Mensuration of the polimerization shrinkage of composites through scanning electron microscope

Abstract

This study evaluated three different brands of composite resins on the slot resulting from the polymerization contraction: Esthet X (Dentsply); Filtek Z350 (3M / ESPE); Concept (Vigodent), all of them in color A3. Composites were placed in a metal matrix with 7mm in internal diameter and 2mm in height, being pressed between 2 glass plaques and photopolymerized for 40 seconds in one of the surfaces with a polymerization system by halogen light XL 3000 (3M/ESPE) to 500 +/- 10 mW/cm2. After that, it was polished in politriz, metallized in gold and taken for analysis of the slot resultant of the polymerization contraction in a scanning electron microscope (SEM, Philips XL30). Four measurements were made for each body of evidence in areas corresponding to 3, 6, 9 and 12 hours. The results were submitted to one-way ANOVA and Tukey’s test, at the signifi - cance level of 5%. The results showed the following average values for the contraction slots of composites: Concept (35.77 µm); Esthet X (22.01 µm); Filtek Z350 (17.95 µm). It demonstrates that Con group was statistically different from the others presenting a bigger average contraction gap. Based on the results it was possible to conclude that Concept composite presented the biggest polimerization contraction when compared with Esthet-X and Filtek Z350.