Zirconium dioxide based prostheses
A process for the manufacture of a zirconium oxide prosthesis, the zirconium oxide being stabilized, which process includes the following steps: a) compacting a zirconium oxide powder at a pressure of at least 45 MPa to an object of a desired form, b) impacting an etchable medium into the surface, c) optionally working the object to a final shape, d) sintering the body at a temperature of above 1170° C. to transfer zirconium oxide into a tetragonal crystalline structure, and e) etching the etchable medium using hydrofluoric acid to remove the medium and impart a micromechanical retention surface. A prosthesis prepared by this process is also disclosed.
1. A process for manufacturing a zirconium oxide prosthesis, the zirconium oxide being stabilized, comprising the steps of:
a) compacting a zirconium oxide powder at a pressure of at least 45 MPa to form an object and simultaneously impacting an etchable medium into a surface of the object;
b) sintering the object at a temperature above 1170° C. and below 2370° C. to transfer zirconium oxide into a tetragonal crystalline structure; and
c) etching the etchable medium using hydrofluoric acid to remove the etchable medium and impart a micromechanical retention surface.
2. The process of claim 1 , wherein the etchable medium is polymer particles.
3. The process of claim 1 , wherein the etchable medium is glass particles.
4. The process of claim 1 , wherein the sintering temperature is 1300 to 1600° C.
5. The process of claim 1 , wherein the zirconium oxide is stabilized with one or more of compounds selected from the group consisting of yttrium oxide, magnesium oxide, calcium oxide, cesium oxide, and combinations thereof.
6. The process of claim 1 , wherein the compacting step a) is carried out at a pressure of 45 to 150 MPa.
7. The process of claim 1 , wherein the compacting step a) is carried out using a cold isostat pressing.
8. The process of claim 1 , wherein the compacting step a) is carried out using a mechanical uniaxial pressure.
9. The process of claim 1 , wherein the compacting step a) is carried using a pressure cuvette.
10. The process of claim 1 , wherein the etching step c) is followed by a rinsing step with a component selected from the group consisting of an organic, inorganic acid, water, and combinations thereof.
11. The process of claim 1 , wherein the hydrofluoric acid in the etching step c) takes place at a concentration of about 5-15% and the etching medium is contacted with the hydrofluoric acid for a time period of about 1 to 3 minutes.
12. The process of claim 1 , wherein the object is obtained using an additive forming process.
13. The process of claim 1 , wherein the object is obtained using a subtractive forming process.
14. The process of claim 1 , further comprising a shaping step between the compacting step a) and the sintering step b), wherein the object is worked in a final shape.
15. The process of claim 1 , wherein the etching step c) forms pits or micro-lacunas on the surface of the object.
16. A process for manufacturing a zirconium oxide prosthesis, the zirconium oxide being stabilized, comprising the steps:
a) compacting a zirconium oxide powder and stabilizing oxides selected from the group consisting of yttrium oxide, magnesium oxide, calcium oxide and cesium oxide, wherein the compacting is at a pressure of 45 to 150 MPa to form an object and simultaneously impacting an etchable medium into a surface of the object, the etchable medium is selected from the group consisting of polymer particles, glass particles and combinations thereof;
b) working the object to a final shape;
c) sintering the object at a temperature of 1300 to 1600° C. to transfer zirconium oxide into a tetragonal crystalline structure; and
d) etching the etchable medium using hydrofluoric acid to remove the etchable medium and impart a micromechanical retention surface.
17. The process of claim 16 , wherein the hydrofluoric acid etching step d) imparts pits and micro-lacunas on the surface.
18. The process of claim 16 , wherein the hydrofluoric acid in the etching step d) is at a concentration of about 5-15% and the etching medium is contacted with the hydrofluoric acid for a time period of about 1 to 10 minutes.
19. The process of claim 16 , wherein the glass particles of the compacting step a) have about 1 to about 40 μm average diameter size.
20. A process for manufacturing a zirconium dioxide prosthesis, the zirconium dioxide being stabilized, comprising the steps:
a) compacting a zirconium dioxide powder and stabilizing oxide of yttrium oxide wherein the compacting is at a pressure of 45 to 150 MPa to form an object and simultaneously impacting an etchable medium into a surface of the object, the etchable medium is glass particles;
b) working the object to a final shape;
c) sintering the object at a temperature of 1300 to 1600° C. to transfer zirconium dioxide into a yttria-stabilized tetragonal zirconia or polycrystals (Y-TZP) structure; and
d) etching the etchable medium using hydrofluoric acid to remove the etchable medium and impart a micromechanical retention surface.