JP2013144155A - Method for producing implant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve biocompatibility and a mechanical property of an implant.SOLUTION: A method for producing an implant includes a step in which a core made of a first metal material is arranged within a mold, a step in which an implant material is formed by injecting, into the mold with the core, a surface part forming compound containing powder of a second metal, a binder and a porous material, and a step in which the implant material is baked after the implant material forming step. In the implant material baking step, the porous material is made to disappear and a surface part having more holes than the core is formed on the outside of the core.

Description

  The present disclosure relates to a method for manufacturing an implant, and in particular, a method for manufacturing a metal dental implant.

  Biomedical implants are generally made of metal or ceramics. As examples of metals, magnesium, aluminum, titanium, iron, nickel, copper and the like are known. Among them, titanium which is difficult to process but excellent in strength and corrosion resistance and excellent in biocompatibility (hereinafter referred to as titanium including pure metal titanium and titanium alloy) is often used. As such a conventional technique, for example, a metal powder such as titanium and a void forming material powder that is burned off by heating are mixed and press-molded, and after heating and burning the void forming material, a sintering treatment is performed. It is disclosed that a porous metal body is manufactured, and a porous composite body for living body that has been subjected to a sintering treatment after filling the voids of the porous metal body with hydroxyapatite is disclosed (Patent Document 1).

  In addition, since the bone contact with the bone tissue is required to be compatible with the bone tissue, after the formation of the shape by machining, a fine undulation is provided on the surface to improve the bond with the bone. . Alternatively, surface treatment such as titanium oxide or apatite is performed to improve compatibility with bone cells. As such a conventional technique, for example, as a method of manufacturing a dental implant, there is a method of forming a skin layer and a core part, forming a skin layer by a metal injection molding method, and manufacturing a core part by an injection molding method. Known (Patent Document 2).

JP 2003-325654 A JP 2005-329244 A

  In patent document 1, a metal porous body with high biocompatibility can be obtained. However, since the sintered material is provided with pores in order to ensure compatibility with a living body, mechanical strength such as compressive strength and pressure strength is insufficient, which has been a problem in practical use.

  In patent document 2, it is a dental implant which consists of the outer main body made from the metal, and the inner main body made from the plastics, Comprising: The outer main body which consists of metals, such as titanium, has a cavity part by a metal injection molding method. The inner body is known to be formed in the cavity by a plastic injection molding method or the like. However, the inside is plastic, and the strength as an implant was insufficient. Further, the bonding strength between the outer main body made of metal and the inner main body made of plastic is not sufficient, and in some cases, there is a problem of peeling.

  The first aspect of the method for manufacturing an implant includes a step of placing a core part made of a first metal material in a mold, a powder of a second metal material in the mold having the core part, and a binder And implanting the surface material forming compound including the porous material to form the implant material, and firing the implant material after the step of forming the implant material, and firing the implant material In the process, the porous material is eliminated, and a surface portion having more holes than the core portion is formed outside the core portion.

  In the first aspect of the method for manufacturing an implant, the core portion may be fired in the step of firing the implant material.

  In the first aspect of the method for producing an implant, the first metal material contains at least 45% by weight of titanium and at least one selected from aluminum, vanadium, zirconium, tantalum, niobium, molybdenum, nickel, and palladium. These metals may be included in a total amount of 0.1 to 55% by weight.

  1st aspect of the manufacturing method of an implant WHEREIN: 1st metal material contains 50 weight% or more of cobalt, and at least 1 sort (s) or more element selected from carbon, silicon, chromium, and molybdenum is 1-total in total. You may contain 50 weight%.

  In the first aspect of the method for producing an implant, the porous material may be one or more selected from ammonium hydrogen carbonate, urea, polyoxymethylene resin, urea resin, expanded polystyrene resin, and expanded polyurethane resin. .

