CURE BEHAVIOR OF VISIBLE-LIGHT ACTIVATED DENTAL COMPOSITES .1. ISOTHERMAL KINETICS

During curing of multifunctional methacrylate-based composites for den tal restorations, strong structural changes, significantly affecting t he final properties of the materials, are observed. In fact, the polym erization of thermoset matrices involves the transformation of a visco us liquid in a glassy network. The final glass transition temperature of the composite matrix may be considered a relevant parameter for the durability of a restoration, in this study, the complex cure behaviou r of a commercial dental composite, activated by visible-light, is ana lysed by differential scanning calorimetry (DSC). The maximum degree o f reaction of the crosslinked resin and the characteristic glass trans ition temperature are quantitatively related to the cure temperature. Furthermore, a kinetic model, accounting also for the diffusion contro l effects associated with vitrification, is presented. Finally, the cu re behaviour expected during practical application of these materials in the oral cavity for dental restorations, is discussed.