Osteoinductive hydroxyapatite-coated titanium implants. 2012

Ugo Ripamonti, and Laura C Roden, and Louise F Renton
Bone Research Laboratory, School of Physiology, Medical Research Council/University of the Witwatersrand, Johannesburg, 2193 Parktown, South Africa. ugo.ripamonti@wits.ac.za

Previous studies have shown that heterotopic induction of bone formation by calcium phosphate-based macroporous constructs is set into motion by the geometry of the implanted substrata, i.e. a sequence of repetitive concavities assembled within the macroporous spaces. The aim of this study was to construct osteoinductive titanium implants that per se, and without the exogenous application of the osteogenic soluble molecular signals of the transforming growth factor-β supergene family, would initiate the induction of bone formation. To generate intrinsically osteoinductive titanium implants for translation in clinical contexts, titanium grade Ti-6A1-4V cylinders of 15 mm in length and 3.85 mm in diameter, with or without concavities, were plasma sprayed with crystalline hydroxyapatite resulting in a uniform layer of 30 μm in thickness. Before coating, experimental titanium implants were prepared with a sequence of 36 repetitive concavities 1600 μm in diameter and 800 μm in depth, spaced a distance of 1000 μm apart. Mandibular molars and premolars were extracted to prepare edentulous mandibular ridges for later implantation. Planar and geometric hydroxyapatite-coated titanium constructs were implanted in the left and right edentulized hemi-mandibles, respectively, after a healing period of 7-8 months, 3 per hemi-mandible. Three planar and three geometric implants were implanted in the left and right tibiae, respectively; additionally, planar and geometric constructs were also inserted in the rectus abdominis muscle. Six animals were euthanized at 30 and 90 days after implantation; one animal had to be euthanized 5 days after surgery and the remaining animal was euthanized 31 months after implantation. Undecalcified longitudinal sections were precision-sawed, ground and polished to 40-60 μm; all sections were stained with a modified Goldner's trichrome. Undecalcified specimen block preparation was performed using the EXAKT precision cutting and grinding system. Histomorphometric analyses of bone in contact (BIC) showed that on day 30 there was no difference between the geometric vs. planar control implants; on day 90, the ratio of BIC to surface within the geometric implants was greater than on the standard planar implants in both mandibular and tibial sites; 31 months after implantation, selected concavities cut into the geometric implants harvested from the rectus abdominis muscle showed the spontaneous induction of bone formation with mineralized bone surfaced by osteoid seams. These data in non-human primates indicate that geometrically-constructed plasma-sprayed titanium implants are per se osteogenic, the concavities providing a unique microenvironment to initiate bone differentiation by induction.

UI MeSH Term Description Entries
D008855 Microscopy, Electron, Scanning Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY. Scanning Electron Microscopy,Electron Scanning Microscopy,Electron Microscopies, Scanning,Electron Microscopy, Scanning,Electron Scanning Microscopies,Microscopies, Electron Scanning,Microscopies, Scanning Electron,Microscopy, Electron Scanning,Microscopy, Scanning Electron,Scanning Electron Microscopies,Scanning Microscopies, Electron,Scanning Microscopy, Electron
D009132 Muscles Contractile tissue that produces movement in animals. Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D010012 Osteogenesis The process of bone formation. Histogenesis of bone including ossification. Bone Formation,Ossification, Physiologic,Endochondral Ossification,Ossification,Ossification, Physiological,Osteoclastogenesis,Physiologic Ossification,Endochondral Ossifications,Ossification, Endochondral,Ossifications,Ossifications, Endochondral,Osteoclastogeneses,Physiological Ossification
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D014025 Titanium A dark-gray, metallic element of widespread distribution but occurring in small amounts with atomic number, 22, atomic weight, 47.867 and symbol, Ti; specific gravity, 4.5; used for fixation of fractures.
D016348 Osseointegration The growth action of bone tissue as it assimilates surgically implanted devices or prostheses to be used as either replacement parts (e.g., hip) or as anchors (e.g., endosseous dental implants). Peri-implant Endosseous Healing,Endosseous Healing, Peri-implant,Endosseous Healings, Peri-implant,Healing, Peri-implant Endosseous,Healings, Peri-implant Endosseous,Peri implant Endosseous Healing,Peri-implant Endosseous Healings
D016764 Cell Polarity Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains. Cell Polarities,Polarities, Cell,Polarity, Cell
D048549 Papio ursinus A species of baboon in the family CERCOPITHECIDAE found in southern Africa. They are dark colored and have a variable social structure. Chacma Baboon,Baboon, Chacma,Baboons, Chacma,Chacma Baboons
D051379 Mice The common name for the genus Mus. Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus

Related Publications

Ugo Ripamonti, and Laura C Roden, and Louise F Renton
March 1989, Biomaterials,
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
December 1995, Journal of biomedical materials research,
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
September 1994, Biomaterials,
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
January 1992, Dental clinics of North America,
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
August 1991, Journal of biomedical materials research,
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
January 1999, The International journal of oral & maxillofacial implants,
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
January 2012, International journal of nanomedicine,
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
July 2007, Journal of biomedical materials research. Part A,
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
December 2020, Materials (Basel, Switzerland),
Ugo Ripamonti, and Laura C Roden, and Louise F Renton
December 1991, The Journal of arthroplasty,
Copied contents to your clipboard!