Method for the production of a blank, blank and a dental restoration

1 . A pre-sintered or fully sintered blank for use in producing a dental restoration, the presintered or fully sintered blank is formed from a ceramic material comprising regions of different compositions, wherein a first region is of a first ceramic material and at least one second region is of a second ceramic material, wherein the first and second regions are adjacent to each other, wherein the first or the second ceramic material or the first and the second ceramic materials include lithium silicate glass ceramic, wherein the at least one second region extends within the first region and has an outer geometry that tapers from a basal region or base surface;

wherein the at least one second region commencing from the basal region or base surface has a cone shaped cavity dimensioned to accept a grinding tool.

2 . The blank according to claim 1 , wherein the basal region or the base surface of the second region extends in the region of an outer surface of the first region and merges with it.

3 . The blank according to claim 1 , wherein the at least one second region has a cone-like geometry on its outer side.

4 . The blank according to claim 1 , further comprising a third region that extends within the at least one second region and includes a third ceramic material that has a composition that differs from that of the first ceramic material and/or the second ceramic material, wherein the composition of the third ceramic material includes lithium silicate glass ceramic.

5 . The blank according to claim 1 , wherein a plurality of second regions are surrounded by the first region.

6 . The blank according to claim 5 , wherein at least some of the plurality of second regions differ from one another in their outer geometries.

7 . The blank according to claim 1 , wherein the blank is produced of a lithium silicate glass ceramic of the composition that includes the following in percentage of weight:

SiO 2 57.5-60.5%

Li 2 O 13.5-20.5%

ZrO 2 8.5-11.5%

P 2 O 5 3.0-7.5%

Al 2 O 3 0.5-6.0%

K 2 O 0.5-3.5%

CeO 2 0.5-2.5%

B 2 O 3 0-3%

Na 2 O 0-3%

At least one additive 0-4%.

8 . The blank according to claim 1 , wherein the blank is produced from lithium silicate starting glass that includes, in percentage of weight:

SiO 2 57.5-60.5%

Li 2 O 14.0-16.0%

ZrO 2 9.0-10.5%

P 2 O 5 5.0-6.0%

Al 2 O 3 2.5-3.0%

K 2 O 1.0-1.5%

CeO 2 0.5-1.0%

B 2 O 3 2.5-3.0%

Na 2 O 0.1-2.0%

V 2 O 5 0.1-0.7%

Er 2 O 3 0-1.0%

Y 2 O 3 0.3-0.5%

MnO 2 0-0.2%.

9 . The blank according to claim 1 , wherein the second ceramic material differs from the first ceramic material in coloration, and includes the addition of at least one rare earth oxide.

10 . The blank according to claim 9 , wherein the rare earth oxide comprises MnO, Fe 2 O 2 , Y 2 O 3 , V 2 O 3 , and/or CeO 2 .

11 . The blank according to claim 1 , wherein after sintering to frill density the restoration produced from the blank has a higher translucency on an incisal side than on a dentin side.

12 . The pre-sintered or fully sintered blank of claim 1 , wherein the cone shaped cavity is dimensioned to accept a spherical ball head grinding tool.

13 . A pre-sintered blank for use in producing a dental restoration, wherein the pre-sintered blank is formed from a ceramic material comprising regions of different compositions, wherein a first region is of a first ceramic material and at least one second region is of a second ceramic material, wherein the first and second regions are adjacent to each other, wherein the first or the second ceramic material or the first and the second ceramic materials include lithium silicate glass ceramic, wherein the at least one second region extends within the first region and has an outer geometry that tapers from a basal region or base surface;

wherein the at least one second region commencing from the basal region or base surface has a cavity; and

wherein the cavity includes a cone shaped cavity dimensioned to accept a grinding tool.

14 . The pre-sintered blank of claim 13 , wherein the cone shaped cavity is dimensioned to accept a spherical ball head grinding tool.