Chemical and physical evaluation of the luting systems for veneers submitted to accelerated artificial aging

Abstract

To evaluate the effect of accelerated artificial aging (AAA) on chemical and physical properties of four different resin cements and two flowable resins. Forty-eight human incisors were prepared and the IPS Empress Esthetic laminate veneers were fabricated. The samples were randomly divided into the groups: dual-polymerizing cements (RelyX ARC and Variolink II), light-polymerizing cements (RelyX Veneer and Variolink Veneer) or flowable composite resins (Filtek Z350 Flow and Tetric N-Flow). The degree of conversion was determined in a Fourier transform infrared spectroscopy. The first cylinder was measuring the initial bond strength and, the remaining cylinder was submitted to AAA before bond strength test. The fracture pattern was analyzed by stereomicroscopy. The results were analyzed by one-way and two-way split-spot ANOVA/ Tukey's test (α =0.05). There were clinically perceptible color changes for all materials. The degree of conversion, the following decreasing sequence was found: RelyX ARC> Variolink II> RelyX Veneer > Filtek Z350 Flow > Variolink Veneer = Tetric N-Flow. For the microshear bond strength, RelyX ARC = Variolink II > Variolink Veneer = RelyX Veneer > flowable composite resins. AAA induced color change and decreased microshear bond strength for all luting systems evaluated.