JP2003210570A - Implant material having living body active layer and method for covering living body active layer on implant basic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an implant material coated with a living body active layer containing β-TCP of a stable composition and a biodegradable polymer. <P>SOLUTION: The implant material comprises an implant basic material consisting of a living body structure material and the living body active layer on the surface thereof. The living body active layer contains an intermediate layer formed on the surface of the implant basic material and containing the biodegradable polymer and β-tricalcium phosphate and a covering layer formed thereon and containing β-tricalcium phosphate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an implant material having a bioactive layer and a method for coating a bioactive layer on an implant substrate.

[0002]

2. Description of the Related Art Titanium, alumina, and the like are known as biomaterials used for implants such as dental roots and artificial joints. However, although these materials have a high affinity for living bodies, they do not have the property of binding to bone or the like or serving as a scaffold for bone formation (osteoconductivity). Therefore, conventionally, a method of coating the surface with calcium phosphate has been adopted in order to impart bioactivity, which is a property of binding to bone or a scaffold for bone formation, to these biomedical structural materials.

Among calcium phosphates, at present, hydroxyapatite (HAP) is generally coated by plasma spraying. However, although HAP has osteoconductivity, it does not have the property of substituting into autologous bone, and in the long term, the adhesive strength between the coating layer and the implant substrate becomes a problem.

On the other hand, among the calcium phosphates, β-tricalcium phosphate (β-TCP) has the property of being absorbed into the living body together with the osteoconductivity, and this β-T
If CP is coated on the implant base material, the coating portion will be replaced with autologous bone in the future, which is desirable as a component of the bioactive layer.

[0005]

However, when the implant substrate is coated with β-TCP by the plasma spraying method similarly to the above-mentioned HAP, β-TCP is 1150.
When the temperature is higher than 0 ° C, phase transition occurs in α-TCP, and there is a problem that only a coating in which α phase and β phase are mixed can be formed at a high temperature during thermal spraying.

Japanese Unexamined Patent Publication No. 63-134672 discloses a method of coating β-TCP on an implant substrate using a glass binder. In this method, the glass component and β-TCP react with each other. Therefore, in order to control the glass to function as a binder, delicate heat treatment conditions are required.

Further, in Japanese Patent Publication No. 2998852,
A coating method using crystallized glass for depositing β-TCP crystals is disclosed. However, since the β-TCP crystals in the coating layer are deposited in the glass phase, it is unclear whether they contribute sufficiently in terms of osteoconductivity. It is clear. Furthermore, including the glass binder method, it is feared that glass phases other than β-TCP will not be absorbed.

The present invention has been made in view of these problems, and impairs the properties of an implant material coated with a bioactive layer containing a stable composition of β-TCP and a biodegradable polymer, and β-TCP. It is an object to provide a method that makes it possible to coat an implant substrate with a bioactive layer containing β-TCP and a biodegradable polymer without having to do so.

[0009]

In order to solve the above problems, the present invention is an implant material comprising a bioactive layer formed on the surface of an implant base material made of a biostructure material, wherein the bioactive layer comprises: An intermediate layer containing a biodegradable polymer and β-tricalcium phosphate formed on the surface of the implant substrate; and a coating layer containing β-tricalcium phosphate formed on the intermediate layer. A featured implant material is provided.

Further, the present invention is an implant material comprising a bioactive layer formed on a surface of an implant base material made of a biostructure material, wherein the bioactive layer is formed on the surface of the implant base material. A first intermediate layer containing a degradable polymer, a second intermediate layer formed on the first intermediate layer and containing a biodegradable polymer and β-tricalcium phosphate, and on the second intermediate layer And a coating layer containing β-tricalcium phosphate formed on the surface of the implant material.

Further, the present invention comprises a step of heating an implant base material made of a biostructure material, and spraying β-tricalcium phosphate powder having a particle surface coated with a biodegradable polymer on the surface of the implant base material. Thaw,
A step of forming an intermediate layer, a step of further spraying a β-tricalcium phosphate powder on the coating surface of the implant substrate to form a coating layer, and a kneading process for cooling the implant substrate. Provided is a method for coating a characteristic implant substrate with a bioactive layer.

