Dental restoration, method for its production and ingot

1. A method for producing a dental restoration comprising a lithium silicate glass ceramic, wherein

a) an amorphous glass with the composition

50 to 75 wt-% SiO 2 ,

17 to 25 wt-% Li 2 O,

8 to 20 wt-% HfO 2 or of a mixture of HfO 2 and ZrO 2 ,

0 to 8 wt-% Al 2 O 3 ,

0 to 8 wt-% K 2 O, and

0 to 15 wt-% additives

is provided as an ingot and

b) the ingot is transformed to a dental restoration by at least one transformation process, wherein during the at least one transformation process at least a partial crystallisation occurs due to increased temperatures,

wherein the transformation process is a lost wax process.

2. The method of claim 1 , wherein the amorphous glass has the following composition:

55 to 64 wt-% SiO 2 ,

17 to 22 wt-% of Li 2 O,

8 to 20 wt-% HfO 2 or of a mixture of HfO 2 and ZrO 2 ,

0.1 to 5 wt-% of Al 2 O 3 ,

0.1 to 5 wt-% of K 2 O,

2 to 8 wt-% P 2 O 5 , and

0 to 10 wt-% of additives.

3. The method of claim 1 , wherein during the transformation process, thermal energy is conveyed to the ingot, with temperatures of at least 800° C.

4. The method of claim 1 ,

wherein in a further step c) subsequent to the transformation process, the dental restoration is subjected to a heat treatment with temperatures from 850° C. to 1100° C.

5. The method of claim 1 , wherein the additives are selected from nucleating agents, fluorescent agents, dyes, glass colouring oxides, coloured pigments, and mixtures thereof.

6. The method of claim 5 , wherein the nucleating agents are selected from phosphorous oxide, titanium oxide, tin oxide, and mixtures thereof, and noble metals.

7. The method of claim 5 , wherein the fluorescent agents are selected from oxides of strontium, bismuth, rare earth elements, and mixtures thereof.

8. The method of claim 5 , wherein the glass colouring oxides are selected from oxides of iron, titanium, copper, chromium, cobalt, nickel, manganese, selenium, silver, indium, gold, vanadium, rare earth elements, and mixtures thereof.

9. The method of claim 1 , wherein the additives are selected from boron oxide, fluorine, barium oxide, strontium oxide, magnesium oxide, zinc oxide, calcium oxide, yttrium oxide, titanium oxide, niobium oxide, tantalum oxide, lanthanum oxide and mixtures thereof.

10. The method of claim 1 , wherein before the dental application, the dental restoration is subjected to a finishing process selected from polishing, glazing, sealing, coating, and veneering with a veneering ceramic or glaze.

11. The method of claim 6 , wherein the nucleating agent is present in an amount of 1 to 10 wt-% of the dental restoration.

12. The method of claim 7 , wherein the fluorescent agent is present in an amount of 0.1 to 5 wt-% of the dental restoration.