EP2625154A1

EP2625154A1 - Monolithic ceramic body with mixed-oxide marginal region and metallic surface, method for producing it and use thereof

Info

Publication number: EP2625154A1
Application number: EP11767993.6A
Authority: EP
Inventors: Sorin Lenz; Günter Rübig; Christian Mahringer; Alexander Schreiner
Original assignee: CeramOss GmbH
Current assignee: CeramOss GmbH
Priority date: 2010-10-06
Filing date: 2011-10-06
Publication date: 2013-08-14
Also published as: RS53217B; EP2439183A1; JP6045078B2; MX2013003704A; AU2011311557A1; PL2439183T3; WO2012045830A1; KR101493058B1; CN103201237A; BR112013007305A2; IL225328A0; DK2439183T3; KR20130079581A; CA2816299C; ES2448616T9; CN103201237B; EP2439183B1; RU2552736C2; ES2448616T3; AU2011311557B2

Abstract

The present invention relates to a monolithic ceramic body having a mixed-oxide marginal region and a metallic surface, the ceramic body comprising the oxide of a first metal (I), a mixed-oxide marginal region which comprises the oxide of the first metal (I) and the oxide of a further metal (II) having a high affinity for oxygen, and a metallic surface comprising the metal (II) on the mixed-oxide marginal region, the mixed-oxide marginal region comprising a continuous concentration gradient of the first metal (I), starting from 100% in the core down to 0% in the transitional region to the metallic surface of the ceramic body, based on the total metal content (I+II), and a continuous concentration gradient of the further metal (II), starting from 0% in the core up to 100% in the transitional region to the metallic surface of the ceramic body, based on the total metal content (I+II), the oxygen concentration in the mixed-oxide marginal region remaining constant, and the monolithic structure of the ceramic body having no phase boundaries.

Description

Monolithic ceramic body with mixed oxide edge area and metallic surface, process for its production and its use

Field of the invention

The present invention relates to a monolithic ceramic body, its manufacture and use. In particular, the present invention relates to a monolithic ceramic body with a chemically modified edge region of a mixed oxide, wherein the edge region has a metallic surface.

The ceramic body is used in particular as an implant

Background of the Invention In general, implants serve as a replacement for diseased or lost human or animal anatomical structures such as teeth, joints, extremities, etc. Preferably, such implants should coalesce with the bone in the organism to form a stable, long term resilient connection. There are already both titanium implants and ceramic implants. While titanium implants have a solid place in medicine, dentistry and veterinary medicine with over 30 years of experience, ceramic implants have only recently been used in implantology. They have established themselves in dentistry because of their excellent biocompatibility, bioinertness, corrosion resistance and their good physical properties, especially through their use as implants, but they osseointegrate only badly or not at all.

Titanium has the advantages that it is very well osseointegrated, ie it grows with the bone and is not allergenic. The high oxygen affinity of the titanium leads to the formation of a titanium oxide layer on the titanium implant surface, which leads to the advantageous properties. Bone grows with the titanium oxide layer. To maximize the contact surface between implant and bone as much as technically possible, the surface of the titanium implants is roughened. This can be the Osseointegration be further improved. Today, for example, titanium is used for dental implants or in hip joints for titanium shells that use a ceramic insert, while in orthodontics titanium anchoring implants are used. The use of titanium in restorative dentistry was made possible by further developments of the casting technique as well as by the use of CAD / CAM and spark erosion processes for the production of individual workpieces.

However, titanium has the following drawbacks, especially for dental implantology:

It has a dark, almost black color and, if it is highly polished, a silvery color, leaving the aesthetics in the cervical area much to be desired. Furthermore, titanium implants in dentistry at the point of passage from the gums can not be cleaned with ultrasonic metal tips because the material is scratched and roughness develops which promote increased plaque formation. For cleaning therefore special plastic tips are needed. Oxide ceramics (zirconium oxide ceramics, alumina, zirconia-alumina mixtures, etc.) is an extremely hard, smooth and biologically inert material that is absolutely resistant to corrosion (acids, salts, body fluids). Furthermore, it is extremely resistant to abrasion because of its hardness, ie the surface can only be changed with a diamond tool. Furthermore, the white color of the material - at least for dental implants - in dentistry outstanding aesthetic advantages. These properties are already used in medicine, for example as stents for vessels in cardiology with a ceramic surface so that no accumulation of body cells. In the ceramic dental implants used in dentistry, the above-mentioned advantages are disadvantageous. The fact that the material is biologically inert, the implant is not osseointegrated or insufficiently. In order to combine the advantages of the two materials, oxide ceramics and titanium, and to eliminate the respective disadvantages as far as possible, two approaches have recently been pursued: implants made of a titanium body with a (partial) ceramic coating (veneer) and implants of a ceramic body with a titanium or titanium oxide coating. In the first approach, those areas of the titanium body are provided with a ceramic coating which does not contact bone after implantation. In the second approach, the areas of the ceramic body are coated with titanium or titanium oxide, which are in bone contact after implantation in order to better osseointegrate there. The areas of the implant that have no contact with the bone after implantation remain uncoated.

Due to the material-specific properties of titanium, namely its low thermal expansion coefficient, the extreme affinity of titanium for air and oxygen and crystal lattice transformation at 882 ° C, the previously used metal-ceramic composite systems (metal body with ceramic surface, veneering ceramics) can not be used because It is not possible to "veneer" a ceramic metal in a metallic manner: Reaction with ceramic constituents forms an oxidative reaction layer on the surface of the titanium body at temperatures of 750-800 ° C. At temperatures of approximately 1000 ° C., as in the case of If conventional ceramics are produced, the oxide layers would be extremely intensified and consequently the bond to the ceramic coating would be weakened, Moreover, by the crystal lattice transformation tensions are to be feared, which may also have a composite weakening effect Dental alloys have a particularly low coefficient of thermal expansion. The thermal expansion coefficients of ceramic and metal, however, must be coordinated to avoid cracks and spalling of the ceramic, as would occur in the veneering of titanium with conventional ceramics. As known to those skilled in the art, metals expand on heat while ceramics experience sintering shrinkage. For a long time, no satisfactory bond strength values of titanium ceramic systems could be achieved. The lower adhesion between titanium and ceramic is attributed to both the necessary adjustment of the thermal expansion coefficient and the high oxygen affinity of the titanium, whereby a pronounced growth of the oxide layer takes place during the firing of the ceramic. The brittleness of the oxide layer is considered to be the primary cause of the lower composite values.

