JPS61109570A - Production of implant material for crbonaceous living body hard tissue - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a carbonaceous biological hard tissue implant material. For more details,
When the present invention is implanted in a living body as a material for artificial bones and artificial teeth used to compensate for and prosthetic missing parts of bones and teeth, it has little biological reaction, blends well with living tissue, and bonds strongly. The present invention relates to a method for manufacturing a carbonaceous biological hard tissue implant material having properties and excellent durability.

(Prior Art) Despite various studies and efforts over many years regarding materials implanted into living bodies as artificial bones and teeth, the reality is that many problems still remain. Inorganic materials such as ceramics, glass, and carbon have been developed to replace conventional metals or polymeric resin materials, and have recently attracted attention, and some of them have begun to be put into practical use. Implant materials have various characteristics that are required depending on the shape, size, and function of the site where they are used, and there are many different types of designs and materials to choose from. The conditions necessary for implant materials to function safely in vivo are: (1) They must be non-toxic, non-irritating to tissues, and do not cause problems such as carcinogenesis, allergies, or destructive effects on adjacent tissues. .

(2) Do not cause foreign body reactions (actions that try to expel them from the living body).

(3) It should not be absorbed (decomposed and lost) in the living body.

(4) Do not ionize and elute under the influence of body fluids, etc.

(5) It has a good affinity with tissues (referred to as biocompatibility).

(6) It has high mechanical strength such as bending strength and compressive strength, can withstand stress during use, and does not deteriorate in strength in a biological environment.

(7) Easy to handle and disinfectable.

(8) The hardness and modulus of elasticity can be adjusted to be equal to or slightly greater than that of biological hard tissue, and when integrated with biological tissue, the state can be as close to natural as possible.

The following requirements must be met.

When each material is evaluated against the above requirements, it is found that metal materials meet the requirements listed in <11. (2), (4), +8)
There are problems with the conditions , and with plastic materials, there are many problems with the conditions +2), (3), and +6). On the other hand, ceramic materials, which have been attracting attention recently, meet the conditions (1) to (5) unique to living tissues.
), there are almost no problems. The reason why ceramic materials have not been used in the past is that they do not satisfy the mechanical strength requirement (6) and that their strength deteriorates in a humid in-vivo environment. Regarding this point, with the development of alumina materials such as artificial sapphire single crystals or polycrystals, and sintered hydroxide apatite, the above-mentioned drawbacks have been improved and some of them have been put into practical use. became.

However, the former material, alumina, has extremely high hardness and elastic modulus, and the stress exerted on the living body concentrates on the implant, causing unreasonable stress to act on and destroy the surrounding tissue, or even reaching nerve tissue. There are problems such as causing troubles such as damage to the device and the condition (8) still remains unsatisfactory. The latter sintered hydroxyapatite is a material that closely resembles the hard tissue of living organisms, and does not have the same problems as the alumina material, but it still lacks mechanical strength and is difficult to synthesize and mold apatite powder. There are problems with sintering technology, such as requiring difficult and complicated processes. The above are problems related to materials, but in addition, implant materials are important when repairing fracture sites in normal biological hard tissues (bones and teeth), implanting artificial joints, and implanting artificial tooth roots. (11) A self-locking method in which the implant material and bone tissue are self-fixed by devising the structure or shape.

(2) A method of mechanically fixing using screws, bolts and nuts.

(3) Methods such as bonding the implant material and bone using an adhesive such as medical cement have been adopted. However, no matter which method is used, the implant may become loose over a long period of time, and even if the implant material itself has no defects, it may fall off and have to be replaced. In addition, dental treatment is performed in which an implant material as a tooth root is implanted into the alveolar bone and a tooth crown is fixed thereto, but in this case as well, the various hard implant materials mentioned above are used and the shape is similar to that of a natural tooth root. There are many types such as , pin type, blade type, screw type, etc., and those designed according to each symptom are used.

In this case, all of the above-mentioned problems apply, and the problems are further exacerbated by the constant repetitive functional pressure of mastication. Furthermore, since these tooth root materials are used both within the body and on the body surface, adhesion at the material-living tissue interface is particularly necessary. In other words, adhesion at the part that protrudes from the inside of the body to the body surface is important, and if this cannot be achieved,
Unfavorable results may occur due to bacterial contamination from outside the body or the infiltration of harmful substances into the body.

