US2016157971A1PendingUtilityA1

Controlling Of Sintering Kinetics Of Oxide Ceramics

Assignee: IVOCLAR VIVADENT AGPriority: Jul 22, 2013Filed: Jul 21, 2014Published: Jun 9, 2016

Est. expiryJul 22, 2033(~7 yrs left)· nominal 20-yr term from priority

Inventors:Frank Rothbrust Christian Ritzberger Dmitri Brodkin Ajmal Khan Marcel Schweiger

A61K 6/61C04B 2237/58C04B 2235/604C04B 35/486C04B 2235/3217C04B 2235/6026B32B 5/16B32B 2535/00C04B 2235/5409C04B 2235/96B32B 2307/732C04B 2235/3265C04B 2235/3224C04B 2235/3272B32B 2307/536C04B 2235/9615B28B 1/008C04B 2237/66B32B 2264/107C04B 2237/348C04B 2235/3246C04B 2235/3225C04B 2235/612C04B 35/48C04B 2235/6562C04B 2237/78C04B 2235/9661A61C 13/0022B32B 18/00C04B 2235/327B32B 2264/102B32B 7/02B32B 7/023C04B 2235/6567C04B 35/638C04B 2235/661

PatentIndex Score

Cited by

References

Claims

Abstract

The invention relates to multi-layer oxide ceramic bodies and in particular to presintered multi-layer oxide ceramic blanks and oxide ceramic green bodies suitable for dental applications. These bodies can be thermally densified by further sintering without distortion and are thus particularly suitable for the manufacture of dental restorations. The invention also relates to a process for the manufacture of such multi-layer oxide ceramic bodies as well as to a process for the manufacture of dental restorations using the multi-layer oxide ceramic bodies.

Claims

exact text as granted — not AI-modified

1 . Presintered multi-layer oxide ceramic blank for the manufacture of dental restorations comprising at least two different layers and having a coefficient of distortion

d
=

(

H




V
max

H




V
min

)

H



V

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

2 . Blank according to claim 1 which is suitable for the manufacture of a multi-unit dental restoration.

3 . Blank according to claim 1 , wherein the at least two different layers differ in terms of chemical composition.

4 . Blank according to claim 1 , wherein the oxide ceramic is based on zirconia.

5 . Blank according to claim 1 , wherein the coefficient of distortion is calculated on the basis of measurements of HV 2.5 at measuring points which are distributed at a constant distance along a first line intercepting the different layers on an outer surface of the blank.

6 . Blank according to claim 35 , wherein the constant distance between the measuring points along the first and second lines is not more than 5 mm.

7 . Multi-layer oxide ceramic green body for the manufacture of dental restorations comprising at least two different layers and having a coefficient of distortion

d
=

(

H




V
max

H




V
min

)

H



V

of less than 0.4, which coefficient is calculated on the basis of at least one measurement of HV 2.5 for each of the different layers, after a sintering step at a temperature in the range of 850 to 1350° C.,
wherein:
HV 2.5 is the Vickers hardness measured at a load of 2.5 kgf (24.517 N) according to ISO 14705:2008;
HV max is the maximum of the measured values of HV 2.5 ;
HV min is the minimum of the measured values of HV 2.5 ; and
HV is the arithmetic mean of the measured values of HV 2.5 .

8 . Multi-layer oxide ceramic body for the manufacture of dental restorations comprising at least two different layers, wherein a sintering behavior of the at least two different layers is aligned to allow the ceramic body to be sintered without distortion.

9 . Process for the manufacture of a multi-layer oxide ceramic body having at least two different layers which body can be sintered without distortion, wherein the process comprises aligning a sintering behavior of the different layers.

10 . Process according to claim 9 , wherein the body is suitable for the manufacture of a multi-unit dental restoration.

11 . Process according to claim 9 , wherein the at least two different layers differ in terms of chemical composition.

12 . Process according to claim 9 , which process comprises
(a) providing at least a first oxide ceramic material and a second oxide ceramic material, wherein the first oxide ceramic material and the second oxide ceramic material differ in terms of a sintering behavior; and (b) adapting at least one of the oxide ceramic materials to align the sintering behavior of the first oxide ceramic material to the sintering behavior of the second oxide ceramic material.

13 . Process according to claim 12 , wherein the sintering behavior is the relative linear shrinkage upon sintering at a temperature in the range of 850 to 1350° C.

14 . Process according to claim 12 , wherein in step (a) the sintering behavior of the first oxide ceramic material and the sintering behavior of the second oxide ceramic material differ by at least 0.15%.

15 . Process according to claim 12 , wherein in step (b) the adapting results in the sintering behavior of the first oxide ceramic material and the sintering behavior of the second oxide ceramic material differing by less than 0.15%.

16 . Process according to claim 12 which further comprises
(c) forming layers of the oxide ceramic materials and arranging the layers on top of one another or forming a layer of the oxide ceramic materials which comprises a continuous gradient from the first oxide ceramic material to the second oxide ceramic material;
(d) optionally compacting the oxide ceramic materials to obtain a green body; and
(e) optionally presintering the oxide ceramic materials to obtain a presintered ceramic blank.