For this reason, special binders (adhesion promoters) have been developed which, by virtue of their reducing properties, are intended to prevent the oxidation of titanium during the ceramic firing process (M. Kononen and J. Kivilahti, J Bonding of low-fusing dental porcelain to pure titanium, J Biomed Mater Res 1994, Volume 28, No. 9, pages 1027-35, U. Tesch, K. Päßler and E. Mann, Studies on titanium-ceramic composite, Dent Lab, 1993, Volume 41, pages 71-74). In order to compensate for the high tendency of titanium to oxidize and thereby increase the bond strength values of titanium-ceramic systems, special binders have been developed which dissolve and encase oxides present on the titanium surface and, by their glassy nature, seal the surface against further oxidation (J. Tinschert , R. Marx and R. Gussone, structure of ceramics for the titanium veneer, Dtsch Zahnärztl Z, 1995, Volume 50, page 31 -4). However, studies have shown that this approach only partially led to the desired success. Gilbert et al. reported improvement in the bond (JL Gilbert, DA Covey and EP, Lautenschlager, Bond characteristics of porcelain fused to milled titanium, Dent Mater, 1994, Vol. 10, No. 2, pp. 134-140). Hung et al. however, no significant improvement was found by the use of a binder (CC Hung, M. Okazaki and J. Takahashi, Effect of Bonding Agents on Strength of Pure Titanium-Pocelain System, J Dent Res, 1997, Volume 76, page 60). A disadvantage of the use of binders is that a further ceramic firing is necessary, which in addition to the increased time, especially one additional thermal stress of titanium caused. Likewise, caused by the binder aesthetic disadvantages can not be excluded.

With the aim of reducing the oxidation of titanium during the firing process, attempts have been made to carry out the ceramic firing under a protective gas atmosphere (J.Geis-Gerstorfer, Ch.Chille and P. Klein, Lower Oxidation Tendency Under A Protective Gas Atmosphere, Dent Lab, 1994, Vol , Page 1235-1236), but with little success, since as the main oxygen supplier for the oxidation of titanium above all the ceramic components are held responsible (M. Kononen and J. Kivilahti, Fusing of Dental Ceramics to Titanium, J Dent Res, 2001, Vol. 80, No. 3, pages 848-854).

Another approach to increase the bond strength in a titanium-ceramic system is described in DE 10 2004 041 687 A1, according to which a zirconium oxide layer is deposited on a pure titanium body by a CVD, PVD or plasma immersion ion implantation and deposition process is applied, on which the intended for the veneering of titanium ceramic is burned without a binder. Here, the zirconium layer serves as a bonding agent between the titanium body and the applied ceramic layer.

More recent approaches assume that a ceramic body can be coated with titanium since it is known that titanium-coated ceramics show very good results in terms of osseointegration. For example, WO 03/045268 A1 discloses a one-piece dental implant made of a ceramic base body with a titanium coating.

However, it is also known that the adhesion between the titanium coating and the ceramic poses problems as known from US 2001/0036530 A1. US 2001/0036530 A1 describes an implant made of a composite material of a zirconium oxide ceramic with a first coating of titanium, a second coating also made of titanium and optionally a third coating of hydroxyapatite. Here, for better anchoring of the first coating and the thus desired better adhesion titanium ions implanted by ion implantation in the ceramic. As a result, the adhesion could be improved by 20% over known ceramic-titanium composite systems. However, the disclosed titanium-ceramic composite systems do not have satisfactory properties. Although cracks or cracks could not be observed in the peel strength test, the average peel adhesion of 67 MPa was only marginally higher than the 41 MPa peel strength achieved in the prior art. A similar approach has been disclosed in EP 2 018 879 A1. However, even here satisfactory adhesive strength could not be achieved. Thus, it was not possible to prevent the effect of "bare" ceramics on detachment of the layer, which is not only acceptable, but above all in implantology, as material failure leads to catastrophic consequences, because implants are failing for decades until optimally lifelong in the body.

There are applications, not only but especially for implants that require a very high adhesion of the layer. Such applications are not only dental applications, but also other medical applications, such as bipolar prostheses (hemi-prostheses) for the treatment of femoral neck fractures. The commonly used duo head prostheses consist of a head, a stem and a pan, which consists for example of polyethylene. This results in the problem that wears the polyethylene pan by the high mechanical stress. This wear can lead to the loss of lubricity of the joint. Above all, the abrasion products lead to aseptic bone necrosis. This leads to technical failure of the duo head prosthesis and to consequential damage in healthy tissue. Previous remarks concerning the consequences of abrasion products also apply to metal-metal pairings and metal-plastic pairings in orthopedic joint prostheses. There is therefore a need for materials for implants that fulfill all the requirements for the most diverse fields of use of the implants, both chemically and mechanically. These must have the ability have osseointegrate. In addition, there is a need for a method by which these materials can be easily and cheaply produced in sufficient quantity. Presentation of the invention

It is therefore an object of the present invention to provide a material which is biocompatible, osseointegrated, and does not cause aseptic necrosis by its abrasion products. Furthermore, this material should have the required in all applications of implants chemical and mechanical properties, as well as easy to manufacture. A further object of the invention is to eliminate the layer adhesion problem and to provide a method which allows easy production of the material. Phase formations as they occur in conventional coatings should be avoided

The objects underlying the invention were achieved by providing a monolithic ceramic body according to claim 1, a method for producing a monolithic ceramic body according to claim 10 and its use according to claim 18. Preferred embodiments can be found in the dependent claims. The inventors have recognized that the problem-solving approach for new materials in general, and more specifically for implantology, is in eliminating the layer adhesion problem, to ensure decades of residence and functionality in the body.

The present invention also achieves, in combination, the following advantages and effects:

- Creating an osseointegrating monolithic ceramic body with mixed oxide edge region and metallic surface with one of

Bone structure, in terms of softness, as far as similar structure that microfractures of the bony implant bed under load as much as possible can be prevented. As is known and described in the literature, particularly hard implant materials cause stressful bone osseous microfractures in the implant site at exercise spikes - a problem which has not been solved yet but has been solved by the present invention.

Monolithic ceramic bodies according to the invention with mixed oxide edge area and metallic surface eliminate the weak spots of the ceramic base body which has not yet been changed according to the invention due to microdefects of the surface (preformed predetermined breaking point). After modification according to the invention this is more resistant to impact and impact, and also the splitter inclination is largely eliminated possible. It is known to the person skilled in the art that conventional ceramic is very hard, but also very brittle, and shatters into countless fragments in the event of material failure.

When examining inventive monolithic ceramic bodies in the form of ceramic platelets with a thickness of about 1 mm, it turned out that these bodies were considerably more flexible than non-inventive ceramic bodies, and not at breakage as conventional

Broken ceramic plate into countless small parts, but defined break with a break in two pieces (see Fig. 4, 5a and 5b).

