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During resin-bonding procedures, dentin surfaces are treated with acidic conditioners to remove the smear layer and decalcify the surface to expose the collagen fibrils of the underlying matrix. These decalcified surfaces are then either air-dried or treated with dehydrating solvents, procedures which may modify the physical properties of the dentin matrix.(More)
The purpose of this study was to determine stress corrosion fatigue characteristics of Optec-hsp porcelain. Disks (1 mm thick and 12 mm in diameter) were prepared according to the manufacturer's firing recommendations. Samples were subjected to dynamic loading at multiple constant stressing rates. Dynamic fatigue was measured using a biaxial flexural(More)
The self-glazing technique provides an esthetic and hygienic surface for crowns and fixed partial dentures that use porcelain veneers. A study of the biaxial flexure strengths of polished vs. glazed specimens is needed to verify that current laboratory methods are appropriate for planned fatigue studies. Four groups of 50 porcelain disk specimens each were(More)
The mechanism of formation of nodular material on the surface of a Pd-Ag-based alloy for porcelain during pre-porcelainization heat treatment was investigated using scanning electron microscopy, x-ray diffraction, quantitative metallography, and Auger electron spectroscopy. The nodules were found to form by a Nabarro-Herring creep mechanism driven by the(More)
Bonding between porcelain and dental ceramic alloys is thought to be dependent upon the establishment of a continuous electron structure across the ceramic-metal interface (Pask, Proc. Porcelain Enamel Inst.,33,1,1971). Such a structure most likely results from the compatibility of metal ions at the metal surface saturated in an oxide form with the complex(More)
This study evaluated the microleakage of various restorative materials placed in root surfaces. A minimum of 20 freshly extracted single-rooted teeth were used for each combination of restorative materials. Four preparations were made on the root surface and each restored with a different material. After thermocycling in dye, the root was cut transversely(More)
Twenty-four maxillary anterior composite restorations from a clinical study of resin coating were examined at the time of baseline evaluation and at 23 months; electroplated positive replicas, impression negative replicas, and SEMs were used for evaluation. Coated restorations had smooth surfaces after 23 months, in comparison with rough surfaces of(More)
Several studies (Sherrill and O'Brien, 1974; Southan and Jørgensen, 1974; Jones, 1983) have shown that stress corrosion fatigue occurs in dental porcelains. Morena et al. (1986) reported on an assessment of slow crack growth parameters for dental ceramics. The purpose of the study reported here was to evaluate the fatigue parameters of a model experimental(More)
Certain conclusions may be made on the basis of this study. 1) The effects of alloy, porcelain, and alloy-porcelain interaction on the temperature differential required to induce porcelain crazing are significant. 2) The effect of porcelain is the most significant determinant of delta T values. 3) Under thermal shock conditions, the crazing resistance of(More)