Composite ceramic material and method to manufacture the materia

Details Composite ceramic material and method to manufacture the materia Composite ceramic material and method to manufacture the materia

1991-08-15

1994-04-26

Derrington, James

Compositions: ceramic

Ceramic compositions

501123, 501125, 264 65, 264570, 264 60, C04B 3510, C04B 3546, C04B 3548

Patent

active

053066731

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

The present invention relates to a composite ceramic material having a high strength combined with bioactive properties when the material is used as a dental or orthopedic implant. The invention relates also to a method to manufacture the composite ceramic material.


BACKGROUND ART

Ceramic materials and particularly structural ceramic materials generally have a high resistance to corrosion and erosion. This is true of e.g. several oxides, nitrides, carbides and borides. Also, said materials have no toxic properties. When used as implant materials said materials are completely inactive, i.e. neither positive nor negative reactions with surrounding tissues take place, and consequently it is possible to attain a biological integration to bone tissue without any intermediate connective tissue. Such materials are termed inert when used as implant materials. These properties make several oxides, nitrides, carbides and borides potentially very valuable as inert dental and orthopedic implant materials.
However, it is desirable that materials having a favorable biocompatibility are not only inert, i.e. able to fasten mechanically to a bone tissue, but also bioactive, i.e. the implant can be bonded chemically to a bone tissue. Oxides, nitrides, carbides and borides do not have this property. On the other hand it is known that phosphate-based materials, having a chemical composition similar to the "inorganic" or "ceramic" matter in bone tissue, can display bioactive properties. Such a phosphate-based material is e.g. hydroxylapatite, Ca(PO.sub.4).sub.3. However, a synthetic hydroxylapatite has a low tensile toughness and hence a low strength and also a tendency to gradually develop a continuous crack growth. Another example of a bioactive material having a calcium phosphate-base is tricalcium phosphate Ca.sub.3 (PO.sub.4).sub.2, but this compound has an unsatisfactory strength. Also, it has a not negligible water solubility and consequently may be dissolved before the bond to the bone tissue has developed. Thus, in this respect, hydroxylapatite is preferred as compared to tricalcium phosphate.


DISCLOSURE OF THE INVENTION

The object of the invention is to suggest a composite ceramic material having a so called duo-quality , i.e. a high strength combined with a bioactivity. This and other objects can be attained by using a material, which comprises, when it is used as an implant material, an inert matrix having a high strength and in the matrix evenly distributed 5 -35 percent by volume of at least one second phase, which mainly comprises at least one material having a calcium phosphate-base. This calcium phosphate-base can e.g. be hydroxylapatite and/or tricalcium phosphate, while the matrix can comprise mainly one or several oxides and/or nitrides. The matrix comprises preferably mainly one or several oxides belonging to the group which comprises titanium dioxide, zirconium oxide and aluminum oxide.
The used hydroxylapatite can be entirely synthetic or consist of a bone ash, which also contains other compounds than hydroxylapatite in small contents.
The material is produced by preparing a powder mixture, which mainly consists of partly a first powder, which in the condition the powder material is in during the admixture or it will obtain after a subsequent chemical reaction can form a biologically inert matrix in the finished material when it is to be used as an implant material, and partly a second powder, mainly consisting of a material having a calcium phosphate-base. A raw compact is made of this powder mixture and densified by a hot isostatic pressing at a temperature of 900.degree.-1300.degree. C. and a pressure higher than 50 MPa, preferably at a pressure of at least 150 MPa and preferably not more than 250 MPa. The raw compact (green body) is in this case suitably produced by a cold isostatic compacting, which precedes the hot isostatic compacting, which is facilitated by the admixture of the calcium phosphate powder into the oxide powder. Despite the comparatively low temperature during

REFERENCES:
patent: 4149893 (1979-04-01), Aoki et al.
patent: 4599085 (1986-07-01), Reiss
patent: 4957674 (1990-09-01), Ichitsuka
Chemical Abstracts vol. 108, No. 2, Abstract 11277u Jan., 1988.
Hot Isostatic Press, Kobe Steel, No. 428090, pp. 1-6, Aug., 1982.

Affiliated with

Also associated with

Rating

Composite ceramic material and method to manufacture the materia does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Composite ceramic material and method to manufacture the materia, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composite ceramic material and method to manufacture the materia will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1711585