WO2012063907A1 - 多孔質インプラント素材 - Google Patents
多孔質インプラント素材 Download PDFInfo
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- WO2012063907A1 WO2012063907A1 PCT/JP2011/075951 JP2011075951W WO2012063907A1 WO 2012063907 A1 WO2012063907 A1 WO 2012063907A1 JP 2011075951 W JP2011075951 W JP 2011075951W WO 2012063907 A1 WO2012063907 A1 WO 2012063907A1
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- metal body
- porosity
- porous
- metal
- strength
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
- A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
- A61C8/0012—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools characterised by the material or composition, e.g. ceramics, surface layer, metal alloy
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/28—Bones
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/44—Joints for the spine, e.g. vertebrae, spinal discs
- A61F2/442—Intervertebral or spinal discs, e.g. resilient
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
- A61L27/02—Inorganic materials
- A61L27/04—Metals or alloys
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
- A61L27/02—Inorganic materials
- A61L27/04—Metals or alloys
- A61L27/06—Titanium or titanium alloys
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
- A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
- A61L27/56—Porous materials, e.g. foams or sponges
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/11—Making porous workpieces or articles
- B22F3/1103—Making porous workpieces or articles with particular physical characteristics
- B22F3/1109—Inhomogenous pore distribution
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/11—Making porous workpieces or articles
- B22F3/1121—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers
- B22F3/1125—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers involving a foaming process
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
- B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/08—Alloys with open or closed pores
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
- A61F2002/30003—Material related properties of the prosthesis or of a coating on the prosthesis
- A61F2002/30004—Material related properties of the prosthesis or of a coating on the prosthesis the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis
- A61F2002/30011—Material related properties of the prosthesis or of a coating on the prosthesis the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis differing in porosity
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/3094—Designing or manufacturing processes
- A61F2002/30968—Sintering
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/3094—Designing or manufacturing processes
- A61F2002/30971—Laminates, i.e. layered products
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
- A61F2310/00005—The prosthesis being constructed from a particular material
- A61F2310/00011—Metals or alloys
- A61F2310/00017—Iron- or Fe-based alloys, e.g. stainless steel
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
- A61F2310/00005—The prosthesis being constructed from a particular material
- A61F2310/00011—Metals or alloys
- A61F2310/00023—Titanium or titanium-based alloys, e.g. Ti-Ni alloys
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
- A61F2310/00005—The prosthesis being constructed from a particular material
- A61F2310/00011—Metals or alloys
- A61F2310/00029—Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
- A61F2310/00005—The prosthesis being constructed from a particular material
- A61F2310/00011—Metals or alloys
- A61F2310/00035—Other metals or alloys
- A61F2310/00095—Niobium or Nb-based alloys
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
- A61F2310/00005—The prosthesis being constructed from a particular material
- A61F2310/00011—Metals or alloys
- A61F2310/00035—Other metals or alloys
- A61F2310/00131—Tantalum or Ta-based alloys
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L2430/00—Materials or treatment for tissue regeneration
- A61L2430/38—Materials or treatment for tissue regeneration for reconstruction of the spine, vertebrae or intervertebral discs
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
- B22F7/002—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of porous nature
- B22F7/004—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of porous nature comprising at least one non-porous part
- B22F7/006—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of porous nature comprising at least one non-porous part the porous part being obtained by foaming
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12014—All metal or with adjacent metals having metal particles
- Y10T428/12021—All metal or with adjacent metals having metal particles having composition or density gradient or differential porosity
Definitions
- the present invention relates to a material used as an implant to be implanted in a living body, and particularly relates to an implant material using a porous metal.
- This application claims priority based on Japanese Patent Application No. 2010-251433 for which it applied on November 10, 2010, and uses the content here.
- implants that are implanted and used in a living body include those described in Patent Documents 1 to 3.
- the implant (intervertebral spacer) described in Patent Document 1 is used by being inserted and placed between vertebral bodies after the intervertebral disc has been removed. For the purpose of facilitating the insertion and making it difficult to remove the implant.
- the upper and lower surfaces of the spacer body have a special shape.
- the implant (artificial tooth root) described in Patent Document 2 includes a solid columnar core material made of titanium or a titanium alloy, and a large number of spherical particles that are arranged on the side surface of the core material and made of titanium or a titanium alloy and bonded by sintering.
- the spherical particles are composed of a porous layer composed of a large number of communication holes formed between the spherical particles, and the spherical particles further include a surface layer composed of a gold-titanium alloy, and the spherical particles adjacent to the surface layer. Are connected to each other. It has been proposed as an artificial tooth root having a small size and a high bonding strength with the jawbone.
- the implant described in Patent Document 3 is made of a porous material, and includes a first part having a high porosity and a second part having a low porosity.
- the implant described in Patent Document 3 is made of a porous material, and includes a first part having a high porosity and a second part having a low porosity.
- the second part of the implant made of a titanium inlay-shaped complete high density material into the hole in the first part of the green state titanium foam shaped implant.
- the first part contracts and the second part adheres.
- part with a low porosity performs the operation or fixation of an implant, and since the porosity is low, it is supposed that the abrasion of the particle
- this kind of implant is used as a part of bone in a living body, excellent bondability to the bone and strength suitable for bearing a part of the bone are required. It is difficult to satisfy both of these requirements, for example, when the bondability is pursued, the strength tends to be insufficient, and when the strength is pursued, the bond with the bone is insufficient.
