Bone substitute material made of zirconium dioxide ceramic

Abstract

A bone substitute material is disclosed consisting of a zirconium dioxide ceramic having preferably an open porosity. The bone substitute material can be used in particle form or in block form.

Claims

1. A bone substitute material for use in dental implantology, consisting of a zirconium dioxide ceramic configured in particulate form having a particle size in the range of 0.1 mm to 6.0 mm.

2. The bone substitute material of claim 1, having a particle size in the range of 0.2 to 4.0 mm.

3. The bone substitute material of claim 1, which is macroporous with an open porosity.

4. The bone substitute material of claim 3, comprising macropores with an average pore diameter in the range of 10 micrometers to 500 micrometers.

5. The bone substitute material of claim 1, comprising micropores with an average pore diameter of less than 10 micrometers.

6. The bone substitute material of claim 5, comprising micropores having an open porosity.

7. The bone substitute material of claim 5, comprising micropores with an average pore diameter of less than 1 micrometer.

8. The bone substitute material of claim 1, having a bimodal porosity including macropores and micropores.

9. The bone substitute material of claim 1, consisting of tetragonal, polycrystalline zirconium dioxide (TZP).

10. The bone substitute material of claim 1, wherein the porosity is in the range of 1 to 50%.

11. The bone substitute material of claim 1, wherein the porosity is in the range of 5 to 30%.

Description

EXAMPLES

Example 1

(1) Commercially available TZP powder (stabilized with 3 wt.-% of Y2O3) with an average specific surface area of 50 m.sup.2/g is mixed with 20 wt.-% of short fibers of polyvinylchloride (PVC) having an average diameter of about 50 micrometers and an average length of 500 micrometers, while adding a binder (1 wt.-% of isopropanol), so that the short fibers are randomly distributed. Thereafter an uniaxial pressing is carried out using a suitable steel die (at a pressure of e.g. 20 to 50 bars).

(2) Subsequently, a heating to about 1350 C. at about 50 K/min and a holding at 1350 C. for about 30 to 120 minutes is performed, thereafter cooling by switching off.

(3) In this way there is obtained a macroporous block of TZP ceramic having an open porosity. The material thus obtained can be ground to porous particles by means of a ball mill and can be screened accordingly to a desired particle size distribution.

(4) Instead of an uniaxial pressing, also the powder mixture can be pressed isostatically.

Example 2

(5) For the preparation of powdered BSM, that is non-porous, commercially available zirconium dioxide is ground to the desired particle size distribution and is subsequently sieved. This is of particular interest for smaller particle sizes, such as smaller than 1 to 2 millimeters in diameter.

Example 3

(6) The material of example 1 was not ground, but directly used in block form. It can be brought into the desired size and/or shape by a mechanical treatment using diamond tools.

Example 4

(7) Comercially available TZP powder (stabilized with 3 wt.-% of Y2O3) with an average specific surface area of 50 m.sup.2/g is mixed with 5 wt.-% to 10 wt.-% of short fibers of polyvinylchloride (PVC) having an average diameter of about 50 micrometers and an average length of 500 micrometers, while adding a binding agent (1 wt.-% of isopropanol), and is isostatically pressed thereafter (pressure e.g. 500 to 1000 bars).

(8) This is followed by a heating to about 900 C. at about 50 K/min and a holding for about 15 to 30 minutes, thereafter a cooling by switching off. This provides a macroporous green body which can be machined in the green state, for example by means of an automatically controlled milling device. Herein the degree of shrinkage for the subsequent sintering process is taken into account.

(9) Finally, a final sintering is carried out at about 1300 C. (heating at about 50 K/min, thereafter holding at 1300 C. for about 15 to 60 minutes). This yields a macroporous zirconium dioxide body with open porosity.

Example 5

(10) An open-porous plastic foam is immersed within a slurry with zirconium dioxide powder according to example 1, is impregnated with the slurry, followed by drying (60 minutes at 90 C.), followed by sintering according to example 1. This yields an open porous zirconium dioxide ceramic.

Example 6

(11) A post treatment is performed with respect to the examples 1 to 5, by carrying out an etching treatment by immersing in hydrofluoric acid, in which the fully sintered and optionally ground BSM is immersed for example in 40% hydrofluoric acid and etched 5 to 60 minutes, preferably at elevated temperature, for example at 60 to 70 C.