Accelerated Aging Effects on Color Change, Translucency Parameter, and Surface Hardness of Resin Composites

Abstract

Background. The aging process can induce a change in the surface microstructure of materials, the chemical compositions of matrices, and the filler particles of resin composites. This study is aimed at evaluating the effects of accelerated artificial aging (AAA) on the color change, translucency parameter (TP), and surface hardness of resin composites. Methods. Five resin composite materials (Tetric N-Ceram, Filtek Z250, Charisma Smart, Herculite Classic, and Escom100) were evaluated. A spectrophotometer was used for color measurements ( $L\ast$ , $a\ast$ , and $b\ast$ ). TP and color changes ( $\Delta E_{00}$ ) were calculated using the CIEDE2000 formula. The resin materials were subjected to aging for 300 hours. The hardness and TP values were measured before and after AAA. One- and two-way ANOVA and the Tukey test were used. The significance level was accepted as $p<0.05$ . Results. Escom100 had significantly higher $\Delta E_{00}$ values than the other resin composites, and Charisma Smart had significantly lower $\Delta E_{00}$ values than the other tested materials ( $p<0.05$ ). Before and after AAA, Charisma Smart had the lowest TP values, and Filtek Z250 exhibited the highest hardness values ( $p<0.05$ ). For TP and surface hardness, the effect size value of the composite material was found to be higher than that of AAA. Conclusions. After AAA, the investigated resin composites had $\Delta E_{00}$ values that were above clinically acceptable thresholds. After aging, the tested materials generally exhibited decreases in $L\ast$ values and $a\ast$ values, while increases in $b\ast$ values were observed. The ΔTP values of the resin composites were similar. AAA significantly increased the surface hardness of the tested materials.