17 . Process according to claim 12 , wherein adapting at least one of the oxide ceramic materials comprises incorporating a dopant into said oxide ceramic material.

18 . Process according to claim 17 , wherein said dopant is selected from sintering aids, and sintering inhibitors.

19 . Process according to claim 12 , wherein adapting at least one of the oxide ceramic materials comprises changing at least one of the primary particle size, the secondary particle size or the specific surface area of at least a portion of said oxide ceramic material.

20 . Process according to claim 12 , wherein adapting at least one of the oxide ceramic materials comprises subjecting said oxide ceramic materials to different degrees of partial densification.

21 . Multi-layer oxide ceramic body obtainable by the process of claim 9 .

22 . Process for the manufacture of a dental restoration, which process comprises using a blank according to claim 1 , a green body according to claim 7 , or a ceramic body according to claim 8 .

23 . Process according to claim 22 which comprises shaping the blank or body to a desired geometry to obtain a shaped ceramic product.

24 . Process according to claim 22 , wherein the shaping is carried out by machining using a CAD/CAM process.

25 . Process according to claim 23 , wherein the shaped ceramic product has the shape of a dental framework, abutment or monolithic full-contour dental restoration.

26 . Process according to claim 22 further comprising densely sintering the shaped ceramic product.

27 . Blank according to claim 1 wherein the coefficient of distortion is less than 0.35.

28 . Blank according to claim 1 wherein the coefficient of distortion is less than 0.3.

29 . Blank according to claim 1 wherein the coefficient of distortion is less than 0.25.

30 . Blank according to claim 1 wherein the coefficient of distortion is less than 0.2.

31 . Blank according to claim 1 wherein the coefficient of distortion is less than 0.1.

32 . Blank according to claim 2 wherein the multi-unit dental restoration comprises a dental restoration or bridge spanning two or more units.

33 . Blank according to claim 3 , wherein the at least two different layers have different colors.

34 . Blank according to claim 4 , wherein the zirconia, comprises stabilized tetragonal zirconia polycrystals.

35 . Blank according to claim 5 , wherein the coefficient of distortion is calculated on the basis of additional measuring points which are distributed at a constant distance along a second line that is parallel to the first line on a surface in the center of the blank, which has been made accessible by cutting the blank.

36 . Green body according to claim 7 , wherein the coefficient of distortion is less than 0.35 and wherein the sintering temperature is in the range of 900 to 1200° C.

37 . Green body according to claim 7 , wherein the coefficient of distortion is less than 0.3 and wherein the sintering temperature is in the range of 950 to 1150° C.

38 . Green body according to claim 7 , wherein the coefficient of distortion is less than 0.25 and wherein the sintering temperature is in the range of 1000 to 1100° C.

39 . Green body according to claim 7 , wherein the coefficient of distortion is less than 0.1 and the sintering temperature is at about 1100° C.

40 . Process according to claim 10 , the multi-unit dental restoration comprises a dental restoration or bridge spanning two or more units.

41 . Process according to claim 11 , wherein the at least two different layers have different colors.

42 . Process according to claim 13 , wherein the sintering temperature is in the range of 900 to 1200° C.

43 . Process according to claim 13 , wherein the sintering temperature is in the range of 950 to 1150° C.

44 . Process according to claim 13 , wherein the sintering temperature is in the range of 1000 to 1100° C.

45 . Process according to claim 13 , wherein the sintering temperature about 1100° C.

46 . Process according to claim 14 , wherein in step (a) the sintering behavior of the first oxide ceramic material and the sintering behavior of the second oxide ceramic material differ by at least 0.25%.

47 . Process according to claim 14 , wherein in step (a) the sintering behavior of the first oxide ceramic material and the sintering behavior of the second oxide ceramic material differ by at least 0.5%.

48 . Process according to claim 14 , wherein in step (a) the sintering behavior of the first oxide ceramic material and the sintering behavior of the second oxide ceramic material differ by more than 1.0%.

49 . Process according to claim 15 , wherein in step (b) the adapting results in the sintering behavior of the first oxide ceramic material and the sintering behavior of the second oxide ceramic material differ by less than 0.10%.

50 . Process according to claim 15 , wherein in step (b) the adapting results in the sintering behavior of the first oxide ceramic material and the sintering behavior of the second oxide ceramic material differ by less than 0.05%.

51 . Process according to claim 16 wherein compacting comprises compressing the oxide ceramic materials to obtain a green body.

52 . Process according to claim 18 , wherein said sintering aids comprise Al 2 O 3 and said sintering inhibitors comprise Y 2 O 3 .

53 . Process according to claim 25 , wherein the shaped ceramic product has the shape of a multi-unit dental restoration.

Join the waitlist — get patent alerts

Track US2016157971A1 — get alerts on status changes and closely related new filings.

We store only your email — no account needed. See our privacy policy.