Shaded zirconium oxide articles and methods

• US 8,178,012 B1
• Filed: 03/13/2007
• Issued: 05/15/2012
• Est. Priority Date: 04/06/2006
• Status: Active Grant

• Current Assignee: Ivoclar Vivadent AG
• Original Assignee: Ivoclar Vivadent AG
• Inventors: Khan, Ajmal, Brodkin, Dmitri G., Panzera, Carlino
• Primary Examiner(s): Gupta, Yogendra
• Assistant Examiner(s): HINDENLANG, ALISON L
• Application Number:
  US11/717,199
• Publication Number:
  US 20120139141A1
• Time in Patent Office: 1,890 Days
• Field of Search: 264/20
• US Class Current: 264/20
• CPC Class Codes: A61C 13/082 Cosmetic aspects, e.g. inlays; Determination of the colour A61C19/10 takes precedence
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3239 Vanadium oxides, vanadates or oxide forming salts thereof, e.g. magnesium vanadate
• CPC Class Codes: C04B 2235/3241 Chromium oxides, chromates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3275 Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
• CPC Class Codes: C04B 2235/3279 Nickel oxides, nickalates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3281 Copper oxides, cuprates or oxide-forming salts thereof, e.g. CuO or Cu2O
• CPC Class Codes: C04B 2235/40 Metallic constituents or additives not added as binding phase
• CPC Class Codes: C04B 2235/404 Refractory metals
• CPC Class Codes: C04B 2235/405 Iron group metals
• CPC Class Codes: C04B 2235/443 Nitrates or nitrites
• CPC Class Codes: C04B 2235/444 Halide containing anions, e.g. bromide, iodate, chlorite
• CPC Class Codes: C04B 2235/445 Fluoride containing anions, e.g. fluosilicate
• CPC Class Codes: C04B 2235/449 Organic acids, e.g. EDTA, citrate, acetate, oxalate
• CPC Class Codes: C04B 2235/6026 Computer aided shaping, e.g. rapid prototyping
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/608 : Green bodies or pre-forms with well-defined density
• CPC Class Codes: C04B 2235/616 : Liquid infiltration of green bodies or pre-forms
• CPC Class Codes: C04B 2235/6562 : Heating rate
• CPC Class Codes: C04B 2235/6565 : Cooling rate
• CPC Class Codes: C04B 2235/72 : Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• 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 2235/9661 : Colour
• CPC Class Codes: C04B 35/486 : Fine ceramics
• CPC Class Codes: C04B 35/62655 : Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: C04B 35/638 : Removal thereof

Abstract

A dental article includes yttria stabilized tetragonal zirconia polycrystalline ceramic, and no more than about 0.15 wt. % of one or more coloring agents of one or more of: Pr, Tb, Cr, Nd, Co, oxides thereof, and combinations thereof, whereby the dental article is provided with a color corresponding to a natural tooth shade; and wherein the dental article has a flexural strength of at least about 800 MPa. Corresponding methods are also described.

Claims

1. A method of forming a dental ceramic restorative article, the method comprising:

providing a first uncolored powder, wherein the first uncolored powder comprises zirconia;

combining at least one first coloring agent and a second powder thereby forming a first pigment powder, wherein the first coloring agent is a salt, oxide, inorganic compound, organic compound, organo-metallic compound or a combination thereof and wherein the second powder comprises zirconia;

mixing the first uncolored powder and the first pigment powder, thereby forming a mixed powder;

wherein an amount of the first coloring agent contained in the first pigment powder is selected, a proportion of first pigment powder and first uncolored powder in the mixed powder is selected, so as to provide the resulting dental restorative article with a tooth color having CIE L*, a*, b* color coordinates matching a shade standard within CIE L*, a*, b* color space region associated with tooth colors;

shaping the mixed powder to form a shaped body; and

firing the shaped body to at least 98% of its theoretical density;

thereby producing a dental restorative article comprising a color corresponding to a predetermined natural tooth shade and a flexural strength of at least 800 MPa.

2. The method of claim 1, wherein the first uncolored powder comprises yttria stabilized tetragonal zirconia polycrystalline ceramic.

