Patent ID: 6155830
Filing Date: 2000-12-05
Classification: A61K,C03C

Abstract:
A dental restoration comprising:a dental porcelain powder from a dental composition comprising 40-65% SiO.sub.2, 6-12% Al.sub.2 O.sub.3, 5-15% K.sub.2 O, and 6-12% Na.sub.2 O, 0-3% Li.sub.2 O, 0-4% B.sub.2 O.sub.3, 0-2% F, and 0-3% P.sub.2 O.sub.5 by weight of the total composition, wherein the weight percent of (F+B.sub.2 O.sub.3 +P.sub.2 O.sub.5) is in the range from 0.8-4.0 and the weight percent of (Li.sub.2 O+Na.sub.2 O) is in the range from 6-15, and wherein the porcelain comprises a glassy matrix phase and a leucite crystallite phase, wherein the leucite phase comprises from about 0 to about 20% by weight of the total composition and the leucite crystallites have average diameters of less than about 5 microns; and further wherein the porcelain has a maturing temperature in the range from about 680.degree. C. to about 870.degree. C. and a coefficient of thermal expansion in the range from about 12 to about 15.times.10.sup.-6 /.degree. C. (measured from 25.degree. C. to 470.degree. C.);a ceramic core, wherein the ceramic core comprises 60-75% SiO.sub.2, 11.7-13.0% Al.sub.2 O.sub.3, 8-9.7% K.sub.2 O and 1-2% Cs.sub.2 O in mole percent of the total composition; andwherein the ceramic core exhibits a coefficient of thermal expansion in the range from about 12.5 to about 15.times.10.sup.-6 /.degree. C. (measured from 25.degree. C. to 500.degree. C.) and the metal framework exhibits a coefficient of thermal expansion in the range from about 13.2 to about 15.1.times.10.sup.-6 /.degree. C. (measured from 25.degree. C. to 500.degree. C.).