JP3076637B2 - Composite implant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to composite implants.

[0002]

2. Description of the Related Art The following implants such as artificial roots and bone replacement plates have been proposed. Techniques in which a ceramic mainly composed of calcium phosphate is coated on the surface of a metal base material and the coating layer is a composite material are disclosed in JP-A-63-99867 and JP-A-63-46166. The purpose of the formation is to improve the adhesion strength between the outermost layer of the hydroxyapatite layer or the tricalcium phosphate layer and the metal substrate by the presence of the metal oxide intermediate layer or the alumina intermediate layer. JP-A-63-279835 describes an implant comprising a hydroxyapatite layer and a shock-absorbing resin film. The goal is biocompatibility and shock absorption during occlusion.

[0003]

Although there is no implant which can solve the following problems based on the above-mentioned conventional example, no implant has been proposed yet. 1) No bone resorption occurs at the soft tissue-bone interface. 2) The initial fixation at the time of bone implantation is performed quickly. 3) The effect of bone formation and implant fixation faster than hydroxyapatite (HAP) is simultaneously achieved. 4) First, as described above, the composite implant material composed of the metal substrate and apatite is excellent in biocompatibility and strength.

[0004]

In view of the above SUMMARY OF THE INVENTION The present invention is a calcium phosphate compound was coated on the outer periphery of the core material, it converted to apatite ceramic layer after applying a hydrothermal treatment to the coating layer, this apatite The ceramic layer is used as an intermediate layer, the outer periphery of which is further coated with calcium phosphate, and the outermost layer is a composite implant material, and a part of the outer periphery of the core material is a tricalcium phosphate coating layer, and the other part is a calcium phosphate compound. After coating, an apatite-based ceramic layer converted and formed by hydrothermal treatment was used to realize an implant that solved the above-mentioned problems.

[0005] The present invention provides the hydrothermal conversion described above.
An object of the present invention is to propose an implant having a coating layer in which an apatite-based ceramic layer and a calcium phosphate compound are combined. The features of the implant are as follows. (1) The purpose of coating a metal substrate with, for example, hydroxyapatite (HAP) by a plasma spraying method, a baking method, a thermal decomposition method, or the like is because HAP is excellent in biocompatibility and bone adhesion. At present, it is considered to be the best implant material in terms of biocompatibility and strength. However, this implant further considers initial fixation after bone implantation,
There is an advantage in that bone adhesion is achieved earlier than that having a single coating layer. According to various experiments, when an α-TCP coated implant including an amorphous layer is embedded in bone, bone formation becomes more remarkable than that of HAP alone, and the time is earlier. The reason may be that the α-TCP layer including the amorphous layer has high solubility.
When the CP layer alone was used, the pull-out strength was relatively weak.
It was about 30%. This indicates that the outermost layer is coated with a relatively highly soluble calcium phosphate layer in order to promote bone formation at the early stage of implantation, and after forming the bone, the function of the coating layer composite is such that the HAP layer appears. A composite implant material was produced.

(2) When an α-TCP coated implant containing an amorphous layer is implanted in the jaw bone of an adult dog as in (1), there is almost no bone resorption at the interface between bone and gingiva, and gums are extremely poor. It was beautiful. In that respect, it is considerably better than the implant material of HAP alone. However, as mentioned in (1), since the adhesive strength with bone is slightly inferior to that of HAP alone, α-
A functional material of a coating layer composite was designed such that a TCP or amorphous calcium phosphate layer was coated and a portion in contact with a portion below the cortical bone was used as a HAP layer.
In addition, when such a complexation is applied to a part completely implanted in bone, there is also a function of contributing to bone formation in a part in contact with α-TCP in bone and contributing to fixation of an implant in other parts. Have. The above-mentioned functionality is based on an apatite-based material formed by subjecting a calcium phosphate compound coating layer to a hydrothermal treatment.
The only thing that can be achieved is to have a ceramic layer. That is, conventionally, the formation of the apatite layer using various coating means has been tried, but there are some problems in chemical stability, and the solubility in the living body is often high. Did not have clear functionality.
Therefore, apatite-based ceramics formed by hydrothermal treatment
Since the coating layer has chemical stability, it can be a reference for other compositions. Therefore, apatite-based ceramics
When the thickness and the coating range of the coating layer of another composition including the coating layer are arbitrarily set, the above functionality can be arbitrarily exhibited. Here, the composition indicates a calcium phosphate compound.

