WO2000042940A1 - Implant having a calcium phosphate coating deposited on a substrate surface of the implant which has been blasted with aluminium oxide particles - Google Patents

Implant having a calcium phosphate coating deposited on a substrate surface of the implant which has been blasted with aluminium oxide particles Download PDF

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Publication number
WO2000042940A1
WO2000042940A1 PCT/SE2000/000096 SE0000096W WO0042940A1 WO 2000042940 A1 WO2000042940 A1 WO 2000042940A1 SE 0000096 W SE0000096 W SE 0000096W WO 0042940 A1 WO0042940 A1 WO 0042940A1
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Prior art keywords
implant
calcium phosphate
phosphate coating
substrate surface
implants
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Application number
PCT/SE2000/000096
Other languages
French (fr)
Inventor
John Jansen
Joop Wolke
Tohru Hayakawa
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Astrazeneca Ab
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Publication date
Application filed by Astrazeneca Ab filed Critical Astrazeneca Ab
Priority to AU23381/00A priority Critical patent/AU2338100A/en
Publication of WO2000042940A1 publication Critical patent/WO2000042940A1/en

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Classifications

    • 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
    • A61L27/28—Materials for coating prostheses
    • A61L27/30—Inorganic materials
    • A61L27/306—Other specific inorganic materials not covered by A61L27/303 - A61L27/32
    • 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
    • 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
    • A61C8/0013—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 with a surface layer, coating
    • 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
    • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
    • 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
    • A61L27/28—Materials for coating prostheses
    • A61L27/30—Inorganic materials
    • A61L27/32—Phosphorus-containing materials, e.g. apatite
    • 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
    • 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
    • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
    • A61F2002/30906—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth shot- sand- or grit-blasted
    • 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
    • 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
    • A61F2310/00389—The prosthesis being coated or covered with a particular material
    • A61F2310/00592—Coating or prosthesis-covering structure made of ceramics or of ceramic-like compounds
    • A61F2310/00796—Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Definitions

