WO2010097413A1

WO2010097413A1 - Implant, at least partially comprising a composite material, intermediate composite product and method for producing an implant

Info

Publication number: WO2010097413A1
Application number: PCT/EP2010/052347
Authority: WO
Inventors: Heinrich K. Feichtinger; Peter Uggowitzer
Original assignee: Jossi Holding Ag
Priority date: 2009-02-25
Filing date: 2010-02-24
Publication date: 2010-09-02

Abstract

A composite body (2) made of particles of a magnesium-containing phase (4) and particles (3) of a titanium alloy is applied to the surface of a solid-body implant (1) together with a mixture (5) comprising titanium hydride and a binder, and is subsequently heated under a vacuum and/or under protective gas. After removal of the binder and dissociation of the titanium hydride into titanium, diffusion welding occurs at statistical contact points (13) of the particles among each other and at contacts between said particles and the surface, and at the same time fusing or bonding of the magnesium-containing particles among each other occurs at the statistical contact points, so that two interlocking titanium-containing and magnesium-containing phases develop. After implantation and upon contact with body fluid, the magnesium-containing phase dissolves, wherein the release of magnesium ions results in the precipitation of calcium phosphates that have an osteoinductive effect, whereby peripheral bone tissue augments into the hollow spaces previously filled by the magnesium-containing phase.

Description

Implant, at least partially consisting of a composite material, intermediate composite product and method for producing an implant

The invention relates to an implant, at least partially consisting of a composite material comprising a titanium-containing first component and a magnesium-containing second component, according to the preamble of claim 1, an intermediate product for producing a composite material according to the preamble of claim 7, and a method for producing an implant at least partially consisting of a composite material according to the preamble of claim 16.

Medical implants are known in a variety of forms, in the present case are meant by this term, especially endoprostheses, as they are used in body joints or in dental prosthetics. A variety of materials are used, eg stainless steels, cobalt-chromium-molybdenum alloys and titanium alloys. A particular problem is the anchoring of the endoprostheses in the peripheral bone tissue. Biotolerant and bioinert materials, such as stainless steels or cobalt-chromium-molybdenum alloys require the solid anchoring of, for example, the stem of a hip joint endoprosthesis, the use of a cement high precision when fitting the endoprosthesis requested by the surgeon. In contrast, there are bioactive materials such as titanium and its alloys, which exert an osteoinductive effect on peripheral bone tissue, in particular with favorable surface design, whereby it augments to the surface of the endoprosthesis and forms a firm connection with it. This positive property of titanium surfaces is mainly due to the oxide layer spontaneously formed on titanium surfaces. which has hydroxyl groups to which protein molecules can dock.

Generally, it can be said that the adhesion between bone tissue and a smooth implant surface improves in bulk as this surface is enlarged or patterned. Such a structure can be produced both reductively, with erosive as well as additive, with applying methods.

Reductive methods of machining the titanium surface include e.g. Turning, sandblasting, acid etching and electrochemical oxidation. According to EP 0 388 576, e.g. In a first step, a topography with desired roughness depth is produced by sandblasting with special abrasion materials, which is subsequently exposed to a special etching in a second step, whereby a surface with improved osteoinductive properties is formed.

Additive methods include, for example, the group of TPS methods in which titanium hydride powder with plasma gas is applied to the surface of the implant in a vacuum chamber, wherein the spray parameters are selected to provide an open-pore titanium structure which provides improved osseointegration allows. The favorable effect of such an O berfläche, which is compared to a smooth increased by about six times, can be increased by an additional coating, for example with hydroxyapatite. The TPS method and also other methods, as used in particular for dental implants, are summarized in a book by W. Bücking and R. Suckert (Bücking, W. and Suckert, R .: "Implant Prosthetics", New Merkur Verlag, 1995). US Pat. No. 6,849,230 describes another method for producing a porous bone-like structure. In a preferred variant, titanium hydride is heated together with saline spheres, which are in a packing similar to the closest packing, and a suitable binder in a negative pressure zone, after removal of the binder, upon further heating, decomposition of the titanium hydride and formation of a pure titanium phase firmly sintered on further heating. An essential step of the inventive concept is that the temperature is carried to a range where the common salt is removed by melting and evaporation from the open-pore titanium structure, after which a bone tissue-like structure remains.

Attempts have also been made to coat the surfaces of implants with wire-like surface structures. For example, in accordance with US Pat. No. 3,906,550, an acetabulum is anchored over a mesh of entangled metal fibers which connect to the bone tissue. The metal fibers, preferably of a chromium-cobalt-molybdenum alloy, are connected via welding points both with each other and with the surface of the implant. An advantage of this method is stated that such a fiber structure, in contrast to sintered metal powders has a continuous open-pored pore structure.

In contrast to endoprostheses that remain permanently in the body, there are fasteners for bones, such as plates, screws or nails, for example, whose task is temporarily to fix the bone tissue on both sides of a breakage and immobilize until the break point has grown together again. Once this is the case, these fasteners must be in a second surgical procedure again be removed, which is an additional burden on the patient.

Therefore, the idea was already developed in the first half of the 20th century to manufacture such implants from magnesium alloys, since such magnesium alloys corrode in contact with body fluids and thus dissolve successively, so that their removal is no longer necessary. The problem of these first alloys, however, was the high reactivity of these alloys, because the reduction of the mechanical strength of the implant associated with the dissolution must in fact coincide with the increase of the bone structure so that the stability of the connection is ensured at all times. Another disadvantage of the rapid dissolution of these first alloys was also the strong evolution of hydrogen, which is associated with the corrosion of base metals, this hydrogen could not be absorbed with sufficient rapidity and often formed at undesirable sites with gas-filled caverns, which hindered the healing process. Modern magnesium alloys, as e.g. in EP 1'395'297Bl have a more favorable corrosion behavior.

Of particular interest in the behavior of such controlled corroding magnesium alloys is the fact that the magnesium ions released during the corrosion process, together with the increase in pH, lead to local precipitation of calcium phosphates, which are converted into functioning bone tissue in the subsequent process of osseointegration so that the previously occupied by the implant cavity after completion of the healing process is largely filled by new bone tissue. This concept of magnesium-induced bioactivation has also been used in endoprostheses by vapor-depositing magnesium or a magnesium alloy onto the surface of a stainless steel implant, for example, or by ion implantation into this surface. If one takes into account that the amounts of magnesium offered are relatively small, then only a short-term osteoinductive effect can be maintained.

WO2008 / 122594 describes an implant having an open-pored three-dimensional framework structure made of a first, non-particulate material, wherein the pores are filled with a second, particulate material. First or second material may consist of metal, such as titanium or magnesium, wherein at least one material is biodegradable.

WO2008 / 122595 discloses an implant having an open-pore three-dimensional framework structure made of a first, non-particulate material, wherein the pores are filled with a second, likewise non-particulate material. First or second material may consist of metal, such as titanium or magnesium, wherein at least one material is biodegradable.

An object of the present invention is to avoid the disadvantages of the known and in particular to provide an implant of the type mentioned, which has osteoinduktiv properties and allows the ingrowth of bone tissue in an advantageous manner. This object is achieved with an implant according to claim 1.

The implant according to the invention consists at least partially of a composite material comprising a first titanium-containing component and a second magnesium-containing component. Of the Composite is obtainable by diffusion bonding single bodies of the first component using titanium hydride particles in the presence of single bodies of the second component, which fuse together during diffusion bonding. The individual bodies of the second component have a maximum width of 0.05 mm to 1 mm before the fusion. The two welded or fused components are arranged statistically regularly and / or in a periodically repeating pattern.

The width here is to be understood as meaning the smallest external dimension of the individual body measured at right angles to its longitudinal axis, thus e.g. the outer diameter of an ellipsoid or the smallest narrow side of a prism. In this sense, individual wires or shaped bodies made of individual wires, such as helices, can be regarded as a single body.

