# US 7,608,552 B2 · Dental material or product and method of forming a dental product

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- Number: US 7,608,552 B2
- Document ID: US7608552B2
- Status: Granted
- Kind: B2
- Application number: 10/748,084
- Filed: 2003-12-30
- Published: 2004-09-02
- Granted: 2009-10-27
- Earliest claimed: 2002-12-30
- Assignees: Chemichl AG
- Inventors: Gerhard Meyer; Thomas Conrad
- Web page: https://patentgrep.com/patent/US7608552B2

## CPC

- C04B 35/486: Fine ceramics
- A61K 6/16: Refractive index
- A61K 6/54: Filling; Sealing
- A61K 6/58: specially adapted for dental implants
- A61K 6/807: comprising magnesium oxide
- A61K 6/816: comprising titanium oxide
- A61K 6/818: comprising zirconium oxide
- A61K 6/82: comprising hafnium oxide
- A61K 6/822: comprising rare earth metal oxides
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- C04B 35/111: Fine ceramics
- C04B 35/117: Composites
- C04B 35/46: based on titanium oxides or titanates (containing also zirconium or hafnium oxides, zirconates or hafnates C04B35/49)
- C04B 35/488: Composites
- C04B 35/6261: {Milling}
- C04B 35/62695: {Granulation or pelletising (devices for shaping artificial aggregates from ceramic mixtures B28B1/004)}
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3208: Calcium oxide or oxide-forming salts thereof, e.g. lime
- C04B 2235/3224: Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
- C04B 2235/3225: Yttrium oxide or oxide-forming salts thereof
- C04B 2235/3229: Cerium oxides or oxide-forming salts thereof
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/5454: nanometer sized, i.e. below 100 nm
- C04B 2235/5472: Bimodal, multi-modal or multi-fraction
- C04B 2235/608: Green bodies or pre-forms with well-defined density
- C04B 2235/61: Mechanical properties, e.g. fracture toughness, hardness, Young's modulus or strength
- C04B 2235/612: Machining
- C04B 2235/661: Multi-step sintering
- C04B 2235/9653: Translucent or transparent ceramics other than alumina
- 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
- 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)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

The disclosure relates to metal oxide powders with a bimodal particle size distribution, to ceramics that can be made from these metal oxide powders, especially milling ceramics for use in dental technology, to a method for the production of the metal oxide powders and of the ceramics, to the use of nanoscale metal oxide powders for the production of the metal oxide powders and of the ceramics as well as to dental ceramic products.

## Claims

### Claim 1

A ceramic or dental material or dental product comprising a ceramic, having a bimodal particle size distribution, whereby a first phase comprises a metal oxide having an average particle size of at least 250 nm, and a second phase comprises a metal oxide having an average particle size in a range of 25 nm to 250 nm; made from a bimodal metal oxide powder comprising (a) a first metal oxide powder, and (b) a second, nanoscale metal oxide powder; wherein the first metal oxide powder has a d50 value in a range of 0.2 μm to 12 μm, and the second nanoscale metal oxide powder (b) has a d50 value in a range of 10 nm to 200 nm; wherein the size ratio of the d50 values of (a) to (b) lies at a maximum of 40 to 1; wherein the quantity ratio of (a) to (b) is in a range of 0.1:99.9 to 99.9:0.1; and wherein the metal oxide is selected from one member of the group consisting of ZrO2, HfO2, TiO2, and Al2O3, undoped or optionally doped with one or more dopants selected from the group consisting of CeO2, CaO, MgO, Sc2O3, and Y2O3.

### Claim 2 (depends on 1)

The ceramic or dental material or dental product of claim 1, wherein the size ratio of the d50 value of (a) to (b) lies between 12.4 and 40 to 1.

### Claim 3 (depends on 1)

The ceramic or dental material or dental product of claim 1, wherein a metal oxide includes one or more dopants selected from the group consisting of CeO2, CaO, MgO, Sc2O3, and Y2O3.

### Claim 4 (depends on 1)

The ceramic or dental material or dental product according to claim 1, wherein the second, nanoscale metal oxide powder (b) comprises ZrO2 and is stabilized with 0.5 mole % to 12 mole %, relative to the total amount of the second, nanoscale metal oxide powder (b), said one or more dopants.

### Claim 5 (depends on 4)

The ceramic or dental material or dental product according to claim 4, wherein the dopant is 1 mole % to 5 mole % of Y2O3.

### Claim 6 (depends on 5)

The ceramic or dental material or dental product according to claim 5, wherein the other metal oxide dopant is approximately 3 mole % of Y2O3.

### Claim 7 (depends on 1)

The ceramic or dental material or dental product according to claim 1, wherein the second, nanoscale metal oxide powder (b) is made by means of a plasma synthesis method.

### Claim 8 (depends on 6)

The ceramic or dental material or dental product according to claim 6, wherein the second, nanoscale metal oxide powder (b) has an average particle size of 50 nm.

### Claim 9 (depends on 6)

The ceramic or dental material or dental product according to claim 6, wherein the second, nanoscale metal oxide powder (b) has an average particle size in a range of 15 nm to 100 nm.

### Claim 10 (depends on 9)

The ceramic or dental material or dental product according to claim 9, wherein the second, nanoscale metal oxide powder (b) has an average particle size in a range of 40 nm to 50 nm.

### Claim 11 (depends on 1)

The ceramic or dental material or dental product according to claim 1, wherein the bimodal metal oxide powder comprises 5% to 30% by weight of the second, nanoscale metal oxide powder (b), relative to the total weight of the bimodal metal oxide powder.

### Claim 12 (depends on 11)

The ceramic or dental material or dental product of claim 11, wherein the bimodal metal oxide powder comprises 10% to 25% by weight of the second, nanoscale metal oxide powder (b), relative to the total weight of the bimodal metal oxide powder.

### Claim 13 (depends on 12)

The ceramic or dental material or dental product of claim 12, wherein the bimodal metal oxide powder comprises about 20% by weight of the second, nanoscale metal oxide powder (b), relative to the total weight of the bimodal metal oxide powder.

### Claim 14 (depends on 1)

The ceramic or dental material or dental product of claim 1, produced by a method wherein the bimodal metal oxide powder
(C) undergoes cold isostatic (uniaxial) final compacting or else it is first pre-compacted and then undergoes final compacting or
(C′) is subjected to a pre-sintering at a sintering temperature in a range of 300° C. to 1100° C. for a sintering duration in a range of 0.5 to 8 hours.

### Claim 15 (depends on 14)

The ceramic or dental material or dental product of claim 14, produced by a method wherein the bimodal metal oxide powder
(C) undergoes cold isostatic compacting or
(C′) is subjected to a pre-sintering, and
(D) the ceramic obtained in step (C) or the pre-sinter ceramic obtained in step (C′) is subjected to sintering.

### Claim 16 (depends on 15)

The ceramic or dental material or dental product of claim 15, produced by a method wherein the bimodal metal oxide powder
(C) undergoes cold isostatic compacting or
(C′) is subjected to a pre-sintering;
(E) the green compact ceramic obtained in step (C) or the pre-sinter ceramic obtained in step (C′) undergoes a milling process; and
(D′) the milling ceramic obtained in step (E) is subjected to sintering.