微种植体支抗施力的时机与稳定性的关系

Stability and time of miniscrew used as orthodontic anchorage in dogs

目的:通过动物实验探讨微种植体支抗施力的时机与微种植体支抗稳定性的关系,为微种植体支抗在临床应用提供理论依据。方法:选择犬3只,设为未加力组、即刻加力组与非即刻加力组。全麻条件下将钛微种植体植入实验动物狗的双侧上颌尖牙、磨牙区与下颌磨牙区,所施力值0.2N。8周处死动物,X线拍片进行影像学评价;通过HE染色与GOMORI特殊染色方法进行组织学评价。结果:X线结果显示磨牙区植入的微种植体较尖牙区更多骨结合。HE染色显示实验8周时即刻加力组可观察到微种植体周围骨边缘整齐的成熟的层状骨,可见到大量成纤维细胞;非即刻加力组微种植体周围为高矿化的层状骨组织,可见较多的骨陷窝,内有骨细胞,钙化程度与旧骨组织接近。GOMORI特殊染色显示即刻加力组微种植体周围有较多未矿化结缔组织,非即刻加力组微种植体周围有明显矿化骨组织出现。结论:非即刻加力组较即刻加力组的微种植体有更多的骨性结合,可更好地提供稳定的正畸支抗。

Objective To evaluate the effects of different loading occasions of orthodontic force on the stability of miniscrew as an anchorage. Methods The titanium miniscrews were respectively implanted into canine and posterior region of both upper and lower jaws of 3 crossbred dogs. The implants were immediately loaded with 200 g orthodontic force or loaded after 2 weeks of implantation. The dogs were sacrificed after 8 weeks. The samples including the microserew implant and its around bone tissue were extracted, fixed and X-ray photographed. Then the specimens were decalcified, embedded, sectioned and stained with HE and GOMORI. The sections were examined under light microscope. Results The stability of miniscrew in posterior region of jaws was higher than that in canine region in X-ray photograph. There was more bone trabecular formation between miniscrew and jaw bone in non-immediately loaded group than those in immediately loaded group with HE and GOMORI. Conclusion The non-immediately loaded implant as an anchorage can afford more stability than the immediately loaded implant.