The pattern of the first titanium-containing component has substantially the shape of an open-pore network structure after the diffusion bonding. The magnesium-containing component largely fills the pores of the network structure of the first component after the fusion. It itself forms a magnesium-containing network structure which extends within the pores of the titanium-containing network structure of the first component. After implantation of the implant, the magnesium-containing network structure is dissolved by contact with body fluids, whereby calcium phosphate is precipitated. The advantage of such a structure is that initially there is an implant which has a high strength and only gradually begins to form an osteoinductive open-pore network structure. Furthermore, the growth of new bone cells is due to the dissolution of the magnesium-containing component and the resulting Prevented precipitation of calcium phosphate in the pores of the network structure of the first, titanium-containing component favors.

The pattern of the first, titanium-containing component is obtainable by diffusion bonding of the individual bodies of the first component to one another. The use of titanium hydride particles allows for diffusion bonding at lower temperatures than when no titanium hydride particles are used. The individual bodies of the first component can consist only of titanium hydride particles, which in the case of diffusion welding decompose into titanium and hydrogen and form a network structure of titanium. Alternatively, the first component may also consist of individual bodies of titanium or a titanium alloy, which are mixed with titanium hydride particles and / or coated.

The single bodies of the second magnesium-containing component preferably include magnesium, a magnesium alloy, a magnesium salt or mixtures thereof. In addition, the second component may also contain further salts, preferably calcium salts, such as calcium fluoride, calcium chloride and / or calcium oxide. The advantage of using magnesium salts is that they also release oxy-inductive magnesium ions during the dissolution process, but without the simultaneous formation of hydrogen, as is typical for the corrosion of metallic magnesium or its alloys. The addition of calcium salts has the advantage that the liberated during the dissolution Calciu- ions increase the solubility of calcium phosphate. The individual bodies of the second component are arranged statistically regularly like those of the first component and / or in a periodically repeating pattern. As a result of the heat of the diffusion bonding, the individual bodies of the second component fuse together to form a magnesium-containing network structure which covers the pores of the titanium-containing network structure. tur, which results from the diffusion bonding of the first component, largely fills. As a result, the composite material obtains its stable solid structure after diffusion bonding. The individual bodies of the second, magnesium-containing component have a maximum width of 0.05 mm to 1 mm. By using individual bodies in this size, pores can be produced in the network structure of the first component in the composite material, which have an optimum osteoinductive size.

Preferably, the composite is bonded to the surface of an implant. The implant preferably has a metallic base body. Particularly preferably, the implant has a base body of titanium or a titanium alloy. The composite material is preferably connected by welding to the implant surface. The welding of the composite preferably takes place in the same step as the diffusion bonding of the individual bodies of the first component. Titanium implants are stable, have good biocompatibility and are well established in the market. Because the mesh structure of the first component is titanium or a titanium alloy and is welded to the body, the composite forms an osteoinductive surface of the same or similar material on the implant.

The use of titanium hydride particles in addition to the optionally present individual bodies of titanium or a titanium alloy is an essential prerequisite for the production of the composite material according to the invention on an implant. In the case of titanium implants in particular, care must be taken that the temperature during diffusion bonding does not rise above the transformation temperature of the titanium alloy used. Would the welding process eg without titanium hydride only with titanium powder durch- led, would have to be used for the sintering of these particles temperatures in the range above 1100 ⁰ C in which the structure of the titanium implant body would already be damaged. Another disadvantage of high welding temperatures is also the risk of excessive loss of the magnesium-containing component, since the vapor pressure of magnesium above 900 ⁰ C assumes very high levels. To enable diffusion bonding at a temperature below the transus temperature of titanium alloy implants, titanium hydride is used as an aid. The use of titanium hydride also allows for welding to other metallic or ceramic implant surfaces.

In this sense, the composite material may alternatively be connected to the surface of a ceramic implant. In the so-called active soldering technique, which serves to join metals and ceramics, titanium hydride is an important component in addition to other metallic components, because the titanium hydride is split into hydrogen and highly active reducing titanium when heated, which reacts with the superficial oxygen atoms of the ceramic. On the surface of the oxide ceramic, a metallization occurs, wherein the metallic components of the solder wet the ceramic surface and connect to it. The use of titanium hydride in the first component similarly enables the bonding of the composite to the ceramic implant in the same process step as the diffusion bonding of the single bodies of the first component. In particular, this can be used to provide or coat a joint-stem implant, such as, for example, an acetabular cup, with the osteoinductive composite material according to the invention. Furthermore, the basic implant body can consist of the composite material according to the invention as a whole. Alternatively, only certain areas of the implant base body may consist of the composite material. Alternatively, the composite material according to the invention can be present on the entire surface of the implant base body or only on partial areas thereof.

The first titanium-containing component preferably consists of individual bodies with a maximum width of 1 mm and a maximum length of 5 mm. These are preferably circular in cross section single body. Alternatively, the individual bodies may be elongated, such as wire pieces. If the maximum dimensions of the individual bodies of the first component are complied with, then, after the diffusion bonding of the individual bodies, a network structure with pores is formed which has an optimum geometry and size for the ingrowth of bone cells.

Alternatively, the individual bodies of the first component may have a maximum width of 1 mm and a length of at least 10 mm, more preferably at least 50 mm, the bodies preferably being helical. Accordingly, the network structure of the first titanium-containing component is composed of diffusion-bonded helices joined together. The helical structure of the individual bodies is preferably such that an envelope around the helically extending individual bodies has a maximum diameter of 3 mm. Helically extending single bodies in the first component result in a composite in which the first component and the second component are arranged in a periodically repeating pattern.

Another object of the invention is to provide an intermediate for producing an osteoinductive composite required. This object is achieved with an intermediate composite product according to claim 7.

The intermediate product according to the invention for producing a composite material consists of individual bodies of a first titanium-containing component and individual bodies of a second magnesium-containing component. The individual bodies of both components are arranged such that they are in contact with each other. The individual bodies of the first component are mixed or coated with particles of titanium hydride. Alternatively, the individual bodies of the first component consist of titanium hydride. The individual bodies of both components have a maximum width of 0.05 mm to 1 mm.

The use of such an intermediate product according to the invention for producing a composite material has the advantage that the individual bodies of the first titanium-containing component are diffusion welded together by heating and thus form a titanium-containing network structure. The individual bodies of the second magnesium-containing component will fuse together by the heat and form a second magnesium-containing network structure, which largely fills the pores of the first titanium-containing network structure. Such a composite material has good osteoinductive properties. In addition, the magnesium-containing network structure will dissolve in contact with body fluid and allows the ingrowth of bone cells into the first titanium-containing network structure.

The particles of titanium hydride preferably have a particle size of not more than 0.05 mm. This leads to an optimal distribution of the titanium hydride particles within the first component or as a coating on the individual bodies of the first component. The magnesium-milled particles of the second component are intended to determine the ometric character of the network structure, which is only possible if the titanium hydride particles are much smaller than these. In addition, the fineness of the titanium hydride particles, due to the shorter diffusion paths, enables a faster elimination of the hydrogen and, due to the higher specific surface area, also a higher sintering activity, which has a favorable effect on the diffusion bonding.

A further advantage of a finer particle size of the particles of titanium hydride lies in the fact that the welding of the resulting correspondingly finer titanium particles in the first sintering phase leads to a finely structured surface of the first titanium-containing component.

The particles of titanium hydride and the individual bodies of the second component are preferably mixed with a binder. The mass formed thereby is preferably pressed into a shaped body. As a result, a statistical distribution of the individual bodies of the second component and the particles of titanium hydride can be achieved. By subsequent heating, a composite material according to the invention can be produced from such an intermediate composite product. The mass of the intermediate product is very easy to shape and can be easily pressed to form a molded body of any shape.

Alternatively, the particles of titanium hydride may be mixed with the individual bodies of the first titanium-containing component as well as the individual bodies of the second magnesium-containing component and a binder. The mass thus obtained is preferably pressed into a shaped body. The presence of the individual bodies of the first titanium-containing component in addition to the particles of titanium hydride allows the moldability of the mass as well affect the distribution of titanium-containing material and magnesium-containing material in the mass.

