Abstract: Micaceous glass-ceramics are useful in the fabrication of single and multi-unit dental restorations including but not limited to orthodontic appliances, bridges, space maintainers, tooth replacement appliances, splints, crowns, partial crowns, dentures, posts, teeth, jackets, inlays, onlays, facing, veneers, facets, implants, abutments, cylinders, and connectors by machining the glass-ceramic using CAM/CAM devices. The micaceous glass-ceramics are provided in a plurality of shades and colors to adequately match the colors and shades of teeth found in 95% or more of the human population.

Abstract: Solid free form fabrication techniques such as fused deposition modeling and three-dimensional printing are used to create a dental restoration. Three-dimensional printing comprises inkjet printing a binder into selected areas of sequentially deposited layers of powder. Each layer is created by spreading a thin layer of powder over the surface of a powder bed. Instructions for each layer may be derived directly from a CAD representation of the restoration. The area to be printed is obtained by computing the area of intersection between the desired plane and the CAD representation of the object. All the layers required for an aesthetically sound restoration can be deposited concurrently slice after slice and sintered/cured simultaneously. The amount of green body oversize is equivalent to the amount of shrinkage which occurs during sintering or curing.

Abstract: Ceramic precursor powders are combined with a binder and pressed into blocks or similar shapes to form green bodies. The ceramic powders consist of fairly uniform particles thoroughly dispersed to be essentially free of agglomerates such that it will sinter predictably and isotropically without appreciable distortion. The green bodies may be soft-sintered to a bisque density less than about eighty five percent of the final density. The soft-sintered blocks are then milled to a desired shape and sintered to a final density rendering a high strength dental restorative material. The material may be aluminum oxide, partially stabilized zirconium oxide, mixtures of the two, mullite or any suitable oxide that may be sintered to high strength (i.e., greater than 250 MPa).

Abstract: Solid free form fabrication techniques such as fused deposition modeling and three-dimensional printing are used to create a dental restoration. Three-dimensional printing includes ink-jet printing a binder into selected areas of sequentially deposited layers of powder. Each layer is created by spreading a thin layer of powder over the surface of a powder bed. Instructions for each layer may be derived directly from a CAD representation of the restoration. The area to be printed is obtained by computing the area of intersection between the desired plane and the CAD representation of the object. All the layers required for an aesthetically sound restoration can be deposited concurrently slice after slice and sintered/cured simultaneously. The amount of green body oversize is equivalent to the amount of shrinkage which occurs during sintering or curing.

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: A method for producing a machinable feldspathic porcelain comprising leucite is presented. Machinability is imparted to feldspathic porcelains by achieving homogeneous distribution of fine crystalline constituent comprised of at least one of the following leucite phases: potassium tetragonal leucite, rubidium leucite, cesium stabilized cubic leucite, rubidium stabilized cubic leucite, and pollucite. The porcelains produced in accordance with the present invention are readily machinable by using available diamond tooling techniques. Furthermore, the porcelains are especially useful for the fabrication of dental restorations using CAD/CAM technology.

Abstract: A dental porcelain composition, comprising a glassy matrix and leucite crystallites embedded therein, and having maturing temperatures in the range from about 600.degree. C. to about 885.degree. C. and CTEs in the range from about 11 to about 19, more preferably in the range from about 11.5 to about 18, and most preferably in the range from about 12 to about 17.5.times.10.sup.-6 /.degree.C. (measured from 25.degree. C. to 500.degree. C.). The tetragonal leucite is preferably both fine-grained (i.e, having average diameters of less than about 7 microns) and uniformly-sized. Preferably, the average diameters are less than about 1 to about 3 microns.

Abstract: A dental porcelain composition comprising a continuous glassy phase and a discontinuous, substantially uniform crystalline phase comprising cubic leucite. The porcelain exhibits coefficients of thermal expansion in the range of about 11 to about 17.times.10.sup.-6 /.degree. C. (measured from 25.degree. C. to 500.degree. C.) and fusion temperatures in the range of about 700.degree. C. to about 1200.degree. C. The porcelain composition of the present invention can be used to form dental restorations such as cores for all ceramic restorations. The cubic leucite phase is uniformly dispersed in the glass matrix and has an average grain size not exceeding about 4 .mu.m and about 95% of the leucite grains do not exceed about 8 .mu.m in diameter.

Abstract: A dental porcelain composition, comprising a glassy matrix and rubidium leucite crystallites embedded therein, and having maturing temperatures in the range from about 650.degree. C. to about 800.degree. C. and CTEs in the range from about 13 to about 17, more preferably in the range from about 13.5 to about 16, and most preferably in the range from about 14 to about 16.times.10.sup.-6 /.degree. C. (measured from 25.degree. C. to 400.degree. C.). The tetragonal rubidium leucite is preferably both fine-grained (i.e., having average diameters of less than about 5 microns) and uniformly sized. Preferably, the average diameters are less than about 1 to about 2 microns.

Abstract: Porcelain compositions of the present invention possess non-greening properties and comprise one or more glass or glass-ceramic components. Additionally, an oxygen release agent is included in the compositions. The porcelain compositions may vary depending upon the specific thermal properties desired.The application temperature of the porcelain compositions ranges from about 600.degree. C. to about 930.degree. C. depending upon the method of application of the porcelain. The coefficient of thermal expansion is preferably in the range of about 11.times.10.sup.-6 /.degree. C. to about 16.times.10.sup.-6 /.degree. C. The porcelain is compatible with cores and/or substrates having coefficients of thermal expansion in the range of about 11 to about 20.times.10.sup.-6 /.degree. C.

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: Products having single phases or solid solutions of the formula M.sub.3 X.sub.1 Z.sub.2 wherein M is a transition metal, X is Si, Al or Ge and Z is B, C or N can be prepared by taking a powdered mixture containing M, X and Z to a temperature of about 1000.degree. C. to about 1800.degree. C., optionally simultaneously under a pressure of about 5 MPa to about 200 MPa. The products so formed have excellent shock resistance, oxidation resistance and machinability. The products may also be present as composites, preferably composites which are in thermal equilibrium with the single phase or solid solutions of the formula M.sub.3 X.sub.1 Z.sub.2.