RESUMO
The purpose of this study was to design an optimum glass fiber-reinforced composite (FRC) clasp. Three-dimensional finite element models were constructed of FRC circumferential clasp arms and an abutment tooth. The basic clasp arm was half-oval, without a taper, 2.60 mm wide and 1.30 mm thick. Four modified clasp arms were prepared by changing the width or thickness of the basic clasp (width/thickness: 2.60 mm/0.65 mm, 2.60 mm/1.95 mm, 1.30 mm/1.30 mm, and 3.90 mm/1.30 mm). Forced displacements of 5 mm in the removal direction were applied to the nodes at the base of the clasp arm. The retentive forces and maximum tensile stresses of the five FRC clasp arms ranged from 1.00-16.30 N and from 58.9-151 MPa, respectively. Results showed that an optimum FRC clasp was a circumferential clasp with 2.60 mm width and 1.30 mm thickness, which had sufficient retentive force and low risk of tensile failure.
Assuntos
Resinas Compostas/química , Grampos Dentários , Materiais Dentários/química , Planejamento de Prótese Dentária , Análise de Elementos Finitos , Vidro/química , Dinâmica não Linear , Simulação por Computador , Dente Suporte , Retenção em Prótese Dentária , Falha de Restauração Dentária , Módulo de Elasticidade , Previsões , Humanos , Imageamento Tridimensional/métodos , Modelos Biológicos , Maleabilidade , Estresse Mecânico , Propriedades de SuperfícieRESUMO
The aim of this study was to investigate the effects of water immersion and repeated loading on the mechanical properties of a glass fiber-reinforced composite (FRC) material. Measurements for three-point flexural tests were made at three different temperatures and cross-head speeds, while measurements for fatigue tests were made under three different loads in air or water at 37 degrees C after each cycle. The flexural strength and elastic modulus of the immersed specimens were significantly lower than those of the dry specimens at the same cross-head speed and temperature. On the whole, the values were inferior to those of metal. The deflection increased significantly as the load increased, but there were no significant differences between the values of dry and immersed specimens. With increasing load and number of cycles, the permanent deformation of both specimens increased significantly. The permanent deformation was similar to that of Co-Cr alloy. Based on the results of this study, it is recommended that more effort be devoted to exploring and devising shapes that would render FRC clasp arms with mechanical and physical properties that differ favorably from those of metal.