周组织中破牙骨质细胞数量的变化及牙根吸收面积的差异,研究伊班膦酸钠对大鼠正畸源性牙根吸收的作用。方法:48只SPF级雌性Wistar大鼠,建立正畸牙齿移动动物模型,设置自身对照,对照侧为对侧未注药侧。在大鼠上颌双侧第一磨牙与上切牙之间安置一0.012英寸镍钛拉簧,施力60 g左右,所有大鼠均于安装矫治器前3 d在实验侧(大鼠上颌左侧)移动牙齿近中腭侧黏骨膜下局部注射50μL伊班膦酸钠,对照侧(大鼠上颌右侧)注射50μL 0.9%氯化钠液。每3 d注射一次直至实验结束。实验第3、7、14 d随机选择8只大鼠处死。分离大鼠头颅骨,用游标卡尺(精确度0.02 mm)测量上颌双侧第一磨牙移动的距离,并制备大鼠第一磨牙及其牙周组织切片,HE染色观察两侧牙周组织形态学变化,观察破牙骨质细胞的数量,采用图像处理软件对两侧的牙根吸收指数进行分析。结果:①牙齿移动距离随实验时间延长逐渐增加,组间比较:实验第3 d,实验侧和对照侧的牙齿移动距离平均值差异无统计学意义;实验第7 d和14 d,实验侧的牙齿移动距离均小于对照侧,差异具有统计学意义(P<0.05)。②实验侧第3 d、7 d和14 d大鼠第一磨牙牙周组织压力侧破牙骨质细胞数量均小于对照侧,且第7 d和14 d结果差异具有统计学意义(P<0.05)。③实验侧第3 d、7 d和14 d大鼠牙根吸收指数均小于对照侧,牙根吸收程度均比对照侧轻,且第7 d和14 d结果差异具有统计学意义(P<0.05)。结论:局部应用伊班膦酸钠可以减缓正畸牙齿移动的速度,减少牙周组织压力侧破牙骨质细胞的数量,减少正畸源性牙根吸收的发生。

Effects of ibandronate on orthodontic root resorption.

Objective： To investigate the influence of Ibandronate on orthodontic tooth resorption in rats through ob serving the differences of tooth movement distances,the histology changes, cementoclasts in periodontal tissues and root re sorption area. Method： A total of 48 SPF female Wistar rats were chosen in this study. Then the animal model for orthodontic tooth movement of rats was established. 50 μL Ibandronate solution （500 μmol / L） was injected into the subperiosteum area adjacent to the left upper first molar （the experimental side） every three days during the experiment, the right maxillary first molar was served as a control （the control side） with an injection of 50 μL 0.9 % NaC1 solution into the corresponding area at the same time interval. The administration of Ibandronate solution was started three days before the set of appliances. Then the nickeltitanium （NiTi） closed coil springs initially generating an average force of 60 g were inserted in each rat＇s mouth between the bilateral upper first molar and incisor. After applying orthodontic force 3 days,7 days and 14 days, 8 rats were chosen randomly for histology observation of periodontal tissues in each period. The former rats were killed, and then their upper jaws were dissected, the amount of upper first molar movement were measured with vernier caliper （with the ac curacy of 0.02 mm）, in addition, the slices of upper first molar and adjacent periodontal tissues were prepared and were used for observing bilateral periodontal tissue morphological changes, the amount of cementoclasts after staining with HE, the root resorption indexes on both sides were analyzed with the image processing software. Result： 1.The distances of tooth move ment increased gradually as the continuation of experiment, on day 7 and day 14, tooth movement on the experimental side was significantly less than that on the control side, with statistically value （P 〈0.05）.2.HE staining showed that on day 7 and day 14, the number of cementoclasts on the experimental side was significantly less than on the control side （P 〈0.05）. 3.On day 3,7 and 14, the root resorption index were all smaller on the experimental side than that on the control side, with sig nificant differences between two sides on day 7 and 14 （P 〈0.05）. Conclusion： This study demonstrates that the local ad ministration of Ibandronate inhibits orthodontic tooth movement, reduces the number of osteoclasts in the pressure side of pe riodontal tissues, inhibits orthodontic root resorption.