Dental glass ceramics

• US 20090023574A1
• Filed: 05/31/2006
• Published: 01/22/2009
• Est. Priority Date: 06/08/2005
• Status: Active Grant

• Current Assignee: Ivoclar Vivadent AG
• Original Assignee: Ivoclar Vivadent AG
• Inventors: Rheinberger, Volker, Holand, Wolfram, Ritzberger, Christian, Apel, Elke
• Granted Patent: US 7,846,857 B2
• Time in Patent Office: Days
• US Class Current: 501/48
• CPC Class Codes: A61K 6/20 Protective coatings for natural or artificial teeth, e.g. sealings, dye coatings or varnish
• CPC Class Codes: A61K 6/78 Pigments
• CPC Class Codes: A61K 6/807 comprising magnesium oxide
• CPC Class Codes: A61K 6/816 comprising titanium oxide
• CPC Class Codes: A61K 6/818 comprising zirconium oxide
• CPC Class Codes: A61K 6/822 comprising rare earth metal oxides
• CPC Class Codes: A61K 6/827 Leucite
• CPC Class Codes: A61K 6/833 Glass-ceramic composites
• CPC Class Codes: A61K 6/838 Phosphorus compounds, e.g. apatite
• CPC Class Codes: C03B 32/02 Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles C03B27/012 takes precedence
• CPC Class Codes: C03C 10/0036 containing SiO2, Al2O3 and a divalent metal oxide as main constituents
• CPC Class Codes: C03C 4/0021 for dental use

Abstract

The invention relates to dental glass-ceramics and a process for producing them and their use, with these comprising at least one crystal phase containing xenotime or monazite or mixtures thereof.

Claims

1. A dental glass-ceramic, wherein it comprises at least one crystal phase containing xenotime or monazite or mixtures thereof.

2. The dental glass-ceramic as claimed in claim 1, wherein it contains xenotime of the chemical formula YPO4.

3. The dental glass-ceramic as claimed in claim 1, wherein it contains xenotime-type crystals of the chemical formula YPO4 having a proportion of about 0.8 mol of foreign ions or the xenotime crystals correspond to the formula ErPO4 or LuPO4 or TbPO4.

4. The dental glass-ceramic as claimed in claim 1, wherein it contains monazite of the formula CePO4.

5. The dental glass-ceramic as claimed in claim 1, wherein it contains crystals of the monazite type such as LaPO4, DyPO4, GdPO4 and TbPO4.

6. The dental glass-ceramic as claimed in claim 1, wherein the crystals of the xenotime type and/or monazite type have a size of from 0.1 μ

m to 10 μ

m.

7. The dental glass-ceramic as claimed in claim 6, wherein the crystals have a size of from 0.1 μ

m to about 2 μ

m.

8. The dental glass-ceramic as claimed in claim 1, wherein it contains at least SiO₂, Al₂O₃, R oxides and P₂O₅, where R is a rare earth.

9. The dental glass-ceramic as claimed in claim 8, wherein the R oxides are selected from the group consisting of Y₂O₃, Er₂O₃, Lu₂O₃, La₂O₃, CeO₂ and Tb₄O₇.

10. The dental glass-ceramic as claimed in claim 1, wherein it has essentially the composition comprising

11. The dental glass-ceramic as claimed in claim 10, wherein it has

12. The dental glass-ceramic as claimed in claim 11, wherein one or more additional oxides are selected from the group consisting of Li₂O, Na₂O, K₂O, CaO, MgO, ZnO, B₂O₃, TiO₂ and/or ZrO₂.

13. The dental glass-ceramic as claimed in claim 1, wherein it preferably contains from 10 to 30% by mass of additional oxides.

14. The dental glass-ceramic as claimed in claim 1, wherein it is preferably composed of

15. The dental glass-ceramic as claimed in claim 1, wherein it comprises apatite or leucite as further crystals.

16. The dental glass-ceramic as claimed in claim 1, wherein it contains one or more color-imparting or fluorescence-producing metal oxides.

17. The dental glass-ceramic as claimed in claim 16, wherein the metal or metals of the metal oxides are selected from transition groups 1 to 8 of the Periodic Table of the Elements.

21. A process for producing the dental glass-ceramic as claimed in claim 1, wherein

(a) the components required for producing the glass-ceramic are mixed and melted to form a glass,

(b) the glass melt from step (a) is poured into a preferably pre-heated mold and is cooled in a controlled manner to room temperature in order to obtain a shaped glass blank and

(c) the glass blank is subjected to a single-stage or multistage thermal treatment in the temperature range from 700°

C. to 1200°

C. for a period of from 30 minutes to about 6 hours.

26. The use of the glass blank or the glass-ceramic blank as claimed in claim 21, wherein the monolithic body is pressed by means of the ceramic pressing technique to produce a vitreous or ceramic shaped body for use as dental restoration.

27. The use of the glass blank or the glass-ceramic blank as claimed in claim 21, wherein the monolithic body is machined to produce a shaped body for use as dental restoration.

18. A process for producing a dental glass-ceramic comprising at least one crystal phase containing xenotime or monazite or mixtures thereof wherein

(a) the components required for producing the glass-ceramic are mixed and melted to form a glass,

(b) the glass melt from step (a) is converted by fritting into glass granules,

(c) if appropriate, the glass granules are comminuted to give a powder having an average particle size of from 1 to 500 μ

m (based on the number of particles) and

(d) the glass granules from step (b) or the glass powder from step (c) are/is subsequently subjected to a single-stage or multistage thermal treatment in the temperature range from 700°

C. to 1200°

C. for a period of from about 30 minutes to about 6 hours.

19. A process for producing a mixed glass-ceramic, wherein a pulverulent dental glass-ceramic containing xenotime and/or monazite crystals as claimed in claim 18 is mixed with further pulverulent glasses or glass-ceramics.

20. The process for producing a mixed glass-ceramic as claimed in claim 19, wherein the further glasses are preferably selected from the group consisting of opal glasses, alkali metal silicate glasses and/or potassium zinc silicate glasses which sinter at a low temperature and the further glass-ceramics are preferably selected from the group consisting of low-sintering apatite glass-ceramics, translucent apatite glass-ceramics, sinterable lithium silicate glass-ceramics, ZrO₂—

SiO₂ glass-ceramics and/or leucite-containing phosphosilicate glass-ceramics.

22. A use of dental glass-ceramics comprising at least one crystal phase containing xenotime or monazite or mixtures thereof, or a mixed glass-ceramic as opacifying component, dental material, for producing a dental material or a dental restoration.

23. The use of the dental glass-ceramic or the mixed glass-ceramic as claimed in claim 22, wherein the dental material is a coating material or a facing material.

24. The use of the dental glass-ceramic or the mixed glass-ceramic as claimed in claim 22, wherein the dental restoration is a crown, bridge, part crown, an onlay, an inlay, an artificial tooth, a stump buildup or a facing.

25. The use of the dental glass-ceramic or the mixed glass-ceramic as claimed in claim 23, wherein the coating material is used for coating metal and/or ceramic substrates.