Furthermore, the present invention comprises the steps of heating an implant base material made of a biostructure material, and spraying a biodegradable polymer on the surface of the implant base material to melt the implant base material to form a first intermediate layer. A step of spraying a β-tricalcium phosphate powder having a particle surface coated with a biodegradable polymer on the coated surface of the implant base material to melt it, thereby forming a second intermediate layer, and coating the implant base material A method for coating a bioactive layer on an implant base material, which further comprises a step of spraying a β-tricalcium phosphate powder on the surface to form a coating layer, and a step of cooling the implant base material. provide.

In the method for coating the implant material and the implant base material of the present invention with the bioactive layer, examples of the biostructure material include titanium, alumina and zirconia. Further, as the biodegradable polymer, one selected from the group consisting of polylactic acid, polyglycolic acid, and lactic acid / glycolic acid copolymer can be used.

The β-TCP used in the present invention is preferably β-TCP powder produced by the mechanochemical method. Β-TCP generally has both osteoconductivity and bioabsorbability, but its performance is influenced by the synthesis process, and β-TCP synthesized by the mechanochemical method is used.
TCP is the best.

According to the present invention configured as described above,
The bioactive layer containing β-TCP is formed by spraying the heated implant base material surface together with the biodegradable polymer as a binder, not by a coating method involving high temperature such as plasma spraying. The composition is stable and the adhesion is good. In addition, the biodegradable polymer is decomposed in the living body, and β-TCP has both osteoconductivity and bioabsorbability, so that it is replaced with autogenous bone in the bioactive layer, and an implant material suitable as a structural material for a living body is obtained. Can be provided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

The implant material according to the first embodiment of the present invention comprises a bioactive layer formed on the surface of an implant base material, an intermediate layer formed on the surface of the implant base material, which contains a biodegradable polymer and β-TCP. And a coating layer containing β-TCP formed on the intermediate layer.

In such an implant material, the weight ratio of the biodegradable polymer and β-TCP in the intermediate layer is
It is preferably 1: 9 to 7: 3. The thickness of the intermediate layer is
The thickness is preferably 10 to 200 μm. The thickness of the coating layer containing β-TCP is preferably 20 to 500 μm.

The implant material according to the first embodiment of the present invention is prepared by heating an implant base material, spraying β-TCP powder having a particle surface coated with a biodegradable polymer on the surface of the implant base material, and melting it. , The intermediate layer is coated, β-TCP powder is further sprayed to coat the coating layer, and finally, cooling is performed.

The heating temperature of the implant base material may be higher than the melting temperature of the biodegradable polymer, for example, 120 to
It is preferably 300 ° C. The cooling temperature may be room temperature.

The β-TCP powder having the particle surface coated with a biodegradable polymer or the β-TCP powder can be sprayed by any method. As such a method, for example, a dry method can be used by using a syringe. The method of spraying through a nozzle, a wet spray, etc. can be mentioned.

The implant material according to the second embodiment of the present invention comprises a bioactive layer formed on the surface of an implant substrate, and a first intermediate layer formed on the surface of the implant substrate and containing a biodegradable polymer. And a second intermediate layer containing the biodegradable polymer and β-TCP formed on the first intermediate layer, and a coating layer containing β-TCP formed on the second intermediate layer. It is what constitutes.

In such an implant material, the first
The thickness of the intermediate layer is preferably 10 to 200 μm. The weight ratio of biodegradable polymer to β-TCP in the second intermediate layer is preferably 1: 9 to 7: 3. Second
The thickness of the intermediate layer is preferably 20 to 200 μm. The coating layer containing β-TCP has a thickness of 30 to 600 μm.
It is preferably m.

In the implant material according to the second embodiment of the present invention, the implant base material is heated, and a biodegradable polymer is sprayed on the surface of the implant base material to melt the implant base material.
Coating the intermediate layer of the above, and spraying and melting the β-TCP powder having the particle surface coated with the biodegradable polymer to coat the second intermediate layer, and further spraying the β-TCP powder to coat the coating layer. However, it can be obtained by finally cooling. The heating temperature, the cooling temperature, and the spraying method are the same as those described above.

