Process for providing fluorescence to a dental ceramic body

Patent metadata

Field	Value
Publication number	US-2018029943-A1
Application number	US-201615549321-A
Country	US
Kind code	A1
Filing date	Feb 5, 2016
Priority date	Feb 5, 2015
Publication date	Feb 1, 2018
Grant date	—

Abstract

A process for providing fluoresence to a dental ceramic body by treating at least a portion of the outer surface of the dental ceramic body or a precursor thereof with a bismuth containing substance, characterized by the steps of placing the dental ceramic body or the precursor thereof into a closeable container, in particular a crucible; generating a bismuth containing atmosphere in the container and exposing at least a portion of the outer surface of the dental ceramic body or of the precursor to the bismuth containing atmosphere at a temperature above 1000° C.

First claim

1 . Process for providing fluorescence to a dental ceramic body by treating at least a portion of the outer surface of the dental ceramic body or a precursor thereof with a bismuth containing substance, wherein the steps of
a) placing the dental ceramic body or the precursor thereof into a closeable container; b) generating a bismuth containing atmosphere in the container and c) exposing at least a portion of the outer surface of the dental ceramic body or of the precursor to the bismuth containing atmosphere at a temperature above 1000° C.

2 . Process according to claim 1 , wherein the dental ceramic body comprises or essentially consists of zirconia and/or alumina.

3 . Process according to claim 1 , wherein the bismuth containing atmosphere is generated by the evaporation of a bismuth compound from a bismuth source containing the bismuth compound, the bismuth source being placed in a region of the container other than the region where the dental ceramic body is placed.

4 . Process according to claim 1 , wherein the closeable container is a crucible.

5 . Process according to claim 1 , wherein the bismuth containing atmosphere contains bismuth in the form of bismuth oxide.

6 . Process according to claim 1 , wherein the molar concentration of bismuth in the bismuth containing atmosphere is in the range from 1·10 −6 to 1·10 −2 mol/liter.

7 . Process according to claim 1 , wherein exposing the dental ceramic body or the precursor to the bismuth containing atmosphere according to step c) is carried out at a temperature above 1200° C.

8 . Process according to claim 1 , wherein bismuth penetrates into the dental ceramic body, the depth of penetration being 500 μm at most.

9 . Process according to claim 1 , wherein steps b) and c) are performed during sintering the dental ceramic body and/or during a post-sintering step.

10 . Process according to claim 1 , wherein the dental ceramic body is a dental article for use in a dental restoration.

11 . Dental ceramic body based on zirconia and/or alumina comprising or essentially consisting of
a core region being at least essentially free of bismuth and a surface region surrounding the core region and containing bismuth, wherein the surface region in which bismuth is contained reaches down from the surface to a depth of 500 μm at most.

12 . Dental ceramic body according to claim 11 , wherein the molar amount of bismuth contained in the surface region is less than 0.5 mol-%.

13 . Process for providing a fluorescent dental ceramic body based on zirconia and/or alumina comprising the steps of
A) providing a ceramic precursor powder containing apart from zirconia and/or alumina, respectively, bismuth oxide in an amount of lower than 0.7 mol-%, B) pressing the ceramic precursor powder to form a green body, C) debinding the green body obtained in B) to form a porous brown body, and D) sintering the porous brown body obtained in C) to obtain the fluorescent, dense ceramic body.

14 . Process according to claim 13 , wherein the sintering of D) is carried out in the presence of a bismuth containing atmosphere.

15 . Process according to claim 13 , further comprising step
E) milling the dental ceramic body to a dental article.

Assignees

• Straumann Holding Ag

Inventors

• Zwahlen Alexander
• Stephan Marc

Classifications

• A61K6/16 Primary

  Refractive index · CPC title

• A61K6/818

  comprising zirconium oxide · CPC title

• A61K6/802

  comprising ceramics · CPC title

• C04B2235/5436

  micrometer sized, i.e. from 1 to 100 micron · CPC title

• C04B35/64

  Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F}) · CPC title