Interaction of bone-dental implant with new ultra low modulus alloy using a numerical approach

Although mechanical stress is known as being a significant factor in bone remodeling, most implants are still made using materials that have a higher elastic stiffness than that of bones. Load transfer between the implant and the surrounding bones is much detrimental, and osteoporosis is often a consequence of such mechanical mismatch. The concept of mechanical biocompatibility has now been considered for more than a decade. However, it is limited by the choice of materials, mainly Ti-based alloys whose elastic properties are still too far from cortical bone. We have suggested using a bulk material in relation with the development of a new beta titanium-based alloy. Titanium is a much suitable biocompatible metal, and beta-titanium alloys such as metastable TiNb exhibit a very low apparent elastic modulus related to the presence of an orthorhombic martensite. The purpose of the present work has been to investigate the interaction that occurs between the dental implants and the cortical bone. 3D finite element models have been adopted to analyze the behaviour of the bone-implant system depending on the elastic properties of the implant, different types of implant geometry, friction force, and loading condition. The geometry of the bone has been adopted from a mandibular incisor and the surrounding bone. Occlusal static forces have been applied to the implants, and their effects on the bone-metal implant interface region have been assessed and compared with a cortical bone/ bone implant configuration. This work has shown that the low modulus implant induces a stress distribution closer to the actual physiological phenomenon, together with a better stress jump along the bone implant interface, regardless of the implant design

Long-Term Alterations of Cytokines and Growth Factors Expression in Irradiated Tissues and Relation with Histological Severity Scoring

PURPOSE: Beside its efficacy in cancer treatment, radiotherapy induces degeneration of healthy tissues within the irradiated area. The aim of this study was to analyze the variations of proinflammatory (IL-1α, IL-2, IL-6, TNF-α, IFN-γ), profibrotic (TGF-β1), proangiogneic (VEGF) and stem cell mobilizing (GM-CSF) cytokines and growth factors in an animal model of radiation-induced tissue degeneration. MATERIALS AND METHODS: 24 rats were irradiated unilaterally on the hindlimb at a monodose of 30 Gy. Six weeks (n=8), 6 months (n=8) and 1 year (n=8) after irradiation the mediators expression in skin and muscle were analyzed using Western blot and the Bio-Plex® protein array (BPA) technology. Additional histological severity for fibrosis, inflammation, vascularity and cellularity alterations scoring was defined from histology and immnunohistochemistry analyses. RESULTS: A significant increase of histological severity scoring was found in irradiated tissue. Skin tissues were more radio-sensitive than muscle. A high level of TGF-β1 expression was found throughout the study and a significant relation was evidenced between TGF-β1 expression and fibrosis scoring. Irradiated tissue showed a chronic inflammation (IL-2 and TNF-α significantly increased). Moreover a persistent expression of GM-CSF and VEGF was found in all irradiated tissues. The vascular score was related to TGF-β1 expression and the cellular alterations score was significantly related with the level of IL-2, VEGF and GM-CSF. CONCLUSION: The results achieved in the present study underline the complexity and multiplicity of radio-induced alterations of cytokine network. It offers many perspectives of development, for the comprehension of the mechanisms of late injuries or for the histological and molecular evaluation of the mode of action and the efficacy of rehabilitation techniques

Chirurgie périradiculaire (données actuelles)

NANCY1-Bib. numérique (543959902) / SudocSudocFranceF

Environnement anatomique des dents de sagesse maxilliaires et mandibulaires. Protocoles chirurgicaux.

NANCY1-Bib. numérique (543959902) / SudocSudocFranceF

Apport de l'implantologie en secteur irradié

NANCY1-SCD Pharmacie-Odontologie (543952101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Comblement sinusien à visée implantaire (techniques chirurgicales et matériaux de comblement)

Les résorptions osseuses physiologiques ou simplement post-extractionnelles sont susceptibles d'entraîner des défauts osseux quantitatifs et qualitatifs, notamment au niveau du maxillaire supérieur, en regard du sinus maxillaire. Or, un volume osseux insuffisant contre-indique une réhabilitation implanto-portée pour des raisons chirugicales mais également prothétiques. Pour pallier le manque de tissu osseux, des greffes osseuses, après un bilan pré-chirurgical ne révélant pas de contre-indication, peuvent être proposées au patient. Deux techniques de comblement sinusien seront exposées dans cet ouvrage : la technique par voie d'abord latérale avec utilisation de la piézo-chirurgie, et la technique par voie d'abord crestale avec utilisation d'ostéotomes. Actuellement, différents matériaux de comblement, naturels ou synthétiques, peuvent être utilisés. Les techniques d'ingénierie tissulaire permettront à l'avenir de trouver une alternative aux greffes osseuses classiques grâce aux facteurs biologiques de croissance osseuse.NANCY1-SCD Pharmacie-Odontologie (543952101) / SudocSudocFranceF

Intérêt et évolution des différents examens complémentaires radiologiques en implantologie

NANCY1-SCD Pharmacie-Odontologie (543952101) / SudocPARIS-BIUM (751062103) / SudocNANCY1-Bib. numérique (543959902) / SudocSudocFranceF