IMPLANT AND METHOD OF MAKING IT

Abstract: An implant (prosthesis) comprises biological material in its surface intended to face the body tissue. The surface is formed of a layer (3) consisting of a mixture of grains (5) of tissue-compatible type and disintegrated tissue-compatible biological material (4). In a method of making the implant, an implant body (2) and amixture of grains (5) of tissue-compatible type and disintegrated tissue-compatible biological material (4) as well as a nutrient solution (6) for the latter are placed in a mould (8). The biological material is allowed to grow in the mould, both out to the boundary wall of the mould cavity and in to the implant body.

Description: IMPLANT AND METHOD OF MAKING IT The present invention relates to an implant and a method of making it. Implants consisting of or having a surface layer of tissue-compatible material, εuch as titanium and certain types of ceramic materials, are already known, e.g. from SE-7902035-0. A common feature of most of these implants is that they are designed for closely engaging the biological tissue, such that this rapidly contacts and grows into the implant. To this end, femoral prostheses, for exam¬ ple, are often formed with projections by means of which the prosthesis catches onto the inner wall of the femoral cavity. This, however, results in an unresilient joint be- tween the surface of the implant and the opposing body tissue, which is a disadvantage, especially in the case of spongy tissues, such as in jaws. Despite the provision of projections, the healing process will take quite a long time, which not only causes discomfort to the patient but may also give rise to the formation of connective tissue in the joint be¬ tween the implant and the tissue. The object of the present invention is to overcome, or at least substantially reduce the above-mentioned drawbacks in prior-art implants. According to the invention, this object is achieved in that the implant in its surface intended to face the body tissue, comprises tissue-compatible biological ma¬ terial, preferably tissue, and most preferably endoge- nous tissue of the same type as that in which or against which the implant should be inserted or placed, respec¬ tively. The surface of the implant is formed of a layer provided on a supporting body or anchoring elements (the term "supporting body" as used hereinafter should also be considered to include "anchoring elements" ) consisting of or having a surface layer of tissue-com¬ patible material, said layer comprising a mixture of grains/pulverulent material of tissue-compatible type and disintegrated tissue-compatible biological material which has grown, both out to the outer surface of the implant and in to the supporting body, and by the latter growth has been linked to the supporting body, said growth of the biological material also generally linking the pulverulent particles/grains to each other. To pro¬ mote such growth, use is made of a suitable commercially available nutrient solution. The supporting body or its surface layer is advan- tageously of titanium, and its outer surface is advan¬ tageously porous for optimum tissue anchorage. The tissue-compatible grains can be selected from different materials, primarily titanium, but other mate¬ rials known to those skilled in the art can be used, such as bioceramics, bioglass and hydroxyapatite. It will be appreciated that the implant according to the invention, containing biological material in its surface layer r will reduce the time required for healing after implantation, i.e. the time required for biological anchorage of the implant in or against body tissue. The implant according to the invention is advan¬ tageously made in a mould, the cavity of which contains the supporting body (or the part thereof to be provided with said layer) and a mixture of said material in the space between the supporting body and the boundary wall of the mould cavity. To this mixture contained in the mould cavity is added a nutrient solution promoting (optionally after replenishment) the growth of the bio- logical material in the mixture. The growth parameters are available in the literature to those skilled in the art. One advantage of such a technique is that the im¬ plant can easily be tailor-made for the patient. The mould cavity is provisionally shaped after e.g. a dental bed, and any modifications of the implant that may later be required are determined by radiography after implan¬ tation of the implant shaped in the mould. Modifica¬ tions of the mould cavity are then performed for obtain¬ ing a more correct implant. In the illustrated drawing, there are shown two em- bodiments of the invention. Fig. 1 shows a dental prosthesis 1 to be screwed into a jaw. The supporting body 2 of the prosthesis is of tissue-growth promoting titanium having a porous outer surface (obtained by sintering, metal deposition by vaporisation etc). To the supporting body is fixed a layer 3 consisting of a mixture of bone meal 4 ground from jawbone tissue taken from the patient, and titanium powder 5. The mixture has been supplied with a nutrient solution 6 causing the bone meal in the mixture to grow and form tissue 7 linking the components 4 , 5 of the layer 3 to each other and to the supporting body 2. The prosthesis has been made in a silicon mould 8 with threads 9 on its inner side, thus forming threads 10 on the outer surface of the dental prosthesis. Fig. 2 shows a cartilaginous implant 11 provided with several titanium pins 12 embedded with one end in a layer 13 of the mixture described above. With the op¬ posite, free ends of the pins 12, the implant 11 can be fixed to body tissue.

Claims: CLAIMS 1. An implant (prosthesis) comprising biological material in its surface intended to face the body tis¬ sue, c h a r a c t e r i s e d in that said surface is formed of a layer provided on a prosthetic body (2) or a layer from which one or more layer-anchoring ele¬ ments (12) project, said body or anchoring elements consisting of or having a surface layer of tissue-com¬ patible material consisting of a mixture of grains/pul¬ verulent material (5) of tissue-compatible type and dis- integrated tissue-compatible biological material (4), such as bone meal , which by the addition of nutrient has been caused to grow, both out to said surface and in to said body or said anchoring elements so as to be linked thereto, said growth also linking together the components (4, 5) of said mixture. 2. Implant according to claim 1, c h a r a c ¬ t e r i s e d in that said body (2) or said anchor¬ ing elements (12) comprises/comprise titanium having a porous outer surface. 3. Implant according to any one of claims 1-2, c h a r a c t e r i s e d in that the granular/pul¬ verulent material (5) comprises titanium. 4. Implant according to any one of claims 1-3, c h a r a c t e r i s e d in that the biological ma- terial (4) is endogenous. 5. Implant according to any one of claims 1-4, c h a r a c t e r i s e d in that the biological ma¬ terial (4) is tissue of the same type as that in which or against which the implant should be inserted or placed, respectively. 6. A method of making an implant according to any one of claims 1-5, c h a r a c t e r i s e d in that an implant body or implant-anchoring elements and a mix¬ ture of grains/pulverulent material of tissue-compatible type and disintegrated biological material as well as a nutrient solution for the latter are placed in a mould in which the biological material is allowed to grow, both out to the boundary wall of the mould cavity and in to the implant body.

Inventors: BRUCE INGRID, BRUCE LARS, BRUCE, INGRID, BRUCE, LARS
Applicants: IDEA AB, AB IDEA
Application year: 1989
Main classification: A61L27
IPC codes: A61C8, A61F2, A61K6, A61L27