The influence of polymerization conditions on color stability of three indirect composite materials

Abstract

The aim of the present study was to evaluate color change and color stability against aqueous media of three indirect composite materials (Epricord, Estenia, and Twiny) that were polymerized with different systems. Disk-shaped specimens were prepared with their proprietary polymerization systems or with a metal halide light polymerization unit (Twinkle X). The specimens were then immersed in water or tea. Change in color from baseline (24 h) to 4 weeks was determined with a chromameter (ShadeEye NCC) using a white background. The L*, a*, and b* values for both states were determined, and ΔE*_ab values were calculated. The Estenia specimens immersed in tea had significantly lower ΔL* (-7.0 to -5.6) and significantly higher ΔE*_ab values (6.5 to 8.6) than did the Epricord and Twiny specimens, under all polymerization conditions. The results indicate that after tea immersion the Estenia material was less stable against color change than were the other two materials. The Twinkle X metal halide unit was suitable for polymerization of the three composite materials, using an exposure period of 60 s or longer. (J Oral Sci 55, 51-55, 2013)