  • the present invention relates to an implant for implantation in bone, one example of which being a dental implant
  • Implants are known for use as the anchoring members of dental and orthopaedic prostheses. To this end, the implant is inserted into a bore-hole drilled into the bone tissue of a bone tissue structure at a site where a prosthesis is required. A superstructure having the prosthetic part of the prosthesis is then secured to the implant
  • the superstructure will typically consist of a spacer or transmucosal component which engages to the implant to bridge the gingiva overlying the maxilla or mandible at the implant site and the prosthetic part, e.g. a crown, bridge or denture, is then secured to the spacer.
  • the prosthetic part e.g. a crown, bridge or denture
  • the prosthetic part may be secured directly to the implant as in US patent No. 5,180 ⁇ 03 (Homberg/Regents of the University of California).
  • the long-term integrity of the prosthesis is highly dependent on the successful osseointegration of the implant with the bone structure, that is to say, the remodelling of the bone tissue in the bone tissue structure into direct apposition with the implant.
  • a study on the factors which effect the osseointegration of implants was undertaken by Professor Per-Ingvar Brinemark and co-workers and the results were published in a book entitled "Qsseoin ⁇ eg ⁇ ated T n lants ir> +HP Treatment of the Edentulous Taw: Experience from a 10- Year Period". Almqvist & Wiskell International, Sweden, 1977.
  • Implants are not necessarily always used as part of a prosthesis, in some instances they can be a "stand alone” structure. As an example, implants are known for use as bone fixation screws. The success of these "stand alone” implants is also highly dependent on their successful osseointegration.
  • the present invention proposes to provide an implant which gives rise to a beneficial initial bone response thereto when implanted so as to promote the osseointegration of the implant.
  • an implant for implantation in bone tissue having a calcium phosphate coating deposited on a substrate surface of the implant which has been blasted -with particles of an alurr nium oxide.
  • a method of producing an implant for implantation in bone tissue having a calcium phosphate coating deposited on a substrate surface of the implant which comprises the step of blasting the substrate surface with particles of an aluminium oxide prior to deposition of the calcium phosphate coating thereon.
  • the substrate surface of the implant is formed from a titanium-based material, e.g. commercially pure titanium or a titanium alloy.
  • the blasting is carried out with particles of a stoichiometric aluminium oxide.
  • the calcium phosphate coating be thin enough so that the coating f ollows the surface geometry of the substrate surface.
  • PVD physical vapour deposition
  • the preferred PVD technique is the ion sputtering method known as magnetron spu tering, with radio frequency (RF) magnetron sputtering being particularly preferred.
  • the calcium phosphate coating has a thickness which is greater than O.l ⁇ m.
  • the coating thickness may be in the range 2-4 ⁇ m.
  • At least a part of the calcium phosphate coating has a crystalline structure. This can be achieved by heat treating the calcium phosphate coating at an elevated temperature, for instance with infrared radiation.
  • the implant is a dental implant.
  • the implant could, of course, be any other form of implant for implantation in bone tissue, e.g. an orthopaedic implant.
  • the Ca-P coating was deposited on the implants by RF magnetron sputtering with a commercially available unit (Edwards High Vacuum ESM 100 system).
  • a hydroxylapatite plasma-sprayed copper disc served as the target material and the implants were mounted on a water-cooled rotating substrate holder.
  • the sputtering process was carried out at a power of 800 Watts in a vacuum of ⁇ 6xl0 mbar and an Argon pressure of 5x10 mbar for a duration sufficient to produce a coating thickness in the range of 2-4 ⁇ m.
  • the implants were sequentially cleaned ultrasonically in acetone and boiling ethanol and then dried.
  • the implants so cleaned were subjected to a rapid heat-treatment with infrared radiation to a maximum temperature of 600 C.
  • the i frared radiation heat-treatment was carried out under pure argon flow for 17 seconds using a uniform temperature area measuring 30 mm in diameter by defocusing the infrared radiation as is known in the art.
  • prophylactic antibiotic Shiomalin (equivalent to Latamoxef Sodium) was administered post-operatively by a subcutaneous injection.
  • the implants were inserted into the medial femoral condyles and the tibial diaphyses of the rabbits.
  • each animal was ij-rm ⁇ obilised on its back and a hind leg shaved, washed and disinfected with povidone-iodine.
  • the bone preparation was performed with a very gentle surgical technique using a slow drilling speed (500rpm) and continuous internal coolin *gg- After press-fit insertion of one of the implants into the hole so prepared the soft tissues were closed in separate layers using intracutaneous resorbable Vicryl 3-0 sutures.
  • a longitudinal incision was further made on tlie medial surface of the tibia and the bone exposed by blunt dissection.
  • a pilot hole of 0.6 mm was drilled gradually through the medial cortex, medulla and lateral cortex of the tibia which was gradually widened with drills to the diameter of the implants.
  • the soft tissue was closed in separate layers using resorbable sutures.
  • each animal received two of the coated implants, one in the medial condyle of the hind femur and one in the diaphysis of the hind tibia.
  • the position and the fit of the implants was confirmed radiographically.
  • tissue blocks containing the respective implants were extracted and then prepared for light microscopy evaluation of the bone-implant interfaces.
  • the tissue blocks were dehydrated through a graded series of ethanol and embedded in methyl methacrylate.
  • non-decalcified thin sections (10 ⁇ m) were prepared using a modified diamond blade sawing microtome technique. The sections were made in a transverse direction perpendicular to the axis of the implants and were stained with methylene blue and basic fuchsin.
  • the 12 week implants showed an almost completed bone healing response with significant interfacial bone contact being observed with only spot-like areas with no bone contact being present These spot-like areas were filled with fibrous tissue characterised by a lack of inflammatory response and consisting mainly of fibroblasts and collagen bundles. Frequently, the original drill hole could still be clearly recognised.
  • the newly formed interfacial bone had a lamellar appearance. Inside the medullar cavity the implant surfaces were occasionally covered with bone which was derived from the cortical bone, having been guided there over the implant surface.
  • the callus had completely remodelled into mature trabecular bone.
  • the implant surfaces were partially covered with bone and in- between the areas of bone contact bone marrow tissue was present. Only occasionally could the original drill hole be detected. None of the implants were still in contact with the epiphyseal growth plate.
  • an implant with a Ca-P sputter coating on an Al ⁇ -blasted surface has a beneficial effect on the initial bone response to the implant in vivo setting a good foundation for osseointegration of the implant.
  • the implants were formed from a titanium alloy or other biocompatible material suitable for implantation in bone tissue. Similar results would also be expected if non-stoichiometric aluminium, oxide particles were used for the blasting and/or a deposition technique other than RF magnetron sputtering were used.

