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Evaluation of color stability, degree of conversion and shear bond strength of luting systems according to accelerated aging

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Author(s):
Lúcia Trazzi Prieto
Total Authors: 1
Document type: Doctoral Thesis
Press: Piracicaba, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
Defense date:
Examining board members:
Luis Alexandre Maffei Sartini Paulillo; Cíntia Tereza Pimenta de Araújo; Vanessa Castro Pestana da Silveira Bueno; Diogo de Azevêdo Miranda; Giselle Maria Marchi
Advisor: Luis Alexandre Maffei Sartini Paulillo
Abstract

The aim of this " in vitro " study was to evaluate the chemical and physical properties of different resin cements and flowable resin composites used to lute veneers on enamel by color stability and bond strength submitted to accelerated artificial aging, and degree of conversion. Ninety-six extracted human incisors were randomly divided into 6 experimental groups (n = 8), according to the different luting systems evaluated: RelyX Veneer / Single Bond 2 (3M ESPE), RelyX ARC / Single Bond 2 (3M ESPE), Filtek Z350 XT Flowable/ Single Bond 2 (3M ESPE), Variolink Veneer / Tetric N - Bond (Ivoclar Vivadent), Variolink II / Tetric N - Bond (Ivoclar Vivadent) and Tetric N -Flow / Tetric N - Bond (Ivoclar Vivadent), used shade A1. To evaluate the color stability, wears of 0.6 mm thick were performed on labial surface to simulate veneer preparations. Forty-eight IPS Empress Esthetic veneers were cemented according to the experimental groups evaluated. Twenty-four hours after luting procedures the initial color was measured with spectrophotometry (Easyshade-Vita). After accelerated aging by UV-B light for 300 hours (150Kj/min), final color readout was measured. To evaluate the microshear bond strength another 48 human incisors was selected. Two ceramic cylinders (IPS Empress Esthetic) (d=1 mm x 2 mm thick) were lute on the labial enamel surface previous prepared as described before. After twenty-four hours, the first cylinder was coupled to the EZ -test machine for measuring the initial bond strength and, the remaining cylinder was submitted to accelerated artificial aging by light, and before bond strength test. Fracture pattern was analyzed under light microscope. To evaluate the degree of conversion 60 specimens (n=10) of each resin material (5x0.5 mm) were obtained and Fourier transform infrared spectroscopy (FTIR) was used to evaluate the absorption spectra. The data were submitted to ANOVA and Tukey test ('alfa'= 0.05). There was clinically perceptible color change ('delta'E > 3.3) for all materials tested; there were no statistical difference among the color stability of any luting materials. For bond strength test the luting systems single Bond2/ RelyX ARC and Tetric N-Bond/Variolink II showed the highest values when compared to others systems, Tetric N-Bond/Variolink Veneer and Single Bond 2/RelyX Veneer were similar between and superior to flowable resin composites, which showed lowest values. Regarding fracture pattern the dual cured resin cements showed a higher percentage of cohesive fracture patterns on ceramic (62.5%) and the light-cured resin cement and the flowable resin composites, adhesive fracture pattern (50-75%). For the degree of conversion, the following decreasing sequence was found: RelyX ARC>Variolink II>RelyX Veneer>Filtek Z350 XT Flowable>Tetric Flow>Variolink Veneer. For the microshear bond strength Single Bond 2/RelyX ARC=Tetric N-Bond/Variolink II =Tetric N-Bond/Variolink Veneer+Single Bond2/RelyX Veneer >flowable resin composite. Based on the results it was concluded that the luting systems showed great after artificial aging, in relation to microshear bond strength test and the degree of conversion of the dual-cured resin cements obtained better performance compared to light-cured resin materials tested (AU)

FAPESP's process: 11/11937-8 - Evaluation of color stability, degree of conversion and bond strength of luting systems after artificial aging
Grantee:Lucia Trazzi Prieto
Support Opportunities: Scholarships in Brazil - Doctorate