Efeito da fonte de luz de alta intensidade na contração pós-gel em resinas de polimerização rápida: análise por extensometria elétrica

Abstract

The aim of this study was to evaluate the effect of the photopolymerization technique on the post-gel shrinkage of composite resins. The study was developed using a polywave LED light source (Bluephase Powercure – Ivoclare Vivadent, Schaan, Liechtenstein). Two types of resin composite were used: 1. conventional bulk fill (Tetric N-Ceram Bulk Fill – Ivoclare Vivadent, Schaan, Liechtenstein); and 2. ultra-fast curing bulk fill (Tetric Powerfill – Ivoclare Vivadent, Schaan, Liechtenstein). The materials were cured according to the manufacturer's instructions: 20s at the high-power mode (Tetric N-Ceram) and 3s at the maximum power (Tetric Powerfill). The linear post-gel shrinkage was obtained by extensiometry (n=5). The tip of the light source was kept 1 mm away from the composite surface and the deformation values were collected for 5 min. Data analysis was performed with a significance level of 5%. One-way ANOVA and Tukey's tests were used. Regarding the results obtained, it was found that the tested resins demonstrated a significant difference in post-gel contraction (p=0.032), with the ultra-fast polymerization resin presenting the lowest values.