Surface Structure of Bioactive Ceramics

为了揭示影响陶瓷生物活性的因素，采用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，研究了三种生物活性玻璃、四种生物活性玻璃陶瓷和两种生物活性烧结陶瓷与两种非生物活性玻璃陶瓷的表面结构变化，并与模拟体液及其改性液体进行了比较。结果发现，所有被检测的生物活性陶瓷，包括玻璃，在模拟体液中表面形成一层薄薄的磷灰石，其成分和结构与天然骨磷灰石相似，其离子浓度几乎等于人类血浆中的离子浓度。而在非生物活性陶瓷上则没有形成这样的磷灰石层。因此，我们得出结论，陶瓷与活骨结合的必要条件是在人体环境中在其表面形成磷灰石层，并且通过模拟体液中检测表面磷灰石形成的体外实验可以预测陶瓷的生物活性。

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.