Avaliação de grau de conversão e propriedades mecânicas de compósito comercial com sistema APS (Advanced Polymerization System) de polimerização..

Abstract

The present study evaluated the degree of conversion and mechanical properties of a new commercial composite with advanced polymerization system (VT: Vittra APS - FGM) in comparison to four conventional composite resins (AU: Aura – SDI; Estelite Quick Sigma- TOKUYAMA; FZ: Filtek Z350 XT – 3M ESPE; OP: Opallis - FGM). Degree of conversion (DC, n = 3), immediately and after 24 h, was evaluated by FTIR spectroscopy; for Knoop hardness number (KHN, n = 3), indentations were performed at the top and base of 2 mm thick specimens; for measurement of the flexural strength (FS, n = 10), threepoint method in a universal test machine was used and polymerization stress (PS) was determined by photoactivation of material (1.0 mm height) between sticks of PMMA in universal testing machine. Photoactivation was performed with Valo Cordless LED (1,000 mW / cm2 x 20 s: 20J). Results were analyzed through ANOVA and complemented by Tukey's test (α = 0.05). The highest DC values (immediate and 24h) were observed for VT and OP resins, followed by FZ, AU and ES. FZ resin (top and base) showed the highest values of KHN, similar to the top of VT. The resins AU, ES, OP and VT presented statistically different KHN among their base top surfaces. The highest FS values were observed for FZ, followed by OP / VT, ES and AU. The highest PS values were observed for FZ, OP and VT. Based on the results, it can be concluded that the APS resin presented satisfactory results. However, it was not able to be superior to the Opallis resin (from the same manufacturer) and the resin used as a positive control, in this case the Z350 XT resin in all tests. However, for the proposals given by the manufacturer of greater manipulation under light of the reflector, lower concentration of CQ and greater mechanical properties considered advantages of the APS system, further studies should be performed.