Thermocycling effect on microhardness of laboratory composite resins

ABSTRACT

The aim of this study was to evaluate the thermocycling effect on microhardness of laboratory composite resins. 30 disks were fabricated, 5 mm of diameter and 2mm of width, using 3 laboratory resins G1 (n=10) - RESILAB MASTER (Wilcos-Brasil), G2 (n=10) - Vita VMLC (VITA Zahnfabrik-Germany), and G3 (n=10) û Vita Zeta (VITA Zahnfabrik-Germany). Vickers microhardness (HV) of all specimens was evaluated using a microhardness tester FM-700 (Future Tech- 50 g/10s). The specimens were measured before and after the thermocycling (3.000 times and 12.000 times - 5º /55ºC±1). The microhardness values before cycling were (mean±SD) G1 55.50±4.6; G2 35.54±2.5; G3 27.97±1.6.; after 3.000 thermocycles G1 55.54±3,9; G2 29.92±2,73; G321.01±1.4 and after 12.000 cycles G154.27±3.2; G2 30.91±1.6. G3 23.81±0.9. Variance analysis (ANOVA) and TukeyÆs test was accomplished (p<0,05), the highest microhardness values were observed in G1; G2 and G3 showed reduction of microhardness values. It was concluded that, after thermocycling, the tested laboratory composites resins are susceptible to the decrease of surface microhardness.The aim of this study was to evaluate the thermocycling effect on microhardness of laboratory composite resins. 30 disks were fabricated, 5 mm of diameter and 2mm of width, using 3 laboratory resins G1 (n=10) - RESILAB MASTER (Wilcos-Brasil), G2 (n=10) - Vita VMLC (VITA Zahnfabrik-Germany), and G3 (n=10) û Vita Zeta (VITA Zahnfabrik-Germany). Vickers microhardness (HV) of all specimens was evaluated using a microhardness tester FM-700 (Future Tech- 50 g/10s). The specimens were measured before and after the thermocycling (3.000 times and 12.000 times - 5º /55ºC±1). The microhardness values before cycling were (mean±SD) G1 55.50±4.6; G2 35.54±2.5; G3 27.97±1.6.; after 3.000 thermocycles G1 55.54±3,9; G2 29.92±2,73; G321.01±1.4 and after 12.000 cycles G154.27±3.2; G2 30.91±1.6. G3 23.81±0.9.