Pour les tout petits

Fredel B., Toudy H. Pour les tout petits. In: Manuel général de l'instruction primaire : journal hebdomadaire des instituteurs. 71e année, tome 40, 1904. p. 137

Influence of laser texturing on surface features, mechanical properties and low-temperature degradation behavior of 3Y-TZP

cited By 0This study aims to investigate the influence of different laser surface texturing parameters on Low-Temperature Degradation and mechanical properties of Yttria-tetragonal zirconia polycrystals (3Y-TZP), focused on biomedical applications. The roughness resulted from laser irradiation was characterized by Ra, Rt, Rsk and Rku parameters, as well by SEM analysis. Wettability tests were conducted as a guide to evaluate the ability of the textures to promote osseointegration. Eleven groups of samples were created, such as five according to the laser parameters used, three correspond to the thermal treatments performed and three as different standards. After laser irradiation, all 3Y-TZP samples became black having their whiteness recovered by thermal treatments, which was measured by color analysis. X-Ray photoelectron spectroscopy was used to evaluate chemical changes, presenting the formation of zirconium sub-oxides. These results were corroborated by wettability tests, which exhibited a decrease in surface energy after thermal treatments. Mechanical strength was evaluated by B3B tests, which reveals the potential of laser irradiation combined with thermal treatments for enhancing 3Y-TZP bending resistance and reliability. LTD was accessed by XRD and reveled laser irradiation as a promising approach able to improve the resistance of 3Y-TZP to this phenomenon. © 2019 Elsevier Ltd and Techna Group S.r.l

Inhibition of multi-species oral biofilm by bromide doped bioactive glass

Bioactive glass is an attractive biomaterial that has shown excellent osteogenic and angiogenic effects for oral bone repairing procedures. However, anti-biofilm potential related to such biomaterial has not been completely validated, mainly against multispecies biofilms involved in early tissue infections. The aim of the present study was to evaluate the anti-biofilm effect of 58S bioactive glass embedding calcium bromide compounds at different concentrations. Bioactive glass containing 0, 5, or 10wt% CaBr2 was synthesized by alkali sol-gel method and then characterized by physco-chemical and scanning electron microscopy (SEM). Then, samples were tested by microbiological assays using optical density, real time q-PCR, and SEM. Bioactive glass particles showed accurate chemical composition and an angular shape with a bimodal size distribution ranging from 0.6 to 110 μm. The mean particle size was around 29 μm. A significant anti-biofilm effect was recorded for 5wt% CaBr2-doped bioactive glass against S. mitis, V. parvula, P. gingivais, S. gordoni, A. viscosus, F, nucleatum, P. gingivais. F. nucleatum and P. gingivalis. Such species are involved in the biofilm structure related to infections on hard and soft tissues in the oral cavity. The incorporation of calcium bromide into bioactive glass can be a strategy to enhance the anti-biofilm potential of bioactive glasses for bone healing and infection treatment. Key words: Bioactive glass, anti-biofilm, bromide, sol-gel synthesis, bone infection, bone healingstatus: publishe

Chitosan/β-TCP composites scaffolds coated with silk fibroin: a bone tissue engineering approach

Bone regeneration and natural repair are long-standing processes that can lead to uneven new tissue growth. By introducing scaffolds that can be autografts and/or allografts, tissue engineering provides new approaches to manage the major burdens involved in this process. Polymeric scaffolds allow the incorporation of bioactive agents that improve their biological and mechanical performance, making them suitable materials for bone regeneration solutions. The present work aimed to create chitosan/beta-tricalcium phosphate-based scaffolds coated with silk fibroin and evaluate their potential for bone tissue engineering. Results showed that the obtained scaffolds have porosities up to 86%, interconnectivity up to 96%, pore sizes in the range of 60â 170 µm, and a stiffness ranging from 1 to 2 MPa. Furthermore, when cultured with MC3T3 cells, the scaffolds were able to form apatite crystals after 21 d; and they were able to support cell growth and proliferation up to 14 d of culture. Besides, cellular proliferation was higher on the scaffolds coated with silk. These outcomes further demonstrate that the developed structures are suitable candidates to enhance bone tissue engineering.The authors especially acknowledge financial support from Coordenaç˜ao de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)—PVE/Project 407035/2013-3. This work was also financially sup ported by Portuguese FCT (PD/BD/135247/2017, SFRH/BPD/93697/2013, SFRH/BPD/100760/2014), PhD programme in Advanced Therapies for Health (PATH) (PD/00169/2013), FCT R&D&I projects with references PTDC/BII-BIO/31570/2017, PTDC/CTM-CTM//29813/2017, PTDC/BII-BIO/28870/2017 and R&D&I Structured Projects with reference NORTE-01-0145-FEDER-000021