نتایج جستجو برای: zirconia
تعداد نتایج: 6536 فیلتر نتایج به سال:
Nitration of toluene has been studied in the liquid phase over a series of modified zirconia catalysts. Zirconia, zirconiaceria (Zr0.98Ce0.02)O2, sulfated zirconia and sulfated zirconiaceria were synthesised by co precipitation method and were characterised by X-ray diffraction, BET surface area, Infra red spectroscopy analysis (FTIR), Thermogravimetric analysis (TGA), Scanning Electron Microsc...
By excluding metals from synthesis, growth of carbon nanostructures via unreduced oxide nanoparticle catalysts offers wide technological potential. We report new observations of the mechanisms underlying chemical vapor deposition (CVD) growth of fibrous carbon nanostructures from zirconia nanoparticles. Transmission electron microscope (TEM) observation reveals distinct differences in morpholog...
This study evaluates tensile bond strength (TBS) of metal orthodontic attachments to sandblasted feldspathic porcelain and zirconia with various bonding protocols. Thirty-six (36) feldspathic and 36 zirconia disc samples were prepared, glazed, embedded in acrylic blocks and sandblasted, and divided into three groups according to one or more of the following treatments: hydrofluoric acid 4% (HF)...
+*Clarke, I C, Brown, S, Pezzotti, G, Green, D D, T. Donaldson, T D +Loma Linda University, Loma Linda, CA [email protected] INTRODUCTION The feature that makes yttria-stabilized, tetragonal zirconia polycrystalline (Y-TZP) ceramic both strong and fatigue resistant is its ability to partially transform under stress from tetragonal phase to its monoclinic phase, i.e. an inherent metastability [1]....
This study focuses on titanium implants in a conventional manner and the newly introduced and highly popular Zirconia implants. Some of the major areas covered here are clinical considerations and material science which includes implant materials as well as the impacts of its physical properties on outcomes of the treatment. Titanium is the gold standard for dental implants fabrication in spite...
It is acknowledged that cellular responses are highly affected by biomaterial porosity. The investigation of this effect is important for the development of implanted biomaterials that integrate with bone tissue. Zirconia and alumina ceramics exhibit outstanding mechanical properties and are among the most popular implant materials used in orthopedics, but few data exist regarding the effect of...
OBJECTIVE The aim of this study was to compare the initial stability as insertion and removal torque and the clinical applicability of novel orthodontic zirconia micro-implants made using a powder injection molding (PIM) technique with those parameters in conventional titanium micro-implants. METHODS Sixty zirconia and 60 titanium micro-implants of similar design (diameter, 1.6 mm; length, 8....
Cast metal post-core systems have a long history of successful use because of their superior physical properties. However, their high elastic modulus can cause stress concentrations within the surrounding radicular dentin, resulting in root fractures. Moreover, the increasing demand for more esthetically appealing and biocompatible restorations has led to the development of tooth-colored, trans...
Zirconia is a relatively new material with many promising practical applications in medical imaging, biolabeling, sensors, and other fields. In this study we have investigated lanthanide and niobium doped zirconia by luminescence and XRD methods. It was proven that charge compensation in different zirconia phases determines the incorporation of intrinsic defects and activators. Thus, the struct...
This in vitro study was conducted to evaluate the shear bond strength of "non-self-adhesive" resin to dental zirconia etched with hydrofluoric acid (HF) at room temperature and to compare it to that of air-abraded zirconia. Sintered zirconia plates were air-abraded (control) or etched with 10%, 20%, or 30% HF for either 5 or 30 min. After cleaning, the surfaces were characterized using various ...
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