- the implants described in Patent Document 2 and Patent Document 3 have a composite structure of a solid core material and a porous layer, or a first portion having a high porosity and a second portion having a low porosity.
- metal materials are generally stronger than human bones, so when used as an implant, most of the load on the bone is reduced.
- the implant receives the stress shielding phenomenon (a phenomenon in which the bone around the portion where the implant is embedded becomes weak). Therefore, these implants are required to have a strength close to that of human bones, but human bones are a combination of biological apatite and collagen fibers having a hexagonal crystal structure and are preferentially oriented in the C-axis direction. Strength characteristics. For this reason, it is difficult to make an implant close to a human bone by simply forming a composite structure as described in these patent documents.
- the present invention has been made in view of such circumstances, and has a strength characteristic close to that of a human bone, and is capable of ensuring sufficient connectivity with bone while avoiding the occurrence of a stress shielding phenomenon. It aims to provide a quality implant material.
- a plurality of metal bodies having different porosities are joined through a joint interface parallel to one direction, and the porosity of the whole joined body of these metal bodies is 50% to 92%.
- the metal body having a high porosity is a porous metal body having a three-dimensional network structure in which a plurality of pores formed by a continuous skeleton communicated, and the metal body having a low porosity has a porosity of 0.
- the area occupancy in the cross section perpendicular to the axial direction is 0.5% to 50% when one direction along the bonding interface is the axial direction.
- the strength when compressed in the direction parallel to the direction along the interface is 1.4 to 10 times the strength when compressed in the direction parallel to the direction orthogonal to the bonding interface.
- this porous implant material allows bones to easily enter into a plurality of communicating pores in a porous metal body having a high porosity so as to be united with the bone.
- the compressive strength in the joining interface direction is increased. Therefore, as a whole joined body, the compressive strength in the direction along the joint interface and the compressive strength in the orthogonal direction are different, and it has strength characteristics having anisotropy similar to that of human bones.
- the stress shielding phenomenon can be more effectively prevented by embedding in the body together with the directionality of the above. In this case, if the total porosity is less than 50%, the bone penetration rate is slow, and the function of bonding with bone as an implant is insufficient.
- the porosity exceeds 92%, the compressive strength is low, and the function of supporting bone as an implant is insufficient.
- the area occupation ratio of the metal body having a low porosity is less than 0.5%, the strength of the implant material tends to be insufficient, and if it exceeds 50%, the bone penetration rate is slow and the implant is fixed. It tends to take time.
- various block shapes can be easily manufactured.
- a metal material including a hole or a space formed on a molten metal such as punching metal or expanded metal can be used as the metal body having a low porosity. It is set as the ratio of the volume of the hole and the space part which occupies for the whole volume.
- a material having a porosity of 0% is a plate-like melted material having no holes, and a solid material such as a titanium plate is used.
- pores formed in the porous metal body having at least a high porosity are formed in a flat shape that is long in the direction along the joint interface and short in the direction orthogonal to the joint interface.
- the length of the pores in the direction along the joining interface is preferably 1.2 to 5 times the length in the direction perpendicular to the joining interface.
- the pores have a flat shape, whereby the directionality of the strength can be easily imparted. If the ratio of the pore length in the direction along the joint interface to the length in the orthogonal direction is less than 1.2 times, the strength may be insufficient. If the ratio is more than 5 times, the pores become too flat and the bone penetration rate May slow down and bond may be insufficient.
- the porous metal body having a high porosity may be a foam metal obtained by molding and foaming and sintering a foamable slurry containing a metal powder and a foaming agent.
- Foam metal can easily form a three-dimensional network structure with a continuous skeleton and pores, and the porosity can be adjusted in a wide range by foaming of the foaming agent, and it is suitable for the site to be used. Can be used.
- foam metal can manipulate the surface opening ratio independently of the overall porosity, so increasing the metal density on the surface (decreasing the opening ratio) improves the strength in the direction along the bonding interface. Anisotropy can be easily imparted in combination with the strength characteristics of the structure and the flat shape of the pores.
- the penetration of bone can be facilitated by the porous metal body, and the compressive strength in the direction along the joint interface can be obtained by adopting the joint structure of the metal body.
- It has a strength characteristic with anisotropy close to that of human bones, because it is higher than that in the orthogonal direction and a metal body with a low porosity is bonded with a specific area occupancy.
- the porous implant material 1 of the present embodiment includes a plate-like porous metal body 4 made of a foam metal having a three-dimensional network structure in which a plurality of pores 3 formed by a continuous skeleton 2 communicated, a punching metal, It is constructed by laminating a plurality of melted materials such as expanded metal, or a normal sintered metal, and a metal body 5 made of a low-porosity low-porosity metal through a joint interface F parallel to one direction. ing.
- the porous metal bodies 4 and the metal bodies 5 are alternately laminated.
- each porous metal body 4 and the like is formed by forming and foaming a foamable slurry containing a metal powder and a foaming agent and the like, as described later,
- the pores 3 are open on the front and back surfaces and the side surfaces, and the front and back surfaces are densely formed with respect to the central portion in the thickness direction.
- the porous implant material 1 formed by laminating the porous metal body 4 and the metal body 5 of the foam metal has a total porosity of 50% to 92%.
- the internal pores 3 are long in the direction along the surface (the direction along the bonding interface F, the vertical direction in FIG. 2) and perpendicular to the surface (thickness direction, FIG. 2). Is formed in a flat shape that is short in the horizontal direction.
