Resumo (EN)
Objective – This study evaluated the influence of toothbrushing and thermal cycling on surface roughness and weight alterations of four different composite resins. Methods – Five specimens of two nanofilled composites (Filtek Supreme and Esthet X), one submicron composite (spherical filler) (Palfique Estelite) and one microhybrid composite (irregular filler) (Filtek Z250/3M ESPE), were prepared according to the manufacturer’s directions. Each specimen was thermal cycled 1,200 times and subjected to 40,000 toothbrushing cycles. At baseline and after thermal cycling and tootbrushing cycles, surface roughness and weight were determined. Results – After thermal cycling and toothbrush abrasion no statistically significant difference in weight was found, however, the Esthet X and Palfique Estelite showed decrease in weight while Filtek Supreme and Z250 showed increase in weight. The surface roughness increased after thermal cycling and toothbrushing (p<0.01). The spherical submicron filler (Palfique Estelite) showed the smoothest surface. Conclusion – According to the methodology applied in this study, all resins studied showed resistance to abrasion, however, Palfique Estelite after the tests showed the smoothest surface.