JP2004267440A - Method for manufacturing biomaterial with controlled surface shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an implant material having an optional pore shape on a metal surface. <P>SOLUTION: Materials to form a porous body such as metal powder or metal wires are arranged on the surface of a metallic member (titan or stainless steel, or the like) which serves as a base material, and electric power is supplied directly to the materials. When the materials to form the porous body are joined by utilizing local heat generated by this power supply, a porous material having optional pores on the surface is formed. Also, when metal foils having the holes of different sizes are stacked and joined by supplying power, the implant material 3 having the holes expanded in its inside is prepared. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
[0001] The present invention relates to a method for producing a metal implant material having arbitrary pores on its surface.
[0002]
2. Description of the Related Art Metal materials are used for various biological materials such as stems of artificial hip joints and artificial dental roots. In recent years, the development of ceramic materials such as hydroxyapatite has been remarkable, but there are concerns about the mechanical properties, and the development and improvement of implant materials utilizing the characteristics of metals have become increasingly important.
[0003]
When using a metal material as an implant material, it is necessary to fix it to living bone. At this time, it is fixed using polymethyl methacrylate called bone cement, but if used for a long time, loosening occurs between the implant material and the living bone.
In addition, when a metal implant is used, various problems occur, such as heat generated by a polymerization reaction when the bone cement hardens, and influence on the surrounding tissue due to residual monomers. Then, in order to improve the bond between the metal implant material and the living bone, it is conceivable to make the entire implant material or the surface porous. By making the material porous, the new bone penetrates into the pores, mechanical interlocking occurs between the porous metal implant and the bone, and the material can be connected to the bone.
[0004]
In the case of porous bioceramics, it was confirmed that if pores of about 100 μm or more were vacant, bones growing from adjacent living bones could enter the pores and cause mechanical interlocking to form an adhesive state. And recognition of porous biomaterials is increasing.
[0005]
However, a porous ceramic material having air holes (about 100 μm or more) has a drawback that its mechanical strength is remarkably reduced and its use is limited to a portion where no load is applied. In recent years, porosity has been increased by sintering powder of titanium (Ti) or Ti alloy, and porosity has been increased by plasma spraying hydrogen Ti powder on a Ti base material together with a carrier gas. I have. In these methods, it is difficult to produce a porous body having pores of an arbitrary shape.
[0006]
In addition, as a well-known example relevant to the present invention, there are JP-A-2002-143290 and JP-A-2002-097531, but the purpose is different from that of the present application.
[0007]
According to the present invention, a surface shape control material is formed by laminating a metal powder, a wire, or a foil in which pores have been removed in advance by photoetching or the like so that a desired shape can be obtained. After assembling, the laminate is heated for joining for a certain period of time while pressurizing the laminate between the electrodes, and the joint is heated and joined. Titanium and stainless steel are characterized by high electrical resistance and the ability to efficiently heat a small number of joints with large Joule heat due to contact resistance and to join with little deformation.
[0008]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a method for producing an implant material provided with metal powder and wires as a porous material. When a metal material is used as an implant material, it is necessary to arrange a part of the implant material (3) with a metal powder or a metal wire (4) to make it porous as shown in FIG. . Metals used as implant materials are often titanium and stainless steel. It is necessary to efficiently join only the point contact portions of the implant material having such a shape with little change in shape and without contamination.
[0009]
Research on sintering of powdered metal, current bonding with a powder or metal wire sandwiched between metal materials has been made, and the present invention has been completed. For example, as shown in FIG. 1, a metal powder or a metal wire (4) is arranged on the surface of an implant material (3), and a pulse or DC current is sandwiched between the electrodes (1) and (2). When energized, current flows through the contact. As a result, Joule heat due to the current is intensively generated at the contact portion. Such local heat is generated at the contact portion, and the contact portion is intensively heated. Also, the material with poorer heat conduction heats the contact point more efficiently. Therefore, in the case of materials having poor heat conduction, such as titanium and stainless steel, the temperature easily reaches about 1000 ° C. in a short time, the contact portion changes to a joining point, the shape change of the laminated member is reduced, and the laminated assembly bonding is performed. Becomes possible. On the other hand, when the round bars are butted together and the butted entire surfaces are joined, it is not possible to efficiently heat only that surface.
