Characterization of New Categories of Bioactive Based Tellurite and Silicate Glasses

Abstract

New types of tellurite glass ceramics were prepared and studied from the viewpoint of bioactivity. The obtained results were compared with those of silicate glass ceramics. The crystallization behaviors of both silicate and tellurite glass ceramics with equal ratio of CaO/P2O5 were investigated. The silicate glass samples were transformed to glass ceramics by a thermal treatment process. While the tellurite glass ceramics were directly obtained without any thermal treatment. The microstructure of these materials was characterized by X-ray diffraction (XRD), Fourier transform infrared absorption spectroscopy (FTIR) and a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (SEM/EDX). The results revealed clear proof that TeO2 promoted the nucleation and crystallization processes which led to the formation of different crystalline bio-phases. While the silicate glasses showed a much lower degree of crystallinity than that presented by the tellurite glass ceramics. The crystals of tellurite containing glass were needle- like morphology, which is attributed to the one-dimensional rapid growth of the apatite-tellurite phase. On the other hand, a particle-like morphology is shown in the silicate glass matrix. Bioactivity of the glasses in simulated body fluids (SBF) was investigated. Tellurite containing glass ceramics showed a better bioactivity during the in vitro test than that of the silicate one. This was attributed to a great analogous between the morphology of crystals of tellurite glass and the morphology of hydroxyapatite in human bone, since both possess a needle-like morphology.