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  • Health & Medical Sciences (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Chemical & Material Sciences (AREA)
  • Epidemiology (AREA)
  • Transplantation (AREA)
  • Orthopedic Medicine & Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Dentistry (AREA)
  • Inorganic Chemistry (AREA)
  • Dermatology (AREA)
  • Medicinal Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Cardiology (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Vascular Medicine (AREA)
  • Prostheses (AREA)
  • Materials For Medical Uses (AREA)

Abstract

An implant for implantation in bone tissue has a calcium phosphate coating on a substrate surface of the implant. Prior to depositing the coating the substrate surface is blasted with particles of an aluminium oxide. The implant gives rise to a beneficial initial bone response to the implant in vivo.

Description

IMPLANT HAVING A CALCIUM PHOSPHATE COATING DEPOSITED ON A SUBSTRATE SURFACE OF THE IMPLANT WHICH HAS BEEN BLASTED WITH ALUMINIUM OXIDE PARTICLES
HELD OF THE LNVE TTON
The present invention relates to an implant for implantation in bone, one example of which being a dental implant
BACKGROUND OF THE INVENTION
Implants are known for use as the anchoring members of dental and orthopaedic prostheses. To this end, the implant is inserted into a bore-hole drilled into the bone tissue of a bone tissue structure at a site where a prosthesis is required. A superstructure having the prosthetic part of the prosthesis is then secured to the implant
In the case of a dental prosthesis, the superstructure will typically consist of a spacer or transmucosal component which engages to the implant to bridge the gingiva overlying the maxilla or mandible at the implant site and the prosthetic part, e.g. a crown, bridge or denture, is then secured to the spacer. There are various other forms that the superstructure can take as is known in the art. For instance, the prosthetic part may be secured directly to the implant as in US patent No. 5,180^03 (Homberg/Regents of the University of California).
The long-term integrity of the prosthesis is highly dependent on the successful osseointegration of the implant with the bone structure, that is to say, the remodelling of the bone tissue in the bone tissue structure into direct apposition with the implant. A study on the factors which effect the osseointegration of implants was undertaken by Professor Per-Ingvar Brinemark and co-workers and the results were published in a book entitled "Qsseoinτegτated T n lants ir> +HP Treatment of the Edentulous Taw: Experience from a 10- Year Period". Almqvist & Wiskell International, Stockholm, Sweden, 1977. It was found by Branemark et al that successful osseointegration depends upon inter alia the use of biocompatible materials for the implant, for example commercially pure (cp) titanium and alloys thereof, and the surgical procedure adopted, for example leaving the implant unloaded for several months before adding the superstructure.
Implants are not necessarily always used as part of a prosthesis, in some instances they can be a "stand alone" structure. As an example, implants are known for use as bone fixation screws. The success of these "stand alone" implants is also highly dependent on their successful osseointegration.
The present invention proposes to provide an implant which gives rise to a beneficial initial bone response thereto when implanted so as to promote the osseointegration of the implant.
SUMMARY OF THE INVENTION
According to the present invention there is provided an implant for implantation in bone tissue having a calcium phosphate coating deposited on a substrate surface of the implant which has been blasted -with particles of an alurr nium oxide. The provision of a calcium phosphate coating on an alurrdnium oxide- blasted substrate surface of an implant leads to a beneficial initial bone response to the implant in vivo.
According to the present invention there is further provided a method of producing an implant for implantation in bone tissue having a calcium phosphate coating deposited on a substrate surface of the implant which comprises the step of blasting the substrate surface with particles of an aluminium oxide prior to deposition of the calcium phosphate coating thereon. Preferably, the substrate surface of the implant is formed from a titanium-based material, e.g. commercially pure titanium or a titanium alloy.
