Dental blank comprising a pre-sintered porous zirconia material, process of its production and dental article formed from said dental blank

Patent metadata

Field	Value
Publication number	US-9592105-B2
Application number	US-201314418973-A
Country	US
Kind code	B2
Filing date	Aug 1, 2013
Priority date	Aug 3, 2012
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

The invention relates to a dental mill blank comprising a pre-sintered porous zirconia material, the porous pre-sintered zirconia material showing a N2 adsorption of isotherm type IV according to IUPAC classification, the porous pre-sintered zirconia material having a Vickers hardness from about 25 to about 150, the dental mill blank comprising means for reversible attaching it to a machining device. The invention also relates to a process of producing a zirconia dental article comprising the steps of providing a dental mill blank comprising a porous pre-sintered zirconia material, placing the dental mill blank in a machining device, machining the porous zirconia material and to a dental article obtained by such a process.

First claim

What is claimed is:

1. A dental mill blank comprising a porous pre-sintered zirconia material, comprising:
the porous pre-sintered zirconia material showing a N 2 adsorption and/or desorption of isotherm type IV according to IUPAC classification;
the porous pre-sintered zirconia material having a Vickers hardness from about 25 to about 150; and
an attachment for reversibly attaching the dental mill blank to a machining device.

2. The dental mill blank of claim 1 , the porous pre-sintered zirconia material being characterized by at least one of the following features:
showing a nitrogen adsorption and desorption isotherm with hysteresis loop;
showing a hysteresis loop of type H 1 according to IUPAC classification;
showing a N 2 adsorption and desorption isotherm with a hysteresis loop in a p/p 0 range of 0.70 to 0.95;
average connected pore diameter: from about 10 to about 100 nm;
average grain size: less than about 100 nm;
BET surface: from about 10 to about 200 m 2 /g;
Biaxial flexural strength: from about 10 MPa to about 40 MPa;
x, y, z dimension: at least about 5 mm;
Vickers hardness: from about 35 to about 140;
density: about 30 to about 95% of theoretical density;
having an isotropic shrinkage behaviour.

3. The dental mill blank according to claim 2 , the porous pre-sintered zirconia material being further characterized by at least one of the following features:
ZrO 2 content: from about 70 to about 98 mol %;
HfO 2 content: from about 0 to about 2 mol %;
Y 2 O 3 content: from about 1 to about 15 mol %;
Al 2 O 3 content: from about 0 to about 1 mol %.

4. The dental mill blank according to claim 1 having the shape of a disc or block.

5. The dental mill blank according to claim 1 , the attachment for reversibly attaching the dental mill blank to a machining device being selected from frame(s), stump(s) and combinations thereof.

6. The dental article according to claim 1 , the attachment for reversibly attaching the dental mill blank to a machining device being selected from groove(s), notch(es), recess(es), stamp(s), and combinations thereof.

7. The dental mill blank according to claim 1 , the porous pre-sintered zirconia material being obtained by a process comprising the step of heat treating an aerogel.

8. The dental mill blank according to claim 7 , the aerogel being characterized by at least one of the following features:
comprising crystalline zirconia particles having an average primary particle diameter in a range from about 2 nm to about 50 nm;
content of crystalline zirconia particles: at least about 85 mol.-%;
having a surface area in the range of 100 m 2 /g to 300 m 2 /g;
having an organic content of at least about 3 wt.-%.

9. The dental mill blank according to claim 7 , the aerogel having been heat treated to a temperature of about 900 to about 1100° C.

10. The dental mill blank according to claim 1 , the porous pre-sintered zirconia material being obtained by a process comprising the steps of
providing a zirconia sol comprising crystalline metal oxide particles,
optionally concentrating the first zirconia sol to provide a concentrated zirconia sol,
adding a radically reactive surface modifier to the zirconia sol to provide surface-modified particles of the zirconia sol and adding a radical initiator to the radically polymerizable surface-modified particles of the zirconia sol,
casting the zirconia sol into a mold to provide a casted zirconia sol,
curing the radically polymerizable surface-modified particles of the zirconia sol to form a gel,
optionally removing water, if present, from the gel via a solvent exchange to provide an at least partially de-watered, solvent containing gel,
extracting solvent, if present, from the gel by super critical extraction to provide an aerogel,
optionally cutting the aerogel into smaller pieces,
heat treating the aerogel.

11. A process of producing a zirconia dental article comprising the steps of:
providing a dental mill blank comprising a porous pre-sintered zirconia material comprising:
the porous pre-sintered zirconia material showing a N 2 adsorption and/or desorption of isotherm type IV according to IUPAC classification;
the porous pre-sintered zirconia material having a Vickers hardness from about 25 to about 150; and
an attachment for reversibly attaching it to a machining device;
placing the dental mill blank in a machining device; and
machining the porous zirconia material.

12. The process according to claim 11 , the machining step being done with a milling, drilling, cutting, carving, or grinding device.

13. The process according to claim 11 comprising the additional step of sintering the machined porous zirconia material.

14. A dental article obtained by the process described in claim 11 .

15. The dental article of claim 14 having the shape of a crown, bridge, inlay, onlay, veneer, facing, coping, crown and bridged framework, implant, abutment, orthodontic appliances and parts thereof.

Assignees

• 3M Innovative Properties Co

Inventors

• Hauptmann Holger
• Schmittner Sybille
• Schechner Gallus
• Kolb Brant U
• Herrmann Andreas

Classifications

• C04B35/63488

  Polyethers, e.g. alkylphenol polyglycolether, polyethylene glycol [PEG], polyethylene oxide [PEO] · CPC title

• C04B35/486

  Fine ceramics · CPC title

• A61C13/0022 Primary

  Blanks or green, unfinished dental restoration parts · CPC title

• C04B2235/96

  Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance · CPC title

• C04B35/48

  based on zirconium or hafnium oxides, zirconates, {zircon} or hafnates · CPC title