- Monolithic ceramic bodies according to the invention are substantially impact and pressure resistant by absorption and uniform pressure redistribution, since the mixed oxide edge region and the metallic surface are much more elastic than ceramic and thereby prevent micro-cracks. This means that the mechanical overloading takes place much later until fracture, since, as known from the literature, microcracks on the surface of ceramic rapidly pull through the ceramic and cause it to shatter.

Such splintering is just like a catastrophe in the human body, because all the splinters have to be removed, which is not always completely successful. Consecutively, the fragments left in the human body cause persistent symptoms. This problem is eliminated as far as technically feasible by the use of implants according to the invention and as far as possible avoided.

- Monolithic ceramic bodies according to the invention behave on the surface like metals. Thus, a further desired change or processing of the surface as already known from the metal processing can be done inexpensively.

The particular advantage of the monolithic ceramic body according to the invention with mixed oxide edge area and metallic surface is the cumulative solution of many problems not yet solved (listed above). In addition, a cumulative significant improvement in the ceramic properties over conventional ceramic bodies is achieved. This result is achieved without loss of the desired and required positive properties of conventional ceramic body (hardness, abrasion resistance, etc.), since the preparation of monolithic ceramic bodies according to the invention with mixed oxide edge region and metallic surface takes place in the low temperature range. In addition to the problem solutions described, a further advantage is achieved when using the monolithic ceramic body according to the invention with mixed oxide edge region and metallic surface as protective armor. The surface serves as a lubricant (slipping agent) at e.g. impacting projectiles.

The ceramic body according to the invention consists of the oxide of a first metal (I) with a mixed oxide edge region (metal I + II) and a metallic surface of the metal (II). The mixed oxide edge region comprises the oxide of the first metal (I) and the oxide of the further metal (II), which has a high affinity for oxygen. The inventors have surprisingly found that the mixed oxide edge region has a continuous, uniform concentration gradient of the first metal (I), starting from 100% in the core to 0% in the transition region to the metallic one Surface of the ceramic body, based on the total metal content (l + ll), and a continuous, uniform concentration gradient of the further metal (II), starting from 0% in the core up to 100% in the transition region to the metallic surface of the ceramic body, based on the total metal content (l + ll). By contrast, the oxygen concentration remains constant in the mixed oxide boundary region. The surface of the monolithic body according to the invention is metallic (metal II), and is thus no (metallic) coating.

The production according to the invention produces a monolithic ceramic body with mixed oxide edge area and metallic surface. The phase boundaries which are clearly discernible in the case of a coating do not exist in the ceramic body according to the invention, since it is not a coating but a monolithic structure resulting from a thermochemical reaction. Phase boundaries (typical feature of coatings) are neither in the transition region metal (I) to the mixed oxide edge region of the metals (l + ll), nor in the mixed oxide edge region itself, nor in the transition region of the mixed oxide edge region (metal l + ll) to the metal surface ( Metal II) of the ceramic body detectable. Phase-free within the meaning of the present invention is to be understood as a concentration gradient in which there are no substance limits.

"Area" in the sense of the invention, in contrast to the term "layer", means that the chemical composition varies within the "area", even within an atomic layer of the area, whereas a "layer" is characterized by having phase boundaries and the entire layer has a defined chemical composition that is the same across the layer.

"Ceramic" in the context of the invention includes in addition to the raw materials that are used for the production of ceramic products, and their preparation for the actual ceramics and formed from ceramics and fired objects themselves, as components, protective armor for civilian and military purposes - in persons , Vehicles, buildings (persons = body protection, Building armor, vehicle armor on vehicles, ships, submarines aircraft, rockets, etc.), utensils and ornaments or tools are used. "Metal (I)" and "metal (II)" in the context of the invention does not mean the oxidation state of the metals. The numbers (I) and (II) serve to distinguish the metal which is part of the ceramic, using the term "first metal" or "metal (I)" for this purpose. The metal used to form the mixed oxide edge region uses the term "further metal" or "metal (II)" for this purpose. The terms "first metal" and "metal (I)" as well as "additional metal" and "metal (II)" are used interchangeably.

"Edge region" in the sense of the invention is the region of the ceramic body according to the invention which begins below its metallic surface and runs in the direction of the interior of the ceramic body up to its core from the oxide of the first metal (I).

"Edge zone" in the sense of the invention is the region of the ceramic body according to the invention, which is formed by the metallic surface and the underlying edge region.

The term "unfinished ceramic body" in the sense of the present application is a ceramic body which has not yet been modified according to the invention.

The advantages achieved by the invention are to be seen in particular in that one can no longer speak of a composite material, ie a ceramic body with a metal coating in the ceramic body according to the invention (since phase boundaries no longer exist as a characteristic of a coating are). Instead, it is a monolithic ceramic body with mixed oxide edge area and metallic surface. Accordingly, it is no longer possible to speak of a "layer adhesion" and adhesive strength, but rather an area of the ceramic body which has been thermochemically altered.

Conventional composite systems involve three groups of forces between the metal and the veneering ceramic that result in bonding, namely mechanical, adhesive and chemical forces. The mechanical forces are created by shrinking a ceramic onto the metal framework during the sintering process. For the forces, the thermal expansion coefficients and the retention, i. the mechanical interlocking of the partners with each other, responsible. The intermolecular forces of attraction (Van der Waals forces) are responsible for the adhesion between the composite partners. These include in particular the dipole interactions and the hydrogen bonds. The formation of a mixed oxide leads to the chemical force. The surface of the metals to be coated with a ceramic is, depending on the type of metal more or less, not of pure metal but of metal oxide. These metal oxides are retentively and adhesively bonded to the metal framework. The chemical bond between the metal framework and the ceramic takes place on the oxidized surface of the metal. In ceramic fires, there are common bonds between the metal oxide layer and the ceramic matrix. So-called oxygen bridges are formed. Decisive in the conventional composite systems, however, is not only what force acts to which extent, but also how strongly the metal oxide layer adheres to the metal. Regardless of which force prevails in the respective composite, the composite system consists of many different layers.

The inventors have found in the inventive monolithic ceramic body with mixed oxide edge region and metallic surface that the ceramic body to the surface has no layer structure (phase boundaries missing). It is not like a coating thin layers with the same chemical composition and thus layers lying opposite each other with different chemical composition, which adhere to each other, but one obtains a complex system in which the metal ions (II) react with the oxygen of the ceramic (I), so that a new chemical compound consisting of Metal ions (I), metal ions (II) and oxygen is formed. The inventors suspect that a (thermo) chemical reaction takes place between the oxygen atoms of the ceramic (oxide of metal I) as solid and the metal ions (II), whereby a region is formed in which the edge region of the ceramic body is continuously chemically altered, to an outer metal surface, without, as usual, only "incorporation" of the metal ions (II) in the lattice of the ceramic material (here phase boundaries are present), whereby the grid would be disturbed and ions would be knocked out of the ceramic grid.