The individual bodies of the first component can preferably consist of wire sections made of titanium or a titanium alloy which are preferably circular in cross-section. More preferably, the individual bodies of the second component of preferably circular cross-section wire sections made of magnesium or a magnesium alloy. The wire sections of the first component are preferably coated with titanium hydride. Alternatively, particles of titanium hydride may be mixed with the wire sections of the first and second components. By cross-sectionally preferably circular wire sections, the intermediate composite product can be easily produced.

The pieces of wire have a length which is preferably between 50% and 150% of their diameter. Particularly preferably, the wire sections have a length which corresponds to their diameter. As a result, an optimal contact density of the individual bodies is achieved, similar to the case of Raschig rings in the packed column technique, since this geometry leads to a statistical spatial arrangement of the individual bodies.

Alternatively, in the case of the intermediate composite product according to the invention, the individual bodies of the first component consist of wires made of titanium or a titanium alloy and the individual bodies of the second component consist of wires made of magnesium or a magnesium alloy, the wires of both components being connected to form a braid, a woven fabric or a knitted fabric are. This enables the production of composite material with regular network structures. In a further preferred embodiment, the intermediate composite product has a plurality of strands of wires, twisted together, of the first and second components, which are arranged side by side and / or one above the other on a metallic or ceramic base body. The strands consist of at least one wire of titanium or a titanium alloy and at least one wire of magnesium or a magnesium alloy. The titanium-containing wire is at least partially coated with titanium hydride. The number and diameter of the titanium and magnesium wires twisted together depends on the desired volume fraction of the two components within the composite to be produced. Strands of wires twisted together have the advantage that by simple twisting of wires regular network structures of the first as well as the second component can be produced. In the finished composite material then the wires of the first titanium-containing component are due to the twisting in helical form, in the second magnesium-containing component, this strict geometric helical arrangement is canceled by the melting process.

Another object of the present invention is to provide a method of making an implant having osteoinductive properties. This object is achieved by the method according to claim 16.

The method according to the invention comprises the following steps for producing an implant which consists at least partially of a composite material comprising a titanium-containing first component and a second magnesium-containing component. In this case, a first component is presented, which consists of particles of titanium hydride and optionally individual bodies of titanium or a titanium alloy. Thereafter, the first and second components are brought together to form an intermediate composite product, so the individual bodies of the two components touch each other statistically and / or in a periodically repeating pattern. The intermediate product is then optionally heated under pressure, until the dissociation of the titanium hydride to titanium and the formation of diffusion bonds between the individual bodies of the first component and to the fusion of the single body of the second component with each other.

The first component contains particles of titanium hydride. In addition, the first component may optionally also include titanium single body or a titanium alloy. The titanium hydride allows the formation of diffusion bonds at lower temperatures compared to pure titanium or a titanium alloy. In a next step, the first and second components are brought together. Depending on how the two components are brought together, the individual bodies of the two components touch each other statistically and / or in a periodically repeating pattern. The regularity and / or periodicity of the touches can be influenced by suitable choice of the individual bodies in terms of their dimensions and shape and by their quantitative ratio to one another. In the last step, the intermediate composite product produced by bringing the two components together is heated so that the titanium hydride dissociates to titanium and hydrogen and the freshly formed titanium particles form diffusion bonding sites with one another and with any titanium-containing bodies of the first component. This leads to the formation of a first titanium-containing network structure. Due to the heat, the individual bodies of the second component also fuse together. This forms a second, magnesium-containing network structure, wherein both network structures penetrate each other. The individual bodies of the second component preferably have a maximum width of 0.05 mm to 1 mm. The volume occupied by the single bodies of the second component before melting defines the pattern of the network structure of the first component. The use of individual bodies with a maximum width of 0.05 mm to 1 mm results in the composite material with a titanium-containing network structure, which is optimally suitable for the ingrowth of bone cells.

The heating can be done either at positive or negative pressure. In order to avoid reactions between the titanium hydride and the air, the heating may alternatively be carried out under a protective gas atmosphere.

Preferred is a mixture of particles of titanium hydride with a binder such as e.g. in the powder metallurgy of titanium alloys is used submitted. Important in this context is that the binder can be completely removed by the heat of the process in the sense of a debindering, without leaving any residues, which can adversely affect growing into the titanium-containing network structure bone cells. By using a binder, the particles of titanium hydride are present in a viscous mass which is easy to handle and which has e.g. easy to press into a mold.

In addition, single bodies of titanium or a titanium alloy can be admixed to the mass of the binder and the titanium hydride particles. As a result, the statistical regularity and / or the periodically repeating pattern of the contact points between the individual bodies of the two components can be additionally influenced. Also, this can be adapted to the statics of the composite material. Alternatively, the individual bodies of the first component may be coated or coated with titanium hydride particles. In order to ensure the cohesion of the particles of the first titanium hydride precoated and the second component in the context of a green body or a coating, a binder can also be mixed in this case.

The mass of titanium hydride particles and binder is particularly preferably mixed with the individual bodies of the second magnesium-containing component and applied to an implant base body. The application may take a variety of forms, e.g. by brushing, spraying or by pressing done, the adhesive effect of the binder can be used. As a result, a part of an implant can be provided with a composite material which has osteoinductive properties and allows the ingrowth of bone cells. The implant base body may be partially coated with titanium hydride, in order to achieve a better weld between the first component and the implant body. By applying to a basic implant body can also produce complicated shapes.

Alternatively, the individual bodies of the first and second components can consist of cut pieces of wire. Initially, titanium- and magnesium-containing wires are cut to a suitable length. Depending on the length and diameter of the wires and the ratio of the length to the diameter, the properties of the network structures formed by the components can be influenced; for example, wire sections whose length corresponds to their diameter preferably arrange statistically, while wire sections whose length exceeds the diameter yourself preferably store parallel to each other, which leads, for example, to directional mechanical properties.

A further alternative embodiment of the method according to the invention also provides that the individual bodies of the first and the second component consist of wires or pieces of wire which are brought together in such a way that at least one wire or piece of wire of the first component with at least one wire or piece of wire of the second component twisted a strand. If wires are twisted, then a relatively long strand can be produced, which can be wound, for example, around an implant main body. However, it is also possible to divide the twisted strands into shorter sections. Such pieces of wire can be welded, for example, as a bed of composite material bez. merge. The shell diameter of these strands may be e.g. can also be chosen equal to the length, whereby the strands preferably randomly arrange in a bed, but at the same time there is a periodicity of the sequence of titanium and magnesium-containing components within the single strands.

Alternatively, wires of the first and second components may first be twisted together into a strand. This strand is then divided into partial strands and pressed onto an implant body. The partial strands can also be pressed into a mold.

Another embodiment for producing certain structures based on titanium- and magnesium-containing wires is that the wires are wound into spirals by a known winding method, the spirals subsequently being cut into shorter sections and optionally pressed with a binder into a composite body where the spiral Body of the two components partially interlock. In this case, preferably, the spiral body of the first component can be precoated with titanium hydride, but it is also possible to introduce the titanium hydride only with the binder in the bed.

Alternatively, at least one wire of each component may be tangled together. The volume fractions of the two components can be varied, e.g. by different feeding speeds of the wires when tangled. Also in this case, the wire of the first component may preferably be precoated with titanium hydride, but it is also possible to add the titanium hydride particles together with the binder during or after the entanglement process.

Under entangling in the sense of the application, the chaotic entanglement of wires of the first and the second component is understood together.