(Problems to be Solved by the Invention) In view of the current situation where the above-mentioned problems remain, one of the inventors of the present application proposed that carbon has excellent antithrombotic properties, no tissue irritation, and is compatible with living organisms. It is a material that is highly compatible, has outstanding stability under various environments inside and outside the body, and has excellent mechanical strength.As a result, it is often used as an artificial heart valve. Successful cases have been announced, and we will focus on the fact that it has also been put to practical use in ligaments, root materials, and artificial joints, and will continue to conduct further research to strengthen the bond with biological hard tissues. By considering various materials and structures, and devising a shape design that provides sufficient strength to maintain biological functions, we will create an excellent implant material for living hard tissue that has never been seen before. (Japanese Patent Application Laid-Open No. 57-134154, Carbonaceous Artificial Replenishment, Replacement Materials and Method for Manufacturing the Same). That is, this Japanese Patent Application Laid-Open No. 57-1341
The implant according to No. 54 is characterized by having a porous layer on the surface of the implant with a thickness of 0.1 mm or more and a structure that allows three-dimensional interweaving with the newly generated living tissue.

Although the implant material obtained by this method produced extremely excellent therapeutic effects in subsequent clinical experiments, the following problems were discovered in the manufacturing process. That is, (1) a carbonaceous core material is used as a base material, and a porous layer of felt or nonwoven fabric made of carbon fiber is applied to the core material.

0, (Chemical Vapor Deposit
ion) method to bond and fix with pyrolytic carbon, depending on the difference in thermal expansion coefficient and heat transfer coefficient between the carbonaceous core material and the carbonaceous porous layer, cracks may occur at the bonding interface between the core material and the porous layer. Separation and even peeling phenomena may occur. In other words, improving the mechanical properties of the core material tends to increase its expansion coefficient, and when using a core material with excellent mechanical strength, the above-mentioned bonding interface between the core material and the porous layer has a strong tendency to increase. It becomes difficult to prevent the peeling phenomenon. For this reason, it is difficult to improve the properties of the core material due to changes in the coefficient of thermal expansion.

(2) When shaping based on the desired design shape,
It is necessary to perform cutting on the carbon material that serves as the core material. For this reason, core materials are limited to soft graphite materials that are easy to cut, and high hardness and high strength core materials that are difficult to cut have extremely low productivity. It cannot be expected that it will be used on a regular basis. Furthermore, since felt, nonwoven fabric, etc. made of carbon fibers are rigid, it is difficult to process them into a state in which they are closely bonded to a core material having a curved surface or a complicated shape.

(3) When joining, carbon fiber felt or the like is wrapped around the formed core material using long carbon fibers and fixed, and then C, V,
D. Pyrolytic carbon is precipitated to fix the fibrous material internally and to bond and fix the interface between the fiber layer and the core material, but such a method not only requires complicated manual processing for pretreatment, but also There are also many problems with reproducibility. In addition, since it takes a long time to process C, V, and O, this method is not suitable for industrial mass production and is not economical. It becomes difficult.

(Means for Solving the Problems) In order to solve the above problems, the inventors of the present application have conducted further improvement research and found that in order to prevent separation between the fiber porous layer and the core material interface, it is necessary to At the stage of the raw material resin material before carbonization treatment, the interface between the resin fiber porous layer and the resin core material is bonded with a resin material having a high carbon yield to form an integrated object. It has been found that it is sufficient to perform an insoluble/infusible treatment to impart heat deformation resistance, and then simultaneously carbonize the material in an inert gas phase atmosphere. By adopting this method, when shaping based on the desired design shape,
It becomes possible to apply conventional resin molding processing technology,
It is now possible to freely process products with curved surfaces or complex shapes.

Furthermore, by considering the resin material used, there is an advantage that an implant core material having high hardness, high strength, and impermeability after carbonization can be obtained without performing post-processing such as cutting. Therefore, by using the method of the claimed invention,
Implant materials for biological hard tissues that have extremely excellent therapeutic effects can be mass-produced industrially at low cost and with guaranteed quality.

In the implant material of the present invention, in a static environment where there is no movement between the living hard tissue and the implant material due to the action of external stress, the joint site is completely covered by new bone, and the implant and the living hard tissue are completely covered. In a dynamic environment where biological hard tissues and implant materials undergo repeated movement due to the action of external stress, new biological m The tissue changes into hard tissue in the deep part of the surface porous layer of the implant, that is, in the part close to the surface of the core material, and is firmly fixed there. As a result, both ends of the implant are fixed to biological hard tissue inside and outside the implant, and the middle part thereof is characterized by a flexible connection method that remains as soft tissue.

