| abstract |
The present invention provides a method for preparing a glass-ceramic containing leucite crystals, comprising the steps of: mixing (1) a glassy material comprising 53 to 65 wt. % of SiO2, 13 to 23 wt. % of Al2O3, 9 to 20 wt. % of K2O and 6 to 12 wt. % of Na2O and (2) synthetic leucite seed crystals comprising 53 to 64 wt. % of SiO2, 19 to 27 wt. % of Al2O3 and 17 to 25 wt. % of K20, and heat-treating the mixture at 750 to 950° C. for 1 to 5 hours; and a dental porcelain powder and a metal-ceramic restoration both comprising a glass-ceramic prepared by the method. The porcelain comprising the glass-ceramic prepared by the method is substantially free of opacification and decrease in the coefficient of thermal expansion, during fusion-bonding to a metal frame. |