成年和青少年Beagle犬下颌骨植入微型支抗种植体的组织学比较研究

Histological Study of Miniscrew Implanted in Lower Mandibles of Juvenile and Adult Beagle Dogs

目的探讨成年和青少年Beagle犬下颌骨植入的微种植体不同愈合时间的组织学差异,为青少年患者应用微植体支抗提供指导。方法6只成年Beagle犬和6只青少年Beagle犬,选择下颌第四前磨牙(P4)和第一磨牙(M1)牙根间间隙,M1近远中牙根间间隙为植入部位,共植入48颗微种植体。愈合3周和12周后,对含微种植体的标本进行组织学检查,并进行骨整合率计算。结果微种植体在观察期无松动、脱落。微种植体与周围组织有良好的生物相容性,周围骨组织中破骨细胞和成骨细胞的功能活跃,骨整合率随着愈合时间的延长而增高。青少年Beagle犬微种植体-骨整合率术后3周低于成年Beagle犬的微种植体-骨整合率;但术后12周却高于成年Beagle犬的微种植体-骨整合率。结论青少年Beagle犬的骨质量低,但生长发育快,经过12周愈合,能弥补青少年Beagle犬早期骨结合率的不足。

Objective To examine the histological discrepancies between juvenile and adult Beagle dogs at different concrescence times after miniscrew implants. Methods Miniscrew implants were performed in six juvenile Beagle dogs and six adult Beagle dogs. The space between the fourth premolar root and first molar root, and the spaces in distal and mesial of M1 root were picked up for the implants of the 48 miniscrews. The lower jaw specimens including the miniscrews were harvested 3 and 12 weeks after the implants for the histological examinations and bone implant contact （BIC） calculations. Results There was no miniscrew falling off or becoming loose. The miniscrews had favorable biological consistencies with the tissues around them. The osteoblasts and osteoclasts showed active functions in the peri-bones of the minisrews. The BIC became higher when the healing time was prolonged. The juvenile Beagle dogs had lower BIC than the adults 3 weeks after the implants. But the BIC of the juvenile dogs surpassed the adults 12 weeks after the implants. Conclusion The osseointegration of the miniscrews is hindered by the poorer bone quality of the juvenile Beagle dogs. But the early osseointegration deficiency can be made up by the rapid development and growth of the bones of the juvenile dogs.