RESUMEN
Composition, microstructure, mechanical properties, and alloy-porcelain bond strength of two proprietary nickel-chromium-based crown-and-bridge alloys were studied. The materials exhibited compositional as well as microstructural differences. Wiron-S was significantly stronger and harder than Microbond-NP. Microbond-NP yielded alloy-porcelain bond strength values comparable to those of precious alloy-porce-lain combinations.
Asunto(s)
Aleaciones de Cromo , Coronas , Recubrimiento Dental Adhesivo , Porcelana Dental , Dentadura Parcial , Níquel , Fenómenos Químicos , Química Física , Elasticidad , Calor , Estrés Mecánico , Resistencia a la TracciónRESUMEN
Composition, microstructure, castability, mechanical properties, and heat treatment characteristics of two gold-palladium-silver-based alloys were studied. The materials exhibited compositional as well as microstructural differences. Clinically acceptable castings could not be obtained when manufacturers' recommended casting temperatures were used. Ultimate tensile strength, yield strength, modulus of elasticity, and Brinell hardness values for the alloys were comparable. The elastic limit of Cameo, however, was significantly higher than that of vivo-star. Maximum rehardening of annealed castings occurred on reheat treatment at temperatures between 1,200 and 1,300 F. As-cast specimens, however, were not heat hardenable. The sequence of heat treatments used in the application of porcelain reduced slightly the hardness of both alloys. Hardness of the metal substructures was not increased by return of porcelain-coated specimens to a 1,250 F oven for final heat treatment.
Asunto(s)
Restauración Dental Permanente , Aleaciones de Oro/normas , Revestimiento para Colado Dental/normas , Técnica de Colado Dental/normas , Porcelana Dental , Análisis del Estrés Dental , Oro/análisis , Aleaciones de Oro/análisis , Dureza , Calor , Indio/análisis , Paladio/análisis , Tamaño de la Partícula , Plata/análisis , Análisis Espectral , Estaño/análisisRESUMEN
Properties, compositions, microstructures, and heat-treatment characteristics of three high-fusing white ceramic-metal alloys were studied. The materials displayed different compositions and as-cast microstructures, but similar tensile properties and heat-treatment responses. Hardness of cast specimens subjected to the porcelain firing cycle was increased by an additional 20 minute heat treatment at 1,300 degrees F.