The invention relates to glass ceramics and glasses with a europium content, containing the following components:

TABLE-US-00001 Component wt.-% SiO.sub.2 30.0 to 75.0 Al.sub.2O.sub.3 10.0 to 45.0 Europium, calculated as Eu.sub.2O.sub.3 0.05 to 5.0

and which are suitable in particular for the production of dental restorations, the fluorescence properties of which largely correspond to those of natural teeth.

Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools.

The invention relates to a method to derive a medical form body of lithium silicate glass ceramic. To increase its strength it is proposed that in the form body comprising lithium silicate glass or containing lithium silicate glass the lithium ions are replaced by alkali ions of greater diameter to generate a surface compressive stress. To this end the form body is covered with a melt containing an alkali metal for which an aliquoted quantity of salt containing the alkali metal is used.

A pre-sintered porcelain block for dental restoration; the pre-sintered porcelain block does not contain crystal phases and has a Vickers hardness of 0.5-2 GPa. Due to a hardness which is significantly lower than that of the porcelain block containing a lithium metasilicate crystal phase, the pre-sintered porcelain block may be processed by using dry machining and can simultaneously be processed by using wet machining when being mechanically processed into a dental restoration shape.

Included is a step of exposing a glass blank at a temperature lower than the temperature at which crystals of lithium metasilicate are generated, to an atmosphere at a temperature equal to or higher than the temperature at which crystals of lithium disilicate are generated and lower than the melting point of the crystals of lithium disilicate, to heat the glass blank so that the main crystalline phase of the glass blank is of lithium disilicate.

A block for dental prostheses is in the form of a column or a board, a main crystalline phase of the block being of lithium disilicate, and when the block is observed in a field of view of a partially enlarged cross section of the block, the proportion of the total area of crystals having a length of at least 0.5 μm, the crystals appearing in the field of view, to an area of the field of view is at most 21%.

Disclosed is a pre-sintered ceramic block for a dental restoration, which has a low pre-sintering temperature, contains a silica main crystal phase, but does not contain or contains a small amount of lithium metasilicate crystal phase. The pre-sintered ceramic block has a low hardness, with a Vickers hardness of 0.5-3 GPa, which is significantly lower than that of a ceramic block containing a lithium metasilicate crystal phase, and same is suitable for dry machining and also wet machining when being machined into a dental restoration. (FIG. 2)

Provided are methods and compositions relating to a dental composition more specifically to prepare the damaged dentin of the tooth for animals and pets such as canine, feline and members of the taxonomic family Equidae prior to repair. The dental compositions include a bioactive glass and a non-aqueous solvent comprising an alcohol, anti-inflammatory and anti-pain reliever.

Disclosed is a machinable dental bulk block that is a glass ceramic block including an amorphous glass matrix and crystalline phases introduced into the matrix. A major crystalline phase is lithium disilicate and minor crystalline phases are lithium phosphate and at least one of spodumene and virgilite. The dental block is made of a functionally gradient material in which the major crystalline phase exhibits a gradient of particle sizes in a depth direction of the dental block and which has no interface at a point where the gradient of particle sizes of the major crystalline phase changes. The dental bulk block is useful for production of a dental prosthesis (artificial tooth) similar to a natural tooth. The dental bulk block can reduce time and the number of processing steps to manufacture a dental prosthesis and provides improved structural stability through good force distribution obtained by functionally graded mechanical properties.

Lithium silicate-low quartz glass ceramics are described which are characterized by a combination of very good mechanical and optical properties and can therefore be used in particular as restoration material in dentistry.