Body made of a ceramic material

Abstract

A body made of a ceramic material having a surface region extending from the surface of the body to a predetermined depth and a core region being integrally formed with the surface region. The ceramic material in the surface region includes a calcium containing crystalline phase.

Claims

1. A body made of a ceramic material comprising zirconia and having a surface region extending from the surface of the body to a predetermined depth and a core region being integrally formed with the surface region, wherein the ceramic material in the surface region comprises a calcium containing crystalline phase and an yttrium or yttria stabilizing agent, which is obtained by depositing calcium carbonate as a calcium component and the yttrium or yttria stabilizing agent in one step on a surface of the ceramic material and thermally treating the ceramic material thereby causing co-diffusion of the calcium component and the stabilizing agent, wherein the body is an implant or an abutment for an implant, and wherein a proportion of calcium of the ceramic material decreases continuously in a direction from the surface of the body to the core region, and wherein said thermal treatment is carried out for a temperature and time sufficient to result in a normalized atomic concentration of calcium of at least 10% at a depth of 5 m.

2. The body according to claim 1, wherein the calcium containing crystalline phase is solely present in the surface region.

3. The body according to claim 1, wherein the crystal structure of the ceramic material in the surface region is such that the content of monoclinic phase is less than 25%.

4. The body according to claim 1, wherein the surface region extends from the surface of the body to a depth of at least 5 nm.

5. The body according to claim 1, wherein the surface region extends from the surface of the body to a depth ranging from 5 nm to 200 m.

6. The body according to claim 1, wherein at least a part of the surface of the body has a roughened surface.

7. The body according to claim 1, wherein the body is made of a ceramic material additionally comprising alumina.

8. The body according to claim 7, wherein the calcium containing crystalline phase is a CaZrO phase.

9. The body according to claim 8, wherein the calcium containing crystalline phase is a CaOZrO.sub.2 phase.

10. The body according to claim 1, wherein the body is made of a ceramic material comprising yttria-stabilized zirconia.

11. The body according to claim 9 wherein the CaOZrO.sub.2 phase is selected from the group consisting of a monoclinic CaZr.sub.4O.sub.9 phase, a cubic CaZrO.sub.3 phase and an orthorhombic CaZrO.sub.3 phase.

12. The body according to claim 11, wherein the CaOZrO.sub.2 phase is an orthorhombic CaZrO.sub.3 phase.

13. The body of claim 1, wherein the implant or the abutment for an implant is a dental implant, or an abutment for a dental implant.

14. The body of claim 1, wherein the normalized atomic concentration of calcium is at least 20% at the surface.

15. A process for preparing a body according to claim 1, said process comprising the steps of applying the calcium component and the yttrium or yttria stabilizing agent in one step onto the surface of a basic ceramic body; and thermally treating the basic ceramic body with the calcium component and yttrium or yttria stabilizing agent applied thereon at a temperature of at least 500 C., whereby the calcium component diffuses into the basic ceramic body in an amount sufficient that a calcium containing crystalline phase is formed.

16. The process according to claim 15, further comprising the step of roughening at least a part of the surface of the basic body by a subtractive treatment before applying the calcium compound.

17. The process according to claim 15, wherein the subtractive treatment comprises an etching step.

18. The body obtained by the process according to claim 15.

Description

(1) The invention is further illustrated by way of the figures, of which

(2) FIG. 1 shows a graphical representation of the normalized atomic concentration of the elements (Zr, Y, C, Ca and O) comprised in the body obtained according to the Example 1 in relation to the depth of the body;

(3) FIG. 2 shows a graphical representation of the content of monoclinic phase as a function of the duration of a simulated aging treatment for a machined ceramic body according to the present invention (sample 2A, referred to as CaZrO.sub.2) in comparison to a reference example (sample 2B, referred to as ZrO.sub.2 reference); and

(4) FIG. 3 shows a graphical representation of the content of monoclinic phase as a function of the duration of a simulated aging treatment for a number of sand-blasted and etched ceramic bodies according to samples 3A (referred to as Ca(HCO.sub.2).sub.2, 2 h, 1150 C.), 3B (referred to as Ca(HCO.sub.3).sub.2, 3 h, 1150 C.), 4 (referred to as CaCO.sub.3, 3 h, 1150 C.) and 5 (referred to as Ca-Gel, 2 h, 1150 C.) of the present invention.

(5) As shown in FIG. 1, the material of the body according to Example 1 shows at a depth of 5 m a normalized atomic concentration of calcium of more than 10%; by extrapolation, it can be concluded that calcium is present even at a depth of about 10 m.

(6) The body of the present invention shows almost no hydrothermal aging, as shown in FIG. 2. Specifically, the content of the monoclinic phase is for sample 2A lower than 10% even after subjecting the sample to 135 C. for 22 hours. Thus, the requirement according to ISO 13356 that the content of monoclinic phase is less than 25% after simulated aging at 135 C. for 5 hours is fully met.

(7) This is in contrast to reference sample 2B. Sample 2B shows a lower initial hydrothermal stability and a relatively fast decrease in the hydrothermal stability.

(8) As shown in FIG. 3, almost no formation of monoclinic phase was determined for sample 5, for which a calcium containing gel was applied. Regarding hydrothermal stability, this sample showed thus the best results followed by the sample 4 for which only a very minor increase in monoclinic phase could be determined.