Papers by Keyword: Bone Ingrowth

Abstract: Surface biofunctionalization is a common strategy to improve the material-tissue interface of inert implant surfaces. In this context we coated alumina-toughened zirconia (ATZ) ceramics after titanium plasma spraying with two different porous calcium phosphate layers and subsequently functionalized the obtained surfaces either with an RGD containing cell adhesion peptide sequence or a bone morphogenetic protein (BMP)-glycosaminoglycan complex. We studied initial cell adhesion densities, integrin expression, and alkaline phosphatase activity as an osteogenic marker of the coatings in vitro in comparison to the non-functionalized ATZ ceramics to evaluate the bone ingrowth potential of these biofunctionalized implant coatings.

Abstract: A new powder metallurgical processing route for porous Ti coatings on Ti-6Al-4V substrates based on the electrophoretic deposition (EPD) of TiH₂ suspensions is presented. After dehydrogenation and sintering in vacuum, coatings with a fully interconnected porosity (up to 51%, interconnective pore channels (IPC) of 2-50 µm) and high adhesion strength (up to 47 MPa) are obtained. Further evaluation of these coatings for potential use in biomedical implants shows that EPD Ti coatings are significantly less prone to bacterial adhesion compared to state-of-the-art vacuum plasma sprayed (VPS) coatings, while still allowing substantial bone ingrowth. Using EPD, the coating process can easily be transferred to complex-shaped implant components.

Abstract: This study evaluates the manufacturability and performances of periodic cellular lattice structures designed by repeating a cubic unit cell and produced by SLM using titanium powder. The effects of unit cell size on the manufacturability, density, compression and bending properties of the manufactured cellular lattice structures were investigated. Lattice structures manufactured with various unit cell sizes ranging from 0.5 to 1.2 mm could be produced free of defects by the SLM process, with a novel type of supports. By the increasing of the cell size, a decrease of the applied load together with an enhancement of the flexure extension were observed. Specimens with a cell size higher than 1 mm manifested an excellent flexibility by flexure tests.

Abstract: Porous tantalum; biomaterials; bone ingrowth; laser cladding; Abstract. Porous tantalum, a new low modulus metal with a characteristic appearance similar to cancellous/trabecular bone, is currently available for use in several orthopedic applications (hip and knee arthroplasty, spine surgery, and bone graft substitute). The open-cell structure of repeating dodecahedrons is produced via carbon vapor deposition/infiltration of commercially pure tantalum onto a vitreous carbon scaffolding. This transition metal maintains several interesting biomaterial properties, including: a high volumetric porosity (70-80%), low modulus of elasticity (3MPa), and high frictional characteristics. Tantalum has excellent biocompatibility and is safe to use in vivo as evidenced by its historical and current use in pacemaker electrodes, cranioplasty plates and as radiopaque markers. The bioactivity and biocompatibility of porous tantalum stems from its ability to form a self-passivating surface oxide layer. This surface layer leads to the formation of a bone-like apatite coating in vivo and affords excellent bone and fibrous in-growth properties allowing for rapid and substantial bone and soft tissue attachment. Tantalum-chondrocyte composites have yielded successful early results in vitro and may afford an option for joint resurfacing in the future. The development of porous tantalum is in its early stages of evolution and the following represents a review of its biomaterial properties and fabrication methods for applications as implant biomaterials.

Abstract: It was demonstrated that microstructured surfaces improve cell spreading and bone ingrowth. Particularly, the surface roughness modulates the osseointegration of orthopaedic and dental implants. We have developed an innovative grit blasting process using Biphasic Calcium Phosphate, a Resorbable Biocompatible Blast Media (RBBM). PEEK is biocompatible but an inert material, involving no direct bone bonding. Implants coming from a rabbit experimental study, were processed for X-rays Micro tomography. Light microscopy and SEM were performed.It was demonstrated in this study that the surface treatment on PEEK improve the quality of bone architecture in direct contact with the sample surface, compared to the classical surface of PEEK. These data demonstrate that PEEK rough surface obtained by RBBM blasting maintain high biocompatibility and bone osteoconduction, and promote higher stability of the implant.