- the length (length in the longitudinal direction of the pores) Y of the pores 3 along the surface (bonding interface F) of the porous metal body 4 is the length X in the direction orthogonal to the surface (bonding interface F).
- the metal body 5 has a plurality of holes 6 formed by machining or the like for a material made of a melted material and a material made of an ordinary sintered metal, and is also made of a foam metal having a low porosity. Since a large number of pores (the pores of the metal body 5 are also referred to as the holes 6 in order to distinguish them from the pores 3 of the porous metal body 4), the pores 3 of the porous metal body 4 are formed through these holes 6. Communication is established.
- the hole 6 of the metal body 5 has an occupation ratio of 0 to 50% with respect to the entire volume of the metal body 5. In the present invention, the occupation ratio of the hole 6 is also referred to as a porosity.
- the occupation ratio of the holes 6 being 0% indicates a solid material having no holes 6.
- one direction along the bonding interface F is defined as an axial direction C when being embedded in a living body, and the metal body 5 occupies an area in a cross section in a direction orthogonal to the axial direction C.
- the ratio of the metal body 5 as a whole is 0.5% to 50%.
- the direction along the vertical direction is the axial direction C
- the area occupancy in the horizontal section perpendicular to the axial direction C is 0.5 to 50. %.
- the strength when compressed in a direction parallel to the axial direction C (longitudinal direction of the pore 3) indicated by the solid line arrow in FIG. It is set to 1.4 to 10 times the strength when compressed in a direction parallel to the direction perpendicular to the axial direction indicated by.
- the porous metal body 4 constituting the porous implant material 1 is formed into a sheet by forming a foamable slurry containing a metal powder, a foaming agent or the like into a sheet shape by a doctor blade method or the like, and forming a green sheet, This green sheet is manufactured by degreasing and sintering and foaming. At that time, a plurality of green sheets with different amounts of foaming agent are prepared, and a plurality of these are laminated and sintered to form a laminate of porous metal bodies 4 and 5, which is pressed. Or the porous implant raw material 1 is manufactured by compressing in a lamination direction by rolling.
- the foaming slurry is obtained by kneading metal powder, a binder, a plasticizer, a surfactant, and a foaming agent together with water as a solvent.
- the metal powder is composed of powders of metals and their oxides that are not harmful to the living body, and for example, pure titanium, titanium alloy, stainless steel, cobalt chromium alloy, tantalum, niobium, etc. are used. Such a powder can be produced by a hydrodehydrogenation method, an atomization method, a chemical process method, or the like.
- the average particle size is preferably 0.5 to 50 ⁇ m, and is contained in the slurry in an amount of 30 to 80% by mass.
- methyl cellulose hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose ammonium, ethyl cellulose, polyvinyl alcohol, or the like can be used.
- the plasticizer is added to impart plasticity to a molded product obtained by molding a slurry.
- polyhydric alcohols such as ethylene glycol, polyethylene glycol, and glycerin
- fats and oils such as coconut oil, rapeseed oil, and olive oil, petroleum ether, etc.
- Ethers such as diethyl phthalate, di-N-butyl phthalate, diethyl hexyl phthalate, dioctyl phthalate, sorbitan monooleate, sorbitan trioleate, sorbitan palmitate, sorbitan stearate, and the like can be used.
- Surfactants include anionic surfactants such as alkylbenzene sulfonate, ⁇ -olefin sulfonate, alkyl sulfonate, alkyl ether sulfate, alkane sulfonate, polyethylene glycol derivatives, polyhydric alcohol derivatives, etc.
- anionic surfactants and amphoteric surfactants can be used.
- the foaming agent is not particularly limited as long as it can generate gas and form bubbles in the slurry.
- the volatile organic solvent for example, pentane, neopentane, hexane, isohexane, isopeptane, benzene, octane, toluene, etc.
- the water-insoluble hydrocarbon-based organic solvent can be used.
- the content of the foaming agent is preferably 0.1 to 5% by weight with respect to the foamable slurry.
- This forming apparatus 20 is an apparatus for forming a sheet by using a doctor blade method.
- the hopper 21 stores the foamable slurry S
- the carrier sheet 22 transports the foamable slurry S supplied from the hopper 21, and the carrier sheet.
- a blade (doctor blade) 24 for forming the foamable slurry S on the carrier sheet 22 to a predetermined thickness
- a constant temperature / high humidity tank 25 for foaming the foamable slurry S
- the foamed slurry are dried.
- a drying tank 26 is provided.
- the lower surface of the carrier sheet 22 is supported by a support plate 27.
- the foamable slurry S is put into the hopper 21, and the foamable slurry S is supplied onto the carrier sheet 22 from the hopper 21.
- the carrier sheet 22 is supported by a roller 23 and a support plate 27 that rotate in the right direction in the figure, and its upper surface moves in the right direction in the figure.
- the foamable slurry S supplied on the carrier sheet 22 is formed into a plate shape by the blade 24 while moving together with the carrier sheet 22.
- the plate-like foaming slurry S is foamed while moving in the constant temperature / high humidity tank 25 under predetermined conditions (eg, temperature 30 ° C. to 40 °, humidity 75% to 95%) over 10 minutes to 20 minutes, for example. To do. Subsequently, the slurry S foamed in the constant temperature / high humidity tank 25 moves in the drying tank 26 under a predetermined condition (for example, temperature 50 ° C. to 70 ° C.) over 10 minutes to 20 minutes, for example, and is dried. Thereby, a sponge-like green sheet G is obtained.
