骨皮质切开术对比格犬前磨牙压入移动影响的三维形态学研究

目的 评估骨皮质切开术辅助前磨牙压低的加速效应和牙根、牙槽骨改建情况。方法 8只比格犬的下颌骨两侧随机分为实验侧、对照侧，实验侧用骨皮质切开术和微种植体支抗（MIA）压低第三前磨牙（P3）和第四前磨牙（P4），对照侧用MIA压低P3和P4。在术前和加力后2、4、8、12周分别拍摄锥形束CT，分析P3、P4的压低量、根分叉和根尖区的牙根吸收量以及周围牙槽骨高度降低量。结果 实验侧牙齿的压低量明显大于对照侧（P<0.05）；实验侧和对照侧牙齿根分叉、根尖区的牙根均出现吸收，加力后12周实验侧根尖区牙根吸收小于对照侧（P<0.05）；牙槽骨高度随着加力时间的延长而降低，加力后8、12周时，对照侧牙槽骨高度降低量明显小于实验侧（P<0.05）。结论 骨皮质切开术能加速磨牙的压低，同时能减少压低过程中的牙根吸收。

Three-dimensional morphological analysis of corticotomy-assisted intrusion of premolars in Beagle dogs

Objective This study aims to identify the effects of corticotomy-assisted orthodontic premolar intrusion and evaluate the changes of root resorption and the alveolar bone. Methods Both sides of the mandible of eight male Beagle dogs were randomly assigned into experimental and control groups. The third (P3) and fourth (P4) premolars were intruded with both mini-screw implant anchorage (MIA) and corticotomy on the experimental side. By contrast, P3 and P4 were intruded with MIA alone on the control side. During pre-operation and after 2, 4, 8, and 12 weeks of orthodontic force applications, cone beam computed tomography was performed on every dog. The distance of tooth intrusion and root resorption of furcation, as well as the apex and height changes of the alveolar bone were measured and analyzed. Results The intrusion distance of premolars on the experimental side was greater than that on the control side (P<0.05). The root of furcation and apex on both sides occurred in root resorption, and the root resorption of the apex on the experimental side was lighter than that on the control side after 12 weeks of force application (P<0.05). The alveolar bone height decreased, and the height reduction distance on the experimental side was greater than that on the control side after 8 and 12 weeks of force application (P<0.05). Conclusion Corticotomy accelerates orthodontic molar intrusion and reduces root resorption.