Effect of adhesive materials and polishing technique in amalgam microhardness

Objectives: The aim of this study was to do an “in vitro” evaluation of the microhardness of amalgam bonded margins using different intermediate adhesive materials and polishing techniques. Methods: It was used three adesive materials: Panávia (Kuraray), Relyx (3M/ESPE) and Fuji II LC (GC-Corporation) with Velvalloy (SSWhite). After 24 hours, the specimens, except the control group, were polished with one of the following polishing techniques: P1- prophylactic cup + pumice paste + Robinson brush + zinc oxide paste; P2 - multilaminated bur + P1; P3- abrasive rubber point (brown, green and blue). After superficial treatment and metallographic polishing the margins were delimitated and Vickers microhardness were mensured with Wolpert microhardness device (200g/30s). Results: The medium values were statistically analysed and showed that there was no difference between Fuji II LC (74.53) and Relyx (76.27) and they were superior to Panávia (80.93).The control group (without polishing) (69.47) presented higher values of microhardness, and the groups P1 (78.11) and P2 (78.93) were statistically similars and superiors to P3 (82.46). Conclusions: It could be conclued that the adhesive materials and polishing techniques have influence in margins microhardness of amalgam bonded restorations.