Efeito imediato e tardio da inibição de oxigênio e do acabamento e polimento nas propriedades físico-químicas de resinas compostas convencionais e bulk- fill.

Abstract

Objectives: The aim of this in vitro study was to investigate immediate and delayed effect of oxygen inhibition, finishing and polishing surface procedures on the degree of conversion and shade matching of conventional and bulk-fill composite resins. Materials and methods: Two conventional composite resins, Z350 nanoparticle (Filtek Z350 XT, 3M ESPE) and Z250 microhybrid (Filtek Z250, 3M ESPE), and one bulk-fill composite resin, FP (Filtek Posterior Bulk-Fill, 3M ESPE) were tested in this study. The degree of conversion (DC) of composite resins was monitored using Spectroscopy (FTIR) immediately and then again after 15 days. Shade matching was evaluated using the Spectrophotometer after 24 hours and then again after 15 days of challenge with immersion of cofee. The specimens were divided into 12 groups, according the type of composite resin, finishing and polishing surface procedures and moment of analysis (n=5). The data were statistically analyzed using two-way ANOVA, Tukey’s and Dunnet tests ( = 0.05). DC data passed by Shapiro-Wilk normality test and by equality of variance. Two-way repeated measures ANOVA and Tukey's test (p <0.05) were then applied. Opacity data were tested on the Shapiro-Wilk normality test and equality of variance. Then, Two-way repeated measures ANOVA and Tukey's test (p <0.05) were applied. Results: Surface treatment had an influence on conversion composite degree for all composites analyzed. Bulk-fill show higher Δa than others composites and finishing and polishing can reduce this parameter. Finishing and polishing procedures can reduce Δb especially on bulk fill and nanoparticles resins. There was a difference in the opacity of the composite resins, regardless surface treatment. Microhybrid composite showed higher opacity, followed by nanoparticle and bulk-fill and *L variation was higher to nanoparticle followed by bulk-fill and microhybrid resin and finishing and polishing resulted on the least ΔL. Conclusion: The oxygen inhibition can increases the conversion degree of composites resins tested and immediately finishing and polishing procedures associating with previous oxygen inhibition can reduce the color variation (ΔE) after immersion of coffee.