Rather, it can be observed that the metal (II) concentration increases continuously, starting from 0% in the core of the ceramic to 100% in the transition region to the metallic surface, based on the total metal content, and the metal (I) concentration starting continuously from 100% in the core of the ceramic to 0% in the transition region to the metallic surface, based on the total content, decreases. Surprisingly, the oxygen concentration in the mixed oxide edge region remains constant. Consequently, the chemical composition of the ceramic body changes from the interior of the body to its surface, wherein in the edge region a mixed oxide of metal (I) and metal (II) is formed, which finally in a metallic surface of the metal (II) with a 100% concentration of the Metal (II) ends.

This has the advantage that there is no formation of layers (phases, phase boundaries) and therefore no longer limits the adhesion. All attempts to cause a material failure of the surface of the monolith according to the invention (super-adhesive layer adhesion tests) resulted in the failure of the super-adhesive without exposed ceramic. The monolith according to the invention remained undamaged. The layer adhesion problem is eliminated, as well like the attempts to improve the layer adhesion. This problem has been solved according to the invention. The solution of the other problems already mentioned has already been mentioned. This is consequently not a coating. It can no longer be spoken of layer adhesion or adhesion. The ceramic body has the advantageous properties of a metal-coated ceramic and overcomes the disadvantages of the adhesive strength of conventional metal-ceramic composites. The chemical modification of the edge region of the ceramic creates a monolith with an inseparable chemical bond between the ceramic (oxide of metal I), the mixed oxide edge region based on metals (I) and (II) and the metallic surface of the metal (II).

According to the invention, the ceramic is an oxide ceramic consisting of the oxide of a metal (I), wherein the metal (I) comprises zirconium, aluminum, yttrium, hafnium, silicon, magnesium, cerium, other metal oxides or metallic glass or mixtures thereof. Preferably, the metal (I) is zirconium or comprises zirconium. Zirconium oxide and alumina are white and are therefore preferably used in the dental field.

The ceramic body may be preformed prior to thermochemical formation of the mixed oxide edge region and prior to sintering. This means that a green ceramic is brought into a desired shape and then sintered. This has the advantage that the green ceramic is relatively soft and easy to shape compared to the hard ceramic after sintering. Accordingly, individualized or customized implants can be manufactured at comparatively low cost, eg by 3D reconstruction. This allows the production of even complex anatomical structures. "Green ceramic" in the sense of this invention means ceramic material before the final sintering process. The green ceramic can be made, shaped and processed according to methods known to those skilled in the art, such as hot isostatic pressing, pressing, turning, milling, drilling, grinding or machining, etc., where the methods can be numerically controlled manually or computer-assisted.

The preformed ceramic may be treated mechanically or physically before or after sintering, such as to increase the surface area. The enlarged surface improves the osseointegration when the monolithic ceramic body according to the invention with mixed oxide edge area and metallic surface is used as the implant. The chemical, mechanical or physical treatment is preferably carried out on the green ceramic, since here by the soft material treatment can be faster, easier and cheaper than after sintering, but can also be done after sintering.

"Mechanical treatment" in the sense of the invention comprises, in particular, grinding, sandblasting or irradiation with a water jet, as well as all other processes known to those skilled in the art. "Physical treatment" in the sense of the invention comprises, in particular, irradiation with a laser beam, as well as all other processes known to the person skilled in the art.

In addition, the green ceramic can also be chemically treated, e.g. Etching with an acid or an acid mixture. The acid or the acid mixture may be selected from phosphoric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid, nitric acid / hydrochloric acid mixture such as aqua regia, or hydrochloric acid / sulfuric acid mixture. The same applies to sintered ceramics which can be treated with suitable acids or acid mixtures (all processes known and suitable to the person skilled in the art).

The metal (II) for forming the mixed oxide edge region based on the metals (I) and (II) and the metallic surface of the metal (II) is according to the invention a High oxygen affinity metal and is selected from titanium, niobium, tantalum, as well as compounds and alloys thereof. Other oxygen-affine metals are not excluded. Preferably, the metal (II) is elemental titanium, a titanium compound or a titanium alloy. In some embodiments, the titanium compound may comprise a titanium compound having elements of the 14th (eg, C, Si, Ge, Sn, Pb), 15. (eg, N, P, As, Sb, Bi) or 16. (eg, 0, p , Se, Te, Po) group of the periodic table or a mixture thereof. Particularly preferred as metal (II) elemental titanium, with 100% pure titanium is very particularly preferred.

The thickness of the mixed oxide edge region is determined on the one hand by the penetration depth of the metal ions (II) in implanting according to the invention, on the other hand by their diffusion and by the thermochemical reaction in the ceramic body. Here, the desired chemical reaction takes place, which is the essential distinguishing feature for conventional ion implantation, in which only "incorporation" of metal ions into the lattice of the ceramic material occurs (phase boundaries are present) The reactive edge region has an average thickness of about According to the invention, the thickness is at least 500 atomic layers, but may also be less, but only so far less that no weakening of the monolith is carried out .. At least 700 atomic layers are preferred, and more preferably more than 700 atomic layers. An edge region with a thickness greater than 700 atomic layers is difficult to manufacture, especially particularly costly and brings no apparent advantage or further improvements in the application areas of the monolithic ceramic body with mixed oxide edge area and metallic surface and in terms of material Vortei achieved le.

The thickness of the edge zone from the outer metal surface of the metal (II) to the metal (I) in the interior of the ceramic body (mixed oxide edge region based on Metals (L) + (II) included is on average 6-8 microns. This edge zone can be a thickness of 0.05 microns (lower thickness is expressly not excluded), up to several millimeters (greater thickness is expressly not excluded). Preference is given to thicknesses between 0.05 and 80 micrometers, very particularly preferably between 5 and 20 micrometers

In other embodiments of the invention, the ceramic body may, if necessary, be provided with one or more coatings of the metal (II) and / or one or more coatings of a biocompatible and / or bioactive material, in particular a microporous titanium coating.

One possibility of "bone-friendly" surface design so far is the coating with calcium phosphate (also beta-tricalcium phosphate, etc.), which is considered bioactive (osseoactive), that is, it promotes the formation of bone tissue and provides this inorganic components for growth. Widely used in implantology has found the hydroxylapatite coating.The chemical composition of the coating material, its adhesion to the carrier substance, the coating thickness and resorptive processes within the coating influence the reaction of the bone tissue and thus the clinical applicability of coated implants.

