正畸力作用下大鼠炎性牙周组织牙槽骨改建的研究

目的：通过观察正畸力及炎症条件下大鼠牙槽骨高度的变化，研究正畸力和炎症对大鼠牙周组织改建的作用。方法：将60只sD大鼠随机分为加力对照组（P1组）和炎症对照组（P2组）各30只。施加50g近中向正畸力于P1组大鼠的左上第一磨牙；同时建立实验性牙周炎模型于P2组大鼠双侧上颌第一磨牙，2周后去除双侧牙周炎性刺激物，设右上第一磨牙为炎症对照组（P2组），并施加50g近中向正畸力于左上第一磨牙，为炎症加力组（P3组）。运用组织形态测量法观测各组大鼠上颌第一磨牙加力或去除炎症刺激物后各时点牙槽骨的吸收量。结果：P1组大鼠近中牙槽骨未见明显丧失，P2、P3组可见近远中牙槽骨的丧失，但当去除炎症刺激物后加力，P3组大鼠近中牙槽骨未见明显丧失。结论：只要彻底清除炎性刺激物正畸力不会导致牙槽骨的明显丧失。

The effect of orthodontic force on the inflammatory periodontal tissue and alveolar bone remodeling in rats

Objective To study the combined effect of orthodontic force and inflammation on the periodontal tissue remodeling by evaluating the change of alveolar bone of rats. Methods 60 SD rats were randomly divided into orthodontic tooth movement group （Pl）and periodontitis group （P2）. Fifty gram orthodontic force was loaded on the maxillary left first molars of rats in Pl.Meanwhile, experimental periodontitis was established to the other 30 rats.Inflammatory stimulus was removed after two weeks when the experimental periodontitis was established. We considered the maxillary right first molars as self-controlled periodontitis group （P2）and loaded 50 gram orthodontic force on the maxillary left first molars to be orthodontic tooth movement with periodontitis group （P3）. Histomorphometric analysis was performed to measure the loss of alveolar bone of 3 groups at different time after the application of orthodontic force. Results Obvious alveolar bone loss can be detected in P2 and P3 but not in the mesial side of P1.But after the inflammatory stimulus was removed, further alveolar bone loss can not be observed in the mesial side of P3. Conclusion Orthodontic force can not cause severe alveolar bone loss as long as the local inflammatory stimulus was eliminated.