- predetermined conditions eg, temperature 30 ° C. to 40 °, humidity 75% to 958%
- the green sheet G obtained in this manner is degreased and sintered in a state where the separately produced metal bodies 5 are alternately laminated, thereby forming a laminate of the porous metal body 4 and the metal body 5.
- Sintering is performed at a temperature of 700 ° C. to 1300 ° C. for 60 minutes to 120 minutes.
- metal body 5 having a low porosity pure titanium, a titanium alloy, stainless steel, a cobalt chromium alloy, tantalum, niobium, and the like are used as in the case of the porous metal 4 having a high porosity.
- the porous metal body 4 has a three-dimensional network structure in which pores 3 formed by the continuous skeleton 2 communicate with each other. ing.
- the porous metal body 4 is formed by foaming and sintering a green sheet G formed on the carrier sheet 22, and the surface in contact with the carrier sheet 22 and its opposite surface, that is, the front and back surfaces. Is formed denser (higher metal density) than the central portion in the thickness direction.
- the porous body 4 since each porous metal body 4 has pores 3 opened on the front and back surfaces, the porous body 4 also has pores 3 continuous on the front and back surfaces.
- the metal body 5 when forming the metal body 5 from a low-porosity foam metal, it similarly has a three-dimensional network structure. Further, when the metal body 5 is formed from a melted material, it is diffusion bonded to the porous metal body 4 by heat during the sintering of the porous metal body 4.
- the laminated body of the porous metal body 4 and the metal body 5 is compressed or pressed in a thickness direction (lamination direction) by pressing or rolling at a predetermined pressure.
- the porous metal body 4 having a high porosity is preferentially compressed, and the internal pores 3 are crushed, so that the direction is long in the direction along the surface (the direction along the bonding interface) and perpendicular to the surface.
- a flat shape that is short in the thickness direction.
- the strength of the porous metal body 4 when compressed in a direction parallel to the flat direction is greater than the strength when compressed in a direction orthogonal to the flat direction.
- the metal body 5 when forming the metal body 5 from a melting material or a normal sintered metal, the metal body 5 is not compressed in this compression process. Further, even when the metal body 5 is formed of a foam metal, since the porosity is low, it is hardly compressed in this compression step, and the pores remain almost spherical, but may be slightly compressed. In addition, since each porous metal body 4 is densely formed in the vicinity of the front and back surfaces as described above, the vicinity of each bonding interface F is denser than the central portion between the bonding interfaces F. Yes.
- the melted material or a foam metal having a low porosity, a metal body 5 made of a normal sintered metal is joined, and the pores 3 of the porous metal body 4 having a high porosity are crushed.
- the porous metal body 4 is formed in a long flat shape in the direction along the bonding interface F and the porous metal body 4 is dense in the vicinity of the bonding interface F, the direction parallel to the bonding interface F (solid arrow in FIG. 2).
- the strength when compressed in the direction is greater than the strength when compressed in the direction parallel to the direction orthogonal to the bonding interface F (thickness direction, the direction indicated by the dashed arrow in FIG. 2).
- the laminated body of the porous metal body 4 and the metal body 5 is cut into a desired outer shape.
- one direction along the bonding interface F is defined as the axial direction C, and the axial center.
- the metal body 5 is cut so that the occupied area of the metal body 5 is 0.5% to 50% of the whole.
- the porous implant material 1 manufactured in this way is a porous material having a porosity of 50% to 92% as a whole, it is easy to invade bone when used as an implant and has a binding property to bone.
- the body since it has anisotropy in compressive strength and has strength characteristics close to that of human bones, when used as part of bone, the body is matched to the direction of strength of human bones. It is possible to effectively avoid the occurrence of the stress shielding phenomenon by embedding in.
- the axial direction C along the joint interface F of the porous implant material 1 may be aligned with the C-axis direction of the bone.
- the human bone is composed of a cancellous bone at the center and a cortical bone surrounding it.
- the compressive strength in the axial direction C is 4 to 70 MPa
- the elastic modulus of compression is preferably 1 to 5 GPa.
- the compressive strength in the axial direction C is preferably 100 to 200 MPa
- the elastic modulus of compression is preferably 5 to 20 GPa.
- the compressive strength in the axial direction C is directional so that it is 1.4 to 10 times larger than the compressive strength in the direction perpendicular to the axial direction C. good.
- FIG. 4 shows another embodiment.
- the porous metal body 4 and the metal body 5 are formed and laminated in a plate shape.
- the porous implant material 11 of this embodiment the porosity of the metal body 5 formed in a columnar shape is around. It arrange
- the axial direction C coincides with the longitudinal direction of the cylinder.
- the porous implant material 11 is formed by forming a green sheet by the doctor blade method as described above, combining the green sheet around the metal body 5, and sintering in the combined state, thereby sintering the cylindrical shape.
- the porous implant material 11 has a higher compressive strength in the longitudinal direction of the cylinder (axial direction C) than the compressive strength in the radial direction, and the axial direction C is matched to the strength characteristics of the bone.
- a green sheet was produced using a slurry foaming method, and a porous metal body was produced from the green sheet.