  The second aspect of the method for manufacturing an implant includes a step of arranging a core part made of the first metal material in a mold, a powder of the second metal material in the mold in which the core part is arranged, and a binder. In the step of firing the implant material, the step of injecting the surface portion forming compound including the step of forming the implant material and the step of firing the implant material after the step of forming the implant material. By setting the temperature to 850 to 1400 ° C. and the firing time to 10 minutes to 8 hours, a surface portion having more holes than the core portion is formed outside the core portion.

  The first and second aspects of the method for producing an implant further include a step of forming a titanium oxide film, an apatite film, or a carbonaceous thin film on at least one of the skin surface of the surface portion and the inside of the pores. Also good.

  According to the method of manufacturing an implant of the present disclosure, a composite metal body having excellent biocompatibility and enhanced mechanical properties can be formed.

The figure which concerns on Embodiment 1 and demonstrates the metal complex manufacturing process of a skin material and a core material is shown. The figure which concerns on Embodiment 2 and demonstrates the metal complex manufacturing process of a skin material and a core material is shown. The figure which concerns on Embodiment 3 and demonstrates the manufacturing process of a core material is shown. The perspective view of a test piece is shown. The mechanical strength of an Example and a comparative example is shown. The micrograph of an Example and a comparative example is shown.

  In the present disclosure, a high-density metal core material is manufactured, a metal powder is injection-molded on the outer side to form a porous surface material, and a molded body in which the surface material is integrated with the core material is formed. Then, a composite metal body is formed by performing subsequent sintering, and a composite metal body having excellent biocompatibility and enhanced mechanical properties is formed.

  In the present disclosure, in particular, a metal core material having a high density is produced by using a metal injection molding method, a melting method, etc., and the core material is inserted into an injection mold so as to be porous outside the core material. A composite metal body having excellent biocompatibility and enhanced mechanical properties is produced by injection molding a metal surface material and performing sintering. Alternatively, a metal core material having a high density is produced using a metal injection molding method, a core material that is not sintered is inserted into an injection mold, and a porous surface metal material is injected to the outside. Forming a composite material of core material and surface material, and sintering this composite material together to produce a composite metal body with excellent biocompatibility and enhanced mechanical properties Features. The melting method is a general molding method in which molten metal is poured into a mold, cooled and solidified, and molded into a predetermined shape, and the molded member is called a melted material.

  In addition, an alloy having excellent mechanical strength is used for the core material, and the surface porous body uses pure metal (for example, pure titanium) that does not cause a problem with metal elution, thereby suppressing metal elution and providing high mechanical strength. I was able to achieve both. In particular, it is preferable to improve the compatibility and adhesion of the core material by making the main metal and the surface metal the same.

  A specific example of the implant is a porous implant made of metal in which a surface portion which is a joint portion with a living tissue and a core portion inside the surface portion are provided, and the surface portion is formed with pores The core portion is made of a metal body that has no holes or fewer holes than the surface portion. With such a configuration, a composite metal body having excellent biocompatibility and enhanced mechanical properties can be formed.

  In a specific example of the implant, the surface portion may have a porosity of 10 to 45%. By setting it as such a structure, since it is 10 to 45% by a porosity, it can be set as the hole excellent in biocompatibility. When the porosity is high, the strength is weak, and when the porosity is low, the biocompatibility is deteriorated. Therefore, the above range is preferable.

  In a specific example of the implant, the pores in the surface portion may have a pore diameter of 1 to 1000 μm. By setting it as such a structure, since the hole diameter is 1-1000 micrometers, it can be set as the hole excellent in biocompatibility. If the pore diameter is too large, the strength is weak and the biocompatibility is poor, and if the pore diameter is too small, the biocompatibility is deteriorated. In particular, it is preferable that the diameter does not vary so much in the above range. In particular, the diameter of the pores is preferably 10 to 500 μm.

