Surface Structure of Bioactive Ceramics

为了揭示陶瓷生物活性的影响因素，通过傅里叶变换红外反射光谱、薄膜X射线衍射和扫描电镜观察，研究了3种生物活性玻璃、4种生物活性玻璃陶瓷和2种生物活性烧结陶瓷在模拟体液及其改性流体中的表面结构变化，并与两种非生物活性玻璃陶瓷进行了比较。在模拟体液中，玻璃在其表面形成一层与天然骨磷灰石成分和结构相似的磷灰石薄层，其离子浓度几乎与人体血浆中的离子浓度相同。然而，这种磷灰石层并未形成在非生物活性陶瓷上。因此，得出结论，陶瓷与活体骨结合的必要条件是在身体环境中在其表面形成磷灰石层，并且陶瓷的生物活性可以通过在模拟体液中检查表面磷灰石形成的体外实验来预测。

In order to reveal factors governing bioactivity of ceramics, surface structural changes due to exposure to a simulated body fluid and its modified fluids were investigated for three kinds of bioactive glasses, four of bioactive galss-ceramics and two of bioactive sintered ceramics, in comparison with two kinds of non-bioactive glass-ceramics, by means of Fourier transform infrared reflection spectroscopy, thin-film X-ray diffraction and scanning electronmicroscopic observation.As a result, it was found that all the examined bioactive ceramics including glasses formed a thin layer a apatite similar to the natural bone apatite in its composition and structure on their surfaces in a simulated body fluid, ion concentrations of which were almost equal to those of the human blood plasma. Such apatite layer was, however, not formed on the non-bioactive ceramics. Therefore, it was concluded that essential condition for a ceramic to bond to living bone is to form an apatite layer on its surface in a body environment and that bioactivity of a ceramic is predictable from in vitro experiment in which apatite formation on the surface is examined in the simulated body fluid.