JPH0557010A - Compound implant - Google Patents

Abstract

PURPOSE:To increase the chemical stability and strength of an implant by forming a titanium phosphide layer around the external surface of a core material, and covering the layer with a calcium phosphate layer. CONSTITUTION:A phosphoric triester solution diluted double with propanol is uniformly applied to a core material 11 of titanium, dried at a temperature of approximately 120 deg.C and baked at a temperature of approximately 600 deg.C, thereby forming a titanium phosphide layer 12 on the surface of the core material 11. Then, plasma flame spraying is applied, using alpha-TCP (alpha-tricalcium phosphate) as a flame spraying material, thereby forming an alpha-TCP layer 13 on the outermost surface of the core material 11. In addition, the material 11 so coated is subjected to hydrothermal treatment in a water solution of a calcium phosphate for converting the alpha-TCP layer 13 to a hydroxyapatite layer 13.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to composite implants.

[0002]

2. Description of the Related Art Regarding a composite implant in which an intermediate layer is provided on the interface of a base material such as metal or ceramics and calcium phosphate ceramics such as apatite is coated on the outermost layer, the following prior art documents can be presented. JP-A-58-50737: As an intermediate layer, metal: M
o, Ta, Ni, Ni-Cr-Al, Al, ceramics: Al2O3, TiO2, ZrO2, SiO2, SnO2,
P2O5, CaO and B2O5 are used, and plasma spraying is used as a coating method. The purpose of this document is to improve the adhesion strength between the coating layer and the core material. Japanese Patent Laid-Open No. 2-6537: Titanium oxide and tin oxide are used as an intermediate layer, and a thermal decomposition method is used as a coating method. The purpose of this document is to improve the adhesion strength between the coating layer and the core material. JP-A-60
-48751 gazette: As an intermediate | middle layer, resin (PMMA,
Silicon rubber, polyurethane, high-density polyethylene, and Teflon) are used, and the coating and drying method of apatite-based ceramic powder is used. The purpose of this document is that the coating layer does not peel off when the core material is bent. That is, it is to improve the adhesion strength between the core material and the coating layer. JP 63-1
Japanese Laid-Open Patent Publication No. 60665: As an outline of the document, a laminated structure of four layers is shown, and a functionally graded material is disclosed.
Other similar ones are disclosed in Japanese Patent Laid-Open No. 63-160666. Japanese Patent Laid-Open No. 2-5088: Calcium phosphate-based glass and feldspar-based glass are used as the intermediate layer, and the coating method is a method in which hydroxyapatite is fused to the intermediate layer. The purpose of this document is to improve the strength as an implant.
As a similar document, Japanese Patent Laid-Open No. 63-105766 is disclosed. JP-A-63-46166: Al2O3 is used as the intermediate layer, and plasma CVD or vapor deposition is used as the coating method. The purpose of this document is to improve the adhesion strength between the substrate and the coating layer. In these prior art documents, the purpose of providing the intermediate layer is generally to increase the adhesion strength with the base material, and chemical adhesion is considered in addition to physical adhesion.

[0003]

The following four items are listed as the basic idea of the composite coating implant material. 1: The purpose of the intermediate layer is to increase the adhesion strength between the base material and the calcium phosphate coating of the outermost layer, and the effect is not only physical adhesion but also chemical interdiffusion. thing. 2: Elution except Ca and PO4 ions from the outermost calcium phosphate layer is as small as possible. 3: There is no granular or powdery dropout that causes macrophages due to the destruction of the coating layer. 4: When considering a long-term implant, the calcium phosphate layer itself is relatively stable and has low solubility, and further, the calcium phosphate layer dissolves after a long time after implantation,
Even if the intermediate layer is exposed, it should satisfy 2: 3 :.

