Hardness of composite resins of different colors, at distinc depths, photoactivated by different light-curing units.

Abstract

The aim of this work is evaluate the hardness of composite resins of different colors and depths (top and base) when light-cured with different light-curing units. Two composite resins with different colors and opacities were selected (Filtek Supreme A1E – 3M-Espe, Filtek Supreme A3D – 3M-Espe) and four LED light-cure equipments (Ultra Blue Is 600/DMC - 450 mW/cm2; Optilight LD III/Gnatus - 250 mW/cm2; Ultraled/Dabi Atlante - 250 mW/cm2; Radii/SDI - 700 mW/cm2). Resins were inserted into the nylon polymer matrix (diameter: 5mm, thickness: 3mm) in two increments with 1,5 mm each and light-cured during 20s to each potion. The 24 specimens (sp) were flattened with silicon carbide paper and polished with felt disc. The sp were submitted to Vickers hardness analysis on the “top” and “base”, 4 measures in each surface. The mean of measurements for each sp were calculated and submitted to Variance analysis and Tukey. The hardness of specimens vary according to color of material and utilized equipment. Equipments Raddi and Ultra Blue IS promoted the highest values of hardness. Composite resins presented higher hardness on top than in base and, mainly in the base, the composite resin with highest translucency presented higher hardness than opaque composite resin. Key words: composite resins, hardness, color.