The implant material of the present invention uses a carbon material as a core material, which has a smooth surface, high hardness, excellent mechanical strength such as bending strength and compressive strength, and is impermeable to body fluids. Furthermore, the core material has a thickness of 100 μm or more on the surface.
Preferably, it is characterized by an integral structure with a carbon porous layer of 500 μm or more. This porous structure is extremely important for smooth and strong bonding with the living body, and the pore structure is designed so that cells can easily attach to the surface and fix and proliferate.
As a result of cell proliferation, newly generated collagen fibers enter the porous tissue on the implant surface, creating an interwoven state.

Furthermore, it is important that this surface porous layer has an appropriate pore distribution that allows circulating fluids such as blood to easily penetrate in order to supply oxygen, nutrients, and the like. By satisfying these conditions, living tissue is generated in a state where it can interweave with each other within the carbon porous layer, and becomes ossified over time.

As a result, the biological hard tissue and the implant are not simply bonded between the biological body and the implant, which is generally not expected to be very strong, but are firmly connected by mutually interwoven mm. In addition, when the natural state of living hard tissues and implants is that they are constantly moving relative to each other due to external mechanical stress, as in the case of dental root materials, a slightly different type of bonding is required. state is required. In a natural living body, such mutually movable joints include soft tissues anchored at both ends to each hard tissue. The implant of the present invention can also be used to create connective tissue as described above. however,
In this case, it is desirable that the following considerations be added.

That is, in the vicinity of the core material, the thickness is 50 μm or less, preferably 2
It is preferable to have a pore diameter of 0 μm or less. With this pore diameter, the collagen fiber tissue that has entered the interior without capillary penetration is calcified and firmly adheres to the core material surface, resulting in an anchoring effect. begins to appear. In addition, in the intermediate layer adjacent to the porous layer with a pore diameter of 5 μm or less, 1
It is preferable to have a pore distribution of 00 μm or more, preferably about 200 μm, and in this region, oxygen and nutrients are sufficiently supplied by capillaries. Furthermore, the outermost surface has a 200 I! It is preferable that the porous layer is constructed of a porous layer having a pore size distribution of not less than m and not more than 600 μm, preferably 300 μm.

On the outermost surface with this pore size distribution, body fluids and blood vessels can freely enter, allowing cell proliferation to occur effectively and smoothly, and as a result, from the middle layer to slightly outside the outermost surface. becomes soft tissue, which flexibly and firmly connects the implant material and biological hard tissue through an anchoring effect.
It comes to resemble a completely natural situation.

Next, a method for manufacturing a carbonaceous three-dimensional porous body, which is a component of the implant material in the present invention, will be explained.

Organic polymer fibers used as raw materials for porous bodies include:
No deformation or melting when heated in an inert gas phase,
It shows a high carbon residue yield, for example, thermosetting resins such as phenol resin, furan resin, bismaleide/triazine resin, epoxy resin, or polysaccharides such as pulp and rayon, which have a fused polycyclic aromatic structure as a basic molecular structure. Examples include natural polymer fibers contained within. Further, as the precursor fiber, a carbon fiber precursor that has been made infusible by oxidation or the like is used, such as when carbon fiber is made from a meltable organic fiber. For example, polyacrylonitrile resin, polyvinyl chloride resin, post-chlorinated polyvinyl chloride resin, polyvinyl alcohol resin, polyamideimide resin,
Examples include thermoplastic resins such as polyimide resins and aromatic polyamide resins, or fibers made of petroleum asphalt, coal tar, pitch, or mesophase pitch obtained from these, which are made infusible by oxidation and turned into carbon fiber precursors. It will be done. In addition, the shape of the organic polymer fiber or precursor fiber used here can be obtained by a paper making method, a felting method, a non-woven fabric method such as needle punching, etc.
Suitable materials are paper-like, felt-like, or non-woven fabrics that basically have a structure in which a large number of fibers are overlapped in random directions and woven in a three-dimensional manner.

To increase the porosity of a carbon porous material, choose one with a thick fiber diameter and a coarse weave density, and conversely, to reduce the porosity, choose one with a thin fiber diameter and a high weave density. .

Furthermore, a designed pore distribution can be obtained by appropriately combining these layers and laminating them in multiple layers.

