Patent ID: 6120591
Filing Date: 2000-09-19
Classification: A61K,C03C

Abstract:
A single frit porcelain composition for the manufacture of a dental porcelain, comprising:40-65% SiO.sub.2, 6-13% Al.sub.2 O.sub.3, 5.5-15% K.sub.2 O, and 6-12% Na.sub.2 O, 0.5-3% Li.sub.2 O, 0-4% B.sub.2 O.sub.3, 0-2% F, and 0.8-2.3 CaO by weight of the total composition, wherein the weight percent of (F+B.sub.2 O.sub.3 is in the range from 0.5-4.0, and wherein the porcelain comprisesa glassy matrix phase and a leucite crystallite phase, wherein the leucite phase comprises from about 5 to about 65% by weight of the total composition and the leucite crystallites have average diameters of less than about 7 microns; and further whereinthe porcelain has a maturing temperature in the range from about 600.degree. C. to about 885.degree. C. and a coefficient of thermal expansion in the range from about 11 to about 19.times.10.sup.-6 /.degree.C. (measured from 25.degree. C. to 500.degree. C.).