减阻牵张快速移动牙齿对Beagle犬牙周组织超微结构影响的观察

The effect of rapid tooth movement by reducing resistance and distraction method on the ultrastructure of periodontal tissues in Beagle dogs

目的:观察减阻牵张快速移动牙齿时牙周组织超微结构的改变情况。方法:Beagle犬8只,随机分为加力5、15 d组和加力15 d固定保持10、45 d组共4组,拔除各犬双侧下颌第二前磨牙后,随机选取每只犬的一侧为实验组,用减阻牵张法远移第一前磨牙;另一侧为对照组,用常规方法远移第一前磨牙。按相应分组定期处死各组动物,制备牙周组织超薄切片,透射电镜观察。结果:加力5 d时,实验组牙周组织改建明显,张力侧成骨细胞、成纤维细胞分泌功能旺盛;压力侧破骨细胞、间充质细胞、巨噬细胞增多,线粒体、溶酶体等细胞器发达;加力15 d时实验组移动牙张力侧成骨细胞体积较对照组明显增大,呈长梭形,细胞核位于牵张力方向相反的一侧,胞质基本上由粗面内质网占据;加力15 d后,随固定保持时间的延长,两组牙周组织超微结构的差异逐渐变小。结论:减阻牵张技术更能激发牙周组织细胞的分泌功能,牙周组织改建更活跃。

AIM：To observe the ultrastructural changes of periodontal tissues during rapid tooth movement by reducing resistance and distracting method.METHODS：8 Beagle dogs were randomly divided into 4 groups（n =2） as follows：5-day and 15-day distraction proups,15-day distraction and 10-day retaining group,15-day distraction and 45-day retaining group.The second mandibular premolars of the dogs were extracted on both sides.One side was randomly selected as experimental group and the other side as the control.The first premolar on the experimental side was distalized with reducing resistance and distracting method,while the control side was distalized with conventional method.Animals in each group were killed accordingly,periodontal tissue samples were prepared regularly and observed by transmission electron microscope.RESULTS：In experimental group the remodeling of the periodontal tissues was more active and the function of osteoblasts and fibroblasts was more active on the tension side when distracted for 5 days.The osteoclasts,mesenchymal cells and macrophages increased on the pressure side,in the cells mitochondria,lysosomes and other organelles developed well.The volume of osteoblasts on experimental tension side was increased obviously ompared with that on control tension side at the end of 15-day distraction.The osteoblasts were conical and the nucleus were located on the side opposite to the direction of the retractor tension.The cytoplasm was basically composed of rough endoplasmic reticulum.With the rentention time increase,the difference between experimental and control groups decreased gradually.CONCLUSION：Reducing resistance and distracting method can further stimulate the secretion of periodontal tissue cells and tissue remodeling.