Effect of Heat-Pressing on the Microstructure and Properties of a Novel Lithium Disilicate Glass-Ceramic

The purpose of this study was to investigate the effects of heat pressing on the microstructure and properties of a novel lithium disilicate glass-ceramic located in Li2O-SiO2-K2O-Al2O3-ZrO2-P2O5 system. Before and after respective heat pressing, the crystalline phase composition and microstructures were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Three-point flexural strength of glass-ceramic specimens was measured following the instruction of ISO 6872. The results showed that the bonding strength of the heat-pressed specimens was higher than that of the heat- treated controls. XRD examination showed the main crystallization in specimens after heat pressing was lithium disilicate as controls. SEM examination indicated crysta1s were aligned along the direction of pressing, and while in control groups crystals randomly interlocked. Dental heat pressing procedure leads to an anisotropic structure in lithium disilicate glass-ceramic, which is a useful method to improve the mechanical property. With the results under the present conditions, the novel lithium disilicate glass-ceramic may be considered as a promising candidate material for dental all-ceramic application.