The biocompatible / bioactive material may also be selected from antibiotics, growth factors, peptides, fibronectin and anti-inflammatory agents. Other biocompatible / bioactive materials known to those skilled in the art can be used and are expressly not excluded.

As antibiotics may exemplified amikacin, gentamicin, kanamycin, neomycin, netilmicin, paromomycin, streptomycin, tobramycin, cephalosporins, fluoroquinolone antibiotics, azithromycin, erythromycin, clarithromycin, dirithromycin, roxithromycin, telithromycin, penicillins, ampicillin, sulfonamides, tetracyclines, clindamycin, metronidazole and Vancomycin, etc. are called. Examples of growth factors include transforming growth factor beta (TGF), granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), nerve growth factor (NGF), neurotrophins, platelet-derived growth factor (PDGF). , Erythropoietin (EPO), Thrombopoietin (TPO), Myostatin (GDF-8), Growth Differentiation Factor-9 (GDF9), Acidic Fibroblast Growth Factor (aFGF or FGF-1), Basic Fibroblast Growth Factor (bFGF or FGF-2) , Epidermal Growth Factor (EGF), Hepatocyte Growth Factor (HGF), Insulin-like Growth Factors (IGFs), and Bone Morphogenetic Proteins (BMPs).

As anti-inflammatory agents, glucocorticoids, corticosteroids and non-steroidal anti-inflammatory drugs (e.g., ibuprofen, aspirin and naproxen, etc.) may be exemplified.

For example, a peptide may be a bioactive peptide such as the RGD sequence.

In a particular embodiment of the invention, the biocompatible material comprises a bioactive surface coating of osteochondral / osseous stem cells or chondral stem cells or a mixture thereof. The stem cells improve the osseointegration of the thus coated monolithic ceramic body with mixed oxide edge area and metallic surface. It has proven to be particularly advantageous if the surface of the monolithic ceramic body with mixed oxide edge area and metallic surface is treated chemically, mechanically or physically to increase it before coating with a biocompatible material. With the method according to the invention, monolithic ceramic bodies with mixed oxide edge area and metallic surface can be produced in a simple manner. The method according to the invention for producing a monolithic ceramic body with a mixed oxide edge area and metallic surface comprises the following steps, which are carried out in a thermochemical reaction chamber on an unfinished ceramic body with an edge area:

(a) evacuating the reaction chamber to a vacuum that is 10 ^-3 mbar or less,

(B) activation of the edge region of the unfinished ceramic body

(C) starting the thermochemical treatment of the edge region of the unfinished ceramic body.

In step (a) a high vacuum between 10 ^"3 mbar and 10 ^{" 7} mbar is preferred. Particularly preferred is a vacuum that comes as close as possible to the vacuum to be found in space.

The evacuation is best done hours before the start of the process in order to free the reaction chamber from interfering components and impurities as well as to allow the intended thermochemical reaction on a solid at all. Another advantage of the high vacuum is that the free path of the metal ions (II) is relatively high until collisions with other particles, such as impurities or inert gas atoms or ions, occur, whereby the metal ions (II) can lose energy. Due to the high vacuum no loss of energy of titanium ions occurs by friction in their movement to the ceramic.

Essential to the invention is that the reaction chamber is substantially free of compounds, in particular oxygen, with which the other metal ions (II) can react. As compounds in the context of the invention, chemical compounds and atoms / ions are understood.

If such compounds are in the reaction chamber, the high-energy metal ions (II) with these compounds, in particular Oxygen, which leads to the formation of undesirable compounds such as titanium oxide, and are no longer available for the formation of the mixed oxide edge region. The compounds formed, if their energy is still sufficient, can be further implanted in the edge region of the ceramic body, which can lead to the disadvantages associated with conventional ion implantation, such as the disturbance of the ceramic lattice. Furthermore, the unwanted compounds can settle as a surface coating on the ceramic body and thus build up a disturbing layer, which in turn is able to prevent the formation of the mixed oxide edge region.

It must therefore be ensured that the metal ions (II) are unhindered, i. without reacting on the way between target and ceramic body, impinge on the ceramic body in order to be able to react with it thermochemically and uniformly.

In step (b) of the method according to the invention, the edge region of the unfinished ceramic body is activated. More specifically, the atoms in the edge region of the ceramic body not yet changed according to the invention are put into an energetically excited state. This is necessary to allow the formation of the mixed oxide edge area according to the invention.

For edge area activation, the methods known from the prior art can be used according to the invention, such as flame-treatment with a burner, plasma treatment, corona treatment. Preferably, the edge region activation is performed by a plasma process.

The edge area activation by means of plasma has the advantage that the surface of the ceramic substrate is first of all cleaned, ie freed from impurities. Preference is given to a plasma treatment in which, in addition to the activation of the edge region of the ceramic body, the edge region is additionally etched and activated in the sense of plasma-chemical activation in order to increase the reaction surface and increase the readiness for reacting thermochemical reaction between metal (I) and metal (II) to create. The reactivity of the metal (I) is thereby increased.

The edge area activation preferably takes place with a plasma generated by an electrical gas discharge in a high vacuum, the energy and the duration of the plasma being selected on the surface of the ceramic body such that the atoms of the edge area are activated such that a chemical reaction takes place in the edge area of the ceramic body is possible at all and can take place.

Preferably, before the activation of the edge region of the ceramic body, the released impurities are outgassed. The outgassing is preferably for several hours, but may also be much shorter or longer, at a temperature of 25 ^° C to 400 ^° C, preferably below 350 ^° C, other temperatures are not excluded, and a pressure of preferably 10 ^{" 7} to 10 ^"3 mbar, wherein the gas emissions are pumped out of the reaction chamber by means of vacuum pumps continuously.

The edge region of the material or component is then bombarded for activation by ions and / or electrons which are generated by an electric gas discharge in a high vacuum. The pressure in the reaction chamber is in the range between 10 ^-5 and 10 ^-3 mbar, preferably 10 ^-7 and 10 ^-3 mbar, particularly preferably in the range of the space vacuum. At these pressures, the energy correlated with the mean free path length of the plasma particles is sufficiently large to energetically excite the atoms located in the edge region of the ceramic body in such a way that chemical reactions are possible in the edge region of the ceramic body which are not possible under other conditions.