In contrast to the prior art, the idea according to the invention is an osteoinductive composite zone for anchoring an implant in peripheral bone tissue, which in the sense of the independent claim consists of areas of a magnesium-containing metallic and / or salt-like phase and optionally areas of a titanium-containing metallic phase is formed, wherein the areas at least along a spatial axis have a diameter between 0.05 and 1 mm and are arranged in statistical and / or periodic manner to each other so that it comes to frequent contact with areas of the surface of its own and the other phase, at least the regions of the one component being in diffusion bonding via titanium regions resulting from dissociation of titanium hydride particles with a maximum grain size of 0.05 mm and that the magnesium-containing phase in contact with body fluid with salt-like character in a solubility process and metallic character in the sense of a corrosion process with release of magnesium ions according to their composition and geometry with the formation of calcium phosphate in a timely controlled manner in a solution, after which augmentation of the peripheral bone tissue by conversion of the calcium phosphate in these cavities takes place.

According to claim 16, the inventive idea also includes a method for producing such an osteoinductive composite zone, wherein areas of a magnesium-containing phase, optionally areas of a titanium alloy and titanium hydride particles, which are preferably in admixture with a binder or adhesive, such as in powder metallurgy injection molding is used to form a composite body which either forms the entire implant or is applied to the surface of an implant body, this composite body or composite in an optional first phase corresponding to the nature of the binder or adhesive De bindering on a it is heated in a second phase at gradually increasing temperature under reduced pressure and / or inert gas, which leads to the dissociation of the titanium hydride to titanium with elimination of hydrogen and that d the heating process is conducted in a third phase up to a temperature, where it comes to the diffusion bonding of the newly formed titanium phase with at least one of the adjacent phases and the optional implant body, wherein at the same time either comes to melting and crosslinking of the magnesium-containing phase. In essence, this composite zone thus consists of a network of a permanently remaining in the body and kraftführenden metal phase, preferably titanium or a titanium alloy and in its cavities second cohesive network of a magnesium-containing phase, which in the production phase in the sense of a placeholder the shape of the determines in the second phase after implantation via the onset of contact with body fluid dissolution process an osteoinductive network of cavities, which favors the ingrowth of bone cells, whereby the mechanical stability of the existing metallic network is additionally increased.

If a composite material according to the invention is bonded to a ceramic implant base body by diffusion welding with the aid of titanium hydride, a bond strength can be achieved, which in the ideal case can exceed that of the ceramic. Titanium hydride thus makes it possible, in accordance with the invention, to produce a titanium- and magnesium-containing layer not only on a large number of metallic but also ceramic materials.

Further features and advantages of the present invention will become apparent from the following figures and examples. Show it:

1a-Id different phases in the production and after implantation of a first embodiment of an implant according to the invention with osteoinductive composite material on the surface in a sectional view,

FIGS. 2a-2d show various phases in the production and after implantation of a second embodiment of an implant according to the invention with osteoinductive composite material on the surface in a sectional view; 3a-3e different phases in the production of a third embodiment of an inventive osteoinductive composite material in a sectional view,

4a-4c different phases in the production of a fourth embodiment of an inventive osteoinductive composite material,

5a-5c different phases of the production of a further embodiment of a composite material according to the invention,

6a shows an embodiment of an intermediate composite product according to the invention,

FIG. 6b shows a cross section through the intermediate composite product from FIG. 5a along the axis, FIG.

7a and 7b different phases in the production of a further embodiment of an inventive osteoinductive composite material on the surface of an implant,

8 shows an embodiment of an implant according to the invention with a surface made of a composite material,

9 shows a section through a further embodiment of an inventive implant with a composite material on the surface,

10a and 10b two phases in the production of a further embodiment of a composite material according to the invention, 11a-11c show two phases in the production of an acetabular cup with a composite material according to the invention and a third phase, which shows the implant after implantation and augmentation of the peripheral bone tissue,

12 shows an embodiment of an inventive implant with a subsequently processed composite material, and

13 shows a further embodiment of an osteoinductive composite material which contains an elastically resilient reinforcement.

FIGS. 1 a to 1 d show a first variant of a production method of an implant 1 according to the invention, in which the implant 1 is provided with a composite material 2. As shown in FIG. 1 a, individual bodies of a magnesium-containing component 4 in admixture with titanium hydride particles, which are preferably previously mixed with a binder, as used, for example, in the powder metallurgy of titanium alloys, are mixed to form a mass 5 and placed on an implant 1 applied. Preferably, the applied mass can be pressed into a shaped body, so that a desired surface shape is formed. The individual bodies of the magnesium-containing component 4 may consist of a mixture of at least one magnesium salt and / or at least one metallic magnesium alloy. In the present example are particles of a magnesium alloy with approximately ellipsoidal shape whose width B at 0.35 mm and whose length L is about twice the value. The individual bodies can have shapes that can go from approximately centrally symmetric spherical up to the extremely elongated geometry of a wire, the width of which is between 0.05 and 1 mm. The amount of titanium hydride particles, preferably mixed with binder, whose particle size is preferably is half of 0.05 mm, it is limited in relation to the amount of the individual body of the magnesium-containing component 4 to a value which ensures that it comes to the pressing of the molding to numerous contact points 11 of the individual body 4 below as well as with the surface of the implant 1 , To ensure this, the amount of binder can be limited to a value at which remaining voids remain between the individual bodies 4 after the pressing.

The implant 1, to which the mass 5 is applied to form a composite material 2, preferably consists of titanium or a titanium alloy. However, implant 1 can also be made of a different metal or even of a ceramic mass, since titanium hydride is frequently used in soldering materials for producing metal-ceramic compounds, it being able to metallize the surface of a ceramic due to its high reducing power and to make it suitable for the soldering process.

Figure Ib shows a state after the composite of implant body 1 and mass 5 described in Figure Ia was subjected to a thermal aftertreatment. In a first step, the binder with which the titanium hydride particles have been mixed into mass 5 is removed in the manner of debindering, depending on its chemical nature, with a solvent and / or by careful thermal heating. The binder must in any case be designed in a physical and chemical manner so that it does not react with the titanium-containing component, or the process of debindering should be completed before the titanium hydride dissociates on further temperature increase to titanium and hydrogen, because the statu nascendi formed fine-grained titanium has a high chemical reactivity and would also with small traces of eg oxygen, nitrogen Substance or carbon react. For the same reason, the further heating, in particular the dissociation of the titanium hydride, must be carried out under reduced pressure and / or a suitable protective gas such as argon, in order to avoid a reaction between titanium and the gas atmosphere. The dissociation of titanium hydride begins depending on the gas pressure between 300 and 400 ⁰ C and stops at a temperature between 500 and 600 ⁰ C. As a result of the fine granularity and high reactivity of the titanium particles formed from the dissociation of titanium hydride, sintering already occurs in this temperature range, whereby, as the temperature is further increased, diffusion bonds 10 are produced between the surface of the implant 1 and that due to the dissociation of the titanium hydride formed Reintitans comes, with a contiguous network structure of titanium 6 is formed. Depending on the composition and melting point of the magnesium-containing individual bodies 4 as well as the height of the temperature in the final phase, the magnesium-containing individual bodies 4 merge at the points of contact 11 via fusion or diffusion bonding regions to form a coherent network structure 7 of the magnesium-containing component. The three-dimensional relationship of the network structure 7 is - especially in the case of salt-like magnesium-containing single body 4- supported by the wetting behavior, because while the magnesium-containing single body 4 naturally show good wetting among each other, this is much worse against the pure titanium. This behavior is known from the industrial production of titanium via the Kroll process, where the magnesium and titanium systems are also in contact at high temperatures.