- a raw material titanium powder having an average particle diameter of 20 ⁇ m, polyvinyl alcohol as a binder, glycerin as a plasticizer, alkylbenzene sulfonate as a surfactant, heptane as a foaming agent, and kneading with water as a solvent, a slurry is obtained.
- a slurry was formed into a plate shape and dried to produce a green sheet.
- FIG. 5 is a graph showing the dependence of compressive strength, such as porosity.
- “16% porosity + 85% porosity combination” is a combination of a porous metal body with a porosity of 85% and a metal body with a porosity of 16%.
- the overall porosity was adjusted by combining so that the area occupancy of the metal body having a low porosity was 10%, 15%, and 20%.
- “Punching metal + porosity 85% combination” uses a punching metal made of titanium in which a hole having a diameter of 2 mm is formed as a metal body with an opening ratio (porosity) of 20%. Also in this case, the total porosity was adjusted by changing the number of stacked metal bodies so that the area occupancy of the metal bodies was 10% and 20%.
- Porous metal body with a porosity of 85% and a metal body with a porosity of 16% is a compression of a combination of a porous metal body with a porosity of 85% and a metal body with a porosity of 16% By doing so, the pores of the porous metal body are flattened.
- the flatness of the pores 5 to 10 pores whose shapes are easy to confirm are selected from an optical microscope observation photograph at a magnification of 20 times, and the flatness is calculated by obtaining the Y and X lengths of each pore from the image. The average value thereof was defined as the flatness of the sample.
- a comparative example what was described as “non-laminated” in the drawing and made only of a porous metal body having a porosity of 85% was also produced. The compressive strength was measured based on JIS H 7902 (a compression test method for porous metal).
- the example has a higher compressive strength than the “non-laminated” one, but the same porosity, and the implant can be adjusted to an appropriate porosity. It can be seen that a wide range of compressive strengths can be produced.
- this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
- a porous metal body having two types of porosity a porous metal body having a high porosity and a porous metal body having a low porosity, is joined, but a porous metal body having three or more types of porosity is used. May be joined.
- FIGS. 6 to 8 when joining a plurality of porous metal bodies, various forms as shown in FIGS. 6 to 8 can be employed in addition to the form of laminating plate-like objects as in the embodiment.
- the same reference numerals as in FIG. 1 are used for porous metal bodies having different porosities, and a porous metal body having a high porosity is indicated by reference numeral 4 and a metal body having a low porosity is indicated by reference numeral 5.
- the porous implant material 12 shown in FIG. 6 is provided with a plurality of columnar metal bodies 5 having a low porosity relative to that shown in FIG. 4, and the porous implant material 13 shown in FIG. 7 has a low porosity.
- FIG. 8 in which a metal body 5 and a porous metal body 4 having a high porosity are arranged in a concentric multiple circle shape, is a cross-block-shaped metal body 5 having a low porosity.
- a method of winding a plate-like porous metal body around a specific metal body, rounding the plate-like porous metal body, or the like can also be employed.
- the flat direction of the pores is shown in FIG. 8 as the C direction, and FIGS. 6 and 7 are directions orthogonal to the paper surface.
- a method of diffusion bonding by combining individually sintered materials is also possible. And when compressing these, what has the column-shaped external shape shown in FIG.6 and FIG.7 compresses to a radial direction, rolling the joined body of a porous metal body similarly to the case of embodiment shown in FIG. You may make it do.
- the green body may be compressed before being sintered, or may be compressed after being sintered. In any case, it is important that these joint interfaces F are parallel to one direction, and the compressive strength in the direction parallel to the joint interface F is combined with the directionality of the strength due to the flat pores.
- a metal body having a low porosity may be added.
- a method by vacuum foaming may be used. Specifically, after removing bubbles and dissolved gas from the slurry, the foamed slurry is formed in a state in which bubble nuclei made of the additive gas are dispersed and formed in the slurry by stirring while introducing the additive gas into the slurry. To manufacture.
- the slurry containing the bubble nuclei is depressurized to a predetermined pressure, and the bubble nuclei are expanded by holding the slurry at a pre-cooling temperature that exceeds the freezing point of the slurry at the predetermined pressure and is lower than the boiling point.
- the slurry with increased is lyophilized in vacuo.
- the green body thus formed is sintered to form a porous sintered body.
- the implant material of the present invention can be used as an implant embedded in a living body such as an intervertebral spacer or an artificial tooth root.