  In a specific example of the implant, the core portion contains 45% by weight or more of titanium, and a total of at least one metal selected from aluminum, vanadium, zirconium, tantalum, niobium, molybdenum, nickel, and palladium is 0.1. You may contain -55weight%. By setting it as such a structure, since a core material has titanium 45% or more, what is excellent in biocompatibility and intensity | strength is obtained. Further, since it contains 0.1 to 55% by weight in total of at least one metal selected from aluminum, vanadium, zirconium, tantalum, niobium, molybdenum, nickel and palladium, a core material excellent in strength and formability is obtained. Can be obtained.

  In this case, the surface portion may contain 99% by weight or more of titanium. By setting it as such a structure, since the surface part contains 99 weight% or more of titanium, it can be set as the epidermis which can suppress elution of a metal and was excellent in biocompatibility. Moreover, since it is the same metal as titanium which is the main component of the core material, the compatibility and adhesion of both are excellent.

  In a specific example of the implant, the core part may contain 50 wt% or more of cobalt, and may contain 1 to 50 wt% in total of at least one element selected from carbon, silicon, chromium, and molybdenum. . By adopting such a configuration, the core material contains 50% by weight or more of cobalt, so that the biocompatibility is excellent and the strength is also excellent. Moreover, since at least one element selected from carbon, silicon, chromium and molybdenum is contained in a total amount of 1 to 50% by weight, a core material excellent in strength and formability can be obtained.

  In this case, the surface portion may contain 99% by weight or more of cobalt. By setting it as such a structure, since the surface part contains cobalt 99weight% or more, it can be set as the epidermis which can suppress elution of a metal and was excellent in biocompatibility. Moreover, since it is the same metal as cobalt which is a main component of a core material, both compatibility and adhesiveness are excellent.

  In a specific example of the implant, the core portion may be made of a metal sintered body. By setting it as such a structure, a core part is a metal sintered compact like a surface part, and is excellent in adhesiveness with a skin material. Also, a three-dimensional complicated shape can be formed with high accuracy.

  In a specific example of the implant, the thickness of the surface portion may be 10 to 1000 μm. By setting it as such a structure, since the thickness of a surface part is 10-1000 micrometers, it is excellent in biocompatibility. In particular, if the surface portion is too thin, the biocompatibility is poor, and if it is too thick, the mechanical strength is insufficient. In particular, it is preferable to set it as 20-50 micrometers.

  In the specific example of the implant, the volume of the core part may be 70% to 98% with respect to the biological implant. By setting it as such a structure, since the volume of a core part is 70%-98% with respect to the whole volume, the implant which balanced biocompatibility and mechanical strength can be obtained. Particularly, when the volume of the core is small, the mechanical strength is insufficient, and when the volume of the core is large, the skin material is relatively scooped and biocompatibility is deteriorated.

  In a specific example of the implant, a titanium oxide film may be provided on the skin surface and / or inside the pores of the surface portion. By having such a configuration, the titanium oxide film is provided on the surface of the surface and / or the inside of the pores, so that the biocompatibility is further improved.

  In a specific example of the implant, an apatite film may be provided on the surface of the surface and / or inside the pores. By having such a configuration, since the apatite film is provided on the surface of the surface and / or inside the pores, the biocompatibility is further improved.

  In a specific example of the implant, a carbonaceous thin film may be provided on the skin surface and / or inside the pores of the surface portion. By having such a configuration, the carbonaceous thin film is provided inside the skin surface and / or the pores of the surface portion, so that the biocompatibility is further improved.

  A specific example of the method for producing an implant is that a core portion made of a high-density metal is placed in an injection mold, and metal powder forming the surface portion is injected into a space between the core portion and the injection mold. The implant material formed by overlapping the surface portion on the surface side of the core portion is molded, and the implant material is fired at a sintering temperature: 850 to 1400 ° C. and a sintering time: 10 minutes to 8 hours. A metal sintered body having pores was formed on the surface portion. By adopting such a configuration, a metal sintered body having pores in the surface portion can be provided, a metal body having excellent mechanical strength can be obtained inside, and the adhesion between the two is also excellent. A performance implant can be obtained.

