Abstract: A porcelain blank comprising a porcelain composition for dental restorations comprising a leucite crystallite phase and a glass matrix phase, wherein the leucite crystallites possess diameters not exceeding about 10 micron. Preferably, the porcelain composition has a maturing temperature from about 750° C. to about 1050° C. and a coefficient of thermal expansion from about 9×10?6/° C. to about 17.5×10?6/° C., and comprises: SiO2 57-67? Al2O3 7-15 K2O 7-15 Na2O 6-15 Li2O 0.5-3.

Abstract: A porcelain composition for dental restorations comprising a leucite crystallite phase and a glass matrix phase, wherein the leucite crystallites possess diameters not exceeding about 10 micron. Preferably, the porcelain composition has a maturing temperature from about 750° to about 1050° C. and a coefficient of thermal expansion from about 12×10−6/° C. to about 17.5×10−6/° C., and comprises: Component Amount (wt. %) SiO2 57-66 Al2O3  7-15 K2O  7-15 Na2O  7-12 Li2O 0.5-3.

Abstract: Porcelain compositions of the present invention comprises particulate of one or more glass or glass-ceramic powder components. Additionally, one or more opacifing agents, pigments, fluorescing agents and the like may be included in the composition. Based on volume percent, the particulate has a d10 of from about 1.1 and about 1.8 microns; a d50 of from about 3 to about 6 microns; a d90 of from about 8 to about 16 microns; and about 1.0 to about 4.0% by volume of the particulate has a particle size greater than or equal to about 20 microns. The mean particle size is preferably in the range of about 3.0 microns to about 7.5 microns.

Abstract: A dental restoration comprising a porcelain composition, comprising a glassy matrix and leucite crystallites embedded therein, and having maturing temperatures in the range from about 680.degree. C. to about 870.degree. C. and CTEs in the range from about 12 to about 15, more preferably in the range from about 12.5 to about 14.5, and most preferably in the range from about 13.1 to about 14.5.times.10.sup.-6 /.degree. C. (measured from 25.degree. C. to 470.degree. C.). The porcelain is used in combination with a ceramic core or metal framework. The ceramic core comprises cubic leucite and exhibits maturing temperatures less than about 1200.degree. C. and CTEs in the range of about 12.5 to about 15.0.times.10.sup.-6 /.degree. C. (measured from 25.degree. C. to 500.degree. C.).

Abstract: The present invention relates to a method for preparing the color of a dental restoration using a spectrophotometer and a unique color system for porcelain dental restorations which enables a dentist or technician to manipulate the various color components of the porcelain, hue, chroma, value, and translucency, independently. Color component deltas between consecutive colors in the powder sets are equidistant, with the difference in values being linear in color space. This enables simplified, exact matching of a specified color component value. The method comprises illuminating an abutting tooth with light, gathering reflected light, converting the gathered light to analog signals, correct for ambient light interference, translucency effects (if necessary) and varying illumination, using the result to obtain accurate color component values, and employing those values to chose and, where necessary, mix the appropriate powers to obtain the correct color porcelain for the desired dental restoration.

Abstract: Porcelain compositions of the present invention comprise one or more glass or glass-ceramic powder components. Additionally, one or more opacifying agents, pigments, fluorescing agents and the like may be included in the composition. Based on volume percent, 10% of the particulate in the porcelain has a particle size of less than between about 1.1 microns and about 1.5 microns, 50% of the particulate in the porcelain has a particle size of less than between about 3 and about 6 microns, 90% of the particulate in the porcelain has a particle size of less than between about 8 and about 13.5 microns, and the maximum particle size of the particulate is greater than about 20 microns and less than about 60 microns. The mean particle size is preferably in the range of about 3.0 microns to about 6.5 microns.

Abstract: A porcelain composition for dental restorations comprising a leucite crystallite phase and a glass matrix phase, wherein the leucite crystallites possess diameters not exceeding about 10 micron. Preferably, the porcelain composition has a maturing temperature from about 750.degree. to about 1050.degree. C. and a coefficient of thermal expansion from about 12.times.10.sup.-6 /.degree. C. to about 17.5.times.10.sup.-6 /.degree. C., and comprises:______________________________________ Component Amount (wt. %) ______________________________________ SiO.sub.2 57-66 Al.sub.2 O.sub.3 7-15 K.sub.2 O 7-15 Na.sub.2 O 7-12 Li.sub.2 O 0.5-3.