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Abstract
Description
本願は、2010年11月10日に出願された特願2010-251433に基づき優先権を主張し、その内容をここに援用する。
特許文献1記載のインプラント(椎間スペーサ-)は、椎間板を除去した後の椎体の間に挿入配置して使用されるもので、その挿入を容易にするとともに、抜け難くする等のために、スペーサ-本体の上面及び下面が特殊な形状をしている。
特許文献2記載のインプラント(人工歯根)は、チタン又はチタン合金からなる中実柱状の芯材と、芯材の側面に配置されてチタン又はチタン合金から成り焼結により結合した多数の球状粒子と該球状粒子の間に形成された多数の連通孔とから成る多孔層とから構成されており、その多数の球状粒子はさらに金チタン合金からなる表面層を備え、該表面層により隣接する球状粒子が相互に結合されている。寸法が小さく且つ顎骨との結合強度が高い人工歯根として提案されている。
したがって、これらインプラントを人骨に近い強度とすることが求められるが、人間の骨は、六方晶系の結晶構造を持つ生体アパタイトとコラーゲン繊維の組み合わさった構造で、C軸方向に優先的に配向する強度特性を有している。このため、これら特許文献記載のように単純に複合構造とするだけでは、人骨に近いインプラントとすることは難しい。
この場合、全体の気孔率が50%未満では骨の侵入速度が遅く、インプラントとして骨との結合機能が不足する。気孔率が92%を超えると、圧縮強度が低く、インプラントとして骨を支持する機能が不足する。
また、気孔率の低い金属体の面積占有率が0.5%未満ではインプラント用素材としては強度不足になり易く、50%を超えると、骨侵入速度が遅く、インプラントが固定化されるまでに時間がかかる傾向にある。
また、複数の金属体を接合していることにより、種々のブロック状のものを容易に作製することができる。
なお、このように構成した素材をインプラントとして用いる場合に、必要に応じて前記一の方向に平行な方向とは異なる方向の接合界面によって接合した多孔質金属体又は金属体を加えてもよい。また、気孔率の低い金属体には、パンチングメタルやエキスパンドメタルのような溶製材に孔や空間部を形成したものも用いることができ、気孔率とは、これら孔や空間部を含む金属体全体の体積に占める孔や空間部の体積の比率とする。気孔率が0%のものは孔等を有しない板状等の溶製材であり、チタン板等の無垢材が用いられる。
多孔質金属体と気孔率の低い金属体との接合構造としたことに加えて、気孔を扁平形状としたことにより、強度の方向性を容易に付与することができる。接合界面に沿う方向の気孔の長さと直交方向の長さとの比が1.2倍未満では強度が不足する場合があり、5倍を超えると、気孔が扁平になり過ぎて、骨の侵入速度が遅くなり結合が不充分になるおそれがある。
発泡金属は、連続した骨格と気孔による三次元網目状構造を容易に形成することができるとともに、発泡剤の発泡によって気孔率を広い範囲で調整することができ、用いられる部位に合わせて適切に使用することができる。
また、発泡金属は、表面の開口率を全体の気孔率とは独立に操作できるため、表面の金属密度を上げる(開口率を下げる)ことで、接合界面に沿う方向の強度が向上し、接合構造や気孔の偏平形状による強度特性と相俟って容易に異方性を付与することができる。
本実施形態の多孔質インプラント素材1は、連続した骨格2により形成される複数の気孔3が連通した三次元網目状構造を有する発泡金属からなる板状の多孔質金属体4と、パンチングメタル、エキスパンドメタル等の溶製材、又は通常の焼結金属、発泡度の低い低気孔率の発泡金属からなる金属体5とを一の方向に平行な接合界面Fを介して複数枚積層して構成されている。図示例では、多孔質金属体4と金属体5とは交互に積層されている。また、各多孔質金属体4等を構成する発泡金属は、後述するように、金属粉末と発泡剤等を含有する発泡性スラリーをシート状に成形して発泡させることにより形成したものであり、気孔3が表裏面及び側面に開口し、また、厚さ方向の中心部に対して表裏面近傍が密に形成されている。
この場合、多孔質金属体4の表面(接合界面F)に沿う各気孔3の長さ(気孔3の長手方向の長さ)Yは、表面(接合界面F)に直交する方向の長さXに対して1.2倍~5倍に形成されている。一方、金属体5には、溶製材からなるもの、及び通常の焼結金属からなるものには機械加工等によって複数の孔6が形成され、また、低気孔率の発泡金属からなるものにも多数の気孔(多孔質金属体4の気孔3と区別するため、金属体5の気孔も孔6と称する)が形成されているので、これら孔6を介して多孔質金属体4の気孔3が連通状態となっている。金属体5の孔6は、金属体5全体の体積に対する占有率が0~50%とされており、本発明においては、この孔6の占有率も気孔率と称している。孔6の占有率が0%というのは、孔6を有しない無垢材を示す。
そして、これら多孔質金属体4及び金属体5の接合体としては、図2の実線矢印で示す軸心方向C(気孔3の長手方向)と平行な方向に圧縮したときの強度が、破線矢印で示す軸心方向に直交する方向と平行な方向に圧縮したときの強度に対して1.4倍~10倍とされている。
この多孔質インプラント素材1を構成する多孔質金属体4は、金属粉末、発泡剤等を含有する発泡性スラリーをドクターブレード法等によりシート状に成形して乾燥させることによりグリーンシートを形成し、このグリーンシートを脱脂、焼結工程を得て発泡させることにより、製造される。また、その際に、発泡剤の混入量が異なる複数のグリーンシートを作製しておき、これらを複数枚積層して焼結することにより多孔質金属体4,5の積層体とし、これをプレス又は圧延によって積層方向に圧縮することにより、多孔質インプラント素材1が製造される。
発泡性スラリーは、金属粉末、バインダ、可塑剤、界面活性剤、発泡剤を溶媒の水とともに混練して得られる。
この成形装置20は、ドクターブレード法を用いてシートを形成する装置であり、発泡性スラリーSが貯留されるホッパ21、ホッパ21から供給された発泡性スラリーSを移送するキャリヤシート22、キャリヤシート22を支持するローラ23、キャリヤシート22上の発泡性スラリーSを所定厚さに成形するブレード(ドクターブレード)24、発泡性スラリーSを発泡させる恒温・高湿度槽25、および発泡したスラリーを乾燥させる乾燥槽26を備えている。なお、キャリヤシート22の下面は、支持プレート27によって支えられている。