  In addition, it is obtained by sintering the surface portion provided with pores by firing at a sintering temperature of 850 to 1400 ° C. and a sintering time of 10 minutes to 8 hours. In particular, when the sintering temperature is low, the sintering is insufficient and the strength is insufficient, and when the temperature is high, the material becomes brittle. In addition, if the sintering time is short, the sintering is insufficient, and if the sintering time is long, it becomes brittle. In particular, it is preferably 30 minutes to 4 hours.

  In a specific example of an implant manufacturing method, a mixed powder of the metal powder that forms the surface portion and a void forming material that disappears by sintering is prepared, and the prepared mixed powder is mixed with the core portion and the injection mold. You may inject into this space with the inside. By setting it as such a structure, a void | hole can be obtained reliably.

  In a specific example of the method for manufacturing an implant, a material made of a metal powder and a binder forming the core is injection-molded to form a core material having a predetermined shape, and the core material is used as the core for the injection. You may arrange | position in a shaping | molding die. By setting it as such a structure, a core part can be shape | molded with high precision. Moreover, it is excellent in adhesiveness with a surface part.

  In a specific example of the method for manufacturing an implant, the void forming material may be one or more selected from ammonium hydrogen carbonate, urea, polyoxymethylene resin, urea resin, expanded polystyrene resin, and expanded polyurethane resin. . By adopting such a configuration, the void forming material is one or more selected from ammonium hydrogen carbonate, urea, polyoxymethylene resin, urea resin, expanded polystyrene resin, and expanded polyurethane resin. Holes can be obtained.

  In the present disclosure, the density of the surface portion (that is, the porosity, the size of the pores, etc.) can be controlled by controlling the temperature and time during sintering, and the surface portion in contact with the bone tissue Since the surface porous shape can be controlled at the same time, there is an advantage that it can be manufactured at a lower cost than a manufacturing method by a plurality of steps in which surface undulation is provided by etching or blasting after cutting.

(Embodiment 1)
The manufacturing method of Embodiment 1 is demonstrated based on FIG. First, an insert part (a core material as a core part) having a predetermined shape is produced from a molten material. This method is a normal manufacturing method and will be briefly described. (1) Prepare raw materials and (2) cut into a simple shape. (3) In this way, an insert part having a predetermined shape is produced.

  Next, a method for forming a dental implant using the core material as an insert part will be described. (4) The insert part (core material) produced above is set in a plastic injection mold. (5) After mold clamping, in the space between the outer side of the core material and the mold, a compound for forming a skin material as a surface portion such as titanium, titanium alloy and cobalt alloy is injection-molded, and on the outer side of the core material A dental implant material made of a composite formed by molding metal powder is formed. (6) After opening the mold, the dental implant material is taken out, and then the molded body is degreased and then sintered to produce a composite member.

  The specific structure of a dental implant produced using the above metal injection molding method is a generally known implant shape. For example, JP 2007-135751 A, JP H07-313529 As in the publication, etc., an implant type implant having a threaded portion formed on the outer periphery was manufactured (not shown).

  Next, a specific composition and manufacturing conditions will be described.

(1) Core material The composition of the core material is as follows: titanium: balance% hydrogen (H): 0.013% or less, oxygen (O): 0.3% or less, nitrogen (N): 0.07% or less, iron ( Fe): 0.3% or less, which was produced by melting one having this composition.