Next, a method for producing a dense carbonaceous core material (hereinafter referred to as core material) having high hardness, high strength, and impermeability, which is the other component of the implant material according to the present invention, will be explained.

Regarding the manufacturing method of the core material, one of the methods described below is adopted depending on its design and purpose of use.

1) - As a matrix, thermoplastic resins such as post-chlorinated polyvinyl chloride resin, polyvinyl chloride resin, polyvinyl alcohol/vanillin/tragacanth gum mixed resin, furan resin,
Using one or a mixture of thermosetting resins such as phenol resin and epoxy resin, and using this resin, natural graphite powder with high crystallinity and carbonaceous powder such as carbon black or chopped carbon fiber. The blended composition containing the carbonaceous powder as an extender is strongly kneaded using a mixing roll or pressure kneader with high shear force to cause a mechanochemical reaction at the interface between the matrix resin and the carbonaceous powder, and preferably A molding composition is obtained by uniformly dispersing the carbonaceous powder until it reaches the state of primary particles. Thereafter, this composition is extruded under high pressure using a conventional plunger-type or screw-type extruder using an extrusion die of a desired shape to form a round bar (circular) shape or plate into an intended shape. A green core material shaped body (green core material) is obtained. Here, there are cases where the green core material is used as it is, and cases where the green core material is further subjected to oxidation treatment or hardening treatment in air at 300° C. or lower to be used as a precursor core material.

1 person = 1 A substance that shows a high carbon residue yield after calcination as a matrix and is a mixture of one or more of monomers, prepolymers, or initial polycondensates of polymer compounds that can be relatively easily thermally polycondensed. The same carbonaceous powder as in Method 1 is added to this and dispersed uniformly, and this is strongly kneaded using a mixing roll or pressure kneader with high shear force, and then highly kneaded using a ball mill. A molding powder composition in which mechanical energy is applied to induce a mechanochemical reaction, and a matrix resin is uniformly and physicochemically strongly bonded to the surface of the primary particles of the carbonaceous powder used as a bulking material. Next, this is powder pressure molded into a desired shape using an ordinary hot press molding machine to obtain a green core material.

Here, there are cases where the green core material is used as it is, and cases where the green core material is further subjected to a curing treatment at a temperature of 300''C or less to be used as a precursor core material.

Next, a method of integrally bonding a carbonaceous three-dimensional porous layer to the surface of a carbonaceous core material, which is the main feature of the present invention, will be explained.

Before being subjected to carbonization treatment at 400°C or higher, three-dimensionally interwoven porous organic polymer fibers, which are the raw materials for the porous body, are added to the formed core material obtained by either method 1 or 2. After cutting the body, i.e., paper, felt, or nonwoven fabric, into the desired shape, it is bonded using a bonding material with a high carbon yield made from a liquid composition of organic polymeric substances. to form an integrated excipient. After that,
By performing hardening treatment or insoluble/infusible treatment and then firing at a predetermined temperature in an inert gas phase, the core material and the three-dimensional fiber interweave layer are integrated with the carbonized bonding material, and at the same time A carbonized all-carbonaceous biological hard tissue implant material is obtained.

The liquid composition of the organic polymer substance used as the carbonized bonding material in the first stage may be a liquid or paste-like composition such as furan resin, phenol resin, or epoxy resin, as long as it exhibits strong bonding force at the stage of carbonization. Good, but not particularly limited. In this case, for these liquid compositions,
Carbon powder such as fine graphite or carbon black is 5 to 5
A composition containing 0% by weight, preferably 10 to 20% by weight is preferable because it strengthens the carbonized bond.

Here, if necessary, vapor-phase pyrolytic carbon may be precipitated to produce a finished product for the purpose of hardening the surface and strengthening protection of the obtained implant material, but this vapor-phase pyrolytic carbon treatment , the temperature of the implant material being treated is 600~
It is an excellent method to precipitate pyrolytic carbon by setting conditions such that the temperature is 2300°C, preferably in the range of 700 to 1100°C, and there is a negative temperature gradient from the surface of the core material to the surface of the carbon porous body. It is important for manufacturing implant materials for biological hard tissues.

(Function) According to the method of manufacturing an implant material for biological hard tissue of the present invention, (1) Cracking and peeling phenomena at the bonding interface between the core material and the porous fiber layer do not occur at all.

