IMPLANT, IMPLANT COMPONENT AND METHOD FOR THE PRODUCTION THEREOF

Abstract

An implant and/or an implant component is made available, having a main body which, at least on a surface, contains or consists of an electrically conductive material, and having a layer of calcium hydroxide applied to the electrically conductive material of the main body. The implant or the implant component is characterized in that the layer of calcium hydroxide contains calcium phosphate, specifically in a percentage by weight that is less than the percentage by weight of calcium hydroxide in this layer. A method for making available the implant according to the invention or the implant component according to the invention is also proposed. The implant made available and the implant component made available are characterized in that they have a local and temporary antimicrobial action, prevent formation of antibiotic-resistant microorganisms, act on bone substance in a manner that promotes growth, and produce no adverse side effects in the body.

Claims

1-15. (canceled)

16. An implant or implant component, comprising (a) a base body of an implant or an implant component, comprising an electrically conductive material at least on a surface; and (b) a calcium hydroxide layer comprising calcium hydroxide, the calcium hydroxide layer being deposited on the electrically conductive material of the base body; wherein the calcium hydroxide layer comprises calcium phosphate in a weight percentage less than the weight percentage of calcium hydroxide, the weight percentage being based on the total weight of the calcium hydroxide layer.

17. The implant or implant component according to claim 16, wherein the calcium phosphate comprised in the calcium hydroxide layer comprises a calcium phosphate selected from the group consisting of calcium dihydrogen phosphate, calcium hydrogen phosphate, calcium phosphate, hydroxyapatite, brushite, and combinations thereof

18. The implant or implant component according to claim 17, wherein the calcium phosphate comprised in the calcium hydroxide layer comprises hydroxyapatite and/or brushite.

19. The implant or implant component according to claim 16, wherein the base body comprises a material selected from the group consisting of metals, semi-metals, carbons, plastics, and ceramics.

20. The implant or implant component according to claim 16, wherein the electrically conductive material of the base body (i) is deposited on the base body or is in one piece with the base body; and/or (ii) is selected from the group consisting of metals, semi-metals, carbons and plastics.

21. The implant or implant component according to claim 16, wherein a calcium phosphate layer comprising calcium phosphate is deposited on the electrically conductive material of the base body.

22. The implant or implant component according to claim 21, wherein the calcium phosphate layer comprises calcium phosphate in a weight percentage that is higher than a weight percentage of calcium hydroxide in said layer, wherein the weight percentage relates to the total weight of the calcium phosphate layer.

23. The implant or implant component according to claim 16, wherein the calcium hydroxide layer (i) is deposited by electrochemical deposition; (ii) is present as a layer having an equal layer thickness over the entire extent of the layer; and/or (iii) has a layer thickness in the range from 1 to 50 μm.

24. The implant or implant component according to claim 16, wherein the proportion of calcium phosphate in the calcium hydroxide layer is in the range of >0% by weight to <40% by weight.

25. A method for manufacturing an implant or an implant component, comprising the steps of (a) providing a base body of an implant or an implant component, the base body comprising an electrically conductive material at least on a surface; and (b) depositing a calcium hydroxide layer comprising calcium hydroxide to the electrically conductive material of the base body; wherein the calcium hydroxide layer is deposited such that it comprises calcium phosphate in a weight percentage which is less than the weight percentage of calcium hydroxide, wherein the weight percentage is based on the total weight of the calcium hydroxide layer.

26. The method according to claim 25, wherein the calcium phosphate comprised in the calcium hydroxide layer comprises a calcium phosphate selected from the group consisting of calcium dihydrogen phosphate, calcium hydrogen phosphate, calcium phosphate, hydroxyapatite, brushite and combinations thereof.

27. The method according to claim 25, wherein a base body is provided, which comprises a material selected from the group consisting of metals, semi-metals, carbons, plastics, and ceramics.

28. The method according to claim 25, wherein a base body is provided, the electrically conductive material of which (i) is deposited on the base body or is in one piece with the base body; and/or (ii) is selected from the group consisting of metals, semi-metals, carbons and plastics.

29. The method according to claim 25, wherein a calcium phosphate layer comprising calcium phosphate is deposited on the electrically conductive material of the base body.

30. The method according to claim 29, wherein the calcium phosphate layer comprises calcium phosphate in a weight percentage that is higher than a weight percentage of calcium hydroxide in said layer, wherein the weight percentage relates to the total weight of the calcium phosphate layer.