In an embodiment of the invention the blasting is carried out with particles of a stoichiometric aluminium oxide.
It is preferable that the calcium phosphate coating be thin enough so that the coating f ollows the surface geometry of the substrate surface. To this end, a physical vapour deposition (PVD) technique is advocated, examples of which are vacuum evaporation, ion sputtering, ion plating and ion beam dynamic mixing. The preferred PVD technique is the ion sputtering method known as magnetron spu tering, with radio frequency (RF) magnetron sputtering being particularly preferred.
In a preferred embodiment of the invention the calcium phosphate coating has a thickness which is greater than O.lμm. As an example, the coating thickness may be in the range 2-4 μm.
In a other preferred embodiment of the invention at least a part of the calcium phosphate coating has a crystalline structure. This can be achieved by heat treating the calcium phosphate coating at an elevated temperature, for instance with infrared radiation.
In an embodiment of the invention the implant is a dental implant. The implant could, of course, be any other form of implant for implantation in bone tissue, e.g. an orthopaedic implant.
The invention will now be illustrated by the following non-limiting Example.
EXAMPLE (I) Implant Materials
Twenty four screw-type commercially pure generally cylindrical titanium implants having a diameter of 2.8 mm were grit blasted with AJL,Q3 to a toughness of Ra=4-5μm. The blasted implants were then cleaned ultrasonically in propanol and dried at 100 C preparatory to being coated with a calcium phosphate (Ca-P) coating.
The Ca-P coating was deposited on the implants by RF magnetron sputtering with a commercially available unit (Edwards High Vacuum ESM 100 system). A hydroxylapatite plasma-sprayed copper disc served as the target material and the implants were mounted on a water-cooled rotating substrate holder. The sputtering process was carried out at a power of 800 Watts in a vacuum of <6xl0 mbar and an Argon pressure of 5x10 mbar for a duration sufficient to produce a coating thickness in the range of 2-4 μm.
On completion of the sputtering the implants were sequentially cleaned ultrasonically in acetone and boiling ethanol and then dried. The implants so cleaned were subjected to a rapid heat-treatment with infrared radiation to a maximum temperature of 600 C. The i frared radiation heat-treatment was carried out under pure argon flow for 17 seconds using a uniform temperature area measuring 30 mm in diameter by defocusing the infrared radiation as is known in the art.
Analysis of the Ca-P coatings on the implants by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the coatings had a crystalline structure with the major component being hydroxylapatite. The Ca:P ratio in the coating was 1.93 as determined by energy dispersive X-ray analysis (EDX-ZAF, Hitachi).
(II) Animal Experiment
Following characterisation of the coa ings the implants were sterilised in an autoclave preparatory to carrying out an animal experiment in accordance with the animal experimental ethical guidelines of Nihon University School of Dentistry at Matsudo (Certificate Number: ECA-96-0010).
(a) Implantation Procedure
For the animal experiment twelve three month old female Japanese White Rabbits weighing about 3-5-4 kg were used. Surgery was performed by intravenous
® injection of pentobarbital sodium (Nembutal , 0.4 ml /kg) and under local
Φ anaesthesia by injection of Xylocain . To reduce the perioperative infection risk,
prophylactic antibiotic Shiomalin (equivalent to Latamoxef Sodium) was administered post-operatively by a subcutaneous injection.
The implants were inserted into the medial femoral condyles and the tibial diaphyses of the rabbits. For the insertion of the implants each animal was ij-rmαobilised on its back and a hind leg shaved, washed and disinfected with povidone-iodine.
A longitudinal incision was made on the medial surface of the femur and the medial condyle exposed. After exposure of the condyle a pilot hole of 0.6 mm was drilled which was gradually widened with different drills to the diameter of the implants. The bone preparation was performed with a very gentle surgical technique using a slow drilling speed (500rpm) and continuous internal coolin *gg- After press-fit insertion of one of the implants into the hole so prepared the soft tissues were closed in separate layers using intracutaneous resorbable Vicryl 3-0 sutures.