3. The method of claim 1, wherein the second powder comprises yttria stabilized tetragonal zirconia polycrystalline ceramic.

4. The method of claim 1, further comprising:

combining at least one second coloring agent, wherein the second coloring agent is a salt, oxide, inorganic compound, organic compound, organo-metallic compound or a combination thereof and the second powder thereby forming a second pigment powder;

mixing the first uncolored powder, the first pigment powder, and the second pigment powder, thereby forming the mixed powder, wherein an amount of the second coloring agent contained in the second pigment powder is selected, a proportion of second pigment powder, first pigment powder, and first uncolored powder in the mixed powder is selected, so as to provide the resulting dental restorative article with a tooth color having CIE L*, a*, b* color coordinates matching a shade standard within CIE L*, a*, b* color space region associated with tooth colors.

5. The method of claim 4, further comprising:

combining at least one third coloring agent, wherein the third coloring agent is a salt, oxide, inorganic compound, organic compound, organo-metallic compound or a combination thereof and the second powder thereby forming a third pigment powder;

mixing the first uncolored powder, the first pigment powder, the second pigment powder, and the third pigment powder, thereby forming the mixed powder, wherein an amount of the third coloring agent contained in the second pigment powder is selected, a proportion of third pigment powder, second pigment powder, first pigment powder, and first uncolored powder in the mixed powder is selected, so as to provide the resulting dental restorative article with a tooth color having CIE L*, a*, b* color coordinates matching a shade standard within CIE L*, a*, b* color space region associated with tooth colors.

6. The method of claim 5, wherein the at least one first coloring agent and the at least one second coloring agent, and at least one third coloring agent comprise at least one of:

Pr, Tb, Cr, Nd, Co, Ni, salts thereof, oxides thereof, and combinations thereof.

7. The method of claim 4, wherein the at least one first coloring agent and the at least one second coloring agent comprise at least one of:

Pr, Tb, Cr, Nd, Co, Ni, salts thereof, oxides thereof, and combinations thereof.

8. The method of claim 4, further comprising selecting an amount of first coloring agent contained in the first pigment powder, selecting an amount of second coloring agent in the second pigment powder, and selecting a proportion of first pigment powder, second pigment powder, and first uncolored powder in the mixed powder, so as to provide the resulting dental restorative article with no more than a total of about 0.15 wt. % total coloring agent.

9. The method of claim 4, further comprising selecting an amount of first coloring agent contained in the first pigment powder, selecting an amount of second coloring agent in the second pigment powder, and selecting a proportion of first pigment powder, second pigment powder, and first uncolored powder in the mixed powder, so as to provide the resulting dental restorative article with no more than a total of about 0.10 wt. % total coloring agent.

10. The method of claim 4, further comprising selecting an amount of first coloring agent contained in the first pigment powder, selecting an amount of second coloring agent in the second pigment powder, and selecting a proportion of first pigment powder, second pigment powder, and first uncolored powder in the mixed powder, so as to provide the resulting dental restorative article with no more than a total of about 0.08 wt. % total coloring agent.

11. The method of claim 4, further comprising selecting an amount of first coloring agent contained in the first pigment powder, selecting an amount of second coloring agent in the second pigment powder, and selecting a proportion of first pigment powder, second pigment powder, and first uncolored powder in the mixed powder, so as to provide the resulting dental restorative article with no more than a total of about 0.07 wt. % total coloring agent.

12. The method of claim 1, wherein the at least one first coloring agent comprises at least one of:

Pr, Tb, Cr, Nd, Co, Ni, salts thereof, oxides thereof, and combinations thereof.

13. The method of claim 1, further comprising selecting an amount of first coloring agent contained in the first pigment powder, and selecting a proportion of first pigment powder and first uncolored powder in the mixed powder, so as to provide the resulting dental restorative article with no more than a total of about 0.15 wt. % total coloring agent.

14. The method of claim 1, further comprising selecting an amount of first coloring agent contained in the first pigment powder, and selecting a proportion of first pigment powder and first uncolored powder in the mixed powder, so as to provide the resulting dental restorative article with no more than a total of about 0.10 wt. % total coloring agent.

