Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 13 3 2016 12 31 168 175 EN Masomeh Hasani Tabatabaei Associate Professor, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Farnaz Farahat Assistant Professor, Department of operative dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Elham Ahmadi Assistant Professor, Department of Operative Dentistry, Dental Research Center, Faculty of Dentistry, Tehran University of Medical Sciences, Kargar Ave, Tehran Zahra Hassani Dentist, Private Practice 2015 10 21 2016 04 18 Objectives: The aim of this study was to assess the effect of artificial accelerated aging (AAA) on color change of direct and indirect fiber-reinforced composite (FRC) restorations. Materials and Methods: Direct (Z250) and indirect (Gradia) composite resins were reinforced with glass (GF) and polyethylene fibers (PF) based on the manufacturers’ instructions. Forty samples were fabricated and divided into eight groups (n=5). Four groups served as experimental groups and the remaining four served as controls. Color change (∆E) and color parameters (∆L*, ∆a*, ∆b*) were read at baseline and after AAA based on the CIELAB system. Three-way ANOVA and Tukey’s test were used for statistical analysis. Results: Significant differences were found in ΔE, ΔL*, Δa* and Δb* among the groups after AAA (P<0.05). Most of the studied samples demonstrated an increase in lightness and a red-yellow shift after AAA. Conclusions: The obtained ∆E values were unacceptable after AAA (∆E≥ 3.3). All indirect samples showed a green-blue shift with a reduction in lightness except for Gradia/PF+ NuliteF.   https://fid.tums.ac.ir/index.php/fid/article/view/808 https://fid.tums.ac.ir/index.php/fid/article/download/808/883