FIG. 1c shows the state some time after the composite of implant 1 and composite 2 has been implanted peripherally to bone tissue 15. Coming through contact with body fluid it is the gradual dissolution of the network structure 7 of the magnesium-containing second component. If the magnesium-containing component is a mixture of one or more magnesium salts, for example magnesium chloride, a gradual dissolution process occurs with the release of magnesium ions. If the magnesium-containing second component is a metallic magnesium alloy, the dissolution occurs as part of a corrosion process with simultaneous release of hydrogen. In both cases, the dissolution kinetics are determined, on the one hand, by the stability of the network structure 7 and, on the other hand, by the geometry of the cavity system formed thereby, which determines the proportion and extent of the mass transfer processes occurring via diffusion and convection. Although not shown in the figure, the network structure 7 can also consist of a mixture of metallic and salt-like proportions, wherein the amount of the components can be chosen in particular in connection with their dissolution rate and with regard to the reduction of the undesirable in the corrosion of the network structure 7 amount of hydrogen ,

The dissolution of the network structure 7 leads to the precipitation of calcium phosphate 12. It is a special feature of the idea according to the invention that two osteoinductive principles are used in combination: on the one hand, this is the growth-promoting effect of a titanium structure 6 of optimum geometry, on the other hand the favorable effect of a long-term directed diffusion of magnesium ions, which flows off in a continuous manner by the degradation of the network structure 7 in the direction of the peripheral bone tissue 15 and favors the precipitation of calcium phosphate 12.

1 d shows the later final state in which the bone tissue 15 is augmented by conversion of the calcium phosphate 12 into new bone cells 16 in the titanium structure 6 of the composite material 2. is animal. Thus, a composite zone has now developed between the implant 1 and the bone tissue 15, in which shearing forces that exist between the rigid metallic implant 1 and the more elastic bone tissue 15 can be reduced in an efficient manner. Thus, the different bending behavior between a fully metallic implant 1 and the surrounding bone tissue 15 can be adjusted, which could otherwise lead to dangerous shear stresses at the periphery of the implant 1 and the bone tissue 15.

This first and simplest variant of an inventive implant 1 which at least partially consists of a composite material 2, uses only the titanium structure 6 formed from the dissociation of titanium hydride as a framework for the embedding of the network structure 7 of the magnesium-containing component. After dissolution of the magnesium-containing component, the titanium structure 6 forms osteoinductive cavities into which new bone cells 16 can augment. At the same time, the titanium structure 6 serves to form diffusion bonds 10 even at low temperatures, which results in a stable connection of the composite material 2 with the implant 1, so that the forces coming from the bone tissue 15 can be reliably transmitted to the implant 1.

FIG. 2 a shows a second alternative embodiment of a manufacturing method of an implant 1 according to the invention, which at least partially consists of a composite material 2, which leads to increased mechanical stability. In this case, the composite material 2 is constructed in addition to the individual bodies 4 of the magnesium-containing second component and also of individual bodies 3 of a titanium alloy. The individual bodies 3,4 are applied to the coating in the presence of titanium hydride, which is preferably mixed with a binder to give a composition 5 Part of the surface of the implant 1, preferably using a shaping process, applied or pressed. This results in statistical contact points 11 between the magnesium-containing individual bodies 4, contact points 13 between the individual titanium-containing individual bodies 3, contact points 14 between the titanium-containing individual bodies 3 and the surface of the implant 1 and contact points 10 between the mass 5 and the surface of the implant 1 In this example, the proportion of titanium hydride and binder is so tight that it must inevitably come to these touches upon pressing the mass 5, since any thin layers of titanium hydride are pushed by the forces of the pressing process largely away from the contact points to the side.

FIG. 2b shows, in a broad analogy to FIG. 1b, the state as it appeared after debindering and the dissociation of the mass 5 shown in FIG. 2a and its sintering into titanium structure 6. In addition, however, diffusion bonding occurs here at the contact points 13 of the titanium-containing individual bodies 3, resulting in a net-like three-dimensional structure 8 of the titanium alloy, which is additionally connected to the surface of the implant 1 via diffusion bonds 14, this surface being diffusion-bonded 10 also associated with the resulting from the decomposition of titanium hydride titanium structure 6. In the same way, the magnesium-containing particles 4 are fused via the contact points 11 into a coherent phase 7.

FIG. 2 c shows, analogously to FIG. 1 c, a situation where implant 1 according to the invention has been implanted peripherally to bone tissue 15. Again, there is the controlled dissolution of the magnesium-containing network structure 7 with successive precipitation of calcium phosphate 12th FIG. 2d shows, analogously to FIG. Id, the end state occurring after a prolonged period after implantation, in which the bone tissue 15 is augmented by new bone cells 16 into the titanium mesh structure 7 of the composite material 2.

In these two first variants of the inventive implant 1, which consists at least partially of composite material 2, the composite material 2 is applied as a surface coating, with the aim of the implant 1 in a cement-free manner mechanically stable to connect with peripheral bone tissue 5. However, according to the idea according to the invention, it is quite possible to use the composite material 2 itself as a whole implant, whereby the production according to FIGS. 2a-2d is preferably chosen because of its higher mechanical stability, since the stiffening effect of the implant 1 is missing. By way of the mixing ratio of the titanium-containing individual bodies 3, the magnesium-containing individual bodies 4 and the mass 5 of the titanium hydride binder mixture, the mechanical behavior of the implant can be predetermined within wide limits. Of course, it is also possible to vary this mixing ratio in a strategic manner within the implant body, so that zones of high rigidity and zones of high elasticity are combined in an implant body so that the implant can meet the mechanical requirements in the body in an optimal manner.

FIG. 3 shows a further variant of the structure of a composite layer consisting of magnesium- and titanium-containing particles. 3a, in a first step, a layer 9 consisting of a mass 5 of a binder and fine-grained titanium hydride particles is applied to the surface of an implant. applied tatkörpers 1, wherein this can be done in any way, for example by dipping, spraying or brushing.

3b shows the next step, in which preferably round and almost equal particles of the magnesium-containing component 4 are at least partly pressed into the still soft layer 9. This can e.g. By soaking in a fluidized bed of fluidized particles, by "breading", ie contact of the still liquid and adhesive layer 9 with a loose layer of the particles of the magnesium-containing component 4 or by pneumatic spin-coating of these particles onto the binder layer The aim is to produce a monolayer of the particles of the magnesium-containing components 4 on the implant body 1 which, in accordance with the viscosity and thickness of the layer 9 and the kinetic energy of the particles, leads to more or less deep enclosure of these particles with the layer 9. If the particles can be largely enveloped by the layer 9, can be started after the solidification of the layer 9 already with the thermal treatment, the further process steps in analogy to Figures 1 and 2 take place.

FIG. 3 c shows an optional further step in FIG. 3 b if the particles of the magnesium-containing layer 4 are to be enclosed by the layer 9 in a precisely defined manner. In this case, after solidification of the primary layer 9 of titanium hydride and binder, a secondary layer 9 'of titanium hydride and binder layer is applied to the first layer 9.

Fig. 3d shows the condition after the coating has been subjected to a thermal treatment according to Fig. 3c. In this case, the binder was first removed analogously to Figures 1 and 2 and subsequently the titanium hydride particles are split into titanium and hydrogen, whereupon the formation of a network structure of titanium 6 as well as diffusion bonds 10 between the implant body 1 and the mesh structure 6 of titanium occurs. Where the particles of the magnesium-containing component 4 have contact points 11 to their neighbors, merging occurs and the formation of a network structure 7 of the second component occurs.

Figure 3e shows the last step in which a part of the surface of the composite e.g. is removed by a cutting or grinding process so far that a new O berfläche arises, which consists of truncated areas of the network structure 7 of magnesium and the titanium-containing network structure 8. The particular advantage of this variant is given by the fact that all magnesium-containing areas are accessible for the corrosion process with body fluid.

4 shows a third variant for producing an implant 1 according to the invention, in which both the magnesium-containing individual bodies consist of a wire 20 made of magnesium, preferably a magnesium alloy, and also the titanium-containing individual bodies consist of a wire 21 made of titanium, preferably a titanium alloy. as shown in Figure 4a. The diameter of the wires 29 is preferably from 0.05 to 1 mm, but more preferably between 0.35 and 0.6 mm, in order to achieve an optimal osteoinductive effect for the future titanium structure 6.