Next, the operation of the present invention will be described more specifically. In the present invention, since the surface of the biostructure is coated with the bioactive layer containing β-TCP without impairing the properties of β-TCP, it serves as a binder for β-TCP particles without applying high temperature, and Biodegradable polymers such as polylactic acid, polyglycolic acid, and lactic acid / glycolic acid copolymer are used as materials that can be used in the living body. All of these biodegradable polymers are polymers that are degraded in vivo.

The β-TCP powder coated with these biodegradable polymers is prepared. For example, in the case of polylactic acid, it melts at 120 ° C. or higher.
Heat it to 20 ℃ or more, spray the powder coated with polylactic acid, and keep the polylactic acid in the molten state on the substrate.
If the powder of -TCP alone is further sprayed and then cooled, the polylactic acid is solidified and the β-TCP powder adheres to the implant base material to form a coating layer.

Here, β-TCP coated with a biodegradable polymer such as polylactic acid is used because the coating is smooth and the formed layers (intermediate layer, second intermediate layer) have a functionally gradient structure. Is for heating,
It is also necessary to relieve the stress during cooling.

The method of coating the biodegradable polymer on the β-TCP particles is not particularly limited, but for example, β-T is added to a solution prepared by dissolving the biodegradable polymer in an organic solvent.
There is a method in which CP particles are added and the solvent is dried and volatilized.

In the first embodiment, β-TCP coated with a biodegradable polymer was directly sprayed on the implant substrate to form the intermediate layer, but in the second embodiment, the biodegradable polymer is coated. Β-TCP
Prior to spraying, the biodegradable polymer alone is sprayed to form the first intermediate layer.

In the bioactive layer obtained by the above method, β-TCP contained therein reacts (α-TC
Since there is no treatment at a high temperature such as conversion to P), β-TCP in the bioactive layer maintains the same property as that of the substance alone (α-TCP is not mixed). Also, the biodegradable polymer used as a binder decomposes in vivo,
Since it is absorbed and β-TCP has both osteoconductivity and bioabsorbability, autologous bone replacement is performed in the bioactive layer.

Various embodiments of the present invention will be described below.

Example 1 An implant base material (size: 30 × 10 × 2 mm) made of titanium was placed in an electric furnace for 15 days.
Heated to 0 ° C. Separately, β of 40g average particle size 10μm
-Preparing a powder in which TCP particles were coated with 10 g of polylactic acid was sprayed onto a heated base material, and the powder was fused on the surface of the implant base material to a thickness of about 100 µm. The surface of the β-TCP particles was coated with polylactic acid by dissolving polylactic acid in an organic solvent, adding polylactic acid, and drying and volatilizing the solvent.

Next, the implant base material is set to 150 to 25.
It is put in and taken out of an electric furnace at 0 ° C., the fusion state of the powder is controlled, and polylactic acid having a particle size of 10 to 100 μm is sprayed in the molten state to the surface of the implant base material so that the thickness becomes 300 μm. Glued.

Thus, the surface of the implant base material was sufficiently coated with β-TCP powder, and then cooled to room temperature to solidify the polylactic acid component to obtain an implant material having the surface coated with β-TCP. .

When the bioactive layer on the surface of the implant material obtained in this example was analyzed, α-TCP was not observed, but only β-TCP. When this implant material was embedded in bone tissue, polylactic acid and β-T
CP was absorbed in the body and the bioactive layer was replaced with autologous bone.

Example 2 The same implant base material made of titanium as that used in Example 1 was placed in an electric furnace at 150 ° C.
Heated to. The polylactic acid powder of g was sprayed on the surface of the implant base material so that the coating layer had a thickness of about 50 μm and fused, and the fused state was controlled by putting it in and out of an electric furnace at 150 to 250 ° C. .