Description of Implant Material In the present invention, the term “implant” refers to replacement, prosthesis, reinforcement, etc. for living hard tissues such as artificial roots, artificial bones, and bone plates. The term “composite” means that the composition of the coating layer formed on the implant surface is plural. The core material has a different shape depending on the implant, but is sometimes referred to as a base material. Examples of the material include a Ti-based alloy, a SUS substrate or core material, and ceramics. Calcium phosphate compounds are α or β tricalcium phosphate (TC
P), octacalcium phosphate, amorphous calcium phosphate, etc., alone or in combination. Means for forming the calcium phosphate coating layer include plasma spraying, baking,
Examples include a pyrolysis method, a sputtering method, a CVD method, and a PVD method. In addition, it is not limited to a specific coating means. Coating is also referred to as coating. Hydrothermal treatment and
Depends on the intended apatite ceramic layer,
Calcium phosphate in solutions with different conditions and components
Dip and densify the coated implant material for the specified time and temperature.
Sealing and heating, for example, calcium phosphate coating
To make stoichiometric hydroxyapatite implant material
Hydrothermal treatment means that calcium ion and phosphate ion
Dipping this coated implant material in water, such as an existing aqueous solution,
It indicates sealing and heating. It is intended
The conditions and hydrothermal treatment solution differ depending on the apatite-based ceramic layer.However, in order to mainly obtain a single layer of hydroxyapatite, a solution containing calcium ions, phosphate ions, an aqueous solution of calcium phosphate, or distilled water is used. It is desirable that the temperature be within 100 ° C and within 100 ° C. In the case of the present invention, it is easy to adjust the components of the hydrothermal treatment solution, and to set the processing temperature and the processing time. Therefore, these numerical values on the hydrothermal treatment are generally referred to as environment.
The apatite layer, which shows the apatite ceramic layer obtained by replacing a part of the metal ions and PO ₄ other anions other than Ca obtained by operating components such as the aqueous solution of the above-mentioned hydrothermal treatment, the present invention In this
What apatite is called apatite ceramics
I do. Also, as shown above, the coating layer is apatite.
When using hydroxyapatite, one of the ceramics
In addition, this coating layer is used for other apatite ceramics.
It may be a layer. Amorphous calcium phosphate is mainly generated during thermal spraying and sputtering, and in the former case, the principle of high-temperature quenching, which is a feature of thermal spraying,
The surface of various calcium phosphate powders becomes a low crystalline amorphous phase because it is once melted and solidified. In the latter case, according to various experiments, when the substrate heating temperature is low, the sputtering method using a calcium phosphate target results in low crystallinity. The core material and the apatite ceramic
Further it may be interposed another ceramic layer between the scan layer. Further, another ceramic layer may be interposed between the apatite ceramic layer and the calcium phosphate compound layer.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, (1) is a core material, and (2) is hydroxyapatite (HA).
P) layer, and (3) is an α-TCP layer. The manufacturing method is as follows. The spraying material is α-TCP or β-TCP
When plasma spraying is performed on the metal base material or the core material (1) as a powder, an α-TCP sprayed layer is obtained. The α-TCP sprayed layer thus obtained was coated with Ca ²⁺ PO ₄ having a pH of 6 to 12.
An aqueous solution containing ^3- ions or a calcium phosphate aqueous solution gel is immersed in a gel at pH 5.5 to 12.5, sealed, and placed at 80 to 200 ° C. to perform hydrothermal treatment. The treatment time is within 100Hr. After the above hydrothermal treatment, the crystal structure of the α-TCP layer is converted into the HAP layer, and the stoichiometric and chemically stable HAP layer is converted.
(2) is made. By controlling the hydrothermal treatment time (for example, p
Ca ²⁺ of H6～12, coculture aqueous solution of PO ₄ ^3- ions 120 ° C.
1.5 Hr) A composite material whose surface has been converted to the HAP layer (2) is obtained. Further, after the film is completely converted into the HAP layer as described above, when the α-TCP is formed into a film having a thickness of 5 to 15 μm by plasma spraying, the surface becomes the α-TCP layer (3).