(2) When shaping based on a desired design shape, conventional resin molding processing techniques can be applied, and processing of complex shapes can be performed freely and accurately.

(3) By considering the resin material used, a core material having high hardness, high strength, and impermeability after carbonization can be obtained without post-processing.

(4) Since it is excellent in industrial mass production, product variations are small and quality can be guaranteed, and it is extremely economical.

(5) It has high mechanical strength and precision, and the pore diameter and porosity distribution of the carbonaceous three-dimensional porous structure can be appropriately designed, so a high therapeutic effect can be exhibited.

(Examples) Next, the present invention will be specifically explained by examples, but the present invention is not limited to these examples.

On the other hand, 11 (I-1 material, blade material) As a composition material for forming the core material, a furan resin initial condensate [manufactured by Narita Pharmaceutical Co., Ltd., Q-100] was used.
1) 70% by weight highly crystalline natural graphite (average particle size 5 μm) 23% by weight Furnace black [manufactured by Mitsubishi Chemical Corporation MA-8]
After uniformly dispersing and mixing 7% by weight of the blended composition using a Henschel mixer, the mixture was thoroughly kneaded using a mixing roll whose surface temperature was maintained at 50°C, and the resin was thermally polymerized to improve its plasticity. A mochi-shaped core material molding composition was obtained. This is formed into a plate shape with a thickness of 3 mm using an extrusion molding machine equipped with a vacuum degassing device using a T-die, and then cut out using a punching die having an eleventh shape to produce a blade-shaped core material. Obtained form. next,
Place this in an air oven heated to 180°C.
It was cured for 0 hours to obtain a precursor core material.

Separately, as a three-dimensional porous layer construction material, polyacrylonitrile fibers containing 95 mol% acrylonitrile and 5 mol% methyl acrylate were treated at 255"C under tension in the air to make them highly stretch-oriented. Using a precursor fiber with a fiber diameter of 12 μm that has been subjected to flame-retardant treatment, it is cut into fiber lengths of 5 mm, mixed in a 2% aqueous solution of cellulose sodium glycolate, and stirred for 10 minutes using a high-speed agitator. A slurry in which the precursor fibers were uniformly dispersed was obtained.Next, paper was made by injecting an appropriate amount of the slurry into a Nusoche equipped with a screen, and it was dried to obtain a precursor fiber vapor.At this time, in the slurry By changing the mixed amount of cut fibers appropriately, three types were created: (A) Measuring size 30g/m'' (B) Measuring size 60g7...2 (C) Measuring size 250g7m2.

Subsequently, 1% sodium balatoluenesulfonate was added as a curing agent to the furan resin initial condensate.
After soaking these vapors, three sheets A, B, and C were stacked, excess furan resin liquid was removed using a vacuum filtration machine, and curing treatment was performed at 1.20°C for 3 hours to reduce the porosity of each sheet. A mixed woven fiber porous material with different three-layer structures was obtained. Next, this three-layer porous structure was cut, and a paste composition was prepared by adding 20% by weight of natural graphite powder to 100% by weight of a furan resin initial condensate (VF-302) and thoroughly dispersing the mixture as a carbonized bonding material. Using this method, the +b1 portion of the precursor core material was adhered to both sides of the +b1 portion, with the surface with the smaller porosity facing toward the surface of the core material, to form an integral molded product.

Next, this was subjected to a curing treatment for 5 hours in an air oven heated to 180°C to obtain a carbon precursor. Furthermore,
10"C/hr up to 500℃ in nitrogen gas, 500
The temperature was raised to ~1000°C at a temperature increase rate of 50°C/hr, held at 1000°C for 3 hours, and then allowed to cool naturally to complete the firing, so that the core material and the three-dimensional porous layer of the fibers were carbonized. A blade-shaped tooth root material was obtained which was completely integrated with the bonding material and carbonized at the same time.

The obtained implant surface was robust and hard, and the fibrous porous layer having a three-layer structure had a pore size distribution as designed. That is, the first layer from the surface of the core material had an average thickness of 15 μm, the second layer had an average thickness of 150 μm, and the third layer (surface layer) had an average thickness of 250 μm. Furthermore, the porosity of the outermost layer was approximately 70% and decreased toward the inside. The strength of this plate-shaped sample, including the surface porous layer, had sufficient mechanical strength with a bending strength of 420 MPa, a Young's modulus of 525 GPa, and a compressive strength of 650 MPa.