FIG. 4b shows a first working step, in which both wires 20, 21 into shorter wire sections 23, 24, whose length 28 between 50 - 150%, but preferably 100% of the diameter 29. A ratio in which the diameter and length of a body is the same or similar, for example, in the chemical process engineering of packed beds of Raschig rings turned, since such fillers arrange themselves in such a bed in a statistical manner with their longitudinal axes in any spatial directions. In a preferred embodiment of the method, the titanium-containing wire sections 24 are coated with a thin layer of titanium hydride. This can be done either by immersing the wire sections 24 in a slurry consisting of fine-grained titanium hydride in admixture with a suitable binder or by passing them after impregnation with a suitable adhesive, for example, through a fluidized bed of titanium hydride particles. In both cases, titanium hydride-coated wire sections 25 are formed on all sides, as shown in FIG. 3c. However, it is also possible to make the coating with titanium hydride already on the wire 21 and to cut this only later, the particles produced in this way, however, then contain faces without titanium hydride coating.

4d shows a bed 26 of magnesium-containing wire sections 24 and titanium-containing and titanium hydride-coated wire sections 25, wherein the particles in analogy to Raschig rings have a diameter 29 similar to their length 28, whereby they are statistically randomly aligned in space. This results in a variety of contacts between wire sections 24 and 25, both among themselves as with the wire sections of the other type. In contrast to the previous examples, the titanium hydride is located on the surfaces of the titanium-containing wire sections 25, while the magnesium-containing wire sections 23 largely a free Have surface and thus merge in the subsequent heating without obstruction by titanium skins to a continuous network structure 7 or welded. Of course, the ratio between length 28 and diameter 29 of the wire sections 23, 24, 25 can also be selected larger, which leads to an increasing alignment. tion of the same comes to one another, whereby a desired stiffness and elasticity behavior can be achieved in certain spatial directions.

FIG. 4 e shows the bed 26 after the thermal treatment, in which a debindering in a first phase and in a second phase for the dissociation of the titanium hydride to form pure titanium-coated titanium-containing wire sections 27. At the locations where there is a statistical contact between such wire sections 27, diffusion bonds 10 are formed, resulting in a three-dimensional titanium-containing network structure 8 with high strength and elasticity. At the same time, under the magnesium-containing wire sections 23, a local process of diffusion bonding or a global melting process results in the formation of connection zones 30 and thus likewise a three-dimensional magnesium-containing network structure 7, this process also being assisted by the wetting behavior. While the contiguity, i. the three-dimensional connection of the titanium-containing network structure 8 is of importance primarily with regard to the mechanical strength, the contiguity of the magnesium-containing network structure 7 only contributes to the strength in the first phase after the implantation, then allows access to the body fluid, so that all of its areas is available for the dissolution or corrosion and thus for the augmentation of the bone tissue, which favorably influences the strength in the final state.

5a shows the starting point of a method variant for producing a composite material 2 on an implant 1, in which, in addition to wire sections 23, 24, agglomerates 31 of fine-grained titanium hydride with a suitable binder are used come. In the present case, the agglomerates 31 have an approximately spherical shape and can, preferably, for example, produced by a pelletization process. Alternatively, however, it could also be cylindrical agglomerates 31, which are produced for example by extrusion with subsequent division, in which case they largely correspond in their geometric shape to the wire sections 23, 24. For these agglomerates 31 similar conditions apply in terms of diameter and length as for the wire sections 23, 24 in order to achieve a similarly favorable random bulk behavior within the subsequent bed 32.

5b shows such a bed 32, consisting of magnesium-containing wire sections 23, titanium-containing wire sections 24 and the agglomerates 31, the latter in function of the pressing pressure on the bed 32 and the deformability of the agglomerates 31 within the bed 32 their shape the contours of surrounding wire sections 23, 24 can adjust.

Fig. 5c shows the state after debindering and the further thermal treatment. In this case, the titanium hydride particles of the agglomerates 31 have formed more or less microporous pure titanium zones 33, which are diffusion-welded by contact points to the titanium-containing wire sections 24 to form a three-dimensional titanium-containing network structure 8. At the same time it comes at the random contact points of the magnesium-containing wire sections 23 by welding or melting to form a magnesium-containing network structure. 7

This example shown in FIGS. 5a-5c could also be carried out in a largely analogous manner, but without the inclusion of the titanium-containing wire sections 24, so that the bed 32 shown in FIG. 5b is only replaced by magnesium-containing wire segments. sections 23 and the agglomerates 31 would be constructed. In such a case, the agglomerates 31 preferably have a more cylindrical shape, similar to that of the wire sections 23. The result is analogous to that shown in Fig. 5c, a composite material consisting of a network structure of titanium 6 and a magnesium-containing network structure 8. Such osteoinductive zone has less strength than a zone which has a titanium-containing network structure 7, however, the network structure 8 has microporosity, which can additionally reinforce the osteoinductive effect after dissolution of the magnesium-containing network structure 7.

As an alternative to the variants shown for producing an implant 1 according to the invention in which the arrangement of the magnesium- and titanium-containing particles in the composite material 2 took place in a statistical manner, the particles can alternatively be arranged in a regular and controlled manner.

FIG. 6 a shows a first embodiment of a method for producing a composite material 2 with regular network structures 7, 8 on an implant 1. At least one wire 20 of a magnesium-containing material or a magnesium alloy with at least one titaniferous wire 22 precoated with titanium hydride becomes a strand 35 twisted together. The outer diameter of both wires 20, 22 are preferably the same size, so that the outer surfaces of both wires are within the same enveloping lateral surface as possible. In this embodiment, only the simplest case is shown, where each a magensiumhaltiger wire 20 and a titanium-containing wire 21 are twisted together. Alternatively, however, strands 35 are conceivable in which a plurality of wires 20 containing magnesium and a plurality of titanium-containing wires 21 are twisted together, their number, diameter and composition varying can. In such strands 35, which are composed of more than two wires, created in the vicinity of the single strand an additional periodicity with resulting from the geometry of the individual wires and their winding arrangement contacts their lateral surfaces, while strands 35, as in the case shown here consist only of one wire, a certain randomness of the contact of a Zopfwicklung to benachtbarten arises. As a special case, strands 35 are also conceivable in which only titanium-containing wires 21 are twisted together, for example if it is desired to provide magnesium-poor or even -free porous zones within a composite body whose task is only in the mechanical field to achieve specific strength and rigidity serves.

6b shows a cross-sectional view of the strand 35 shown in FIG. 5a in an outer view, which is guided by the longitudinal axis 36 shown there, after a thermal after-treatment. In contrast to the statistical arrangement of the embodiments described so far, this results in a regular sequence of the magnesium-containing network structure 7 and the titanium-containing network structure 8.

FIG. 7a shows an implant 1, on the surface of which three layer layers 37, 37 'and 37''of strands 35 from FIG. 6b have been pressed. In accordance with the internal geometry of the strand 35, periodic and / or statistical contact points occur between the wires 20, 21 of the same component of different layer layers 37, 37 'and 37 ". In particular, in the case of elongated implants 1, which are to be coated over the entire circumference, a strand 35 can also be wound onto the implant 1, wherein, depending on the winding tension, a pressing of the layer layers 37, 37 ', 37 "against the surface of the implant 1 is superfluous becomes. FIG. 7b shows the state of the laminated composite shown in FIG. 7a after debindering has taken place in combination with heating. The titanium-containing wires 21 of the various layer layers 37, 37 ', 37 "are now connected to one another via diffusion bonding zones 38 resulting from the decomposition of the titanium hydride coating and form a three-dimensional network structure 40. At the contact surfaces between the titanium-containing wire 21 of the innermost layer layer 37 likewise form diffusion bonds 38 to the implant 1 and thus connect the network structure 40 to the implant 1. The magnesium-containing wires 20 also combine to form a three-dimensional network structure 39.

This periodicity of the contact, which is ensured by the use of strands 35, on the one hand has the advantage that both the titanium-containing network 40 as well as the magnesium-containing network 39 has a higher strength and that after implantation ensures in any case that each part of the magnesium-containing network 39 is accessible to the body fluid.