Although the shape shown in FIG. 1 is an example of an artificial tooth root, a manufacturing method suitable for the artificial tooth root will be described below. The surface of the Ti base core material (1) is roughened by sand blasting, bead blasting, acid treatment, or the like, and when the plasma spraying is performed using β-TCP powder having a particle size distribution of 30 to 60 μm as a raw material, the coating layer becomes α- TCP
Becomes After that, the HAP particles were immersed in a HAP gel prepared by dissolving HAP synthesized by a wet method in water so that the HAP particles did not directly touch the artificial tooth root, and subjected to a hydrothermal treatment at 120 ° C. for 30 hours to form a coating layer from the α-TCP layer. Conversion to a HAP layer results in a HAP layer. Next, an α-TCP layer (3) is further formed on the surface of the HAP layer by plasma spraying. The thickness of the layer is the same as in the above embodiment.

Next, another embodiment of the present invention will be described in detail with reference to FIG. The embodiment shown in FIG. 2 shows an example of a bone plate. After masking a part of a metal base material and a core material and forming an α-TCP layer by a plasma spraying method, it is converted into HAP by a hydrothermal treatment, and thereafter, Mask the HAP layer, and apply α-TCP to the previously masked metal surface.
If a layer is formed by the plasma melting method, α-
The TCP layer and the HAP layer are exposed.

In FIG. 2, (1) is a core material, and (2) is a HAP.
Layer (3) is an α-TCP layer. The manufacturing method is as follows. The surface of the Ti-based core material (1) is roughened by sandblasting, the portion (3) is masked with a heat-resistant tape, and α-TCP powder is sprayed by plasma spraying to obtain Ca ²⁺ , PO at pH10. ₄ Dipped in a ^3- ion coexisting solution, sealed, subjected to hydrothermal treatment at 120 ° C. for 48 hours, and then masked the converted HAP layer with a heat-resistant tape.
An α-TCP sprayed layer was formed on the portion (3) by a plasma spraying method. The adhesive of the heat-resistant tape was dissolved by acetone. The α-TCP layer and HA are simultaneously formed on the surface by the above method.
A composite bone implant having an exposed P layer was prepared.

[0012]

As described in detail above, the present invention provides the above-mentioned composite implant by forming: 1) First, as described above, the composite implant material comprising the metal base material and the apatite-based ceramic has biocompatibility and strength. It is also excellent for this implant. 2) The initial fixation at the time of bone implantation is performed quickly. 3) No bone resorption occurs at the soft tissue-bone interface. 4) Faster bone formation and faster implant fixation than HAP. In particular, the effect of 2) is remarkable in the composite implant having the intermediate layer of the apatite ceramics and the outermost layer of calcium phosphate, and the effect of 3) has an amorphous calcium phosphate coating layer on the surface of the single core material. This is remarkable in a composite implant in which an apatite ceramic layer is partitioned and arranged.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 core material 2 hydroxyapatite (HAP) layer 3 α-TCP layer

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Masahiko Yoshizawa 4-19-10 Nihonmatsu, Sagamihara-shi, Kanagawa Examiner Junko Uchida (56) References JP-A-62-221359 (JP, A) JP-A-62-221360 (JP, A) JP-A-63-65871 (JP, A) JP-A-63-93851 (JP, A) JP-A-2-241461 (JP, A) JP-A-1-166765 (JP, A) ( 58) Investigated field (Int. Cl. ⁷ , DB name) A61L 27/00-27/60 A61C 8/00

Claims (3)

(57) [Claims] 1. A core member, the outer periphery of the core material, coated with a calcium phosphate compound, apatite ceramic layer the coating layer converts formed by hydrothermal treatment, the apatite
A composite implant comprising a calcium phosphate compound layer formed on the outer periphery of a base ceramic layer. 2. A core material, an apatite ceramic layer obtained by coating a part of the outer periphery of the core material with a calcium phosphate compound, and forming the coating layer by hydrothermal treatment. A composite implant comprising a calcium phosphate layer containing a tricalcium phosphate layer or amorphous calcium phosphate. 3. The method according to claim 1, wherein said apatite ceramic is hydroxyapatite.
3. The composite implant according to claim 1, which is tight.