RESUMO
A fiberglass-reinforced composite resin (FRP) block using a plain woven fiberglass sheet for CAD/CAM has been introduced in dental practice. The aim of the present study was to evaluate the effects of the fiberglass sheet orientation on the flexural properties of an FRP block. The flexural properties of five types of fiberglass sheet-assigned specimens were examined using a three-point bending test. A one-way analysis of variance revealed that the orientation of fiberglass sheet significantly influenced the flexural strength, 0.2% yield strength, and flexural modulus. The values of the flexural properties of the FRP were the largest when the fiberglass sheets were perpendicular to the applied force, and the smallest when the fiberglass was parallel to the same. The flexural properties of the FRP block were anisotropic and they were significantly influenced by the orientation of fiberglass sheet.
Assuntos
Resinas Compostas , Resistência à Flexão , Vidro , Teste de Materiais , Maleabilidade , Estresse MecânicoRESUMO
The aim of this study was to investigate the bond strength of dental porcelain and the preheated Zr-14Nb alloy, and compare this strength with that of titanium. White oxide layers, which were predominantly composed of monoclinic zirconia, were formed on the preheated sample groups, and exhibited a greater roughness than the control samples. At the metal-ceramic interface, a greater Nb diffusion range was observed than in the control samples. The bond strengths of the samples subjected to 20min preheating treatment were the lowest (33.6 ± 3.2 MPa), which may be ascribed to the formation of a brittle thick oxide layer under excessive heat treatment. The samples subjected to this heat treatment for 5 min exhibited the highest mean bond strength (43.7 ± 5.9 MPa), which was significantly higher than that of titanium (35.3 ± 3.5 MPa). Thus, the Zr-14Nb alloy is a promising candidate for fixed dental prosthesis, as long as the appropriate treatment conditions are adopted.