The plasma activation is carried out by the methods known to the person skilled in the art. As gases for the gas discharge noble gases are used. The noble gas is selected from argon, neon, krypton and xenon, with argon being preferred. Other suitable noble gases are not excluded. It must therefore be ensured that the metal ions (II) unhindered, ie, without reacting on the way between the target and ceramic body, impinge on the ceramic body in order to react thermochemically and evenly. Alternatively to applying a high vacuum to the reaction chamber, methods and / or devices are conceivable with which the interfering impurities, in particular oxygen can be removed from the reaction chamber atmosphere in order to achieve the effect according to the invention. In step (c), the edge region of the unfinished ceramic body is subjected to a thermochemical treatment. In this case, the chemical composition of the edge region of the ceramic body is changed.

Thermochemical treatment in the sense of this invention is a heat treatment which is applied to a material (metal (I)) with the aim of altering the chemical composition of the material by mass transfer with the supplied medium (metal (II)). In general, in the thermochemical treatment, metallic or non-metallic elements are diffused into the surface of a material. In the course of the thermochemical treatment, either a diffusion region or a connection region with underlying diffusion region can arise. Within a diffusion region, the content of the diffused element (metal II) continuously, uniformly decreases gradually towards the core and the content of the reacting element (metal I) continuously, uniformly, gradually towards the surface; By contrast, the concentration drop in a connection area is usually very steep. According to the invention, the start of the thermo-chemical reaction of the ceramic body takes place with the aid of ion implantation. This means that in a first stage, metal (II) ions are implanted in the edge region of the unfinished ceramic body (metal (I)), from where they can further diffuse into the interior of the ceramic body and react. This results in the formation of a connection region, namely in the region of ion implantation, and an underlying diffusion region. Due to the high energy of the metal (II) ions and the edge area activation carried out in step (b), in the second stage the metal (II) ions react with the oxygen atoms of the ceramic material (metal (I)) to form a mixed oxide (metal (II) l) + (II)). This thermochemical reaction takes place only if the reaction chamber has previously been evacuated in the sense of step (a) of the method according to the invention. Preferably, the ion implantation takes place in the plasma. Most preferably, ion implantation is a plasma immersion ion implantation (PIN).

The steps combined in this special way allow in the first place the thermochemical reaction of pure titanium and oxide ceramic as a solid, so that a monolithic ceramic body with a mixed oxide edge area and metallic surface can be created.

In ion implantation processes, ions generated from a target are accelerated in a directional electric field and then strike a solid. The ions penetrate the body forming a superficial penetration layer. The ion implantation can be influenced by the parameters ion energy and ion dose. The ion energy determines the penetration depth, the ion dose the number of implanted ions. With the help of plasma immersion ion implantation (PILL), the advantages of conventional ion implantation can be transferred to large-area, complex-shaped geometries. The workpiece to be treated is - according to the invention in a high-vacuum chamber - surrounded by a plasma generated by a suitable plasma source; by applying negative high-voltage pulses with very short pulse rise times (<1 microsecond) become the more mobile Electron of the plasma then pushed back and accelerated the remaining positive ions on the workpiece (implanted). The acceleration voltages are below that of conventional ion implantation (order of magnitude: 30 kV). Since the entire surface is implanted at the same time, this method is extraordinarily productive, especially in the various complex geometrical forms found in medicine.

As target materials, it is possible to use all suitable metals and alloys in accordance with the desired properties of the monolithic ceramic body according to the invention with mixed oxide edge area and metallic surface. These are vaporized at high energy levels by magnetron, laser, or any other suitable technique to achieve high "vapor concentration" in the high vacuum chamber Suitable target materials include metals having high oxygen affinity Preferably, the target materials include Ti, Nb, Ta. Alloys thereof / or compounds Preferred materials are titanium, a titanium compound or a titanium alloy, the titanium compound being a compound of titanium with elements of the 14th (eg C, Si, Ge, Sn, Pb), 15. (eg N, P, As, Sb, Bi) or 16. (eg, O, S, Se, Te, Po) group of the Periodic Table or a mixture thereof Especially preferred are elemental titanium and its alloys / compounds, with elemental titanium being most preferred.

According to the invention, for the course of the thermochemical reaction in the peripheral region, the ion implantation or the plasma immersion ion implantation with an ion dose of 10 ¹⁵ to 10 ¹⁶ ions / cm ² and an ion energy of 1 keV to 2.3 MeV, preferably 1 MeV to 2.3 MeV, performed, indispensable in combination with high vacuum. The temperature is between room temperature and 400 C, more preferably 350 C and below. The pressure is about 10 ^"3 to about 10 ^{" 7} mbar, more preferably under a space atmosphere.

The plasma can be generated continuously (cw plasma) or pulsed. By the plasma parameters, like the plasma pulse or the energy of the plasma pulse, can the properties of the edge zone, ie the resulting mixed oxide edge area and the resulting metallic surface, are adjusted. According to the invention, either a cw plasma or a pulsed plasma can be used. A combination of the two plasma generation types is also possible. Preferably, in step (c) a cw plasma is used, which can change into pulsed towards the end of the reaction process.

The inventors have surprisingly found that the ion-material interaction phenomena associated with conventional ion implantation, such as radiation damage, defect interactions, amorphization, crystallization, precipitation formation, which require thermal post-treatment (annealing), do not occur. The goal of the ion implantation process hitherto used for the production of dental implants based on a titanium basic body and a ceramic coating was the reduction of the oxygen affinity of titanium during the ceramic coating (L. Wehnert, A. Moormann and W. Freesmeyer, simulations of the thermodynamics of conventional titanium -Ceramic composite and the influence of the composite improving ion implantation method, quintessence Zahntech 1998, Volume 24, pages 1027-1037). In the present invention, however, the high oxygen affinity of the metal (II) is exploited. The inventors assume that the implanted metal ions (II) react due to the high oxygen affinity with the oxygen of the ceramic to form a complex atomic composite. The edge region of the unfinished ceramic body is thereby chemically changed into a boundary zone, ie, a mixed oxide of metal (I) and (II) is formed, and it creates a metallic surface of the metal (II) on the mixed oxide edge region, causing the mentioned problems conventional ion implantation avoided and subsequent annealing is no longer necessary. Damage to the ceramic by the processes is completely avoided, in particular by the choice of relatively low temperature, and it creates a monolithic ceramic with mixed oxide edge region and metallic surface and not a coated ceramic. The absence of phases as well as phase boundaries clarifies the distinction to the coating, and consecutive is the created Ceramic body a monolith and no coated ceramics. The hitherto unsolved layer adhesion problem is thereby solved.