成形装置20においては、まず、発泡性スラリーSをホッパ21に投入しておき、このホッパ21から発泡性スラリーSをキャリヤシート22上に供給する。キャリヤシート22は図の右方向へ回転するローラ23および支持プレート27によって支持されており、その上面が図の右方向へと移動している。キャリヤシート22上に供給された発泡性スラリーSは、キャリヤシート22とともに移動しながらブレード24によって板状に成形される。
このようにして得られたグリーンシートGに、別に作製した金属体5を交互に積層した状態で脱脂・焼結することにより、多孔質金属体4と金属体5との積層体を形成する。具体的には、例えば真空中、温度550℃~650℃、25分~35分の条件下でグリーンシートG中のバインダ(水溶性樹脂結合剤)を除去(脱脂)した後、さらに真空中、温度700℃~1300℃、60分~120分の条件下で焼結する。気孔率の低い金属体5も、多孔質金属多い4と同様、純チタン、チタン合金、ステンレス鋼、コバルトクロム合金、タンタル、ニオブ等、が用いられる。
なお、金属体5を低気孔率の発泡金属から形成する場合は、同様に三次元網目状構造を有する。また、金属体5を溶製材により形成する場合は、多孔質金属体4の焼結時の熱により多孔質金属体4と拡散接合される。
次いで、多孔質金属体4と金属体5との積層体を所定の圧力でプレス又は圧延することにより厚さ方向(積層方向)に圧縮する。
この圧縮工程により、気孔率が高い多孔質金属体4が優先的に圧縮され、内部の気孔3が押しつぶされることにより、表面に沿う方向(接合界面に沿う方向)に長く、表面に直交する方向(厚さ方向)に短い扁平形状となる。この気孔3が扁平形状となると、多孔質金属体4としては、扁平方向に平行な方向に圧縮したときの強度が、扁平方向に直交する方向に圧縮したときの強度よりも大きくなる。なお、金属体5を溶製材又は通常の焼結金属から形成する場合、金属体5は、この圧縮工程においては圧縮されない。また、金属体5を発泡金属により形成する場合でも、気孔率が低いので、この圧縮工程においてほとんど圧縮されず、気孔はほぼ球状のままであるが、わずかに圧縮されるようにしてもよい。
また、各多孔質金属体4は、前述したように表裏面近傍が密に形成されるため、その積層体は、各接合界面F付近が接合界面F間の中心部に比べて密になっている。
そして、この積層体は、溶製材又は気孔率が低い発泡金属、通常の焼結金属からなる金属体5が接合されていること、気孔率が高い多孔質金属体4の気孔3が押しつぶされて接合界面Fに沿う方向に長い扁平形状に形成されていること、及び接合界面F付近で多孔質金属体4が密となっていることから、接合界面Fと平行な方向(図2の実線矢印で示す方向)に圧縮したときの強度が、接合界面Fに直交する方向と平行な方向(厚さ方向、図2の破線矢印で示す方向)に圧縮したときの強度よりも大きいものとなる。
次に、この多孔質金属体4と金属体5との積層体を所望の外形に切断するのであるが、その際に、接合界面Fに沿う一の方向を軸心方向Cとし、その軸心方向Cに直交する方向の横断面において、金属体5の占有面積が全体の0.5%~50%となるように切断する。
この多孔質インプラント素材11は、前述したようにドクターブレード法によってグリーンシートを形成し、金属体5の回りにグリーンシートを巻き付けるようにして組み合わせ、その組み合わせ状態で焼結することにより円柱状の焼結体(中心部が金属体5、その回りが多孔質金属体4)を形成し、その焼結体を転がしながら径方向に圧縮することにより、製造することができる。転がしながら圧縮することにより、気孔率の高い多孔質金属体4の気孔は、半径方向に押しつぶされ、円柱の長手方向及び周方向に沿う湾曲した扁平形状となる。
したがって、この多孔質インプラント素材11は、径方向の圧縮強度に比べて、円柱の長手方向(軸心方向C)の圧縮強度が高いものとなり、この軸心方向Cを骨の強度特性に合わせて埋め込めばよい。
図5は、圧縮強度の気孔率等の依存度を示すグラフである。この図5において、[気孔率16%+気孔率85%組み合わせ」は、気孔率が85%の多孔質金属体と、気孔率が16%の金属体とを組み合わせたものであり、金属体の積層枚数を変更することで、気孔率が低い金属体の面積占有率が10%、15%、20%となるように組み合わせることにより、全体の気孔率を調整した。
また、「パンチングメタル+気孔率85%組み合わせ」は、金属体として2mmの直径の孔が20%の開口率(気孔率)で形成されたチタン製のパンチングメタルを用いたものである。この場合も、金属体の積層枚数を変更することで、金属体の面積占有率を10%、20%となるように組み合わせ、全体の気孔率を調整した。
「気孔率16%+気孔率85%組み合わせ+Y:X=3.3:1」は、気孔率が85%の多孔質金属体と、気孔率が16%の金属体とを組み合わせたものを圧縮することにより、多孔質金属体の気孔を扁平にしたものである。圧延機で圧縮した面に平行な方向の気孔の長さYと、その面に直交する方向の長さXとの比率(Y/X;扁平度とする)がY:X=3.3:1の扁平形状とした。気孔の扁平度は、倍率20倍の光学顕微鏡観察写真から、形状の確認し易い気孔を5~10個選定し、各気孔のYとXの長さを画像から求めて扁平度を算出し、それらの平均値を当該試料の扁平度とした。
また、比較例として、図中「無積層」と表記したもので、気孔率が85%の多孔質金属体のみからなるものも作製した。
圧縮強度は、JIS H 7902(ポーラス金属の圧縮試験方法)に基づき測定した。
例えば、気孔率が高い多孔質金属体と気孔率が低い多孔質金属体との二種類の気孔率の多孔質金属体を接合した例としたが、三種類以上の気孔率の多孔質金属体を接合してもよい。
いずれの場合も、これらの接合界面Fは一の方向に平行となっていることが重要であり、扁平な気孔による強度の方向性と相俟って、接合界面Fに平行な方向の圧縮強度を接合界面Fに直交する方向の圧縮強度に対して大きくすることができる。なお、インプラントとして用いる場合に、目的とする強度の方向性を確保できれば、必要に応じて気孔の扁平方向(一の方向)に平行な方向とは異なる方向の接合界面によって接合した多孔質金属体又は気孔率の低い金属体を加えてもよい。
