2014 Fall Meeting
Bioceramics for Bone and Joint Repair
The objective is to review the state of the art in the processing, characterization and clinical application of bioceramics (from inert ceramics for orthopedic or dental implants to bioactive ceramics to support tissue engineering). The symposium will be a forum for academy and industry to highlight common issues and point future research directions.
The advances in ceramic science during the last decades have led to a significant increase in the research and clinical use of bioceramics for bone substitution and engineering. Usually bioceramics are categorized as either "bioinert" or "bioactive" (able to promote bone formation). However, these terms should be used with care, since any material introduced into the physiological environment will induce a response.
Ceramics are currently making inroads in high volume applications such as dental or orthopedic implants but much work is still needed for them to reach their full potential. The mechanical properties of ceramics, in particular their low toughness and sensitivity to aging in the physiological environment are still a challenge for their general use in implants and scaffolds. In addition, the development and clinical application of optimum ceramic scaffolds for tissue engineering is still a pending issue. This is a very active area of research and recent progress in the fields of materials science, chemistry and biology can help to address these problems. The main objective of this symposium is to bring together scientists,clinicians and engineers in order to provide a truly multidisciplinary forum where to discuss the most current advances in the field and point at key research needs. One of the goals is to define common issues and terminology in order to trigger progress. The symposium will address key problems using a comprehensive approach that will encompass both bioinert and bioactive ceramics. Issues of interest are the development of new processing routes, drug delivery, the effect of biodegradation on the mechanical properties, the engineering of the material surfaces to promote osseointegration or the relationship between structure and mechanical properties at al length scales and the comparison with the natural counterpart: bone. The symposium will be supported through the joint effort of several European projects (Biobone, MATCh, Longlife, Restoration, Glacerco) dealing with the developing of new bioceramics and the training of young professionals. This group of projects involves directly more than 60 scientists and has links with multiple institutions and companies worldwide. It will help to disseminate both the workshop and its contribution as well as to attract a critical mass of attendants.
Hot topics to be covered by the symposium
- Novel processing technologies for ceramic-based scaffolds for bone regeneration-Processing of hierarchical structures and assembly of materials from nano to macro dimensions.
- Ceramic-based structures for drug delivery
- New ceramic-based implant materials
- Osseointegration of ceramic implants
- Mechanical properties of implants and scaffolds
- Interaction of proteins and cells with ceramic surfaces
- Biodegradation of ceramics
- New bioactive glass formulations
- Structure and mechanical properties of bone
- Clinical use of bioceramic implants
Tentative list of scientific committee members
- Julian Jones (bioactive glasses), Imperial College, UK.
- Aldo Boccaccini (bioactive glasses, tissue engineering scaffolds), Univeristy of Erlangen, Germany.
- Marc Anglada (mechanical properties of bioceramics), UPC, Spain.
- Joel de Conninck (surface engineering), University of Mon, Belgium.
- Xiang Zhang (calcium phosphate materials, implants), Ceram, UK.
- Meinhard Kuntz (ceramics for orthopedics), Ceramtec, Germany.
- Jaime Franco (calcium phosphates), Keramat, Spain.
- Nicolas Courtois, (Dental materials), Anthogyr, France.
- Enrica Verné (calcium phosphates, bioactive glasses), Politecnico di Torino, Italy.
- Jonathan Knowles (tissue engineering), University College London, UK.
- Mauro Alini (bone regeneration). AO foundation, Switzerland.
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Session II : -
Authors : MP Ginebra, C Canal, E Montufar, M Espanol
Affiliations : Biomaterials, Biomechanics and Tissue Engineering Group. Dept. of Materials Science and Metallurgy, Technical University of Catalonia, Barcelona, Spain. Biomedical Research Networking Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), Spain.
Resume : Calcium phosphate (CaP) materials have long been used as synthetic bone grafts, due to their excellent biocompatibility, bioactivity and osteoconductivity. One type of CaP of particular interest are calcium phosphate cements (CPCs). Cements are low-temperature self-setting materials that are formed by mixing a solid phase with a liquid phase. The setting reaction allows obtaining hydrated compounds with morphologies and compositions very similar to the calcium phosphates found in the mineralized tissues. Moreover, the entangled network of crystals that are formed via cementitious reactions do not simply mimic the composition of the mineral phase in bone but they also generate porous structures with specific nano/micro porosities. The intrinsic porosity of CPCs allows the incorporation of drugs, biologically active molecules or even cells, without thermal denaturalization or loss of activity during preparation or implantation. Thus, CPCs emerge as potential controlled drug delivery systems for local treatment. The incorporation of active molecules can be used to increase the bone regeneration capacity of the material or to target specific skeletal disorders or pathologies. Moreover, these materials are injectable, making them very attractive for minimally invasive surgery. An additional advantage of CPCs is their versatility, which makes them compatible with many processing techniques for the fabrication of scaffolds, like foaming, robocasting and emulsion-based technologies.
Authors : Chaika E.V.
