Bioactivity of Na ₂ O‐CaO‐SiO ₂ Glasses

Abstract

Bioactivities of Na 2 O‐CaO‐SiO 2 glasses were evaluated by examining the formation of bonelike apatite, which is responsible for their bonding to living bone, on their surfaces in a simulated body fluid, using thin‐film X‐ray diffraction and Fourier‐transform infrared reflection spectroscopy. It was found that glasses in a wide compositional region in the P 2 O 5 ‐free Na 2 O‐CaO‐SiO 2 system can show bioactivity, as those in the P 2 O 5 ‐containing system. The rate of apatite formation on the surfaces of glasses varied largely with the composition of the glasses. Under a constant SiO 2 content of 50 mol%, a glass containing equimole of Na 2 O and CaO showed the highest rate of the apatite formation. Variation in the rate of apatite formation with the glass composition corresponded well with the rate of increase in the degree of the supersaturation of the simulated body fluid with respect to the apatite due to dissolution of sodium and calcium ions from the glasses. Little difference was observed in the rates of ion dissolution and of apatite formation between P 2 O 5 ‐containing Bioglass 45S5‐type and a corresponding P 2 O 5 ‐free Na 2 O‐CaO‐SiO 2 glass. It is believed that P 2 O s ‐free Na 2 O‐CaO‐SiO 2 glasses also show bioactivity as high as that of Bioglass.

Keywords

Affiliated Institutions

• American Ceramic Society US
• Kyoto University JP
• Okayama University JP

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