(2) Skin material (a) Composition The composition of the skin material is pure titanium: 99.5% by weight or more, carbon (C): 0.2% or less, oxygen (O): 0.3% or less, binder: wax A mixture of system binders was prepared, injected and sintered. That is, the core material was a melted material with a high density, the skin material was a porous material, and basically had the same composition to improve the adhesion between them.
(B) Skin molding conditions for injection molding Injection temperature: 155 ° C
Injection pressure: 110MPa
Injection speed: 50m / sec
Injection time: 20sec (injection time 5sec, cooling time 15sec)
(C) Sintering condition of skin material Sintering temperature 1050 ° C
Sintering time 120 minutes (d) Finished sintered composite Thickness of skin material: 0.5 mm

  Thus, the manufactured dental implant is provided with a porous metal body excellent in biocompatibility on the surface portion, and can be a composite metal body with high density and excellent mechanical strength in the core portion, Furthermore, the thing excellent in the adhesiveness of a surface part and a core part was obtained. In particular, since the core material is prepared by a melting method, it can be easily manufactured and a core material having high strength can be obtained.

(Embodiment 2)
A second embodiment will be described with reference to FIG. In the second embodiment, the core material and the skin material are each molded as a sintered compact and sintered together as in the first embodiment, instead of preparing the core material melted in advance. It is characterized by tying.

  First, (1) As a raw material, a metal powder as a core material and a binder such as a thermoplastic resin are prepared. (2) A material (compound) obtained by mixing and kneading them is prepared. (3) The finished compound is injection molded into a mold having a predetermined shape of an injection molding machine for plastic to produce a molded body. (4) Remove the molded body. (5) This molded body is set as an insert part in an injection mold. (6) After mold clamping, a mixture of metal powder, binder, and resin (porous material) that becomes pores is mixed and kneaded in the space between the outside of the core and the mold, and the outside of the core is injection-molded. A dental implant material made of a composite in which metal powder is molded is molded. (7) After opening the mold, the dental implant material is taken out. (8) Thereafter, the molded body is degreased and sintered to produce a metal composite member.

(A) Composition The composition of the core material is titanium: 99.5% by weight or more, carbon (C): 0.2% or less, oxygen (O): 0.3% or less binder: wax-based binder The composition of the skin material is Pure titanium: 99.5% by weight or more, Carbon (C): 0.2% or less, Oxygen (O): 0.3% or less, Binder: Wax binder, porous material: PMMA 50vol%

  Note that the injection conditions of the core material and the skin material are the same as the injection conditions of the skin material of the first embodiment. The core material and the skin material have basically the same composition, but when these are sintered under the same conditions, a porous material is added to the skin material in order to obtain a porous skin material. The porous material is a void forming material described in the claims and is generally known.

(B) Sintering conditions for the composite comprising the core material and the skin material Sintering temperature 1150 ° C
Sintering time 120 minutes

  The finished product (metal composite member) could be made of a high-density material inside and a porous material on the surface.

  In addition, since both the core material and the skin material are sintered under the same conditions, separation and peeling between the two are difficult to occur. The core material and skin material can be sintered together, saving costs.

(Embodiment 3)
In the first embodiment, when preparing the core material in advance, the core material is cut to produce the insert material. However, the present invention is not limited to this method. An insert material made of a sintered body may be used. The manufacturing method is shown in FIG.

  First, a metal injection molding method is shown in FIG. (1) As a raw material, a metal powder as a core material and a binder such as a thermoplastic resin are prepared. (2) A material (compound) obtained by mixing and kneading them is prepared. (3) The finished compound is injection molded into a mold having a predetermined shape of an injection molding machine for plastic to produce a molded body. (4) The molded body is taken out, and the binder is removed in the degreasing step by solvent degreasing with liquid or vaporization by heating. (5) The degreased body, which has become almost only metal powder by removing the binder by heat degreasing, is put into a sintering apparatus and sintered to sinter and harden the metal powder to produce an insert part (core material).

  Then, the method for forming a dental implant using the core material as an insert part is the same as that of the first embodiment, and a description thereof will be omitted.

  In the third embodiment, the porous material of the skin material can be controlled by controlling the sintering temperature without adding a porous material to the skin material, and the adhesion between the skin material and the core material is excellent. You can get something.

