Influência do tipo de fotoativação na contração de polimerização de um compósito nano particulado

Abstract

The objective of the present study was to evaluate in vitro the polymerization shrinkage of a nanofill composite Z350® XT (3M/ESPE, ST.Paul, MN, USA), varying two different LED sources, two types of activation and different activation time. Specimens were confectioned on a mold of 6mm of diameter and 2mm of thickness and were divided into three groups (n=3): Group 1: Z350® XT, Demi LED (Kerr, Orange, CA), 5 seconds, pulse activation; Group 2: Z350® XT, Demi LED 20 seconds, pulse activation; Group 3: Z350® XT, LED Demetron (Kerr, Orange, CA), 32 seconds, continuous activation. To measure the polymerization shrinkage, water picnometry was utilized. Non-polymerized and polymerized samples were weighed and, based on water density, polymerization shrinkage of each sample were measured. For statistical analysis, Statgraphics Plus Program was used and Kruskal Wallis test was applied, with 95% of significance (p=0.05). Results showed no difference between groups for the different sources, time or type of activation.