A phosphor includes, as a main component, a compound represented by a general formula (3-a)YO.sub.3/2.aCeO.sub.3/2.(5-b)AlO.sub.3/2.bGaO.sub.3/2.cKO.sub.1/2.dPO.sub.5/2, where a, b, c and d satisfy 0.12≦a≦0.18, 1.50≦b≦3.00, 0.01≦c≦0.08, and 0.01≦d≦0.08.

The invention relates to a method for the preparation of a lithium silicate glass or a lithium silicate glass ceramic which comprise cerium ions and are suitable in particular for the preparation of dental restorations, the fluorescence properties of which largely correspond to those of natural teeth. The invention also relates to a lithium silicate glass and a lithium silicate glass ceramic which can be obtained using the method according to the invention, the use thereof as dental material and in particular for the preparation of dental restorations, as well as a glass-forming composition which is suitable for use in the method according to the invention.

A phosphor includes, as a main component, a compound represented by a general formula (3-a)YO.sub.3/2.aCeO.sub.3/2.(5-b)AlO.sub.3/2.bGaO.sub.3/2.cKO.sub.1/2.dPO.sub.5/2, where a, b, c and d satisfy 0.12a0.18, 1.50b3.00, 0.01c0.08, and 0.01d0.08.

The invention relates to a method for the preparation of a lithium silicate glass or a lithium silicate glass ceramic which comprise cerium ions and are suitable in particular for the preparation of dental restorations, the fluorescence properties of which largely correspond to those of natural teeth.

The invention also relates to a lithium silicate glass and a lithium silicate glass ceramic which can be obtained using the method according to the invention, the use thereof as dental material and in particular for the preparation of dental restorations, as well as a glass-forming composition which is suitable for use in the method according to the invention.

A phosphor comprises a crystal phase that has a chemical composition of (Y.sub.1-x-y,Ce.sub.x,La.sub.y).sub.Si.sub.-zAl.sub.zN.sub.O, where the satisfies 5.56.5, the satisfies 9.512.5, the satisfies 17.522.5, the x satisfies 0<x0.1, the y satisfies 0y0.4, and the z satisfies 0z0.5. A light emission spectrum of the phosphor includes a peak within a wavelength range of not less than 600 nm and not more than 660 nm.

The invention relates to a method for the preparation of a lithium silicate glass or a lithium silicate glass ceramic which comprise cerium ions and are suitable in particular for the preparation of dental restorations, the fluorescence properties of which largely correspond to those of natural teeth. The invention also relates to a lithium silicate glass and a lithium silicate glass ceramic which can be obtained using the method according to the invention, the use thereof as dental material and in particular for the preparation of dental restorations, as well as a glass-forming composition which is suitable for use in the method according to the invention.

The invention relates to a method for the preparation of a lithium silicate glass or a lithium silicate glass ceramic which comprise cerium ions and are suitable in particular for the preparation of dental restorations, the fluorescence properties of which largely correspond to those of natural teeth.

The invention also relates to a lithium silicate glass and a lithium silicate glass ceramic which can be obtained using the method according to the invention, the use thereof as dental material and in particular for the preparation of dental restorations, as well as a glass-forming composition which is suitable for use in the method according to the invention.