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.

Dental composite composition including a glass ceramic and a curable organic material is described in which the glass ceramic includes a crystal phase having an average grain size of 50 to 400 nm, and the dental composite composition is provided as a dental prosthetic material exhibiting superior transparency and mechanical properties comparing to conventional composite products containing micro-sized crystal grains and also has excellent aesthetics and processability required for prosthetic materials for same-day dental prosthetic service.

Dental composite composition including a glass ceramic and a curable organic material is described in which the glass ceramic includes a crystal phase having an average grain size of 50 to 400 nm, and the dental composite composition is provided as a dental prosthetic material exhibiting superior transparency and mechanical properties comparing to conventional composite products containing micro-sized crystal grains and also has excellent aesthetics and processability required for prosthetic materials for same-day dental prosthetic service.

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.

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.

Provided is a dental bulk block made from a glass-ceramic material having a crystalline phase embedded in an amorphous glass matrix. The crystalline phase includes eucryptite and at least one lithium silicate-based crystalline phase selected from the group consisting of lithium metasilicate and lithium disilicate. The dental bulk block is a functionally graded material having a crystalline size gradient with respect to a depth thereof and having no interface at a point of change in main crystalline size gradient value. The bulk block that is heat-treated at 820° C. for 40 minutes exhibits a characteristic peak of a spodumene crystalline phase in an X-ray diffraction analysis result graph unlike the bulk block that is heat-treated at 820° C. for 2 minutes.

Provided is a dental bulk block made from a glass-ceramic material having a crystalline phase embedded in an amorphous glass matrix. The crystalline phase includes eucryptite and at least one lithium silicate-based crystalline phase selected from the group consisting of lithium metasilicate and lithium disilicate. The dental bulk block is a functionally graded material having a crystalline size gradient with respect to a depth thereof and having no interface at a point of change in main crystalline size gradient value. The bulk block that is heat-treated at 820° C. for 40 minutes exhibits a characteristic peak of a spodumene crystalline phase in an X-ray diffraction analysis result graph unlike the bulk block that is heat-treated at 820° C. for 2 minutes.

The present invention provides a silicate glass that can reduce a color change in base material zirconia even when simultaneously fired with an unsintered zirconia. The present invention also provides a dental product using same. The present invention relates to a silicate glass comprising: 65.0 to 90.0 mol % SiO.sub.2, 4.0 to 15.0 mol % Al.sub.2O.sub.3, 1.0 to 10.0 mol % K.sub.2O, 0.1 to 7.0 mol % Na.sub.2O, and 0.01 to 15.0 mol % CaO, the silicate glass being essentially free of B.sub.2O.sub.3, and satisfying the relation {(number of moles of Al.sub.2O.sub.3)/(total number of moles of RO+R.sub.2O)}≥0.70, wherein R in the metal oxide represented by RO represents a metallic element in group 2 or 12 of the periodic table, and R in the metal oxide represented by R.sub.2O represents a metallic element in group 1 of the periodic table. The present invention also relates to a composite comprising the silicate glass and a base material formed of a ceramic; a sintered body as a fired product of the composite; and a dental product comprising the sintered body.

The present invention provides a silicate glass that can reduce a color change in base material zirconia even when simultaneously fired with an unsintered zirconia. The present invention also provides a dental product using same. The present invention relates to a silicate glass comprising: 65.0 to 90.0 mol % SiO.sub.2, 4.0 to 15.0 mol % Al.sub.2O.sub.3, 1.0 to 10.0 mol % K.sub.2O, 0.1 to 7.0 mol % Na.sub.2O, and 0.01 to 15.0 mol % CaO, the silicate glass being essentially free of B.sub.2O.sub.3, and satisfying the relation {(number of moles of Al.sub.2O.sub.3)/(total number of moles of RO+R.sub.2O)}≥0.70, wherein R in the metal oxide represented by RO represents a metallic element in group 2 or 12 of the periodic table, and R in the metal oxide represented by R.sub.2O represents a metallic element in group 1 of the periodic table. The present invention also relates to a composite comprising the silicate glass and a base material formed of a ceramic; a sintered body as a fired product of the composite; and a dental product comprising the sintered body.

The present invention relates to a spinel glass-ceramic made from a composition with the components 25 to 50% by weight SiO.sub.2, 10 to 35% by weight Al.sub.2O.sub.3, 1 to 15% by weight MgO, 1 to 15% by weight P.sub.2O.sub.5, 1 to 25% by weight ZrO.sub.2 and/or TiO.sub.2, 0 to 20% by weight La.sub.2O.sub.3, 0 to 10% by weight B.sub.2O.sub.3, and 0 to 15% by weight additives. The spinel glass-ceramic contains at least one spinel phase, but no high quartz solid solution phase. The glass-ceramic according to the invention exhibits very high mechanical stability, for example, very high flexural strength, wherein its optical properties can be simultaneously adjusted. In addition, the present invention also relates to a method for producing and the use of the spinel glass-ceramic. Furthermore, the present invention relates to a shaped dental product containing the spinel glass-ceramic.