Give! As a material for the composition for forming the core material, a furan resin initial condensate (Hitafuran V manufactured by Hitachi Chemical Co., Ltd.)
F-302) 100% by weight and 45% by weight of highly crystalline natural graphite (average particle size 2 μm) added as an extender. After uniformly mixing in a kneader, the surface temperature was 50%.
Thoroughly knead the graphite particles using a mixing roll kept at ℃, continue until the graphite particles become primary particles, and repeat until the surfaces of the graphite particles are uniformly coated with furan resin by inducing a mechanochemical reaction. Ta. Next, this was coarsely crushed, put into a ball mill, and crushed for 50 hours to obtain a core material molding composition powder having an average particle size of 5 μm. Using this powder, a mold having the shape shown in FIG.
Powder compression molding was performed at 0° C. and a molding pressure of 100 Kg/cm 2 to obtain a green molded body.

Separately, as a fiber for constructing a three-dimensional porous layer, an aqueous slurry composed only of fibers and fibrids made of wholly aromatic polyamide, that is, poly-m-phenylene isophthalamide, is wet-formed, and then a specific number of sheets are laminated. Adopts a 1.6mm thick board made by Nippon Aroma Co., Ltd., which is pressed into a board shape.
After cutting this, using the same carbonized bonding material as in Example 1, it was bonded to both the front and back sides of this core material forming blade part (b) to integrate it, and was heated to 18'0°C with air. A curing treatment was performed in Osin for 10 hours. The subsequent steps were performed in exactly the same manner as in Example 1 to obtain the desired carbonaceous implant material. The structure of the obtained surface porous layer was distributed within a range of ±20 μm around 100 μm.

The strength of this sample is 320M bending strength including the surface porous layer.
The material had a Young's Pa of 45 GPa and a compressive strength of 520 MPa, showing suitable properties as a tooth root material.

Method J3 (Bay Inubo Material) Post-chlorinated polyvinyl chloride resin [manufactured by Nippon Carbide ■] is used as a material for the core molding composition.
T-742) 35% by weight furan resin initial condensate [Hitachi Chemical Hitafuran VF-302]
35% by weight of highly crystalline natural graphite fine powder (average particle size 2.0 μm) 30% by weight as a plasticizer.
After adding 25% by weight of diallyl phthalate monomer and dispersing using a Henschel mixer, the surface temperature was reduced to 1.
Kneading was repeated sufficiently using a mixing roll kept at 30°C until the graphite particles became close to a primary particle state to obtain a core molding composition in which a mechanochemical reaction was induced.

This core material molding composition was extruded using a plunger extruder at a molding temperature of 130°C while degassing to obtain a round bar (produced shaped body) with a diameter of 3.0 mmφ. This round bar was cured for 10 hours in an air oven heated to 180°C to obtain a precursor core material.

Separately, as a fiber material for constructing a three-dimensional porous layer, phenolic novoloid fiber processed into a felt shape [Japan Kynor @'Jl, S-211, fiber diameter 15
It was cut into pieces with a fabric weight of 300 g/mJ and bonded to the surface of the precursor core material using the same carbonized bonding material as in Example 1 to form an integral molded product.

Next, this was heated to 180°C.
A carbon precursor was obtained by performing a curing treatment in an oven for 5 hours. Furthermore, in nitrogen gas, the temperature up to 500°C is 10'C/hr.
, 5 Q O to 1000°C was heated at a heating rate of 50°C/hr, held at 1000°C for 3 hours, and then allowed to cool naturally to complete the firing, forming a core material and a three-dimensional porous layer of fibers. were completely integrated by carbonizing the bonding material, yielding a round rod-shaped sample that was simultaneously carbonized.

This round rod-shaped sample is placed in a reaction vessel for gas phase pyrolysis, and by directly applying electricity using both ends of the round rod-shaped sample as electrodes, the round rod-shaped sample itself generates resistance heat, and vapor phase pyrolytic carbon is deposited under the following conditions. I did it.

Raw material organic matter Cis-1,2-dichloroethylene carrier gas Argon raw material gas concentration 20% by volume Raw material gas flow rate 470 ml/min Deposition material temperature 900°C Deposition processing time 10 hours Samples that have been deposited have already been carbonized bonding material The surface of the core material and the interwoven fiber layer were joined together, but the pyrolytic carbon deposited also created a strong bond between the interwoven fibers, hardening the surface and strengthening protection.