15. The method of claim 1, further comprising selecting an amount of first coloring agent contained in the first pigment powder, and selecting a proportion of first pigment powder and first uncolored powder in the mixed powder, so as to provide the resulting dental restorative article with no more than a total of about 0.08 wt. % total coloring agent.

16. The method of claim 1, further comprising selecting an amount of first coloring agent contained in the first pigment powder, and selecting a proportion of first pigment powder and first uncolored powder in the mixed powder, so as to provide the resulting dental restorative article with no more than a total of about 0.07 wt. % total coloring agent.

17. The method of claim 1, wherein the dental restorative article comprises a block or blank, a support or framework for a dental restoration, a crown, a partial crown, a veneer, an onlay, an inlay, a bridge, fixed partial dentures, a Maryland bridge, an implant abutment, or whole implant.

18. The method of claim 1, wherein the step of firing the pressed body comprises drying and binder removal steps, followed by a sintering step.

19. The method of claim 18, wherein the sintering step comprises at least one of:

partial sintering, bisque sintering, soft-sintering, sintering to full density, densification, annealing and tempering.

20. The method of claim 1, where firing step comprises one or more heating segments performed in sequence one after the other, or interrupted in between.

21. The method of claim 1, wherein the shaping step comprises one or more of:

compaction, extrusion, pressing, uniaxial pressing, cold isostatic pressing, casting, centrifugal casting, gravity casting, pressure casting, gel casting, slip casting, or slurry casting, freeze casting, injection molding or electrophoretic deposition.

22. The method of claim 1, wherein the mixing step comprises one or more of:

dry-mixing, mixing in liquid medium, ball milling, spray drying, fluidized bed processing, freeze granulation, freeze drying, high shear mixing and granulation.

23. The method of claim 1, wherein the shaping step comprises rapid-prototyping by stereolithography, photo-stereolithography, digital light processing (DLP), selective area laser deposition, selective laser sintering (SLS), electrophoretic deposition(EPD), robocasting, fused deposition modeling (FDM), laminated object manufacturing (LOM), or 3D printing.

24. The method of claim 1, further comprising processing the shaped body into a dental restoration, dental prosthesis or part thereof by machining using CAD/CAM, CAM, CNC or other milling machines.

25. The method of claim 1, wherein the dental restorative article further comprises less than about 0.1 wt. % aluminum oxide.

26. A method of forming a dental restorative article, the method comprising:

providing a first uncolored powder, wherein the first uncolored powder comprises zirconia;

combining at least one first coloring agent and a second powder thereby forming a first pigment powder, wherein the first coloring agent is a salt, oxide, inorganic compound, organic compound, organo-metallic compound or a combination thereof and wherein the second powder comprises zirconia;

combining a second coloring agent and a third powder thereby forming a second pigment powder, wherein the second coloring agent is a salt, oxide, inorganic compound, organic compound, organo-metallic compound or a combination thereof;

mixing the first uncolored powder, the first pigment powder, and the second pigment powder thereby forming a mixed powder, wherein an amount of the second coloring agent contained in the second pigment powder is selected, a proportion of second pigment powder, first pigment powder, and first uncolored powder in the mixed powder is selected, so as to provide the resulting dental restorative article with a tooth color having CIE L*, a*, b* color coordinates matching a shade standard within CIE L*, a*, b* color space region associated with tooth colors;

shaping the mixed powder to form a shaped body; and

firing the shaped body to at least 98% of its theoretical density;

thereby producing a dental restorative article comprising a color corresponding to a predetermined natural tooth shade, and a flexural strength of at least 800 MPa.

27. The method of claim 26, wherein the flexural strength is at least 1200 MPa.

28. The method of claim 26, wherein the first, second and third powders are the same powder.

29. The method of claim 28, wherein the same powder comprises yittria stabilized tetragonal zirconia polycrystalline ceramic powder.

30. The method of claim 29, wherein the yittria stabilized tetragonal zirconia polycrystalline ceramic powder comprises less than 0.1 wt. % aluminum oxide.

31. The method of claim 29, wherein the yittria stabilized tetragonal zirconia polycrystalline ceramic powder comprises a binderized, ready-to-press powder.