  In the present disclosure, it is possible to accurately produce even a three-dimensional complex skin shape by molding by a metal injection molding method. Since different metals can be molded around the material to be inserted and can be manufactured by injection molding, a three-dimensional complicated shape part can also be manufactured.

  The first to third embodiments are merely examples, and the present invention is not limited to this embodiment.

(Examples 1 and 2)
Next, test pieces were prepared and tested in order to compare the mechanical strength of the metal composite of the present disclosure and a comparative example prepared with the same sintered material from the skin material to the core material. The test situation and test results will be described. First, a tensile test piece of JIS Z 2201 14B as shown in FIG. 4 is manufactured.

  The same materials were prepared for Examples 1 and 2.

(A1) As a core material, titanium: remainder, hydrogen (H): 0.013% or less, oxygen (O): 0.3% or less,
Nitrogen (N): 0.07% or less, Iron (Fe): 0.3% or less, Binder: Wax binder (A2) As a skin material, pure titanium: 99.5% by weight or more, carbon (C): 0 .2% or less Oxygen (O): 0.3% or less, binder: wax-based binder,
Porous material: PMMA 50vol%
(A3) Molding Method The core material of (A1) was injected into the gap of the injection mold under the following conditions.
Injection molding conditions Injection temperature: 155 ° C
Injection pressure: 110MPa
Injection speed: 50m / sec
Injection time: 20sec (injection time 5sec, cooling time 15sec)
The molded body (A1) was set as an insert member in an injection mold for a test piece.
The material of (A2) was injection molded under the above injection conditions to form a composite of (A1) and (A2).

And it sintered on the following conditions.
Sintering conditions Sintering temperature Example 1: 1100 ° C Example 2: 1050 ° C
Sintering time 120 minutes (same time as in Examples 1 and 2)
(A4) Completed sintered composite thickness of skin material: 0.5 mm

(Example 3)
The materials of Example 3 were prepared as follows.

(A1) As a core material, titanium: remainder, hydrogen (H): 0.013% or less, oxygen (O): 0.3% or less,
Nitrogen (N): 0.07% or less, Iron (Fe): 0.3% or less (A2) As a skin material, pure titanium: 99.5% by weight or more, carbon (C): 0.2% or less,
Oxygen (O): 0.3% or less, Binder: Wax-based binder (A3) Molding method The core material of (A1) was set in a mold, prepared by a melting method, and cut into a test piece shape. .

Next, the core material was set as an insert material in an injection mold, and the material (A2) was injection molded under the following injection conditions to form a composite.
Injection molding conditions Injection temperature: 155 ° C
Injection pressure: 110MPa
Injection speed: 50m / sec
Injection time: 20sec (injection time 5sec, cooling time 15sec)

And it sintered on the following conditions.
Sintering conditions Sintering temperature 1000 ° C
Sintering time 120 minutes (A4) Finished sintered composite Skin material thickness: 0.5 mm

  In the third embodiment, only the skin material is sintered because the core material is a material obtained by cutting the melted material. In that case, it was preferable to sinter at a relatively low temperature, and sintering was performed at a temperature lower than that in Examples 1 and 2.

  Also, the core material should be prepared in advance as a sintered material or melted material, and when only the skin material is sintered, the core material should be sintered at a relatively low temperature so that a porous material can be easily obtained. Is preferred. Even in this case, a porous material may be mixed to obtain a relatively high sintering temperature.

  The same material was prepared for Comparative Examples 1 to 3.

(B1) The following composition was used without distinction between the core material and the skin material.
Pure titanium: 99.5% by weight or more,
Carbon (C): 0.2% or less, Oxygen (O): 0.3% or less Binder: Wax-based binder (B2) Molding method A specimen of the material of (B1) was injection molded under the same conditions as in Example 1. Thereafter, this material was sintered under the same conditions as in Example 1.

