| abstract |
The present invention provides a method fornpreparing a glass-ceramic containing leucite crystals,ncomprising the steps of: mixing (1) a glassy materialncomprising 53 to 65 wt.% of SiO 2 , 13 to 23 wt.% of Al 2 O 3 ,n9 to 20 wt.% of K 2 O and 6 to 12 wt.% of Na 2 O and (2)nsynthetic leucite seed crystals comprising 53 to 64 wt.%nof SiO 2 , 19 to 27 wt.% of Al 2 O 3 and 17 to 25 wt.% of K 2 O,nand heat-treating the mixture at 750 to 950°C for 1 to 5nhours; and a dental porcelain powder and a metal-ceramicnrestoration both comprising a glass-ceramic prepared bynthe method. The porcelain comprising the glass-ceramicnprepared by the method is substantially free ofnopacification and decrease in the coefficient of thermalnexpansion, during fusion-bonding to a metal frame. |