Ohtsuki C, Kushitani H, Kokubo T, Kotani S, Yamamuro T
Institute for Chemical Research, Kyoto University, Japan.
J Biomed Mater Res. 1991 Nov;25(11):1363-70. doi: 10.1002/jbm.820251105.
Previous studies on surface structural changes in vitro as well as in vivo of bioactive A-W-type glass-ceramics and Bio-glass-type glasses showed that the essential condition for glasses and glass-ceramics to bond to living bone is formation of a bonelike apatite layer on their surfaces in the body. Gross et al., however, had explained the bone-bonding mechanism of Ceravital-type apatite-containing glass-ceramic without mentioning formation of the surface apatite layer. In the present study, apatite formation on the surface of one of Ceravital-type glass-ceramics was investigated in vitro as well as in vivo. An apatite-containing glass-ceramic of the composition Na2O 5, CaO 33, SiO2 46, Ca(PO3)2 16 wt%, which was named KGS by Gross et al., was soaked in an acellular simulated body fluid which had ion concentrations almost equal to those of the human blood plasma. The same kind of glass-ceramic was implanted into a rabbit tibia. Thin-film x-ray diffraction, Fourier transform infrared reflection spectroscopy, and scanning electron microscopic observation of the surfaces of the specimens soaked in the simulated body fluid showed that Ceravital-type glass-ceramic also forms a layer of carbonate-containing hydroxyapatite of small crystallites and/or a defective structure on its surface in the fluid. Electron probe x-ray microanalysis of the interface between the glass-ceramic and the surrounding bone showed that a thin layer rich in Ca and P is present at the interface. These findings indicated that Ceravital-type glass-ceramics also form the bonelike apatite layer on its surface in the body and bond to living bone through the apatite layer.
以往关于生物活性A-W型微晶玻璃和生物玻璃型玻璃在体外及体内表面结构变化的研究表明，玻璃及微晶玻璃与活骨结合的必要条件是在其体内表面形成类骨磷灰石层。然而，格罗斯等人在解释含磷灰石的Ceravital型微晶玻璃的骨结合机制时，并未提及表面磷灰石层的形成。在本研究中，对一种Ceravital型微晶玻璃的表面磷灰石形成进行了体外及体内研究。将一种成分（Na2O 5、CaO 33、SiO2 46、Ca(PO3)2 16 wt%）的含磷灰石微晶玻璃（格罗斯等人将其命名为KGS）浸泡在离子浓度几乎与人体血浆相同的无细胞模拟体液中。将同类型的微晶玻璃植入兔胫骨。对浸泡在模拟体液中的试样表面进行薄膜X射线衍射、傅里叶变换红外反射光谱和扫描电子显微镜观察，结果表明，Ceravital型微晶玻璃在流体中其表面也形成了一层由小晶粒组成的含碳酸羟基磷灰石层和/或有缺陷的结构。对微晶玻璃与周围骨之间的界面进行电子探针X射线微分析表明，在界面处存在一层富含钙和磷的薄层。这些发现表明，Ceravital型微晶玻璃在体内其表面也形成类骨磷灰石层，并通过磷灰石层与活骨结合。
