Compositional dependence of formation of an apatite layer on glass-ceramics in simulated physiological solution

Abstract

In simulated physiological solution, an apatite layer is formed on the surface of apatite-containing glass-ceramics having the ability to bond to living bone. In this study, the influence of composition in the system CaO-P₂O₅-SiO₂-MgO, Al₂O₃ on apatite layer formation is investigated. On CaO-P₂O₅-SiO₂ glass-ceramics, an apatite layer was formed rapidly in simulated physiological solution. However, a solution containing an excess of Mg²⁺ prevented apatite layer formation. On glass-ceramics containing MgO, the amount of apatite formed on the surface decreased. An apatite layer was not formed on glass-ceramics containing Al₂O₃. The prevention of apatite layer formation on glass-ceramics containing MgO is attributed to an increase of Mg²⁺ concentration in the solution. It is thought that glass-ceramics containing Al₂O₃ form are Al₂O₃-rich layer, and that this layer prevents the formation of an apatite layer.