The thermochemical treatment in the sense of step (c) causes high-energy metal (II) ions (eg titanium ions) to penetrate into the edge region of the unfinished ceramic body and there with the oxygen of the metal (I) oxide (eg zirconium oxide) complex metal (I) metal (II) oxide (eg titanium zirconium oxide) and additionally form a metallic surface of the metal (II). They thus cause a chemical reaction and convert the unfinished ceramic body in its edge region in such a peripheral area that in the latter the metal (I) (eg zirconium) and oxygen at the atomic level with the metal (II) atoms (eg titanium atoms , Titanium ions) and also forms a metallic surface of the metal (II). Accordingly, the complex metal (I) metal (II) oxide does not form a coating with its metallic surface, but instead represents a chemical transformation of the edge region of the unfinished ceramic body. The core of the ceramic body and its edge zone therefore form a monolithic structure which is in the Metallic metal (II) surface finish. The concentration of the first metal (I) and the further metal (II) in the edge region of the ceramic body according to the invention is ideally in the middle of the mixed oxide edge region of (I) and (II) 50/50%.

Put simply, the thermochemical reaction converts the unfinished ceramic body into a new monolithic body with no phase boundaries (ceramic in the core, mixed oxide in between, and titanium on the outside). The thickness can be controlled and regulated according to need and application.

In one embodiment according to the invention, the ceramic body with the mixed oxide edge area and metallic surface can furthermore be coated with one or more metals, in particular the further metal (II). The coating with one or more metals is carried out according to the known in the art and conventional in the prior art method for coating metals or ceramics. In another embodiment, the coating of one or more metals can be thermochemically nitrided, borated, carburized, nitrocarburized, etc. Of course, the metallic surface of the monolith of the metal (II) can be nitrided without further coating, borated, carburized, nitrocarburized, etc., if necessary (articular surfaces). This leads to the hardening of the metallic surface of the ceramic body and takes place, for example, by plasma-assisted thermochemical nitriding, boriding, carburizing, nitrocarburizing, etc. In a further embodiment of the invention, the surface of the ceramic body with a mixed oxide edge region and metallic surface with a biocompatible / bioactive as described above Material to be coated. The coating with the biocompatible / bioactive material is likewise carried out by methods known to the person skilled in the art and customary in the prior art for coating ceramics or metals.

The present invention also relates to the use of the ceramic body with a mixed oxide edge region and metallic surface as a medical implant, in particular as a dental implant. Depending on the application, implants may be completely or partially provided with a mixed oxide edge area and a metallic surface. "Partial" is to be understood to mean that the implant areas, which have bone contact, as far as a Mischoxid- edge area and a metallic surface, that a secure osseointegration is guaranteed.

"Medical" within the meaning of the invention relates to the fields of human medicine, including dentistry, veterinary medicine, including the dental field. A medical implant in the sense of the invention is a medical device which serves to replace biological structures in the human or animal body or is inserted into the body for other purposes. Therefore, the medical implants according to the invention include implants and dental implants for humans and for animals. Dental implants, hip implants, epitheses, artificial joints and prostheses are preferred as medical implants.

A prosthesis is an artificial limb which replaces a missing part of the body (e.g., due to illness, accident or amputation), whereas an epithesis primarily has cosmetic function (e.g., as an artificial eye or ear). Medical implants, and in particular prostheses, can be used to manipulate biological structures, such as bones, joints or bone parts, in almost all areas of the body, e.g. Skull, teeth, upper and lower arm, elbows, upper and lower legs, hips, toes, fingers, knees, spine, etc. to replace. But also hearing aids, artificial limbs, replacement joints, and hair prostheses (wigs) and implants for their attachment fall under medical implants according to the invention. In specific embodiments, hearing aids can be integrated into other implants. This also applies to "remedies" implanted in the body or their containers (for example cardiac pacemakers, insulin pumps, etc.).

Implants and dental implants are in some embodiments of the invention one or more part implants. In a preferred embodiment of the invention, only the region of the ceramic body that comes into contact with the bone has a mixed oxide edge region with a metallic surface (completely or partially). In another embodiment, in addition, the region has a mixed oxide edge region with a metallic surface, which comes into contact with the second part of a two-part implant.

A dental implant is in particular a one-, two- or multi-part implant and may comprise a screw thread. Preferably, the dental implant comprises an anchoring part for anchoring the implant in the bone, and a fastening part for receiving the superstructure, wherein only the anchoring part has a mixed oxide edge region. In a special embodiment of the two-part implant, the area of the ceramic body is facing which comes in contact with the other area (eg the abutment at its contact surface between the implant and the abutment), a partial mixed oxide edge area with a metallic surface. In this case, no screw connection between the two parts is required because an optimal fit can be achieved, which leads to a good fit and high stability of the connection (press fit). If a screw is produced according to the invention for a multi-part implant (eg, abutments screwed to the implant), either the entire screw or just the threaded area can have a mixed oxide edge area with a metallic surface.

In cases where the implant is multi-part, either only a part or both parts in the contact region of the two parts can have a mixed oxide edge region with a metallic surface. An example of such an embodiment is an artificial hip joint. In this case, at least a part of the artificial joint may have a mixed oxide edge region with a metallic surface. For example, in addition to the area that comes into contact with the bone, the area of the hip joint also has a mixed oxide edge area with a metallic surface that comes into contact with the head (ball). Or, conversely, only the area that comes into contact with the pan has a mixed oxide edge area with a metallic surface. It is also conceivable to provide both implant parts according to the invention completely with mixed oxide edge region and metallic surface, so that the dreaded fragmentation effect on fracture of the implant is largely prevented. An advantage would be that a mixed oxide edge area with a metallic surface prevents the squeaking or unwanted noise that may occur during movement of the joints. In particular, a mixed oxide peripheral region with a metallic surface in the head region of an artificial hip joint can prevent creaking noises and serves as a "lubricant." The monolithic ceramic body having mixed oxide edge region and metallic surface according to the invention may comprise an additional diamond-like carbon layer (DLC) layer in some embodiments (eg on articular surfaces). DLC is an amorphous extremely hard carbon layer. In some embodiments, the composition may comprise one or more further metal layers, such as gold, silver, platinum, aluminum, copper, iron, nickel, tin, tantalum, zinc and / or chromium, and / or alloys, such as steel or bronze.

figure description

FIG. 1 shows a ceramic body according to the invention in the form of a one-piece

Dental implant. Only the threaded anchoring part for anchoring the implant in the bone has a zirconia-alumina

Titanium mixed oxide edge area, with pure titanium metallic surface. The core of the dental implant consists of zirconia-alumina ceramic. FIG. FIG. 2 shows a broken ceramic body according to the invention with a core of zirconia-alumina ceramic, mixed-oxide edge area of zirconia-alumina and titanium mixed oxide and metallic surface of pure titanium. FIG. The inventive advantage of the lack of Zersplitterneigung is easy to see.