Separately, 40 g of β-TCP particles having an average particle diameter of 10 μm was coated with 10 g of polylactic acid, sprayed on the surface of the implant base material, and the powder was melted so that the coating layer had a thickness of about 200 μm. Dressed Further, it is put in and taken out from an electric furnace at 150 to 250 ° C. to control the fusion state, and in the molten state, β-TCP powder having a particle size of 10 to 100 μm is subsequently sprayed so that the coating layer has a thickness of about 400 μm. Was adhered to the surface of the implant substrate. In this way, the surface of the implant base material is sufficiently β-TCP
After coating with the powder, the polylactic acid component was solidified by cooling to room temperature to obtain an implant material coated with β-TCP.

When the bioactive layer on the surface of the implant material obtained in this example was analyzed, α-TCP was not observed, but only β-TCP. When this implant material was embedded in bone tissue, polylactic acid and β-
TCP was absorbed in the living body, and the bioactive layer was replaced with autologous bone.

[0039]

As described in detail above, according to the present invention, the surface of the implant base material is heated together with the biodegradable polymer as the binder without using the coating method involving high temperature such as plasma spraying. Since the bioactive layer containing β-TCP can be formed by spraying on the surface of the implant base material, an implant base material having a stable composition and good adhesion to the base material can be used. You can get it. Further, the biodegradable polymer is decomposed in the living body, and β-TCP has both the osteoconductivity and the bioabsorbable property, so that the autologous bone is replaced in the bioactive layer, and the implant material is suitable as the biomaterial. Can be provided.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akira Inoue             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. (72) Inventor Koji Hakazuka             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. (72) Inventor Takeaki Nakamura             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. F-term (reference) 4C081 AB03 AB05 AB06 AC03 BA13                       BA16 BB04 CA172 CB012                       CF022 CF121 CF151 CG02                       DA01 DB02 DB07 DC02 DC03                       DC04 DC05 DC06 EA04 EA06                       EA15

Claims (8)

[Claims] 1. An implant material comprising a bioactive layer formed on a surface of an implant base material made of a biostructure material, comprising:
The bioactive layer is an intermediate layer formed on the surface of the implant substrate, the intermediate layer containing a biodegradable polymer and β-tricalcium phosphate, and the coating containing β-tricalcium phosphate formed on the intermediate layer. An implant material having a layer. 2. An implant material comprising a bioactive layer formed on a surface of an implant base material made of a biostructure material, comprising:
The bioactive layer includes a first intermediate layer formed on the surface of the implant substrate and including a biodegradable polymer, a biodegradable polymer formed on the first intermediate layer, and β-phosphate triphosphate. An implant material comprising a second intermediate layer containing calcium and a coating layer containing β-tricalcium phosphate formed on the second intermediate layer. 3. The implant material according to claim 1, wherein the biostructure material is one selected from the group consisting of titanium, alumina and zirconia. 4. The biodegradable polymer is one kind selected from the group consisting of polylactic acid, polyglycolic acid, and lactic acid / glycolic acid copolymer, and any one of claims 1 to 3 is characterized in that The implant material according to the section. 5. A step of heating an implant base material made of a biological structure material, and a β-tricalcium phosphate powder whose particle surface is coated with a biodegradable polymer is sprayed and melted on the surface of the implant base material to form an intermediate product. A step of forming a layer, a step of further spraying a β-tricalcium phosphate powder on the coated surface of the implant substrate to form a coating layer, and a kneading process for cooling the implant substrate. A method for coating a bioactive layer on an implant substrate. 6. A step of heating an implant base material made of a biostructure material, a step of spraying and melting a biodegradable polymer on the surface of the implant base material to form a first intermediate layer, and the implant base material. The β-tricalcium phosphate powder whose particle surface is coated with a biodegradable polymer is sprayed and melted on the coated surface to form a second intermediate layer, and β-tricalcium phosphate is further added to the coated surface of the implant substrate.
A method for coating a bioactive layer on an implant substrate, comprising: a step of spraying tricalcium phosphate powder to form a coating layer; and a step of cooling the implant substrate. 7. The implant base material according to claim 5 or 6, wherein the biostructure material is one selected from the group consisting of titanium, alumina and zirconia. Method. 8. The biodegradable polymer is one selected from the group consisting of polylactic acid, polyglycolic acid, and lactic acid / glycolic acid copolymer, and any one of claims 5 to 7 is characterized in that A method for coating a bioactive layer on the implant substrate according to the above item.