Abstract: A new biphasic calcium phosphate ceramic material Hydros™ has been developed. The main attractive feature of BCP ceramic is their ability to form a strong direct bond with the host bone resulting in a strong interface. Currently, granules are more and more used in moldable, injectable bone substitutes. However, the biological behaviour of the particles can be influenced not only by chemical composition and crystallinity, but also by several parameters as microporosity and nano-micro sized particles. The aim of the study was to assess, in animal experiment, the role played by an Hydrated Putty Bioceramics (Hydros™), based on specific combination of hydrophilic micro and macrosized BCP particles, to obtain high osteogenic Injectable Bone Substitute. No sign of clinical rejection was noticed. In muscular area, no fibrous encapsulation was observed, degradation of the smaller particles is observed by macrophages and giant cells. At 12 weeks, more of 75% of BCP was resorbed. The biocompatibility and safety in human orthopaedic applications (tibial plateau fracture) has been demonstrated.

Abstract: Due to the lack of macroporosity in current available Calcium Phosphate cement used in osteoarticular surgery, Micro and Macroporous Biphasic CaP Cement (MCPC™) was developed. The MCPC™ concept was the association of a settable and a fast resorbable matrix and a sieved fraction of microporous biphasic calcium phosphate (BCP) granules, recognized for the high osteoconductive and osteogenic properties. During the resorption of the matrix, a porous structure is created and the osteoconductive effect of the granules promotes the bone ingrowth. A goat preclinical study was realized to evaluate the efficacy of MCPC™ for C3 and C4 vertebral body filling defects during 6 months. Bone remodelling was evidenced demonstrating bone ingrowth at the expense of the cement and surrounding the residual BCP granules. Bone trabeculae were observed coming from the spongious bone to the implant site. Human vertebral body filling cases demonstrated the biocompatibility and the safety of MCPC™ for bone reconstruction. Results of this study demonstrated the importance of special combination of calcium phosphate granules in the MCPC™ to provide macroporosity and scaffolding for newly formed bone.

Abstract: Calcium phosphate ceramics such as hydroxy apatite (HA), β-tricalcium phosphate (β-TCP) and bicalcium phosphate (BCP) have been used as a bone graft biomaterial because of their good biocompatibility and similarity of chemical composition to natural bones. To increase the mechanical and osteoconductive properties, the granules and spongy type porous bone graft substitutes were prepared by fibrous monolithic process and polyurethane foam replica methods, respectively. The pore sizes obtained using these approaches ranged between 100-600 µm. The cytotoxicity, cellular proliferation, differentiation and ECM deposition on the bone graft substitutes were observed by SEM and confocal microscopy. Moreover, the scaffolds were implanted in the rabbit femur. New bone formation and biodegradation of bone graft were observed through follow-up X-ray, micro-CT analysis and histological findings. After several months (2, 3, 6, 12 and 24 months) of implantation, new bone formation and ingrowths were observed in defect sites of the animal by CaP ceramics and 2 to 3 times higher bone ingrowths were confirmed than that of the normal trabecular bones in terms of total bone volume (BV).

Abstract: We have developed a new injectable bone substitute combining specific granules of BCP with or without radiopaque elements with a reversible thermo sensitive resorbable carrier such as Pluronic F-127. The composite is liquid at ambient temperature and set as hydrogel at 37°C. Rabbit experiment demonstrates high biocompatibility and bone ingrowth at the expense of the injectable bioceramic composite.

Abstract: Surface roughness modulates the osseointegration of orthopaedic and dental titanium implants. High surface roughness is currently obtained by blasting of titanium implants with silica or aluminium abrasive particles. This process includes into the surface abrasive particles and may cause the release of cytotoxic silica or aluminium ions in the peri implant tissue. To overcome this drawback, we currently develop an innovative gridblasting process using Biphasic Calcium Phosphate (BCP) particles (RBBM Resorbable and Biocompatible Blast Media) to generate biocompatible roughened titanium surface. This work present the technique of blasting using RBBM particles to provide a roughened surface which does not release cytotoxic elements and (ii) to assess the effects of such a roughened surface for bone osteointegration in critical size rabbit defect. Our results demonstrate that resorbable biphasic calcium phosphate abrasive particles can be used to create titanium surface roughness. This grid blasting process increases surface roughness of titanium implants and offers a non cytotoxic surface for rapid and efficient osteointegration.