DYNAMIC-MECHANICAL ANALYSIS OF HEAT, MICROWAVE AND VISIBLE-LIGHT CURE DENTURE BASE RESINS

The clinical durability and performance of a denture are limited by the properties of the denture base resins used in the fabrication of the prosthesis. Among the properties considered important for denture base resins are viscoelastic properties such as storage modulus, damping and glass transition. In this study, dynamic mechanical analysis using a flexural mode of deformation in the temperature range 25-180 degrees C has been used to characterize the viscoelastic properties of three denture base resins with different curing modes including conventional thermal cure, microwave cure and visible light cure. The resins studied were popular commercial systems. The results indicate that the microwave cure and conventional thermal cure resins are significantly different in their viscoelastic properties from the current visible light cure resin system. The latter resin is characterized by higher flexural modulus and loss modulus across the entire range of temperatures investigated and in addition shows higher glass transition temperature relative to the other resins studied. The results indicate that filler loading and crosslinking effects may be responsible for this behaviour of the visible light cure resin and may indicate a potential brittle behaviour not desirable in a permanent denture.