Multi sectional dental zirconia milling block, process of production and use thereof

Patent metadata

Field	Value
Publication number	US-10028809-B2
Application number	US-201314436109-A
Country	US
Kind code	B2
Filing date	Oct 2, 2013
Priority date	Oct 17, 2012
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

The invention relates to a porous dental milling block comprising at least two geometrically defined Material Sections A and B, Material Section A comprising a tetragonal zirconia crystal phase in an amount A-T in % and a cubic zirconia crystal phase in an amount A-C in %, Material Section B comprising tetragonal zirconia crystal phase in an amount B-T in % and cubic zirconia crystal phase in an amount B-C in %, wherein (amount of tetragonal phase A-T in %)/(amount of cubic phase content A-C in %)>1 and (amount of tetragonal phase content B-T in %)/(amount of cubic phase content B-C in %)<1.
The invention also relates to a process of production of the porous dental milling block and its use for producing a dental article.

First claim

The invention claimed is:

1. A porous dental milling block comprising at least two geometrically defined Material Sections A and B,
Material Section A comprising a tetragonal zirconia crystal phase in an amount A-T in wt.-% and a cubic zirconia crystal phase in an amount A-C in wt.-%,
Material Section B comprising a tetragonal zirconia crystal phase in an amount B-T in wt.-% and a cubic zirconia crystal phase in an amount B-C in wt.-%,
wherein
(amount of tetragonal phase A - T in wt.-%)/(amount of cubic phase content A - C in wt.-%)>1
and
(amount of tetragonal phase content B - T in wt.-%)/(amount of cubic phase content B - C in wt.-%)<1,

the material of Material Sections A and B showing a N 2 adsorption and/or desorption behaviour of isotherm IV according to IUPAC classification.

2. The porous dental milling block of claim 1 , the material of Material Sections A and B having the following property:
the sintering temperature being in a range of 1200 to 1400° C.

3. The porous dental milling block of claim 1 having at least one of the following features:
the ratio of the tetragonal phase content A-T in % to the cubic phase content A-C in % in Section A being in a range from about 1.2 to about 50,
the ratio of the tetragonal phase content B-T in % to the cubic phase content B-C in % in Section B being in a range from about 0.02 to about 0.8.

4. The porous dental milling block of claim 1 having at least one of the following features with respect to Material Section A before sintering to final density:
showing a N 2 adsorption and desorption behaviour with a hysteresis loop of type H1 according to IUPAC classification;
showing a N 2 adsorption and desorption behaviour with a hysteresis loop in a p/p0 range of 0.70 to 0.95;
average connected pore diameter: from about 10 to about 100 nm;
average grain size of crystalline zirconia: less than about 100 nm;
BET surface: from about 10 to about 200 m 2 /g;
Biaxial flexural strength: from about 10 to about 40 MPa;
x, y, z dimension: at least about 5 mm;
Vickers hardness: from about 25 (HV 0.5) to about 150 (HV 1);
having an isotropic sintering behaviour;
density: 2.2 to 3.3 g/cm 3 ;
sintering temperature: from about 1200 to about 1400° C.;
having an ZrO 2 content: from about 85 to about 98 mol %;
having a HfO 2 content: from about 0 to about 3 mol %;
having an Y 2 O 3 content: from about 1 to about 15 mol %;
having an Al 2 O 3 content: from about 0 to about 1 mol %.

5. The porous dental milling block of claim 4 further having at least one of the following features with respect to Material Section A before sintering to final density:
average connected pore diameter: from about 10 to about 80 nm;
Biaxial flexural strength: from about 15 to about 30 MPa;
x, y, z dimension: at least about 10 mm.

6. The porous dental milling block of claim 5 further having at least one of the following features with respect to Material Section A before sintering to final density:
average connected pore diameter: from about 10 to about 50 nm;
x, y, z dimension: at least about 20 mm.

7. The porous dental milling block of claim 1 having at least one of the following features with respect to Material Section B before sintering to final density:
showing a hysteresis loop when analyzed with regard to its adsorption and desorption behaviour to nitrogen;
showing a N 2 adsorption and desorption behaviour with a hysteresis loop of type H1 according to IUPAC classification;
showing a N 2 adsorption and desorption behaviour with a hysteresis loop in a p/p0 range of 0.70 to 0.95;
average connected pore diameter: from about 10 to about 100 nm;
average grain size of crystalline zirconia: less than about 100 nm;
BET surface: from about 10 to about 200 m 2 /g;
Biaxial flexural strength: from about 10 to about 40 MPa;
x, y, z dimension: at least about 5 mm;
Vickers hardness: from about 25 (HV 0.5) to about 150 (HV 1);
having an isotropic sintering behaviour;
density: 2.2 to 3.3 g/cm 3 ;
sintering temperature: from about 1200 to about 1400° C.;
having an ZrO 2 content: from about 85 to about 98 mol %;
having a HfO 2 content: from about 0 to about 3 mol %;
having an Y 2 O 3 content: from about 1 to about 15 mol %;
having an Al 2 O 3 content: from about 0 to about 1 mol %.

8. The porous dental milling block of claim 7 further having at least one of the following features with respect to Material Section B before sintering to final density:
average connected pore diameter: from about 10 to about 80 nm;
Biaxial flexural strength: from about 15 to about 30 MPa;
x, y, z dimension: at least about 10 mm.

9. The porous dental milling block of claim 8 further having at least one of the following features with respect to Material Section B before sintering to final density:
average connected pore diameter: from about 10 to about 50 nm;

x, y, z dimension: at least about 20 mm.

10. The porous dental milling block of claim 1 , Material Section A and Material Section B having the shape of layers or blocks; being arranged in a core-shell structure; having tooth-like shapes; or a combination thereof.

11. The porous dental milling block of claim 1 not comprising oxides selected from TiO 2 , SiO 2 or mixtures thereof in an amount above 2 mol % with respect to the weight of the porous dental milling block.

12. The porous dental milling block of claim 1 comprising means for attaching it to a machining device, the means for attaching being selected from grooves, notches, recesses, stamps and holding devices, stumps and combinations thereof.

Assignees

• 3M Innovative Properties Co

Inventors

• Jahns Michael
• Hauptmann Holger

Classifications

• A61K6/818

  comprising zirconium oxide · CPC title

• A61K6/82

  comprising hafnium oxide · CPC title

• A61K6/822

  comprising rare earth metal oxides · CPC title

• C04B2235/5409

  expressed by specific surface values · CPC title

• C04B2235/765

  Tetragonal symmetry · CPC title