Bioactive ceramics: State of the art.

Bioactive glasses undergo corrosion with leaching of alkaline ions when exposed to body fluids. This results in the spontaneous formation of a layer of hydroxyapatite (HA) the mineral component of natural bone, which in turn can induce bone growth in vivo. This paper describes the different types of bioactive glasses, the characterization methods currently used, and the main factors that influence their bioactivity. Nucleation and crystallization, the main mechanisms involved in the formation of hydroxyapatite, Ca-10(PO4)(6)(OH)(2,) are discussed as a function of the chemical composition and the reactivity of the surface of the material. Finally, promising applications are considered.