Three Dimensional examination of Bone-Implant interface using various implant materials

必须充分了解骨-种植体界面。关于这一点已经有很多研究报道。然而，由于这些研究是基于有限数量的组织学切片，因此尚不清楚。关于种植体周围的三维骨结构的信息很少。因此，我们开发了一种新的计算机辅助系统，用于种植体周围的三维骨结构。该系统不仅可以显示种植体周围骨的三维视图，还可以显示种植体周围的骨接触率和骨体积率。采用该系统比较了致密羟基磷灰石种植体、市售纯钛种植体和钙混合钛种植体3种种植体的骨反应。植入物植入雄性新西兰大白兔胫骨。兔于植入后2、4、6、8周处死。取下的标本在个人电脑上重建。重建三维模型，测量骨-种植体界面的接触率和种植体周围的骨体积率。结果如下。1)羟基磷灰石种植体的接触率在4周上升到56%，8周下降到39%，钛种植体的接触率从2周的42%逐渐上升到8周的60%。2)羟基磷灰石种植体在种植后2周和4周的接触率高于钛种植体，6周和8周时接触率下降。3)混合钛钙种植体的接触率和骨体积率介于羟基磷灰石种植体和钛种植体之间。

Bone-implant interface must be fully understood. Numerous studies about that have been reported. However, that remains unclear since the studies were based on limited numbers of histological sections. There is little information on the three dimensional bone structure around the implant. Therefore, we developed a new computer-aided system for the three dimensional bone structure around the implant. This system could present not only three dimensional view of bone around the implant, but also bone contact rate and bone volume rate around the implant. Using this system, Bone reactions of three types of implants, dense hydroxyapatite implant, commercially pure titanium implant and calcium mixed titanium implant, were compared. There implants were inserted in the tibiae of male New Zealand white rabbits. Rabbits were sacrificed on 2,4,6 and 8 weeks after implant placement. Removed specimens were reconstructed on the personal computer. From reconstructed 3D model, contact rates at bone-implant interface and bone volume rate around the implant were measured. The results were folllowings. :1) The contact rate of hydroxyaapatite implant increased up to 56% in 4 weeks after and then decreased to 39% in 8 weeks, whereas that of titanium implant increased gradually from 42% in 2 weeks to 60% in 8 weeks.2) The contact rate of hydroxyapatite implant in 2 and 4 weeks after implantation was higher than that of titanium implant, and then declined in the 6 and 8 weeks.3) In calcium mixed titanium, both the contact rate and the bone volume rate were intermediate between those in hydroxyapatite and titanium implant.