Avalia o da resistência à compress o de duas resinas compostas em diferentes espessuras submetidas a diferentes tempos e complementa o de polimeriza o

The aim of this study was to evaluate P60 and Z250 (3M/ESPE) compressive strength in different thickness: 1, 2 and 4mm; light cured in different ways. It was made 180 specimens divided in to 3 groups: A - 1, 2 and 4 mm thickness for each resin (n=10) lightcured by 20s; B - 1, 2 and 4mm thickness for each resin (n=10) ligthcured by 40s; C - 1, 2 and 4 mm thickness for each resin (n=10) lightcured by 20s plus a microwave oven by 5 minutes, at 950W power. Those resins were put inside a cylindrical metal matrix (3mm diameter x 1, 2 or 4 mm high); lightcuring tip was applied in a top side of the specimens. The specimens were tested in a universal testing machine (Versat 500), with axial compressive direction, with 1mm/min speed. The results were analysed by ANOVA, with 5% significance level, that showed statistically significance difference among those groups (P<0,05). Then, it was used Tukey's test, that showed higher compressive strenght for P60 in 1mm thickness, in relation to 2mm, using 20s lightcuring for Z250 resin, high compressive strength was found for 1mm thickness in relation to 2mm and 4mm for 20s lightcuring and 4mm thickness for 40s lightcuring. The microwave oven use, as well as, 40s lightcuring did not turn P60 and Z250 better, in relation to compressive strenght, evaluated in same thickness. P60 and Z250 composite resins did not show statiscally significant difference between them.