[0010]
In this way, the current heating and joining method, in which the contact portion is efficiently heated by direct energization and joined, is suitable as a method of assembling and joining a porous material in which powders and wires are stacked, particularly assembling and joining with a small change in the shape of a stacked member. ing. This method is also suitable for controlling the surface shape to an arbitrary shape.
[0011]
As a method of arbitrarily controlling the surface shape of the implant material (3), as shown in FIG. 2, metal foils (5), (6), and (6) having holes of different sizes in the metal foil by a photoetching method or the like. 7) are sequentially laminated. FIG. 3 is a diagram showing a method of preparing an implant material (3) in which metal foils having different hole sizes are arranged. As shown in FIG. 3, the metal foils (5), (6), (7) and the implant material (3) are laminated between the electrodes (1) and (2), and when they are electrically connected to each other, the holes swelled inside. The implant material (3) having the above can be manufactured. On the other hand, when the metal foil is laminated in the opposite direction to the foils (7), (6), and (5) from above, a mortar shape can be obtained. That is, by controlling the size and shape of the holes of the metal foil to be laminated, it is possible to produce an implant material of any shape at any position on the surface of the implant material.
[0012]
As described above, as a member to be laminated, powder, wire, or foil can be used. When an arbitrary shape is formed on the metal foil, a plastic working method or a punching method may be used in addition to the photo etching. If the target material is other than gold, copper, silver, and aluminum having excellent heat conductivity, bonding can be performed. The current to be applied may be either DC or AC. Further, a pulse power supply used at the time of pulse arc welding may be used. In the method of joining without melting in this way, that is, in the solid-phase joining method, after joining, the joint is heat-treated to improve the joining property of the joint. If necessary, heat treatment is performed later to complete the joint.
[0013]
【Example】
(Example 1) As shown in FIG. 1, a titanium wire (4) having a diameter of 1 mm was laminated on a depression of an implant material (3) made of pure titanium, and this was used as an electrode (1) in a vacuum vessel. And electrode (2). After evacuation, pressure was applied at a joining load of 500 N, and current was supplied at a DC current of 500 A for 1 minute. After joining, the wire (4) was broken with a tensile tester, and the fracture surface was observed. As a result, dimple formation was confirmed on the fracture surface of the joint, and the contact portion was sufficiently joined.
[0014]
(Example 2) As shown in FIG. 3, stainless steel foils (5), (6), and (7) having different hole shapes were laminated and placed between stainless steel implant materials (3). Then, it was installed between the electrodes (1) and (2) in the vacuum vessel. After evacuation, it was pressurized with a bonding load of 500 N and energized with a direct current of 600 A for 1 min. After joining, the joint was cut and the cross section was observed. As a result, no deformation of the hole was observed, and the contact portion was joined well.
[0015]
According to the production method of the present invention, an arbitrary pore shape can be produced on the surface, an implant material having pores into which new bone can penetrate can be produced, and the bone can be connected to the bone by an interlocking effect of the bone. It becomes.
[0016]
[Brief description of the drawings]
FIG. 1 is a diagram showing a method for producing an implant material provided with metal powder and wires as a porous material.
FIG. 2 is a diagram showing a state in which metal foils having different hole sizes are stacked.
FIG. 3 is a diagram showing a method for producing an implant material in which metal foils having different hole sizes are arranged.
[0017]
[Explanation of symbols]
(1) Electrode (2) Electrode (3) Implant member (4) Metal powder or wire (5) Foil with hole (6) Foil with different hole diameter (7) Foil with different hole diameter

Claims (1)

After laminating a metal powder or wire, or a laminate of foils with holes formed by photoetching, etc., at the required location of the pores on the metal surface serving as the base material, press this laminate between the electrodes while pressing A method for producing a biomaterial with a controlled surface shape, characterized in that a current is supplied for a certain period of time to heat and join a joint.

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