Provided is a powder material for forming a three-dimensional object, the powder material containing granulated particles containing: a resin; and inorganic particles of which primary particles have a volume average particle diameter of 1 micrometer or less, wherein the granulated particles have a volume average particle diameter of 10 micrometers or greater but 70 micrometers or less and a BET specific surface area of 6 m.sup.2/g or greater but 8 m.sup.2/g or less.

A process for the preparation of multi-coloured dental restorations is described, in which glasses and glass ceramics with various compositions are given the shapes of dental restorations and colour changes are effected in the glasses and glass ceramics by irradiating them with artificial electromagnetic radiation and subjecting them to a heat treatment.

A process for the preparation of multi-coloured dental restorations is described, in which glasses and glass ceramics with various compositions are given the shapes of dental restorations and colour changes are effected in the glasses and glass ceramics by irradiating them with artificial electromagnetic radiation and subjecting them to a heat treatment.

Process for treating a porous dental zirconia block with a coloring solution, the process comprising the steps of providing a porous dental zirconia block having two opposing surfaces, surface U and surface L, treating the upper surface U of the porous dental zirconia block with a coloring solution A.sub.1, wherein the coloring solution is provided with a volume VA.sub.1, turning the porous dental zirconia block around, treating the lower surface L with a coloring solution A.sub.2 which is provided with a volume VA.sub.2. wherein the coloring solutions A.sub.1 and A.sub.2 comprise a solvent and coloring ions, wherein the volume of at least one of the coloring solutions A.sub.1 or A.sub.2 is applied in portions, wherein the following condition is met: Vo=ΣV.sub.AX, with x≥2, with Vo being the overall amount of coloring solution used to infiltrate the porous dental zirconia block.

A powder intended for the manufacture of a sintered dental article, The powder has a chemical analysis such that, as weight percentages based on the oxides: Al.sub.2O.sub.3: 0.2%, oxides other than ZrO.sub.2, HfO.sub.2, Yb.sub.2O.sub.3, Y.sub.2O.sub.3 and Al.sub.2O.sub.3: <0.5%, and ZrO.sub.2+HfO.sub.2+Yb.sub.2O.sub.3+Y.sub.2O.sub.3: balance to 100%, with HfO.sub.2<2%. The contents of Yb.sub.2O.sub.3 and Y.sub.2O.sub.3, as molar percentages based on the sum of ZrO.sub.2, HfO.sub.2, Yb.sub.2O.sub.3 and Y.sub.2O.sub.3, being such that Yb.sub.2O.sub.3≥1%, 0.5%≤Y.sub.2O.sub.3<2%, and Yb.sub.2O.sub.3+Y.sub.2O.sub.3≤5.5%. The powder has a specific surface area of greater than or equal to 5 m.sup.2/g and less than or equal to 16 m.sup.2/g. The powder has a median size of greater than or equal to 0.1 μm and less than or equal to 0.7 μm.

A powder intended for the manufacture of a sintered dental article, The powder has a chemical analysis such that, as weight percentages based on the oxides: Al.sub.2O.sub.3: 0.2%, oxides other than ZrO.sub.2, HfO.sub.2, Yb.sub.2O.sub.3, Y.sub.2O.sub.3 and Al.sub.2O.sub.3: <0.5%, and ZrO.sub.2+HfO.sub.2+Yb.sub.2O.sub.3+Y.sub.2O.sub.3: balance to 100%, with HfO.sub.2<2%. The contents of Yb.sub.2O.sub.3 and Y.sub.2O.sub.3, as molar percentages based on the sum of ZrO.sub.2, HfO.sub.2, Yb.sub.2O.sub.3 and Y.sub.2O.sub.3, being such that Yb.sub.2O.sub.3≥1%, 0.5%≤Y.sub.2O.sub.3<2%, and Yb.sub.2O.sub.3+Y.sub.2O.sub.3≤5.5%. The powder has a specific surface area of greater than or equal to 5 m.sup.2/g and less than or equal to 16 m.sup.2/g. The powder has a median size of greater than or equal to 0.1 μm and less than or equal to 0.7 μm.

ZrO.sub.2-toughened glass ceramics having high molar fractions of tetragonal ZrO.sub.2 and fracture toughness value of greater than 1.8 MPa.Math.m.sup.1/2. The glass ceramic may also include also contain other secondary phases, including lithium silicates, that may be beneficial for toughening or for strengthening through an ion exchange process. Additional second phases may also decrease the coefficient of thermal expansion of the glass ceramic. A method of making such glass ceramics is also provided.

ZrO.sub.2-toughened glass ceramics having high molar fractions of tetragonal ZrO.sub.2 and fracture toughness value of greater than 1.8 MPa.Math.m.sup.1/2. The glass ceramic may also include also contain other secondary phases, including lithium silicates, that may be beneficial for toughening or for strengthening through an ion exchange process. Additional second phases may also decrease the coefficient of thermal expansion of the glass ceramic. A method of making such glass ceramics is also provided.

The invention relates to glass-ceramics based on the lithium silicate system which can be mechanically machined easily in an intermediate step of crystallization and, after complete crystallisation, represent a very strong, highly-translucent and chemically-stable glass-ceramic Likewise, the invention relates to a method for the production of these glass-ceramics. The glass-ceramics according to the invention are used as dental material.

Disclosed herein is a ceramic particle comprising a core substrate chosen from yttria-stabilized zirconia, partially stabilized zirconia, zirconium oxide, aluminum nitride, silicon nitride, silicon carbide, and cerium oxide, and a conformal coating of a sintering aid film having a thickness of less than three nanometers and covering the core substrate, and methods for producing the ceramic particle.