また、スラリーをドクターブレード法によってシート状に成形する場合、図6に示すように、ホッパを複数並べて、発泡剤の混入量の異なる発泡性スラリーを積層状態に供給して、積層状態のグリーンシートを成形するようにしてもよい。
2 骨格
3,3A,3B 気孔
4 気孔率の高い多孔質金属体
5 気孔率の低い金属体
11 多孔質インプラント素材
12~14 多孔質インプラント素材
F 接合界面
C 軸心方向
Claims (4)
- 気孔率の異なる複数の金属体が一の方向に平行な接合界面を介して接合されるとともに、これら金属体の接合体全体の気孔率が50%~92%であり、気孔率が高い金属体は、連続した骨格により形成される複数の気孔が連通した三次元網目状構造を有する多孔質金属体であり、気孔率が低い金属体は、気孔率が0~50%で、かつ前記接合界面に沿う一の方向を軸心方向としたときに、該軸心方向に直交する方向の断面における面積占有率が0.5%~50%であり、前記接合界面に沿う方向と平行な方向に圧縮したときの強度は、前記接合界面に直交する方向と平行な方向に圧縮したときの強度に対して1.4倍~10倍とされていることを特徴とする多孔質インプラント素材。
- 少なくとも気孔率が高い多孔質金属体に形成される気孔は、前記接合界面に沿う方向に長く、前記接合界面に直交する方向に短い扁平形状に形成されるとともに、前記接合界面に沿う方向の前記気孔の長さは、前記接合界面に直交する方向の長さに対して1.2倍~5倍に形成されていることを特徴とする請求項1記載の多孔質インプラント素材。
- 前記気孔率が高い多孔質金属体は、金属粉末と発泡剤を含有する発泡性スラリーを成形して発泡及び焼結させてなる発泡金属であることを特徴とする請求項1記載の多孔質インプラント素材。
- 前記気孔率が高い多孔質金属体は、金属粉末と発泡剤を含有する発泡性スラリーを成形して発泡及び焼結させてなる発泡金属であることを特徴とする請求項2記載の多孔質インプラント素材。
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US13/884,203 US9707321B2 (en) | 2010-11-10 | 2011-11-10 | Porous implant material |
CN201180053751.4A CN103200902B (zh) | 2010-11-10 | 2011-11-10 | 多孔植入体材料 |
GB1308794.5A GB2502890A (en) | 2010-11-10 | 2011-11-10 | Porous implant material |
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JP (1) | JP5648432B2 (ja) |
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JP2013248064A (ja) * | 2012-05-30 | 2013-12-12 | Mitsubishi Materials Corp | 多孔質インプラント素材 |
JP2013248063A (ja) * | 2012-05-30 | 2013-12-12 | Mitsubishi Materials Corp | 多孔質インプラント素材 |
JP2013248062A (ja) * | 2012-05-30 | 2013-12-12 | Mitsubishi Materials Corp | 多孔質インプラント素材 |
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JP2017529297A (ja) * | 2014-07-22 | 2017-10-05 | セラムテック ゲゼルシャフト ミット ベシュレンクテル ハフツングCeramTec GmbH | 椎体を融合するための部材 |
US20180093318A1 (en) * | 2015-04-24 | 2018-04-05 | Sumitomo Electric Industries, Ltd. | Composite material and method for producing composite material |
JP7010105B2 (ja) * | 2018-03-23 | 2022-01-26 | 三菱マテリアル株式会社 | 金属多孔体 |
AU2021349250A1 (en) * | 2020-09-24 | 2023-05-25 | Alphatec Spine, Inc. | Composite porous interbodies and methods of manufacture |
US11872105B1 (en) * | 2022-12-01 | 2024-01-16 | Robert Parker | Dental implant device for regeneration of dental pulp and dentin |
US11931224B1 (en) | 2022-12-19 | 2024-03-19 | Robert Parker | Tooth pod |
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CN103200902A (zh) | 2013-07-10 |
US9707321B2 (en) | 2017-07-18 |
JP5648432B2 (ja) | 2015-01-07 |
GB201308794D0 (en) | 2013-06-26 |
GB2502890A (en) | 2013-12-11 |
CN103200902B (zh) | 2016-03-09 |
US20130230734A1 (en) | 2013-09-05 |
JP2012100848A (ja) | 2012-05-31 |
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