Effect of Chlorinated Water on the Color Stability of Different Resin Composites: An In Vitro Comparative Study

Abstract

Objective: This study evaluated the effect of chlorinated water on the color stability of different resin composites, simulating prolonged exposure experienced by frequent swimmers. Materials and Methods: Sixty disk-shaped samples of microhybrid (Arabesk Top), nanohybrid (Grandio) and Ormocer-based (Admira Fusion) composites (n = 20) were prepared. Each group was randomly divided into two subgroups, immersed in either chlorinated (approximate to 3.5 ppm) or distilled water. Spectral reflectance was measured at baseline, 2 weeks, and 2 months using a Datacolor 600 spectrophotometer, and CIE L*a*b* coordinates were calculated using the 2 degrees standard observer. Color stability was assessed with CIEDE2000 (Delta E-00) and the Whiteness Index for Dentistry (WID). Two-way MANOVA analyzed the effects of composite type, storage medium, and their interaction with Bonferroni-adjusted post hoc tests (alpha = 0.05). Results: All Delta E-00 and Delta WID values were below the acceptability thresholds, though several exceeded perceptibility. Composite type and storage medium significantly influenced Delta E-00 and Delta WID (p < 0.05) with interactions. Overall, at 2 weeks, Admira (p < 0.001) and Grandio (p = 0.008) showed greater Delta E-00 in chlorine; Admira exhibited higher Delta WID in chlorine than control (0-2 m p = 0.001; 2 w-2 m p < 0.001). Conclusion: Chlorinated water caused greater short-term discoloration in the Ormocer-based composite, whereas the nanohybrid showed superior long-term stability. The microhybrid composite presented progressive Delta E-00 increase with highest Delta WID.