Partner und Internationale Organisationen
(Englisch)
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Samo SpA (I), Flametal SpA (I), EU-JRC, Teer Coatings Ltd (GB), CSIC Barcelona (E), Biomatech SA (F), Straumann Deutschland (D)
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Abstract
(Englisch)
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In the last two decades, the success rate of dental implants has been greatly enhanced by the use of materials, among which titanium, allowing a high degree of osseointegration. However, further improvements must be achieved in the transgingival zone, that is in the upper zone of the implant in contact with the oral soft tissues. This region is determinant for the perimucosal seal efficiency, on which the implant success possibly depends. Whereas titanium shows an excellent behaviour in the bone region, a smooth ceramic-coated surface can provide a better soft tissue-implant contact. It also decreases the rate of plaque build-up and facilitates personal and professional hygiene procedures. Another advantage of such surfaces is the possibility to produce them in a colour close to that of natural teeth or gingiva. This greatly improves implant aesthetics, particularly in the case of gingival retraction commonly associated with dental implants.
An improved dental implant could therefore be obtained by the combination of different materials (titanium in the bone region, ceramic or surface modified titanium in the transgingival zone). The first objective of this project, proposed by a dental implant distributor (Straumann GmbH), is to develop this new dental implant by means of four different technologies (plasma spraying, PACVD, magnetron sputtering, ion implantation + anodisation) and to assess the technical and biological performance of these coatings.
Joint replacement implants have also experienced important improvements in the last decades, although knee prostheses participated to a much lower extend to this trend: they still show a lower rate of clinical success due to their complicated geometry and function, which have until now strongly limited the use of improved wear-resistant materials such as ceramics on the gliding surfaces of the joint. The technical requirements for improved knee prostheses are very similar to those for the transgingival zone of dental implants: in both cases, a material with a high mechanical resistance and a hard but topographically very smooth outer surface is sought. Therefore a manufacturer of joint prosthesis (SAMO) will use the know-how that was be acquired in the development of improved dental implants and transfer it to knee prosthesis.
Development of coated ceramics or modified surfaces on implants were run simultaneously by the 3 coating partners (Flametal, JRC, TCL). Fabrication parameters were optimised, so that the surface properties (including adherence, thickness, dimensional precision, colour, roughness, friction, resistance to wear, fatigue and ageing) correspond to specifications for dental implants and knee prostheses. Physical characterisation tests were done at the coating partners' (simple on-site tests), at ICMAB (advanced tests), at STW and SAMO (mechanical tests). The biocompatibility of the coatings were assessed during in vitro tests performed by Biomatech.
At the end of the project, coatings for dental application were developed. All requirements regarding the quality of the coating for dental implants could be fulfilled except the most critical one from the consumer's point of view: The colour is not tooth-like (cream white) or red (gingiva-like).
The second objective of the program (the development of surface treatment in order to limit wear on UHMWPE for knee joint prosthesis) was successfully reached, as considering all surface treatments developed and investigated one was found particularly interesting, magnetron sputtering PVD of CoCrMo, capable of introducing a high degree of innovation on the artificial joint (both knee and hip), and leading great potential benefits inside the European Community, both socially (reduction of wear debris production of UHMWPE leading to a longer life of prosthetic devices) and economically (as such coating has not been studied and developed by any of the major extra European multinational companies).
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