骨质疏松状态下钛种植体周围骨形成的动态观察

Observation of dynamic peri-implant bone formation in status of osteoporosis

目的观察骨质疏松大鼠股骨干骺端钛种植体周围的骨形成过程。方法卵巢切除12周后,于大鼠股骨干骺端植入粗化处理的纯钛种植体。于6周和12周时取含钛种植体的股骨分别行组织学检测、扫描电镜分析和生物力学测试,并比较两个时间点内各项指标的差别。结果荧光标记显示钛种植体周围骨形成始于其邻近区域,并向外围生长,同时向内生长。向外生长的速度(0.91μm/d)大于向内生长的速度(0.75μm/d),差异有统计学意义(t=-2.27,P<0.05)。从6周到12周,骨-钛种植体接触率(BIC)增加,相对骨面积(BA)下降,差异均有统计学意义(t分别=-5.40、2.79,P均<0.05)。扫描电镜分析显示6周时钛种植体与周围骨在部分区域存在间隙,12周时这种间隙很少出现。生物力学测试发现12周时的推出力值明显大于6周时的力值,差异有统计学意义(t=9.07,P<0.05)。结论骨质疏松状态下钛种植体周围骨形成始于其邻近区域,而非钛种植体表面,随后向外和向内两个方向生长,向外生长的速度大于向内生长的速度。

Objective To investigate the peri-implant bone formation process of femoral metaphysis in the rats with osteoporosis. Methods Twelve weeks after bilateral ovariectomy,sandblasted and acid-etched titanium implants were longitudinally inserted into femoral metaphysis of ovariectomized（OVX） rats. After 6 weeks and 12 weeks,distal femora were retrieved and subjected to histological observation,scanning electron microscope（SEM） analysis and biomechanical test,and the indexes of two time points were compared. Results Fluorescence labeling revealed that peri-implant bone formation originated from the area adjacent to implants and grew towards outside and inside. The outside speed（0.91 μm per day） was significantly faster than the inside speed（0.75 μm per day）（t=-2.27,P〈0.05）. From 6 weeks to 12 weeks,the bone-to-implant contact（BIC） was increasing while bone area ratio（BA） was decreasing（t =-5.40,2.79,P〈0.05）.SEM showed that the gap was existed between implants and the surround bone after 6 weeks of implantation,but it was rarely to found in 12-week specimens. Biomechanical test showed that the maximum load was significantly higher in 12-week specimens than that in 6-week specimens（t=9.07,P〈0.05）. Conclusion Peri-implant bone formation originated from the adjacent areas of implants,but not from implant surface in osteoporotic femoral metaphysis. Then,it grew towards outside and inside,and the outside speed was faster than the inside speed.