Superfine powders of poly (methyl methacrylate) (PMMA) have been prepared by means of an emulsion polymerization method. These have been used as templates in the synthesis of tetragonal phase mesoporous zirconia by the sol-gel method, using zirconium oxychloride and oxalic acid as raw materials. The products have been characterized by infrared spectroscopy, X-ray diffraction analysis, transmiss...

The wear performances of bovine tooth enamel (BTE) against translucent tetragonal zirconia polycrystals (TZP) compared to that of feldspar porcelain and the influence of surface treatments of translucent TZP were investigated by the two-body wear test. Translucent TZP and feldspar porcelain were used as hemisphere abrader specimens with a radius of curvature of 5 mm; flat BTE surfaces were used...

BACKGROUND The potential transfer of engineered nanoparticles (ENPs) from plants into the food chain has raised widespread concerns. In order to investigate the effects of ENPs on plants, young cabbage plants (Brassica oleracea) were exposed to a hydroponic system containing yttrium oxide (yttria) ENPs. The objective of this study was to reveal the impacts of NPs on plants by using K-edge subtr...

PURPOSE The purpose of this in vitro research project was to evaluate and compare the wear behavior of human tooth enamel opposing monolithic zirconia and other different ceramic restorative materials and also to observe the tetragonal to monoclinic phase transformation in zirconia-based ceramics that may occur while simulating wear occurring at room temperature in a wet environment. MATERIAL...

The objective of this study was to establish the mechanism(s) controlling degradation of yttria-tetragonally-stabilized zirconia (Y-TZP) powder in aqueous suspensions and determine the significance of this degradation to the aqueous physical chemistry of Y-TZP. Experiments were performed on commercially available Y-TZP powder placed in aqueous suspensions at 25°C. Experimental investigations in...

a r t i c l e i n f o Using first-principles calculations, we have carried out a systematic comparative study of the microscopic atomic defect configurations in cubic and tetragonal yttria-stabilized zirconia (YSZ) and their correlation with the macroscopic lattice parameters and relative phase stability, as a function of Y concentration. We found that Y atoms sit at the second-nearest-neighbor...

objectives : because of poor bond between resin cement and zirconia ceramics, laser surface treatments have been suggested to improve adhesion. the present study evaluated the effect of co 2 and nd:yag lasers on the shear bond strength (sbs) of resin cement to zirconia ceramic. materials and methods : ninety zirconia disks (6×2 mm) were randomly divided into six groups of 15. in the control gro...

Zirconia femoral heads retrieved from patients after different implantation periods (up to 13 years) were analysed using vertical scanning interferometry, atomic force microscopy and Raman microspectroscopy. A range of topographical and compositional changes on the surface of the retrievals are reported in this work. The study revealed that changes in roughness are the result of a combination o...