Effect of P105 on Crystallization Behavior and Chemical Resistance of Dental Glasses inthe Li10-Si01-Zr01System

Commercial dental lithium disilicate based glass-ceramics containing various amounts of P205 were synthesized. Regarding the crystallization behavior and physico-chemical properties of the glasses, the optimum percent of P205 was determined as 8 %wt. Crystallization behavior of the glasses was investigated by X-ray diffraction (XRD) fJ1Id differential thermal analysis (DTA). The micro-hardness and chemical resistance of both glass fJ1Id glass-ceramic searies were also determined. According to our results, lithium phosphate was precipitated prior to crystallization of the main phases, i.e lithium meta silicate and lithium disilicate. This earlyprecipitation led to evacuation of residual glass phase from lithium ions, which caused increasing the viscosity of glass fJ1Id so shifting of crystallization to higher temperatures. In addition, increasing in P205 amounts fJ1Id consequently increasing in Lijl'04 , led to significant decrease in the crystallite size and aspect ratio of crystals. Furthermore, while the chemical resistance of the glasses was decreased with P20,_ it was increased with P205 after heat treatment proces6. The chemical solubility of the glass-ceramica was between 2080 and 1188 pg!cm2.