A longitudinal incision was further made on tlie medial surface of the tibia and the bone exposed by blunt dissection. A pilot hole of 0.6 mm was drilled gradually through the medial cortex, medulla and lateral cortex of the tibia which was gradually widened with drills to the diameter of the implants. Following press-fit insertion of one of the implants into the hole so prepared the soft tissue was closed in separate layers using resorbable sutures.
It can thus be gathered that in this way each animal received two of the coated implants, one in the medial condyle of the hind femur and one in the diaphysis of the hind tibia. The position and the fit of the implants was confirmed radiographically.
(b) Implant Evaluation
Half of the rabbits were sacrificed 2 weeks after surgery by injecting an overdose
® of pentobarbital sodium (Nembutal ) peritoneally and the remaining half were similarly sacrificed 12 weeks after surgery.
During the test periods the animals remained in good health and at sacrifice no clinical signs of inflarrLmation or adverse tissue reaction could be seen. All implants were still in situ at sacrifice.
Immediately after sacrifice of the animals the femurs and tibiae with the implants were excised and the excess tissue of the excised femurs and tibiae removed. Following fixation of the femurs and tibiae in 10% buffered formali solution, tissue blocks containing the respective implants were extracted and then prepared for light microscopy evaluation of the bone-implant interfaces. In this connection, the tissue blocks were dehydrated through a graded series of ethanol and embedded in methyl methacrylate. After polymerisation, non-decalcified thin sections (10 μm) were prepared using a modified diamond blade sawing microtome technique. The sections were made in a transverse direction perpendicular to the axis of the implants and were stained with methylene blue and basic fuchsin.
(c) Tibia Implant Results
In the 2 week implants there was frequently no callus formation or other sign of wound healing observed. The original drill hole could clearly be identified and a very small gap existed between the wall of the drill hole and the implant surface. Also, no increased remodelling activity due to the implantation process could be observed in the bone close to the implants.
The 12 week implants showed an almost completed bone healing response with significant interfacial bone contact being observed with only spot-like areas with no bone contact being present These spot-like areas were filled with fibrous tissue characterised by a lack of inflammatory response and consisting mainly of fibroblasts and collagen bundles. Frequently, the original drill hole could still be clearly recognised. The newly formed interfacial bone had a lamellar appearance. Inside the medullar cavity the implant surfaces were occasionally covered with bone which was derived from the cortical bone, having been guided there over the implant surface.
(d) Femoral implants
In the 2 week implants the original drill hole could still be recognised and clear signs of callus formation were observed at the implant surface and in the near vicinity of the implants. Besides callus tissue, small bone fragments could be observed which were apparently loosened during drilling. The bone fragments were interspersed between bone marrow spaces. Clear signs of remodelling of these fragments were observed. Some of the implants appeared to be placed into the epiphyseal growth plate because of the small size of the condyles resulting in a more extensive callus formation.
In the 12 week implants the callus had completely remodelled into mature trabecular bone. The implant surfaces were partially covered with bone and in- between the areas of bone contact bone marrow tissue was present. Only occasionally could the original drill hole be detected. None of the implants were still in contact with the epiphyseal growth plate.
(e) Conclusion
The provision of an implant with a Ca-P sputter coating on an Al^-blasted surface has a beneficial effect on the initial bone response to the implant in vivo setting a good foundation for osseointegration of the implant.
Similar results to those outlined in the Example would be expected if, instead of cp titanium, the implants were formed from a titanium alloy or other biocompatible material suitable for implantation in bone tissue. Similar results would also be expected if non-stoichiometric aluminium, oxide particles were used for the blasting and/or a deposition technique other than RF magnetron sputtering were used.

