植入不同皮质骨厚度区域微种植体骨整合的组织形态学和生物力学研究

Histomorphometric and biomechanical analyses of the osseointegration of loaded orthodontic microscrews inserted at different cortical bone thickness sites

目的:研究植入不同皮质骨厚度(CBT)区域应力加载下正畸微种植体的骨整合。方法:将48枚微种植体植入12只Beagle犬两侧胫骨,并分为厚和薄CBT组(n=24)。1、3、5、7周后,处死动物,制备骨-微种植体标本用于多重荧光序列标记、显微CT和生物力学拉拔测试。结果:随时间延长,薄CBT组所有显微CT指标均增加,厚CBT组降低。厚CBT组微种植体F max第1周达顶峰,第3周降至谷底。薄CBT组骨重塑、骨沉积和3种荧光标记的沉积面积均显著高于厚CBT组(P<0.05)。结论:较大CBT在早期更有利于获得初期稳定性,而较小CBT更易在之后愈合中达到更高长期稳定性。

Objective:To evaluate the osseointegration of loaded orthodontic microscrews inserted at various sites with different cortical bone thickness(CBT).Methods:48 microscrews were inserted bilaterally in tibias of 12 beagles,and were divided into thick and thin CBT groups(n=24)according to the insertion sites.1,3,5 and 7 weeks after implantation,the dogs were killed and bone-screw specimens were prepared for polyfluorochrome sequential labeling,Micro-CT analysis and biomechanical pull-out test.Results:All Micro-CT parameters were increased in thin CBT group,and decreased in thick CBT group with time prolonged.F max in thick CBT sites reached the peak in week 1,but dropped to the lowest level in week 3.Remodeling,apposition,and measured deposition areas of 3 labels in thin CBT group were higher than those of thick CBT group(P<0.05).Conclusion:Relatively larger CBT is favorable for primary stability at early time,whereas thinner CBT is more appropriate for achieving long-term stability with prolonged time.