  The sintering temperature was the same time that Comparative Examples 1 to 3 corresponded to Examples 1 to 3.

  Five test pieces of Examples 1 to 3 and Comparative Examples 1 to 3 were prepared and tested based on a metal material tensile test method (JIS Z 2241). The result is shown in FIG.

  In FIG. 6, in the example in which only the skin material is porous (denoted as tilted porous), the area ratio of the porous portion is obtained by the value (area method) measured by image processing from the SEM photograph of the skin material. . On the other hand, the relative density of the comparative example (indicated as porous), that is, the same porous sintered body from the surface to the core, is measured by the Archimedes method and divided by the true density. Value.

  The porosity (100-relative density) of the skin material was calculated as a ratio to the total area by calculating the total area of the pores shown in the micrograph shown in FIG. As a result, in Examples 1 to 3, the relative densities were 90.1%, 91.1%, and 94.0%, respectively. Moreover, the relative densities of Comparative Examples 1 to 3 were 89.9%, 90.8%, and 93.8%, respectively.

  As can be seen by comparing Examples 1 to 3 and Comparative Examples 1 to 3 with the same porosity (100-relative density), only the surface portion has this porosity, and the core portion has no pores. In this example, which is a case where a metal body is used, the mechanical strength is excellent as compared with a case where the whole is a porous body having the same relative density.

  In the present disclosure, the dental implant has been described. However, the present invention is not limited to this and can be applied to other biological implants.

  In addition, surface treatment such as a titanium oxide film, an apatite film, and a carbonaceous thin film may be performed on the surface of the surface and / or the inside of the pores. Processing may be added. Such a treatment may be performed on the skin surface of the surface portion and / or a necessary portion inside the pores, and it is not necessary to carry out all of the treatment.

  The implant manufacturing method according to the present disclosure can provide an implant body with a better prognosis. In particular, the method for manufacturing an implant according to the present disclosure can be used for various implants, but is particularly effective for dental implants that require high mechanical strength due to biting or the like.

Claims (7)

Disposing a core made of the first metal material in the mold;
Injecting a compound for forming a surface portion containing a powder of a second metal material, a binder, and a porous material into a mold in which the core portion is disposed, and forming an implant material;
A step of firing the implant material after the step of forming the implant material,
The method for manufacturing an implant, wherein in the step of firing the implant material, the porous material is eliminated, and a surface portion having more voids than the core portion is formed outside the core portion.   The manufacturing method of the implant of Claim 1 which bakes the said core part in the process of baking the said implant raw material.   The first metal material contains 45% by weight or more of titanium, and a total of at least one metal selected from aluminum, vanadium, zirconium, tantalum, niobium, molybdenum, nickel, and palladium is 0.1 to 55 in total. The method for producing an implant according to claim 1 or 2, wherein the implant is contained in% by weight.   The first metal material contains cobalt in an amount of 50% by weight or more and contains in total 1 to 50% by weight of at least one element selected from carbon, silicon, chromium, and molybdenum. 3. A method for producing an implant according to 2.   5. The porous material according to claim 1, wherein the porous material is one or more selected from ammonium hydrogen carbonate, urea, polyoxymethylene resin, urea resin, expanded polystyrene resin, and expanded polyurethane resin. Method for manufacturing an implant. Disposing a core made of the first metal material in the mold;
Injecting a compound for forming a surface portion containing a powder of a second metal material and a binder into a mold in which the core portion is disposed, and forming an implant material;
A step of firing the implant material after the step of forming the implant material,
In the step of firing the implant material, by forming the firing temperature at 850 to 1400 ° C. and the firing time from 10 minutes to 8 hours, a surface portion having more voids than the core portion is formed outside the core portion. A method for manufacturing an implant.   7. The method according to claim 1, further comprising a step of forming a titanium oxide film, an apatite film, or a carbonaceous thin film on at least one of the skin surface of the surface portion and the pores. Method for manufacturing an implant.