Effect of activation mode of dual-cured resin cements on polymerization kinetics, mechanical properties, bond strength and stress generation

Abstract

The aim of this study will be to evaluate the influence of the light-curing and the moment when this is carried on the kinetic and degree conversion, mechanical properties, bond strength and stress generation of three dual-cured resin cements. The methodology of this study will be divided in five parts: kinetic and degree of conversion, flexural strength and elasticity modulus, bonding test, ultimate tensile strength and stress of polymerization shrinkage. The resin cements that will be evaluated are Panavia F, RelyX ARC and Enforce. The modes of activation will be: chemical activation alone, immediate light-curing or after five minutes of the material mixing, both carried through the composite blocks of 2 mm of thickness. The kinetics of conversion evaluation, in first ten minutes, and of the degree of conversion, after 24 hours, will be evaluated with Fourier-transformed infrared (FTIR) spectroscopy connected to an element of attenuated total reflectance (ATR). Specimens with 25x2x2mm will be used for the measurement of the flexural strength and the elasticity modulus of these cements, immediate and after 24 hours. The micro-shear test will be used to measure the bonding, immediate and after 24 hours, of cements. The ultimate tensile strength of cements and the stress generation by polymerization shrinkage will be also evaluated, this last through the photo elasticity method.