Considering the above, as the problem of the present situation, * 4 is not satisfied in the case of resin or metal as the intermediate layer, which is not suitable for long-term embedding. In particular, in the case of resin, deterioration in vivo is considered. * When Al2O3 is used as the intermediate layer, the adhesive strength between the base material and the intermediate layer is increased, but the adhesive strength between the intermediate layer and calcium phosphate cannot be expected. (The same can be said for other ceramics.) * When TiO2 was used as the intermediate layer, the results were not good in animal experiments. T to the in vivo tissue as a cause
The diffusion of i ions and granular TiO2 was considered. * If the intermediate layer is a glass layer, the strength of the intermediate layer itself is the cause. Furthermore, after long-term implantation, 4: is no longer satisfied. In general, if the middle layer itself is very thin,
Although the strength of the layer itself can be ignored to some extent,
When long-term implantation is considered, chemical adhesion is achieved and C
a, a stable intermediate layer that does not elute metals other than PO4 and anions is not yet suitable.

[0005]

In view of the above, the present invention provides a T
i, a titanium phosphide layer is provided as an intermediate layer on the outer periphery of a core material made of a Ti-based alloy and the like, and an apatite or calcium phosphate layer such as tricalcium phosphate is formed as the outermost layer on the outer periphery thereof to form a base material. The calcium phosphate layer was chemically adhered by mutual diffusion of calcium ions or phosphorus ions, and it was possible to obtain a chemically long-term stable and high-strength implant in which other ions were not eluted even after long-term implantation.

Description of Implant The term “implant” as used in the present invention refers to an artificial tooth root, an artificial bone, a substitute for a biological hard tissue such as a bone plate, a prosthesis, or a reinforcement.
The core material has a different shape depending on the implant, but may be referred to as a base material by another name. Ti, Ti as material
Indicates a system alloy or the like. Titanium phosphide is TiP2, Ti4P
3, TiP2O7, Ti1.7P, etc. are shown. Moreover, CaTi4 (PO4) 6 etc. are also mentioned as those composite materials.

As a method for forming the titanium phosphide layer, the following method is exemplified. A baking method in which an organic phosphorus compound is applied to a core material and baked A CVD method using an organic phosphorus compound as a raw material After the titanium phosphide intermediate layer is formed by the above method, a calcium phosphate layer such as hydroxyapatite and tricalcium phosphate is formed. Let As the method, in order to cause mutual diffusion of calcium ions or phosphorus ions with the intermediate layer, a pyrolysis method (the above diffusion reaction occurs according to the firing process) is performed by a sputtering method and then a firing process. A method in which the intermediate layer is reduced by dry etching after forming the intermediate layer by sputtering or the CVD method, and the intermediate layer is coated thereon. (By this method, a strong bond is obtained at the interface between the intermediate layer and the calcium phosphate.) Plasma spraying method (since the calcium phosphate powder is laminated on the place where the intermediate layer is rapidly heated by the high-temperature plasma flame). The calcium phosphate layer thus obtained is preferably as chemically stable as possible, and the one whose stabilization is promoted by hydrothermal treatment or the like is used. The method for forming the titanium phosphide layer and the method for forming the calcium phosphate layer are not limited to the above, and other methods may be used. The titanium phosphide layer may be at least interposed between the core material and the calcium phosphate layer, and another ceramic layer may be added as an intermediate layer.

Embodiment 1 FIG. 1 shows an embodiment of the present invention. FIG. 1 is an example of an artificial tooth root. The Ti core material (11) is evenly coated with a phosphoric acid triester solution that has been twice diluted with propanol, and the temperature is 120 ° C.
After drying at 600 ° C, calcination is performed in the atmosphere for 10 minutes. As a result, a titanium phosphide layer (12) is formed on the surface of the core material (11), and then plasma spraying is performed using α-TCP as a spraying raw material to form an α-TCP layer (13) of 40 μm as the outermost layer. Finally, in calcium phosphate aqueous solution, 120 ℃, 15H
Hydrothermal treatment of r is performed to convert the α-TCP layer (13) into a hydroxyapatite layer (13).

[0009]

INDUSTRIAL APPLICABILITY As described above in detail, the present invention provides titanium phosphide as an intermediate layer so that it has high chemical adhesion, and even after the calcium phosphate layer is dissolved in the living body after long-term implantation in the living body, An important implant is obtained because a harmless implant can be obtained and the production method is simple in mass production.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

 11 core material 12 titanium phosphide layer 13 hydroxyapatite layer

Claims (1)

[Claims] 1. A composite implant comprising a core material, a titanium phosphide layer formed on the outer periphery of the core material, and a calcium phosphate layer formed on the outer periphery of the titanium phosphide layer.