Methods: The specimen had been confectioned in a bipartite acrylic matrix contends rectangular niches measuring 25mm x 2mm x 2mm as specifications of norm ISO 4049, being 20 of each direct resin and 10 of indirect resin. The samples of direct resins had been polymerized in a conventional way on 600mW/cm, and half of them received an additional polymerization from 180 seconds in oven with stroboscopic light curing unit. The samples of R-A had been curing in the xenon stroboscopic light curing unit according the manufacturer's instructions. The test was carried through on universal testing machine EMIC DL10000 with a crosshead speed of 0,75mm/minute.
Results: The results expressed in MPa and submitted a Tukey's test with the significantly of 5% had indicated that the additional polymerization increased the values of resistance to flexural strength of direct resins, differing statistically of the conventional polymerization.
Conclusions: With the results, we can even though conclude that the best performance was of the R-D resin, overcoming even R-A, what it leads to a reflection concerning the indications of direct resins when submitted to the additional methods of polymerization.