The round rod thus obtained was cut into a length of 25 mm using a diamond cutter to obtain the desired completed implant material. The pore diameters forming the surface porous layer of this implant material were distributed within a range of ±50 μm with a center of 150 μm.

In addition, the sample has a core part diameter of 2.2 mm and a maximum outer diameter of 3.6 mm.
mm, bending strength 480 MPa, Young's modulus 60 GPa.

It had sufficient mechanical strength with a compressive strength of 580 MPa. (Refer to Figure 3) Although the examples have been explained above, Examples 1 and 2 are as follows.
It is used as a dental implant, and in Figs. 1 and 2, part fb1 is the part to be implanted into the alveolar bone and has a porous structure on the surface, but part 81 has no epithelial tissue. This is the part that penetrates and is exposed in the oral cavity, does not have a porous structure layer on its surface, and is the part to which the artificial tooth crown is attached.

In addition, in Fig. 3, (a) is made for bone repair, but as in fb), the width of the porous structure layer portion is narrowed, leaving a portion where the core material is exposed. By molding it and then subjecting it to the same treatment, we were able to create an artificial tooth root material with the same mechanical properties.

(Effect of the invention) The round rod-shaped sample obtained in Example 3 was implanted in the lower leg bone of a crabeater monkey, and after one year, it was extracted together with the surrounding bone, and the porous layer on the implant surface was measured using a load cell. The shear adhesive strength between the specimen and biological tissue was measured.

A push-out test was performed at a push-in speed of 1 mm/min, and the result was approximately 95 Kgf/cm2.

Also. The bone defect created at the time of implantation has been completely repaired, and the results of microradiogram photography using soft X-rays show that new bone has been formed inside the porous structure layer and is composed of carbon interwoven fibers. It was discovered that the bones were intricately intertwined and strongly connected to each other. In addition, new bone has grown close to the implant surface, and no foreign body reaction or giant cells have been observed, demonstrating that this implant material has excellent compatibility with living tissue. ing.

The dental implant materials obtained in Examples 1 and 2 were implanted into the mandible of a crab-eating monkey, and after one year, the results of observation were very good, and even under masticatory pressure,
No loosening was observed. In addition, biological epithelial tissue and blade-type implant material cervical fa
) The bonding condition at the contact area is good, and gingival inflammation does not occur. The long-term course is currently under observation.

As described above, the carbonaceous biological hard tissue implant material of the present invention shows an extremely excellent therapeutic effect, and by adopting this manufacturing method, the above material can be produced industrially with high quality and at low cost. This makes it possible to manufacture and is extremely important in supplying large quantities of materials for filling and prosthetic bone and tooth defects.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a blade-shaped core material production body formed by die cutting in Example 1. FIG. 2 is an explanatory diagram of a green molded body subjected to powder compression molding in Example 2. FIG. 3 is an explanatory diagram of the round bar-shaped implant material obtained in Example 3.

Claims (2)

[Claims] (1) Carbonaceous fine powder such as crystalline graphite or carbon black, or a molded body of an organic polymer resin material composite reinforced with carbon fibers (referred to as green core material), or hardening treatment or insoluble/infusible treatment, etc. Basic fibers made using organic polymer fibers or carbon fiber precursor fibers (referred to as precursor fibers) in a core material consisting of a molded body (referred to as precursor core material) that has been subjected to carbon precursor treatment. A porous layer made of paper, felt, non-woven fabric, etc., which has a three-dimensionally interwoven structure in which many fibers overlap in random directions and is appropriately cut according to the designed shape, is prepared before carbonization treatment at 400°C or higher. , the core material and the porous layer are bonded together using a high carbon yield bonding material made of a liquid composition using one or more organic polymeric substances, and the core material and the porous layer are integrally shaped. The core material and the three-dimensional porous fiber layer are strengthened by the carbonized bonding material by applying a post-hardening treatment or insoluble/infusible treatment and then firing at a predetermined temperature in an inert gas phase. A method for manufacturing a carbonaceous biological hard tissue implant material consisting essentially only of carbon materials, characterized by having a coarse and dense integrated structure that is bonded and simultaneously carbonized. (2) A pyrolytic carbon coating is applied by vapor phase pyrolytic carbon treatment for the purpose of hardening and strengthening the surface of the biological hard tissue implant material, which is essentially composed only of a carbon material. The method for producing the carbonaceous biological hard tissue implant material according to item 1.