Search results for "Zirconi"
showing 10 items of 413 documents
Prospective study of monolithic zirconia crowns: clinical behavior and survival rate at a 5-year follow-up
2020
Purpose To evaluate the clinical behavior and survival of full coverage monolithic zirconia crowns on posterior teeth over a 5-year follow-up. Methods Fifty patients were recruited and underwent restoration with a Lava Plus monolithic zirconia crown (Lava™ Frame Zirconia, 3M Espe, Germany) on premolars or molars. Patients were monitored over a 5-year follow-up (2014-19), recording any biological and/or mechanical complications; these data were used to estimate the crowns' success rate. Periodontal clinical parameters were recorded (pocket probing depth (PPD), plaque index (PLI), bleeding on probing (BOP), and gingival recession (GR)). Wear to the zirconia crowns and antagonist teeth were al…
Morphology, mechanical properties and thermal degradation kinetics of PMMA-zirconia nanocomposites prepared by melt compounding
2012
Zirconia nanoparticles were synthesized by means of a sol-gel method and embedded in poly(methyl methacrylate) (PMMA) by melt compounding. The zirconia was well dispersed in the PMMA matrix, with only a few clusters, especially for the highest investigated zirconia content. NMR results showed heteronuclear dipolar interactions involving the carbons and the surrounding hydrogen nuclei. The effect of the amount of zirconia, in the range of 1–5!wt%, on the thermomechanical properties and thermal degradation kinetics of PMMA was also investigated by means of dynamic mechanical analysis (DMA), thermogravimetric analyses (TGA), and Fourier-transform infrared spectroscopy (FTIR). The presenc…
Spark plasma sintering of zirconia/nano-nickel composites
2015
Open Access
Fracture strength of endodontically treated lateral incisors restored with new zirconia reinforced rice husk nanohybrid composite
2020
Background This study aimed to compare the fracture strength, fracture pattern and type of fracture of endodontically treated maxillary lateral incisors restored with new zirconia reinforced rice husk nanohybrid composite. Material and Methods Eighty mature permanent maxillary lateral incisors from patients age range of 30-60 years with single canal were selected and randomly divided into: Group 1 – RCT + nanofilled composite (Filtek), Group 2 – RCT + microhybrid composite (Zmack), Group 3 – RCT + new nanohybrid composite (Zr-Hybrid) and Group 4 - Intact teeth (control). Standardized mesio-palatal-distal cavity was prepared, and endodontic treatment was carried out using crown-down techniqu…
Chemical Mimicry: Hierarchical 1D TiO2@ZrO2 Core−Shell Structures Reminiscent of Sponge Spicules by the Synergistic Effect of Silicatein-α and Silint…
2011
In nature, mineralization of hard tissues occurs due to the synergistic effect of components present in the organic matrix of these tissues, with templating and catalytic effects. In Suberites domuncula, a well-studied example of the class of demosponges, silica formation is mediated and templated by an axial proteinaceous filament with silicatein-α, one of the main components. But so far, the effect of other organic constituents from the proteinaceous filament on the catalytic effect of silicatein-α has not been studied in detail. Here we describe the synthesis of core-shell TiO(2)@SiO(2) and TiO(2)@ZrO(2) nanofibers via grafting of silicatein-α onto a TiO(2) nanowire backbone followed by …
Formation of layered titania and zirconia catalysed by surface-bound silicatein
2005
Silicatein immobilised on self-assembled polymer layers using a histidine-tag chelating anchor group retains its hydrolytical activity for the formation of biosilica, and catalyses the formation of layered arrangements of biotitania and biozirconia.
ODS ferritic steels obtained from gas atomized powders through the STARS processing route: Reactive synthesis as an alternative to mechanical alloying
2018
Authors acknowledge ALBA synchrotron (Spain) for the provision of beamtime on the beam line BL22-CLAESS (Proposal 2016081797). Transmission electron microscopy observations were accomplished at Centro Nacional de Microscopía Electrónica, CNME-UCM. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Financial support from Basque Government through the ELKARTEK ACTIMAT 2016 project is also acknowledged.
In situ XRD analysis of the oxide layers formed by oxidation at 743 K on Zircaloy 4 and Zr–1NbO
2000
Abstract Two alloys, having different oxidation behaviour (Zy4 and Zr–1NbO), have been investigated during oxidation at high temperature (743 K) and low oxygen pressure (10 kPa) by in situ X-ray diffraction (XRD). Tetragonal phase content and ‘pseudo-stresses’ on the monoclinic phase have been measured as a function of the oxide layer thickness. The tetragonal phase contents are similar for both alloys and decreased with the oxide layer thickness. Pseudo-stresses were much more compressive on Zr–1NbO alloy, with limited changes at the corrosion kinetics transition. On cooling, the tetragonal fractions do not change, while ‘pseudo-stresses’ decreased in different ways for the two alloys. Wit…
Micro-Raman analysis of the fuel-cladding interface in a high burnup PWR fuel rod
2017
International audience; New insights on the fuel-cladding bonding layer in high burnup nuclear fuel were obtained using micro-Raman spectroscopy. A specimen was specifically prepared from a fuel rod which had been irradiated to an average burnup of 56 GWd.tU-1 in a pressurized water reactor (PWR). Both inner and outer corrosion scale regions were investigated. A 10-15 et956;m thick zirconia bonding layer between fuel and cladding materials which consisted of three distinct regions was observed. Close to the fuel, tetragonal, then monoclinic zirconia was identified as the main phases. Close to the bonding layer-cladding interface, peculiar Raman signals were observed. Similar signals were ob…