CH586166A5 - Material for surgical prosthesis - comprising metal (oxide) FIBRE REINFORCED CERAMICS - Google Patents

Abstract

Material comprises fibres esp. of W, Mo, Ta, Ti, metal oxide, carbide nitride, boride or of a metalloid such as C, B, etc., in a matrix of ceramic material, esp. pure Al2O3 or dental porcelain (K2O, Al2O3. 6SiO2). Esp. for hip joints but also suitable for dental protheses, bridges, and also esp. for tools for making plates corners and other prosthetic joints. The fibres improve the resistance to bending and fracture of the prostheses without affecting the biological passivity, the corrosion resistance or the compressive strength adversely. Use for tools avoids introduction of metal particles into threaded holes, meshes, etc. to cause harmful effects on the patient.

Description

  

  
 



   The present invention relates to equipment for bone surgery. This material is suitable for orthopedic hip prostheses, for example, plates, screws and other devices intended for the reduction of fractures and various instruments intended for fixing in the human body the prostheses or other devices described above.



   Currently, hip prostheses, plates, screws, angles used for fracture reduction are made of a special alloy such as titanium, vitallium, prota-sul or stainless steel.



   Dental implants are made of chrome, cobalt, titanium, tantalum or vitallium. In fact, modern implantology fixes a metal or ceramic framework in or on a bone arch. They are therefore artificial structures called upon to support one or more false teeth.



   There are two main classes of implants: endosseous and juxtaosseous. The first are placed deep in the arch, after perforation of an artificial socket, while the second, also called grids, are made from the very precise impression of the bony arch that they come to marry before 'be embedded in the periosteum and fibromucosa which connect the gum to the bone.



   Both endoosseous and juxtaosseous emerge in the form of small rods called abutments on which the practitioner fixes the tooth, bridge or prosthesis, either directly or through a second metal frame, the superstructure.



   The endos are in the form of spirals, screws or even needles, while the grids intimately embrace a surface of the bone arch as small as possible. Being metallic, they present certain dangers specific to metals such, for example, electrolytic phenomena in the mouth.



   Bone prostheses, devices intended to help reduce fractures by fixing the broken parts together within the human body itself, also present phenomena of rejection.



   Alumina ceramic, a biologically inert material, tends to impose itself more and more on the market. But if its corrosion resistance is almost absolute, its complete biological passivity and its good compressive strength, its flexural and shear strengths are nowhere near as satisfactory.



   The aim of the present invention is to overcome these drawbacks by providing a material for bone surgery which combines good resistance to biological agents with mechanical qualities.



   It is characterized in that it is formed of fibers embedded in a ceramic matrix, the fibers providing resistance to bending and shearing, the ceramic matrix providing biological insulation.



   The ceramic used can be a pure oxide ceramic such as alumina ceramic (au203). It can also be formed from dental porcelain (K2O. Ah03. 6 SiO2) or any other ceramic having qualities of sufficient mechanical strength, biological inertia and compatibility with the reinforcing fibers.



   The fibers can be tungsten, molybdenum, tantalum, titanium. They can also be metal oxide, carbide, nitride, boride or even metalloids such as carbon, boron, etc.



   It is preferable to choose materials which can withstand the sintering temperature of ceramics which varies between 1000 C and 1900 C depending on the Au203 content. In the choice of fiber and ceramic, account should also be taken of the wettability of the fiber by the latter.



   These fibers can be polycrystalline in the form of rolled metal threads, but also monocrystalline in the form of whiskers or whiskers.



   The design and manufacture of the devices must be carried out in such a way that the metal wires are embedded in the ceramic mass so that they do not come into contact with the bone or with the fibromucosa.



   The devices for bone surgery, made of the material according to the invention, are mechanically resistant and resist corrosion. They can advantageously replace the metallic devices known to date.



   The material described can also be used to manufacture elements other than implants, conventional elements of dentistry such as bridges, prostheses.



   But a particularly interesting application of the equipment described is the making of tools serving to prepare the seat of the implants proper, prostheses, plates or angles serving for the reduction of fractures. These tools can be bits, taps, cold chisels, for example. Because it is not uncommon that, when drilling or tapping a bone, tiny parts of the metal of the tool remain fixed in the bone material, causing a phenomenon of rejection harmful for the patient.



   Another advantage of using the equipment described is that the age of the patients on whom bone prosthesis fixation operations are performed could be lowered by several years given the absence of biological rejections.

 

Claims (1)

I. Equipment for bone surgery, characterized in that it is formed of fibers embedded in a ceramic matrix, the fibers ensuring resistance to bending and shearing, the ceramic matrix ensuring biological insulation. He. Use of the material according to claim I for manufacture of apparatus for bone surgery.