Sintered apatite glass-ceramic and nanophase formation in glass-ceramics

The formation of fluorapatite in translucent glass-ceramics was studied in the SiO2-Li2O-K2O-ZnO-CaO-P2O5-F system by SEM and thermal analysis. Needle-like apatite represented the main crystal phase of the glass-ceramic. By means of the precipitation of fluorapatite crystals, optical properties similar to those of natural teeth were achieved. Therefore, the glass-ceramic was proposed as a biomaterial for restorative dental treatment. The apatite glass-ceramic is characterized by a flexural strength of 106 +/- 17 MPa (requirement according to dental ISO standards: 50 MPa), good chemical durability in 4% acetic acid, and a thermal expansion coefficient (100-400 degreesC) of 9.75 +/- 0.25 . 10(-6) K-1. Additionally, the material can be homogeneously sintered at 750 degreesC with low residual porosity. Nanophase formation was studied in apatite-containing glass-ceramics. The main goal of the investigation was to control the nucleation processes. Glassy nanophases and crystalline nanophases were developed in glass-ceramics for dental applications.