FIG. 8 shows an alternative embodiment of an implant 1 according to the invention, which partly consists of a composite material 2. This embodiment has a single-layer winding of a strand 35. The surface 41 of the implant 1 is preferably coated with titanium hydride before the strand 35 is wound up. However, this titanium hydride layer is not necessary because the titanium-containing wire 21 of the strand 35 is coated with titanium hydride. In the present case, compared to the diameter of the implant body 1, a relatively thin and porous layer composite is produced, as it is today also produced by other methods, for example plasma spraying of titanium particles. can not be produced, but with a defined void volume containing areas of magnesium-containing phases.

Fig. 9 shows an alternative embodiment of the present invention. Shown is a cross section through an implant 1, on which 4 layer layers 37, 37 ', 37' 'and 37' '' are wound up as a coating. In a symbolic manner, the case is shown in this image, in which a plurality of superimposed layer layer of a composite material 2 with periodic titanium and magnesium-containing network structures 7, 8 generated. Such a case represents a transition to the use of the composite material 2 in the sense of a full implant, because unlike in the case of a bare surface coating, which is to ensure a cementless and secure connection to peripheral bone tissue, takes the wider composite zone and a part of the inside of the Implant occurring forces, while the mass is reduced compared to an existing only of solid material implant and the bending behavior of the adjacent bone structure can be better adapted.

10a shows, as in FIG. 6a, a strand 35 which, as in the simplest case shown here, consists in each case of a titanium hydride-coated wire 22 made of titanium or a titanium alloy and a wire 20 consisting of magnesium or a magnesium alloy, the strand 35 being cut into sections 42 is divided, whose length 43 in relation to the diameter 44 of the surrounding enveloping surface is also in the range of 50 to 150%, but preferably at 100%. The strand sections 42 can be used analogously to the production method for a composite material 2 described in FIG. FIG. 10b shows, analogously to FIG. 4d, a bed 45 in which randomly arranged strand sections 42 are combined with one another. In contrast to a bed 32 consisting only of wire sections 23, 24, a bed 45 consisting of strand sections 42 has a higher periodicity of the contacts between identical components within a strand section

42, while the arrangement of the strand sections 42 is largely statistically characterized. However, if a higher degree of periodicity is also desired at this level, for example when constructing a structure which can endure higher bending moments in a desired direction, then it is also quite possible to have the ratio of the length shown in FIG. 10a

43 to the diameter of the envelope 44 to the strand section 42 either positively or negatively deviate from the value of 100%, wherein in the first case strand sections 42 with the shape of approximated elongated cylinder, in the second case, short, platelet-shaped cylinder arise in a bed Arrange 45 preferably along its Hauptausdehnungsrichtung.

11a shows an embodiment of the inventive idea in which a composite material 2 forms a porous full implant in the form of an acetabulum implant 50. The picture is otherwise to be regarded only as a basic section and does not claim to be a true to scale representation of an actual acetabulum implant 50. The composite material 2 is produced according to one of the embodiments previously shown, for example by a bed 34 of magnesium-containing wire sections 20 and titanium-containing wire sections 22 as shown in FIG. 3d or by pigtail sections 42 as shown in FIG. 10b. In analogy to FIG. 9, a multilayer winding of a strand 35 onto a substrate body with the function of a spacer is alternatively possible, which forms the negative shape of the inner curvature of the inner region 51 of the hip joint. In the context of which due to its physical and chemical properties either already disappears during heating or can be removed after the sintering process, so that a hemispherical cavity remains behind.

However, for the specific requirements of this acetabulum implant 50, it is necessary that the outer region, the surface of which later comes into contact with peripheral bone tissue, comprises a composite material 2, while the inner region 51 consists of a titanium-containing open-cell network structure 8 without magnesium components. This can be accomplished by the fact that this inner region 51, depending on the production method consists of particles, wire sections, plait sections or a cable winding, which consists only of titanium-containing material, the areas are connected in accordance with one of the methods described above via bridges of pure titanium, the the decomposition of titanium hydride are formed.

Fig. IIb shows a second embodiment of the hip joint socket implant 50 shown in Fig. IIa, in which e.g. a plastic 52 of a material suitable for mating with the ball joint has been sprayed, whereby a portion of the plastic 52 penetrates into the inner region 51 and is firmly crosslinked with the three-dimensional network structure of the titanium. In this case, the plastic can not penetrate into the composite material 2, whose cavities are still filled with the magnesium-containing component at this time.

FIG. 11c shows, in a schematic way, the situation as it has occurred a long time after the implantation of an acetabulum implant 50. After successively reducing the magnesium-containing component by solution and / or corrosion, That is, the peripheral bone tissue 15 is firmly anchored in the pan by the bone mesh 16 augmented in the titanium mesh structure. Thus, such an implant can be viewed as a composite by seamlessly blending a plastic phase into bone tissue via a porous titanium structure, thereby providing optimal mechanical performance.

FIG. 12 shows a further example of a possible application of the composite material 2 according to the invention, this time as a coating 54 of a dental implant 53 made of titanium or a titanium alloy. In the present example, the coating 54 was pressed either as a helical body, the screw shape could also subsequently on the finished sintered material, e.g. produced by a machining process. Of course, the composite material 2 may also have the shape of a cylinder or a cone instead of a helical shape. However, it may also have a more complex shape, e.g. is achieved by means of machining methods in order to adapt the outward contour exactly to a bone surface, in particular e.g. in a case where the thickness of the jawbone to be augmented is insufficient for anchoring a normal dental implant.

A dental implant constructed and manufactured according to the invention has several significant advantages. On the one hand, the optimum porosity and depth of the composite material 2 provides optimal anchoring in the peripheral bone tissue, which is particularly important in cases where only a small amount of bone material is available in the jaw. On the other hand, the high osteoinductive effect of the resulting peripherally after implantation cavities leads to an accelerated ingrowth of the bone cells, which shortens the unpleasant transition phase for the patient. A third advantage can be under There may be circumstances in which a long-term antiseptic effect is achieved both by the continued formation of magnesium ions, while the slow outflow of hydrogen in the form of a protective gas prevents germs from entering countercurrently, since inflammation is a dreaded side effect of implantation.

FIG. 13 shows a further variant of the inventive concept, which is listed only as a basic arrangement without reference to a concrete use case in the body to show the versatility of the principle of this composite material. The picture shows a spiral made of a wire 46, preferably of a titanium alloy, which is integrated in an osteoinductive structure 47 which consists of components containing magnesium and titanium. This wire represents a reinforcement, which stiffens the implant in one direction, but ensures increased elastic deformability in another direction. This principle, which is demonstrated here with a spiral spring, can also be varied with leaf springs or other components.

Three exemplary examples for the production of an implant according to the invention with a composite material follow:

In a first example, a mixture of 45% by volume of magnesium powder with a mean particle size of 300 μm and 55% by volume of titanium hydride powder with a mean particle size of 20 μm was mixed with a PMMA-based binder to give a mortar-like mass. Subsequently, this mass was applied to the surface of an implant body of a stainless steel alloy in a thickness of about 250 microns. The coated implant body was placed in the retort of a vacuum furnace in a next step and heated to 600 ⁰ C for 20 hours, first removing the PMMA binder and then decomposing the titanium hydride into titanium and hydrogen. Subsequently, the furnace chamber was flooded with argon to just below atmospheric pressure to prevent the magnesium from boiling. Thereafter, the temperature was increased to 950 ⁰ C and held for 20 minutes. It was then cooled rapidly to room temperature. As a result, an open-pored titanium layer was formed, which was welded at the contact points with the stainless steel surface, wherein the open-pore titanium structure was partially filled with magnesium.