Affiliations : Donetsk Institute for Physics and Engineering named after O.O. Galkin, National Academy of Sciences of Ukraine
Resume : Implants used in dentistry and surgery for bone repair have complex and varied shapes. Often, these implants should have the original form for a particular patient. For production of such implants we suggest to use powder technology of isostatic pressing in thermoplastic molds at elevated temperature. Moulds made of thermoplastic materials are well keep their shape under normal conditions. When heated, they melt into the plastic state and ensure the quality of the isostatic process. As a result, the shape of compacts may be as close as possible to the shape of the finished articles. Thermoplastic molds are manufactured using 3D-printing. Forms of molds can be designed according the patient's imaging data. This manufacturing method has the advantage that the isostatic pressing and 3D-printing of plastic materials are well-known technologies. Application of 3D-printing allowed to accelerate the production of thermoplastic molds and reduce their costs. The technology has been tested in the manufacture of surgical implants (plates and screws) and parts of surgical instruments (drills and screwdriver) made from partially stabilized zirconia ceramics. Also, it is possible to use this method for manufacturing compacts from metal powders. Compacts of cermet with a composition of 80% Ti + 20% hydroxyapatite were prepared. Some of advantages and problems inherent to the method are revealed and discussed.
Authors : Bartłomiej Wysocki 1, Joanna Idaszek 1, Krzysztof Jan Kurzydłowski 1, Danuta Leszczyńska 2, Wojciech Święszkowski 1
Affiliations : 1 Warsaw University of Technology, Faculty of Materials Science and Engineering, Woloska 141 St., 02-507 Warsaw, Poland 2 Interdisciplinary Nanotoxicity Center, Department of Civil and Environmental Engineering, Jackson State University, 1325 Lynch Street, Jackson, Mississippi 39217-0510, USA
Resume : The easiest method to obtain a coating on a porous titanium implant with interconnected pores of diameter bellow 400 µm is electrodeposition were titanium acts as a cathode. In the present work, how addition of the COOH functionalized carbon nanotubes,CNTs, to the electrolytic solution influences on the morphology and chemical composition of the created composite (Ca-P-CNTs) coatings is investigated. Furthermore, influence of a heat-treatment on the coatings crystallinity is shown. Cells interaction with new coatings is also evaluated. The Ca-P-CNTs coatings were successfully fabricated on the porous titanium scaffolds made by Selective Laser Melting (SLM). The calcium and phosphorous ions molarity in the electrolytic solution had a critical influence on the calcium-phosphate ceramic presented in the coating. Microscopic observations showed that higher calcium and phosphorous molarity facilitates brushite formation, while lower molarity results in hydroxyapatite. CNTs dispersed in the electrolyte had improved ionic transport in the solution hence coatings thickness. The X-ray diffraction results indicated that heat-treatment in temperatures below 700 ˚C did not cause CNTs degradation while it improved hydroxyapatite crystallinity. Summarizing, a very promising method for fabrication of the novel composite calcium-phosphate ceramic coating reinforced with CNTs was developed to improve bioactivity of porous titanium implants.
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Authors : Marta Fornabaio1, Paola Palmero1, Rebecca Traverso1, Helen Reveron2, Laura Montanaro1 and Jérome Chevalier2,3
Affiliations : 1 Department of Applied Science and Technology, INSTM R.U. PoliTO, LINCE Lab., Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy; 2 Université de Lyon, INSA de Lyon, MATEIS UMR CNRS 5510, Bât. Blaise Pascal 7, Av. Jean Capelle, 69621 Villeurbanne, France; 3 Institut Universitaire de France, 103 bd Saint-Michel, 75005 Paris, France
Resume : In the frame of the European Project Longlife (7th Framework Program), innovative zirconia-based nanocomposites materials have been designed and developed with the aim of fulfill the clinical requirements for strong, tough and stable ceramics used for dental applications. Ceria-stabilized zirconia (Ce-TZP) was selected as composite matrix in order to improve phase stability, while both equiaxial α-Al2O3 and elongated SrAl12O19 particles were selected as second phases in order to improve strength, hardness and toughness simultaneously. Furthermore, in order to obtain high transformability, the ceria content in the composite materials was carefully tailored: four different ceria contents (in the range 10.0-11.5 mol%) were investigated. As assessed by SEM and TEM analyses, a perfect tailoring of all the compositional and microstructural features in the developed materials was successfully obtained by applying a new nano-powder engineering approach. Precisely, the composite powders were produced by a simple but reliable surface coating process, in which zirconia powders were coated by inorganic precursors (nitrates aqueous solutions) of the second phases, which crystallize on the zirconia particles surface under proper thermal treatment. Composite materials were obtained by sintering slip cast bodies at 1450°C for 1 h. Mechanical properties were evaluated in terms of Vickers Hardness, flexural strength and fracture toughness revealing a strong influence of the ceria amount on the mechanical behavior: materials having 10.5 mol% of ceria showed the best results with σf of about 900 MPa and KIC above 10 MPa√m. Accelerated hydrothermal tests revealed stable materials in the time scale of biomedical applications when the ceria amount was above 10 mol%.
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