Multilayer oxide ceramic body with aligned sintering behaviour

Patent metadata

Field	Value
Publication number	US-11801668-B2
Application number	US-201716470813-A
Country	US
Kind code	B2
Filing date	Dec 23, 2017
Priority date	Dec 23, 2016
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

The invention relates to multilayer oxide ceramic bodies and in particular presintered multilayer oxide ceramic blanks and oxide ceramic green bodies, which comprise at least two different layers and are suitable for dental applications, wherein at least one layer contains La2O3 and the at least two different layers differ in their content of La2O3. These bodies can be thermally densified by further sintering without distortion and are therefore particularly suitable for the production of dental restorations. The invention also relates to a process for the production of such multilayer oxide ceramic bodies as well as a process for the production of dental restorations using the multilayer oxide ceramic bodies.

First claim

The invention claimed is:

1. Presintered multilayer oxide ceramic blank for the production of dental restorations, which comprises at least two different layers, wherein the oxide ceramic is based on stabilized tetragonal zirconia polycrystal, at least one layer comprises 0.005 to 1.0 wt.-% La 2 O 3 and the at least two different layers differ in their content of La 2 O 3 , and all layers comprise 0.1 to 12.5 wt. % Y 2 O 3 .

2. Blank according to claim 1 , in which at least one layer comprises 0.01 to 1.0 wt.-% La 2 O 3 .

3. Blank according to claim 1 , in which at least one layer comprises Al 2 O 3 and/or MgO.

4. Blank according to claim 3 , in which at least one layer comprises La 2 O 3 and at least one other layer comprises Al 2 O 3 and/or MgO.

5. Blank according to claim 3 , wherein the at least one layer which comprise Al 2 O 3 and/or MgO comprises 0.001 to 5 wt.-% Al 2 O 3 and/or MgO.

6. Blank according to claim 3 , wherein the at least one layer which comprise Al 2 O 3 and/or MgO comprises 0.001 to 5 wt.-% Al 2 O 3 .

7. Blank according to claim 3 , wherein the at least one layer which comprise Al 2 O 3 and/or MgO comprises 0.001 to 5 wt.-% MgO.

8. Blank according to claim 3 , wherein the at least one layer which comprise Al 2 O 3 and/or MgO comprises Al 2 O 3 and MgO in a weight ratio of 10:1 to 1:10.

9. Blank according to claim 1 , in which at least two different layers differ in their content of Y 2 O 3 , wherein the difference in the Y 2 O 3 content between a layer with the lowest Y 2 O 3 content and a layer with the highest Y 2 O 3 content is at least 1.0 wt.-%.

10. Blank according to claim 9 , in which the layer with the highest Y 2 O 3 content comprises 0.001 to 5 wt.-% Al 2 O 3 and/or MgO.

11. Blank according to claim 1 , in which the layer with the lowest Y 2 O 3 content comprises 0.005 to 1.0 wt.-% La 2 O 3 .

12. Blank according to claim 1 , in which the proportion by weight of La 2 O 3 in each of at least two different layers is calculated according to the following formula:
m (La 2 O 3 )= m min (La 2 O 3 )+( m max (Y 2 O 3 )− m (Y 2 O 3 ))* f,

wherein
m(La 2 O 3 ) is the proportion by weight of La 2 O 3 in the respective layer,
m min (La 2 O 3 ) is the minimum proportion by weight of La 2 O 3 of all layers,
m(Y 2 O 3 ) is the proportion by weight of Y 2 O 3 in the respective layer,
m max (Y 2 O 3 ) is the maximum proportion by weight of Y 2 O 3 of all layers, and
f is in the range of from 0.01 to 1.00.

13. Blank according to claim 1 , which is suitable for the production of a multi-unit dental restoration.

14. Blank according to claim 1 , in which the at least two different layers have different colours.

15. Blank according to claim 1 , which has a coefficient of distortion

d
=

(

HV
max

-

HV
min

)

HV
_

of less than 0.4, wherein the coefficient is calculated on the basis of at least one measurement of HV for each of the different layers,
wherein:
HV is the Vickers hardness measured at a load in the range of from 2.5 to 5.0 kgf (24.517 to 49.034 N) in accordance with ISO 14705:2008;
HV max is the maximum of the measured values of HV;
HV min is the minimum of the measured values of HV; and
HV is the arithmetic mean of the measured values of HV.

16. Blank according to claim 1 , in which the sintering behaviour of the at least two different layers is aligned such that the blank can sinter without distortion.

17. Process for the production of a dental restoration, in which a blank according to claim 1 is used.

18. Process according to claim 17 , in which the blank is given the shape of a desired geometry in order to obtain a shaped ceramic product, wherein the shaping is carried out by machining.

19. Process according to claim 18 , in which the shaped ceramic product has the shape of a dental framework or abutment or of a monolithic fully anatomical dental restoration or a multi-unit dental restoration.

20. Process according to claim 18 , in which furthermore the shaped ceramic product is densely sintered.

21. Blank according to claim 1 , which comprises at least two different layers, which are formed from at least one first oxide ceramic material and one second oxide ceramic material, wherein the layers of the oxide ceramic materials exhibit a continuous change of composition from the composition of the first oxide ceramic material to the composition of the second oxide ceramic material.

22. Multilayer oxide ceramic green body for the production of dental restorations, which comprises at least two different layers, wherein the oxide ceramic is based on stabilized tetragonal zirconia polycrystal, at least one layer comprises 0.005 to 1.0 wt.-% La 2 O 3 and the at least two different layers differ in their content of La 2 O 3 , and all layers comprise 0.1 to 12.5 wt.-% Y 2 O 3 .

23. Green body according to claim 22 , wherein at least one layer comprises Al 2 O 3 and/or MgO.

24. Process for the production of a blank according to claim 1 , in which
(a) at least one first oxide ceramic material and one second oxide ceramic material are provided which differ in terms of their chemical composition,
(b) La 2 O 3 is added to at least one of the oxide ceramic materials, and
(c) optionally, Al 2 O 3 and/or MgO is added to at least one oxide ceramic material.

25. Process according to claim 24 , in which at least one oxide ceramic material is infiltrated or coated with La 2 O 3 and/or at least one oxide ceramic material is infiltrated or coated with Al 2 O 3 and/or MgO.

26. Process according to claim 24 , in which furthermore
(d) layers of the oxide ceramic materials are formed and the layers are arranged one on the other,
(e) the oxide ceramic materials are compacted in order to obtain a green body, and
(f) the green body is presintered in order to obtain a presintered ceramic blank.

27. Process according to claim 26 , in which the layers of the oxide ceramic materials exhibit a continuous change of composition from a composition of the first oxide ceramic material to a composition of the second oxide ceramic material.

28. Presintered multilayer oxide ceramic blank or multilayer green body which is obtainable by a process according to claim 24 .

Assignees

• Ivoclar Vivadent Ag

Inventors

• Reinshagen Jörg
• Meyhöfer Henning

Classifications

• B32B18/00 Primary

  Layered products essentially comprising ceramics, e.g. refractory products · CPC title

• A61C13/0022

  Blanks or green, unfinished dental restoration parts · CPC title

• C04B35/48

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

• C04B35/645

  Pressure sintering · CPC title

• C04B2235/3206

  Magnesium oxides or oxide-forming salts thereof · CPC title