In a second example, a mixture of 25 vol-% magnesium alloy powder (alloy AZ31) with a mean particle size of 100 microns with 50 vol% titanium powder Grade 5 (alloy Ti6AlV4) with a mean particle size of 20 microns and 25 vol% titanium hydride powder with a mean particle size of 8 microns and a PMMA-based binder mixed into a thin slurry, which was applied in a thin layer on a part of the surface of a dental implant made of alumina. This body was then heated under vacuum for 20 hours to 600 ⁰ C to remove the organic binder and dissociation of titanium hydride to form titanium. Thereafter, the pressure in the furnace with argon was increased to 950 mbar and the temperature was adjusted to 980 ⁰ C and held for 1 hour. The titanium hydride behaved in this example as Aktivlötkomponente, ie its disintegration resulted in pure titanium, which leads by its strong reducing effect to the formation of titanium aluminates, which form a transition layer between the aluminum oxide and the open-pore titanium layer, the magnesium particles melt simultaneously and within the pores the titanium layer remain. In a third example, a previously sandblasted acetabulum made of titanium alloy Ti6AlV4 with its outer side was repeatedly placed in a slurry of 50% by volume magnesium alloy powder (alloy AZ31) with an average particle size of 50 μm and 50% by volume titanium hydride powder and a polyacetal binder immersed so that a layer of 150 microns was formed. The thus-coated acetabulum was then heated for 25 hours to 550 ⁰ C and then held at this temperature for a further 5 hours, so that it came to the removal of the binder and complete decomposition of the titanium hydride. Thereafter, the furnace chamber was flooded with argon to 700 mbar and heated to 830 ⁰ C under this pressure. This temperature was held for 3 hours. As a result, an open-pore titanium structure was formed, the pores of which were partially filled with the magnesium alloy welded at the contact points with the surface of the acetabular cup.

Claims

claims

1. implant, at least partially consisting of a composite material (2) of a titanium-containing first component (3) and a magnesium-containing second component (4), obtainable by diffusion bonding of individual bodies of the first component (3) using particles of titanium hydride in the presence of Individual bodies of the second component (4), which merge with each other in the diffusion bonding, wherein at least the single body of the second component (4) before the fusion has a maximum width (B) of 0.05mm to lmm, and wherein the two welded or fused Components (3,4) statistically arranged regularly and / or in a periodically repeating pattern.

2. Implant according to claim 1, characterized in that the composite material (2) with the surface of a metallic implant base body (1), preferably made of a titanium alloy, connected, preferably welded.

3. Implant according to claim 1, characterized in that the composite material (2) with the surface of a ceramic implant body (1) is connected.

4. Implant according to one of claims 1 to 3, characterized in that the magnesium-containing second component (4) consists of one or more magnesium salts, optionally in admixture with other salts, preferably calcium salts, preferably calcium chloride and / or calcium fluoride and / or calcium oxide ,

5. Implant according to one of claims 1 to 4, characterized in that the titanium-containing first component (3) consists of diffusion-bonded individual bodies of a maximum width of 1mm (B) and a maximum length of 5mm (L).

6. Implant according to one of claims 1 to 4, characterized in that the titanium-containing first component (3) consists of diffusion-bonded individual bodies of not more than 1 mm width (B) and more than 10 mm, preferably more than 50 mm length (L), wherein the individual bodies are preferably helical.

7. Intermediate composite product for producing a composite material, in particular for the production of an implant according to one of claims 1 to 6, characterized in that the individual body of a titanium-containing first component (3) and single body of a magnesium-containing second component

(4) are arranged in mutual contact with each other and that the individual bodies of the first component (3) are mixed or coated with particles of titanium hydride or consist of titanium hydride, the individual bodies of both components

(3,4) have a maximum width (B) of 0.05mm to 1mm.

8. Intermediate composite product according to claim 7, characterized in that the particles of titanium hydride have a maximum particle size of 0.05 mm.

9. Intermediate composite product according to one of claims 7 or 8, characterized in that the particles of titanium hydride and optionally single body made of titanium or a titanium alloy together with the single body of the second component (4) in admixture with a binder form a preferably pressed molding.

10. Intermediate composite product according to one of claims 7 or 8, characterized in that the particles of titanium hydride, as well as the individual bodies of the first titanium-containing component (3) and the individual bodies of the second magnesium-containing component

(4) mixed together with a binder to form a preferably pressed molding.

11. Intermediate composite product according to one of claims 7 or 8, characterized in that the individual bodies of the first component (3) in cross-section preferably circular wire sections made of titanium or a titanium alloy (24,25) and the single body of the second component (4) in the Cross section preferably circular wire sections made of magnesium or a magnesium alloy (23), wherein the individual bodies of the first component (3) are coated with titanium hydride and / or the individual bodies of both components (3.4) titanium hydride particles are mixed.

12. Intermediate composite product according to claim 11, characterized in that the wire sections (23, 24, 25) of the two components (3, 4) have a length (28) which corresponds to their diameter (29).

13. Intermediate composite product according to claim 11, characterized in that the wire sections (23, 24, 25) of the two components (3, 4) are in the form of helices.

14. Intermediate composite product according to claim 7 or 8, characterized in that the individual bodies of the first component (3) wires of titanium or a titanium alloy (21,22) and the individual bodies of the second component (4) wires of magnesium or a magnesium alloy (20) are, with the wires (20,21,22) of both components (3,4) are connected to a braid, a woven or knitted fabric together.

15. Intermediate composite product according to claim 14, characterized in that a plurality of strands (35) of mutually twisted wires

(20,21,22) of the first and the second component (3,4) with each other and / or one above the other on a metallic and / or ceramic base body (1) are arranged.

16. A method for producing an implant, at least partially consisting of a composite material (2) from a titanium-containing first component (3) and a magnesium-containing second component (4), in particular according to one of claims 1 to 6, characterized by

(A) presenting the first component (3) consisting of particles of titanium hydride and optionally individual bodies of titanium or a titanium alloy;

(b) bringing the first and second components (3, 4) together to form an intermediate composite product such that the

Individual bodies of the two components (3, 4) touch statistically regularly and / or in a periodically repeating pattern; and

(c) heating the intermediate, optionally under pressure, until dissociation of the titanium hydride to titanium and formation of diffusion bonds (38) between the individual bodies of the first component (3) and until the individual bodies of the second component (4) fuse together.

17. The method according to claim 16, characterized in that the individual bodies of the second component (4) has a maximum width

(B) from 0.05mm to 1mm.

18. The method according to any one of claims 16 or 17, characterized in that the particles of titanium hydride initially mixed with a binder to a mass (5) are mixed.

19. The method according to claim 18, characterized in that in addition to the titanium hydride particles, single bodies of titanium or a titanium alloy in the mass (5) are mixed.

20. The method according to any one of claims 16 or 17, characterized in that the individual bodies of the first component (3) are coated with the Titanhydridpartikeln.

21. The method according to any one of claims 18 or 19, characterized in that the mass (5) is pressed prior to heating to an implant base body (1).

22. The method according to any one of claims 16 to 21, characterized in that the individual bodies of the first component (3) of cut titanium-containing wire sections (24,25) and / or the individual body of the second component (4) of cut-to-length magnesium-containing wire sections (23) consist.

23. The method according to claim 22, characterized in that the cut wire sections (23,24,25) of the two components (3,4) are present as helices.

24. The method according to any one of claims 16 to 22, characterized in that the individual bodies of the first component (3) and the single body of the second component (4) made of wires

(20, 21, 22) or wire sections (23, 24, 25) and that the components (3, 4) are brought together in such a way that in that at least one wire (21, 22) or wire section (24, 25) of the first component (3) is twisted into a strand (35) with at least one wire (20) or wire section (23) of the second component (4) ,

25. The method according to claim 24, characterized in that the strand (35) in a plurality of juxtaposed and / or superimposed layers (37) on an implant base body (1) is applied, preferably by wrapping or pressing.

26. The method according to claim 24, characterized in that the strand (35) is subdivided into a plurality of strand sections (42), wherein the strand sections (42) are applied to an implant base body (1) or pressed into a mold.