نتایج جستجو برای: ceramic
تعداد نتایج: 23262 فیلتر نتایج به سال:
PURPOSE The aims of the presented study were to define the fracture rate of implant-supported metal-ceramic restorations delivered in private practice, and to identify if a restoration's contact during eccentric mandible movements has any influence on ceramic fracture rates. MATERIAL AND METHODS Within the period from 2005 to 2008, 251 patients, namely 105 men (42%) and 146 women (58%), recei...
PURPOSE To evaluate the effects of hydrofluoric acid etching and Er,Cr:YSGG laser irradiation on the shear bond strength of resin cement to lithium disilicate ceramic. MATERIALS AND METHODS Fifty-five ceramic blocks (5 mm × 5 mm × 2 mm) were fabricated and embedded in acrylic resin. Their surfaces were finished with 1000-grit silicon carbide paper. The blocks were assigned to five groups: 1) ...
BACKGROUND This study aimed to investigate the microshear bond strength of universal bonding adhesives to leucite-reinforced glass-ceramic. METHODS Leucite-reinforced glass-ceramic blocks were polished and etched with 9.5% hydrofluoric acid for 1 min. The specimens were assigned to one of four groups based on their surface conditioning (n = 16): 1) NC: negative control with no further treatme...
In the 1980s and 1990s, the development of oxygen ion conductors for solid electrolytes, as well as mixed oxygen–electron conductors as electrodes for solid oxide fuel cells, brought scientists to envision a possibility of mixed-conducting oxygenpermeable ceramic membranes. Today this field is well established, and ceramic membranes are close to implementation in processes for oxygen extraction...
purpose: the aim of this study was to evaluate the effect of two gingival finishing lines (90° shoulder and deep chamfer) on the marginal fitness of two types of full anatomic all-ceramic crowns; zirconia crowns (zikonzhan) and glass ceramic crowns (ips e-max cad) milled with cad/cam system. materials and methods: two dentoform teeth of left maxillary first molar were prepared with chamfer fini...
The technology of hot-pressed Cr(2+):ZnSe ceramic preparation is reported. Comparative gain-switched lasing of hot-pressed ceramic and CVD grown Cr(2+):ZnSe samples with slope efficiencies up to 10% and output energies up to 2 mJ were demonstrated. This is a milestone in the development of future large scale mid-IR laser systems based on ceramic TM(2+):II-VI materials. This evolving technology ...
All ceramic restorations benefit from resin cement bonding to the tooth. No currently available luting agent is ideal for all situations. The comparison of the bonding ability of different luting cements to ceramic and dentin is thus deemed necessary. The purpose of this study was to evaluate the shear bond strength of different luting cements to both ceramic and dentin and then to evaluate the...
PROF. MOHAMMED YUNUS, DR.J. FAZLUR RAHMAN Abstract— Ceramic coated components have the advantage features of both metal and ceramics, i.e. good toughness, high hardness and wear resistance. Despite their outstanding characteristics, ceramic materials are not used in many cases due to high cost of machining. A major draw back to engineering applications of ceramic is due to their brittleness and...
BACKGROUND Most contemporary total disc replacements (TDRs) use conventional orthopaedic bearing couples such as ultrahigh-molecular-weight polyethylene (polyethylene) and cobalt-chromium (CoCr). Cervical total disc replacements incorporating polyetheretherketone (PEEK) bearings (specifically PEEK-on-PEEK bearings) have been previously investigated, but little is known about PEEK-on-ceramic bea...
BACKGROUND Although ceramic-on-ceramic bearings for total hip arthroplasty (THA) show promising results in terms of bearing-surface wear, fracture of the bearing, insertional chips, and squeaking remain a concern. QUESTIONS/PURPOSES Our primary objective of this report was to determine overall survivorship of a titanium-encased ceramic-on-ceramic bearing couple. Our secondary objectives were ...
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