31. The method of claim 29, wherein the calcium phosphate layer is (i) deposited on the electrically conductive material of the base body by means of an electrochemical deposition or a plasma spraying process; (ii) deposited as a layer having an equal layer thickness over the entire extent of the layer; (iii) deposited as a porous layer; and/or (iv) deposited up to a layer thickness in the range from 2 to 500 μm.

32. The method according to claim 25, wherein the calcium hydroxide layer is (i) deposited by electrochemical deposition; (ii) deposited as a layer having an equal layer thickness over the entire extent of the layer; and/or (iii) deposited up to a layer thickness in the range from 1 to 50 μm.

33. The method according claim 25, wherein the proportion of calcium phosphate is in the range from >0% by weight to <10% by weight, based on the total weight of the calcium hydroxide layer.

34. The method according to claim 33, wherein the calcium phosphate is present in the form of particles in the calcium hydroxide layer.

Description

Example 1—Manufacture of an Implant According to the Invention without a Calcium Phosphate Intermediate Layer

[0068] An implant is used, the base body of which consists of a titanium alloy. The base body is coated with two layers of pure titanium in a vacuum. The first layer (adhesive layer) has a thickness of 30 μm and the second layer has a thickness of 150 μm. Said sprayed titanium layer forms an electrically conductive layer and is then provided with a calcium hydroxide layer in an aqueous electrolyte.

[0069] The composition of the aqueous electrolyte and the process parameters used are listed in Table 1.

TABLE-US-00001 TABLE 1 Electrolyte Ca(NO.sub.3).sub.2 75 mmol/l (NH.sub.4)H.sub.2PO.sub.4 40 mmol/l Citric acid 20 mmol/l Process temperature 60° C. Current density 90 mA/cm.sup.2 Time 20 min. Layer thickness 15 μm

[0070] The deposited calcium hydroxide layer comprises not only calcium hydroxide but also calcium phosphate. The reason for this is that calcium hydroxide constitutes an intermediate phase in the electrochemical deposition of calcium phosphate. The presence of citric acid in the electrolyte suppresses the formation of calcium phosphate, but in the specified concentration only to such an extent that a calcium hydroxide layer still comprising calcium phosphate forms. However, the proportion of calcium phosphate is lower than the proportion of calcium hydroxide.

[0071] The ratio of the two material components can be shifted by changing the amount of citric acid used. This means that with a higher concentration of citric acid (or citrate ions) in the electrolyte, the amount of deposited calcium phosphate decreases and with a lower concentration of citric acid (or citrate ions) the amount of deposited calcium phosphate increases. A higher proportion of calcium phosphate reduces the bactericidal effect a little, but the osseointegrative effect of the calcium phosphate increases, which is desired according to the invention. Very high concentrations of citrate ions in the electrolyte are also disadvantageous since said concentrations produce a lower pH value in the aqueous electrolyte and thus cause the deposited layer to redissolve more quickly, whereby the maximum achievable layer thickness decreases before a dynamic equilibrium is established.

[0072] The electrolyte described in Table 1 has a concentration of citrate ions that is advantageous since, on the one hand, it provides a high content of calcium hydroxide in the layer and, on the other hand, it ensures that only a small redissolution of the deposited layer is effected and that the deposited layer also comprises calcium phosphate.

Example 2—Manufacture of an Implant According to the Invention with a Calcium Phosphate Intermediate Layer

[0073] An implant is used, the base body of which consists of a titanium alloy. The base body is coated with two layers of pure titanium in a vacuum. The first layer has a thickness of 30 μm and the second layer has a thickness of 50 μm. Said sprayed titanium layer forms an electrically conductive layer and is then provided with a calcium phosphate layer having a thickness of 100 μm in a vacuum.

[0074] The implant equipped with the calcium phosphate layer is then provided with a calcium hydroxide layer in an aqueous electrolyte.

[0075] The composition of the aqueous electrolyte and the process parameters used are listed in Table 2.

TABLE-US-00002 TABLE 2 Electrolyte Ca(NO.sub.3).sub.2 75 mmol/l (NH.sub.4)H.sub.2PO.sub.4 40 mmol/l Citric acid 20 mmol/l Process temperature 55° C. Current density 110 mA/cm2 Time 20 min. Layer thickness 20 μm

[0076] The calcium hydroxide layer has comparable properties to the calcium hydroxide layer from Example 1, but is not deposited directly on the electrically conductive material of the base body, but on the calcium phosphate layer, which in turn is deposited directly on the electrically conductive layer of the base body.