NON-PRE- COLORED MULTI-LAYER ZIRCONIA DENTAL BLANK THAT HAS A GRADUAL CHANGE IN CHROMA THROUGH A THICKNESS AFTER SINTERING

• US 20150173869A1
• Filed: 12/03/2014
• Published: 06/25/2015
• Est. Priority Date: 02/23/2012
• Status: Active Grant

• Current Assignee: B & D Dental Corporation
• Original Assignee: B & D Dental Corporation
• Inventors: Jung, Yunoh, Jung, Daniel Yonil, Jun, Yoonho, Kim, Young Jin
• Granted Patent: US 9,649,179 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61C 13/0006 Production methods
• CPC Class Codes: A61C 13/0022 Blanks or green, unfinished dental restoration parts
• CPC Class Codes: A61C 13/082 Cosmetic aspects, e.g. inlays; Determination of the colour A61C19/10 takes precedence
• CPC Class Codes: A61C 13/083 Porcelain or ceramic teeth A61C13/081 takes precedence; preparations A61K6/80
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3246 Stabilised zirconias, e.g. YSZ or cerium stabilised zirconia
• CPC Class Codes: C04B 2235/3248 Zirconates or hafnates, e.g. zircon
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/608 Green bodies or pre-forms with well-defined density
• CPC Class Codes: C04B 2235/612 Machining
• CPC Class Codes: C04B 2235/6567 Treatment time
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 2235/9615 Linear firing shrinkage
• CPC Class Codes: C04B 2235/9653 Translucent or transparent ceramics other than alumina
• CPC Class Codes: C04B 2235/9661 Colour
• CPC Class Codes: C04B 2237/348 Zirconia, hafnia, zirconates or hafnates
• CPC Class Codes: C04B 2237/582 by joining layers or articles of the same composition but having different additives
• CPC Class Codes: C04B 2237/704 of one or more of the ceramic layers or articles
• CPC Class Codes: C04B 35/48 : based on zirconium or hafnium oxides, zirconates, zircon or hafnates
• CPC Class Codes: C04B 35/486 : Fine ceramics
• CPC Class Codes: Y10T 428/24934 : including paper layer
• CPC Class Codes: Y10T 428/24967 : Absolute thicknesses specified

Abstract

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 white with a substantially consistent optical characteristic of chroma across the thickness, and is subsequently millable and sinterable to form the dental prosthesis with an optical characteristic of decreasing chroma through a thickness of the dental prosthesis.

Claims

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 and white with a substantially consistent optical characteristic of color intensity/chroma 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 is subsequently millable, colorable and sinterable to form the dental prosthesis with the multiple different layers having optical characteristics of a gradually decreasing color intensity/chroma level towards an incisal or an occlusal area of the prosthesis after dipping in a color liquid and sintering.

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 multiple different layers each having a different chemical composition between adjacent layers and being substantially opaque and white with a substantially consistent optical characteristic of color intensity/chroma across the layers;

c) the different chemical composition including different amounts of yttria between adjacent layers with a lower layer having 4.5-6 wt % yttria and an upper layer 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 is subsequently millable, colorable and sinterable to form the dental prosthesis with the multiple different layers having optical characteristics of gradually decreasing color intensity/chroma level towards an incisal or an occlusal area of the prosthesis after dipping in a color liquid and sintering.

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 multiple different layers having different optical characteristics of color intensity/chroma after sintering.

8. A device in accordance with claim 6, wherein the multiple different layers have different thicknesses with respect to one another with the lower layer having a thickness between 2-5 mm and the upper layer having a thickness between 0.5-2 mm.

9. A method for making a dental blank for use in producing a dental prosthesis, the method comprising:

a) forming zirconia and yttria into a desired shape;

b) increasing an amount of yttria through a thickness of the desired shape; and

c) pre-sintering or soft sintering the desired shape to form a green body dental blank with a different chemical composition of the amount of yttria through the thickness and being substantially opaque with a substantially consistent optical characteristic of color intensity/chroma across the thickness, the green body dental blank 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.

10. A method in accordance with claim 9, wherein the amount of yttria is increased incrementally from 4.5-6 wt % in a lower portion to 6-10 wt % in an upper portion.

11. A method in accordance with claim 9, wherein forming zirconia and yttria into a desired shape and increasing the amount of yttria through a thickness of the desired shape further comprises:

a) combining zirconia with a first amount of yttria in a first mixture;

b) forming the first mixture into a first layer;

c) combining zirconia with a second different amount of yttria in at least a second mixture; and

d) disposing the at least the second mixture into a second layer on the first layer.

12. A method in accordance with claim 11, wherein the amount of yttria is increased incrementally from 4.5-6 wt % in a lower layer to 6-10 wt % in an upper layer.

13. A method in accordance with claim 11, wherein the 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.

14. A method in accordance with claim 9, wherein the pre-sintering is done in the presence of atmospheric air.

15. A method in accordance with claim 9, wherein the zirconia powder and yttria are formed without color pigment.

16. A method in accordance with claim 9, further comprising:

a) milling a green body dental prosthesis from the green body dental blank;

b) coloring the green body dental prosthesis by dipping the green body dental prosthesis into a specific color liquid; and

c) sintering the green body dental prosthesis to form the dental prosthesis with an optical characteristic of decreasing color intensity/chroma across a thickness of the dental prosthesis after sintering.

17. A method for making a dental a dental prosthesis, the method comprising:

a) obtaining a green body dental blank including zirconia and having multiple different layers each having a different chemical composition with different amounts of yttria between adjacent layers and being substantially opaque and white with a substantially consistent optical characteristic of color intensity/chroma across the layers, the green body dental blank 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;

b) milling a green body dental prosthesis from the dental blank;

c) coloring the green body dental prosthesis by dipping the green body dental prosthesis into a specific color liquid;

d) sintering the green body dental prosthesis to form the dental prosthesis with the multiple different layers having different optical characteristics of color intensity/chroma after sintering.

18. A method in accordance with claim 17, wherein the sintering is done in the presence of atmospheric air.