FIG. FIG. 3: shows the SEM image of a breakpoint of an inventive. FIG

Ceramic body with core of alumina ceramic, mixed oxide edge region of alumina-titanium mixed oxide and metallic surface of pure titanium. In the background, the metallic surface can be recognized, which here has a "soft" bone-like structure and should avoid microfractures in the implant bed.The bare surface in the foreground is the mixed oxide edge region and the alumina core.

FIG. 4 shows two approximately 1 mm thick oxide ceramic plates, left according to the invention with a metallic surface of titanium and right conventional without titanium surface. The ceramic chip according to the invention has a core of zirconia-alumina ceramic and a mixed oxide edge region made of zirconia-alumina-titanium mixed oxide and a metallic surface made of pure titanium.

FIG. 5a, 5b: each two defined fragments of the invention

Ceramic plate of Fig. 4. A fragmentation into many items did not occur at the fracture test. During bending to rupture, there was also no chipping tendencies of the surface, as common in conventional coatings. FIG. 6: shows a cross-cut test of an inventive

Ceramic body with core of alumina ceramic, mixed oxide edge region of alumina-titanium mixed oxide and metallic surface of pure titanium. There are no signs of chipping. The core forming ceramics is not exposed.

FIG. 7 shows the SEM cross-sectional image (high magnification) of a ceramic body according to the invention with a core of zirconia-alumina ceramic, mixed oxide edge region of zirconia-alumina-titanium mixed oxide and metallic surface of pure titanium. In the lower area, the ceramic core is bright. This is followed by the greyish mixed oxide edge region (about 700 atomic layers) on top, on which the unevenly dark gray-black surface made of pure titanium is located. FIG. 8: shows an EDX diagram relating to the ceramic body of FIG. 7. It shows the concentration curves of the metals (I) and (II) in the mixed oxide edge region. Starting at 0%, the concentration of the respective metal is plotted on the y-axis in the direction of the top of the diagram. The depth coordinate running in the direction of the core of the ceramic body is plotted on the x-axis, the abscissa value x = 0 lying in the transition region between the mixed oxide edge region and the metallic surface; Curve 1 (zirconia-alumina) shows the metal (I) concentration running towards the surface (to the left) at 0%;

Curve 2 (titanium) shows the metal (II) concentration running towards the core at 0%;

The tent-shaped structure resulting from the two curves shows the desired effect of the concentrations of 50/50% of the metals (I) / (II) in the middle of the mixed oxide edge region. It can be seen that the two curves running uniformly towards each other in the direction of the center of the mixed oxide edge region and uniformly apart from the center of the mixed oxide edge region show the EDX diagram according to FIG. 8, which in the SEM cross-sectional view of FIG. 7 is projected in the appropriate place. The same applies to FIG. 8 said.

Claims

claims

A monolithic ceramic body with mixed oxide edge region and metallic surface, wherein the ceramic body, the oxide of a first metal (I), a mixed oxide edge region containing the oxide of the first metal (I) and the oxide of another metal (II), which has a high affinity to oxygen, comprises, and has a metallic surface of the metal (II) on the Mischoxid- edge region,

wherein the mixed oxide edge region

a continuous concentration gradient of the first metal (I), starting from 100% in the core to 0% in the transition region to the metallic surface of the ceramic body, based on the total metal content (l + ll), and

a continuous concentration gradient of the further metal (II), starting from 0% in the core up to 100% in the transition region to the metallic surface of the ceramic body, based on the total metal content (l + ll),

having,

the oxygen concentration in the mixed oxide edge region remains constant, and the monolithic structure of the ceramic body is formed without a phase boundary

The ceramic body according to claim 1, wherein the first metal (I) is selected from aluminum, zirconium, yttrium, niobium, hafnium, silicon, magnesium, cerium or mixed forms of said metals.

The ceramic body of claim 2, wherein the first metal (I) is zirconia or alumina or a zirconia-alumina mixture.

The ceramic body according to any one of the preceding claims, wherein the further metal (II) is biocompatible.

The ceramic body of claim 4, wherein the biocompatible metal (II) is titanium. The ceramic body according to claim 3 and 5, wherein said mixed oxide edge portion is formed of a titanium-zirconium composite oxide, titanium-alumina composite oxide or titanium-alumina-zirconia composite oxide, and said metallic surface is made of pure titanium.

The ceramic body according to any one of the preceding claims, wherein an edge zone of the ceramic body comprising the mixed oxide edge portion and the metallic surface thereon is between 0.05 and 140 m thick.

The ceramic body according to one of the preceding claims, which further comprises one or more layers of further metals, in particular the metal (II).

The ceramic body according to any one of the preceding claims, which additionally comprises one or more biocompatible and / or bioactive coatings.

10. A method for producing a ceramic body having a mixed oxide edge region with a metallic surface according to one of claims 1 to 9, which comprises the following steps to be carried out in a thermochemical reaction chamber on an unfinished ceramic body with an edge region:

Evacuation of the reaction chamber to a vacuum that is 10 ^"3 mbar or less,

Activation of the edge area of the unfinished ceramic body, and thermochemical treatment of the edge area of the unfinished ceramic body. 1 1. The method of claim 10, wherein the surface activation in step (b) is by means of a plasma treatment.

12. The method of claim 10 or 11, wherein in step (c) the thermochemical treatment is initiated by ion implantation.

The method of claim 12, wherein the ion implantation is a plasma immersion ion implantation.

14. The method of claim 12 or 13, wherein the ion dose is 10 ¹⁵ to 10 ¹⁶ ions / cm ² and the ion energy is 1 keV to 2.3 MeV. 15. The method according to any one of the preceding claims, wherein step (c) is carried out at a temperature of 20 ° to 400 ° C.

16. The method according to any one of the preceding claims, wherein the method comprises the additional step (d) of coating the surface of the ceramic body with one or more metals, in particular the metal (II).

The method of any one of the preceding claims, wherein the method further comprises the step (e) of coating the surface of the ceramic body with a biocompatible and / or bioactive material.

18. The method according to any one of the preceding claims, wherein the mixed oxide edge region with a metallic surface is formed only in a partial region of the unfinished ceramic body.

19. Use of the ceramic body according to one of claims 1 to 9 or of the ceramic body produced according to any one of claims 10 to 18 as an implant.

20. Use of the ceramic body according to one of claims 1 to 9 or of the ceramic body produced according to one of claims 10 to 18 as

Protective armor for persons or land vehicles or aircraft or watercraft or buildings or spacecraft.