Claims

1. An implant for implantation in bone tissue having a calcium phosphate coating deposited thereon characterised in that the coating is deposited on a s substrate surface of the implant which has been blasted with particles of an alurniniurn oxide.
2. An implant according to claim 1 characterised in that the calcium phosphate coating has a thickness which is greater than 0.1 μm.
3. An implant according to claim 1 or 2 characterised in that the calcium phosphate coating has a thickness in the range 2-4 μm.
4. An implant according to any one of the preceding claims characterised in that at least a part of the calciu phosphate coating is of a crystalline structure.
5. An implant according to any one of the preceding claims characterised in that the substrate surface is formed from a titanium-based material.
6. An implant according to any one of the preceding claims characterised in that the implant is a dental implant
7. A method of producing an implant for implantation in bone tissue having a calcium phosphate coating deposited on a substrate surface of the implant characterised by the step of blasting the substrate surface with particles of an aluminium oxide prior to deposition of the calcium phosphate coating thereon.
8. A method according to claim 7 characterised in that the blasting is carried out with particles of stoichiometric aluminium oxide.
9. A method according to claim 7 or 8 characterised by the further step of the calcium phosphate coating being deposited by radio frequency magnetron sputtering.
10. A method according to claim 7, 8 or 9 characterised by the further step of subjecting the calcium phosphate coating to an infrared heat treatment sufficient for crystallisation to occur in the coating.
PCT/SE2000/000096 1999-01-22 2000-01-18 Implant having a calcium phosphate coating deposited on a substrate surface of the implant which has been blasted with aluminium oxide particles WO2000042940A1 (en)

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AU23381/00A AU2338100A (en) 1999-01-22 2000-01-18 Implant having a calcium phosphate coating deposited on a substrate surface of the implant which has been blasted with aluminium oxide particles

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SE9900189A SE9900189D0 (en) 1999-01-22 1999-01-22 Implant
SE9900189-3 1999-01-22

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Publication number Priority date Publication date Assignee Title
WO2004040037A1 (en) * 2002-10-31 2004-05-13 Cerbio Tech Ab Method of making structured ceramic coatings and coated devices prepared with the method
WO2004040036A1 (en) * 2002-10-31 2004-05-13 Cerbio Tech Ab Method of making structured ceramic coatings and coated devices prepared with the method
CN113663140A (en) * 2021-07-20 2021-11-19 南方医科大学珠江医院 Implant and preparation method and application thereof

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EP0310574A1 (en) * 1987-09-29 1989-04-05 Permelec Electrode Ltd Process for producing composite materials having a coating of calcium phosphate compound
WO1992005745A1 (en) * 1990-10-08 1992-04-16 Aktiebolaget Astra Method for the preparation of implants made of titanium or alloys thereof
EP0806211A1 (en) * 1996-05-10 1997-11-12 Matrix Medical B.V. Implant material and process for producing it

Patent Citations (3)

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EP0310574A1 (en) * 1987-09-29 1989-04-05 Permelec Electrode Ltd Process for producing composite materials having a coating of calcium phosphate compound
WO1992005745A1 (en) * 1990-10-08 1992-04-16 Aktiebolaget Astra Method for the preparation of implants made of titanium or alloys thereof
EP0806211A1 (en) * 1996-05-10 1997-11-12 Matrix Medical B.V. Implant material and process for producing it

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004040037A1 (en) * 2002-10-31 2004-05-13 Cerbio Tech Ab Method of making structured ceramic coatings and coated devices prepared with the method
WO2004040036A1 (en) * 2002-10-31 2004-05-13 Cerbio Tech Ab Method of making structured ceramic coatings and coated devices prepared with the method
CN113663140A (en) * 2021-07-20 2021-11-19 南方医科大学珠江医院 Implant and preparation method and application thereof

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