# US 12,005,131 B2 · Method of masking a dental support structure of a dental prosthesis made of highly translucent ceramic material

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- Number: US 12,005,131 B2
- Document ID: US12005131B2
- Status: Granted
- Kind: B2
- Application number: 17/166,942
- Filed: 2021-02-03
- Published: 2021-08-05
- Granted: 2024-06-11
- Earliest claimed: 2020-02-03
- Assignees: James R. Glidewell Dental Ceramics, Inc.
- Applicants: James R. Glidewell Dental Ceramics, Inc.
- Inventors: Yan Yang; Sreeram Balasubramanian; Yang Soon Park
- Web page: https://patentgrep.com/patent/US12005131B2

## CPC

- A61K 6/818: comprising zirconium oxide
- A61K 6/15: Compositions characterised by their physical properties
- A61K 6/20: Protective coatings for natural or artificial teeth, e.g. sealings, dye coatings or varnish
- A61K 6/78: Pigments
- A61K 6/84: comprising metals or alloys
- C04B 35/48: based on zirconium or hafnium oxides, zirconates, {zircon} or hafnates
- C04B 35/486: Fine ceramics
- C04B 35/4885: {with aluminium oxide}
- C04B 35/62685: {characterised by the order of addition of constituents or additives}
- C04B 35/6303: {Inorganic additives}
- C04B 35/6325: {based on organo-metallic compounds}
- C04B 41/009: {characterised by the material treated}
- C04B 41/4535: {applied as a solution, emulsion, dispersion or suspension}
- C04B 41/85: with inorganic materials
- C04B 2111/00836: {for medical or dental applications}
- C04B 2111/805: {Transparent material}
- C04B 2111/82: Coloured materials
- C04B 2235/3208: Calcium oxide or oxide-forming salts thereof, e.g. lime
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3225: Yttrium oxide or oxide-forming salts thereof
- C04B 2235/3227: Lanthanum oxide or oxide-forming salts thereof
- C04B 2235/3232: Titanium oxides or titanates, e.g. rutile or anatase
- C04B 2235/3246: Stabilised zirconias, e.g. YSZ or cerium stabilised zirconia
- C04B 2235/3284: Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
- C04B 2235/441: Alkoxides, e.g. methoxide, tert-butoxide
- C04B 2235/444: Halide containing anions, e.g. bromide, iodate, chlorite
- C04B 2235/448: Sulphates or sulphites
- C04B 2235/608: Green bodies or pre-forms with well-defined density
- C04B 2235/6562: Heating rate
- C04B 2235/6565: Cooling rate
- C04B 2235/75: Products with a concentration gradient
- C04B 2235/77: Density
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B 2235/9653: Translucent or transparent ceramics other than alumina
- C04B 2235/9661: Colour
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE

## Abstract

A method for masking the appearance of a support structure underlying a highly translucent ceramic dental restoration is provided. The porous form of a zirconia ceramic dental restoration is treated with a liquid masking composition comprising 0.4 wt % to 50 wt % of one or more masking agents. The masking composition is applied to the internal surface of a restoration and a region of the facial surface of the restoration that is opposite the internal surface. After application of the masking compositions, treated zirconia restoration is sintered to greater than 98% theoretical density.

## Claims

### Claim 1

A method for masking a dental substructure through a highly translucent yttria-stabilized zirconia dental restoration, comprising:
i. obtaining a masking mixture comprising 0.4 wt % to 50 wt % of one or more masking components that comprise Zn, Ti, Al, La, Mg, Sc, Si, Sr or Ca;
ii. obtaining a porous ceramic body in the shape of a dental restoration comprising an internal surface and a facial surface comprising an overlying region opposite the internal surface and wherein the ceramic body comprises zirconia stabilized with 3 mol % yttria to 8 mol % yttria having a transmittance between 45% to 80% at 700 nm (when tested on a 1 mm thick sintered body);
iii. applying the masking mixture to the internal surface to form an inner masking surface to mask a substructure;
iv. applying the masking mixture to the overlying region opposite the inner masking surface to form an outer masking surface; and
v. sintering the porous ceramic body to obtain a fully sintered ceramic body having a density that is at least 98% of the theoretical density, wherein the fully sintered ceramic body has a perceptual lightness (L*) value of at least 75 at a location that is on a centerline of the overlying region of the ceramic body and that is 69% of a distance from an incisal edge toward a gingival margin, and wherein perceptual lightness is measured using a SpectroShade® Micro II spectrophotometer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the masking mixture comprises one or more masking components that comprise Zn or Al.

### Claim 3 (depends on 2)

The method of claim 2, wherein the masking mixture comprises one or more of zinc sulfate, zinc nitrate, or aluminum chloride.

### Claim 4 (depends on 1)

The method of claim 1, wherein the dental restoration comprises a veneer, a crown, a bridge, an implant-supported partial denture, or an implant-supported full-arch denture.

### Claim 5 (depends on 1)

The method of claim 1, wherein the fully sintered ceramic body has a Measured Lightness Slope Value (MLSV) that is between 7 and 22, wherein perceptual lightness (L*) is measured using a SpectroShade® Micro II spectrophotometer.

### Claim 6 (depends on 1)

The method of claim 1, wherein the fully sintered ceramic body has a Measured Lightness Slope Value (MLSV) that is between 9 and 17, wherein perceptual lightness (L*) is measured using a SpectroShade® Micro II spectrophotometer.