Non-pre-colored multi-layer zirconia dental blank that has a gradual change in translucency through a thickness after sintering
A dental block for producing a dental prosthesis comprises a green body including zirconia and having a chemical composition including increasing amounts of yttria through a thickness of the green body. The green body is substantially opaque with a substantially consistent optical characteristic of non-translucency with respect to visible light across the thickness, and is subsequently millable and sinterable to form the dental prosthesis with an optical characteristic of increasing translucency through a thickness of the dental prosthesis.
1. A dental block device for producing a dental prosthesis, the dental block device comprising:
a) a green body comprising zirconia;
b) the green body having multiple different layers each having a different chemical composition between adjacent layers;
c) the different chemical composition including different amounts of yttria between the adjacent layers;
d) the green body being substantially opaque with a substantially consistent optical characteristic of non-translucency with respect to visible light across the layers;
e) the green body having a brightness/lightness L* value between 10 to 20 for a sample thickness of 1 to 1.3 mm in accordance with CIE L*a*b* colorimetric system; and
f) the green body being subsequently millable and sinterable to form the dental prosthesis with the multiple different layers having different optical characteristics of translucency.
2. A device in accordance with claim 1 , wherein the amount of yttria is increased incrementally from a lower layer to an upper layer.
3. A device in accordance with claim 2 , wherein the amount of yttria is increased incrementally from 4.5-6 wt % in the lower layer to 6-10 wt % in the upper layer.
4. A device in accordance with claim 1 , wherein the multiple different layers have different thicknesses with respect to one another with a lower layer having a thickness between 2-5 mm and an upper layer having a thickness between 0.5-2 mm.
5. A device in accordance with claim 1 , wherein the green body is without color pigment.
6. A dental block device for producing a dental prosthesis, the dental block device comprising:
a) a green body comprising 60-99.9 wt % zirconia that is soft sintered or pre-sintered without color pigment;
b) the green body having a different chemical composition through a thickness of the green body and being substantially opaque with a substantially consistent optical characteristic of non-translucency with respect to visible light through the thickness;
c) the different chemical composition including increasing amounts of yttria through the thickness with a lower portion having 4.5-6 wt % yttria and an upper portion having 6-10 wt % yttria;
d) the green body having a brightness/lightness L* value between 10 to 20 for a sample thickness of 1 to 1.3 mm in accordance with CIE L*a*b* colorimetric system; and
e) the green body being subsequently millable, colorable and sinterable to form the dental prosthesis with an optical characteristic of increasing translucency through a thickness of the dental prosthesis.
7. A device in accordance with claim 6 , wherein the green body is millable to form a green dental prosthesis that is colorable and sinterable to form the dental prosthesis with the optical characteristic of increasing translucency through the thickness of the dental prosthesis after sintering.
8. A device in accordance with claim 6 , wherein the green body has multiple different layers with different thicknesses with respect to one another with a lower layer having a thickness between 2-5 mm and an upper layer having a thickness between 0.5-2 mm.
9. A device in accordance with claim 6 , wherein the green body has a continuous change in the amount of yttria through the thickness.