Influence of Different Immersion Media on the Color Stability of Resin-Based Composites

Abstract

ABSTRACT Background: Color instability continues to be a major reason for replacing composite restorations. Sports and energy drinks contain low pH, artificial colorants, and high sugar levels; however, their impact on universal-shade resin-based composites (RBCs) is still not well understood. Materials and Methods: Seventy-two disc-shaped specimens (10 mm diameter × 1 mm thickness; n = 12 per group) of two universal-shade RBCs, Omnichroma (Tokuyama Dental) and Transcend Universal (Ultradent Products), were fabricated and light-cured at a verified irradiance of 873 mW/cm² for 20 seconds. Pre-immersion measurements served as individual reference baselines per ISO 4049:2019. Specimens were immersed in C4 Energy Drink (Bombsicle), Gatorade (Lemon Lime), or water for 1, 3, and 7 days. Color was measured using a Konica Minolta CM-700d spectrophotometer with a custom silicone putty jig and a 3 mm aperture of the spectrophotometer. Data were recorded with SpectraMagic NX2 software. Overall color change was calculated as ΔE₀₀ (CIEDE2000), and data were analyzed by three-way ANOVA with Tukey HSD post-hoc comparisons (α = .05). Results: Composite type, immersion medium, and time point each significantly affected ΔE₀₀ (all p < .001). Transcend showed greater overall color change than Omnichroma (1.942 ± 0.056 vs. 1.603 ± 0.056; p < .001). C4 and Gatorade produced comparable ΔE₀₀ values (both significantly greater than water) but opposite chromatic shifts along the b* axis: Gatorade toward yellow (Δb* ≈2.4) and C4 toward blue (Δb* ≈−2.2). Transcend in both beverages exceeded the 100:0% acceptability threshold (ΔE₀₀ ≈ 3.6) by Day 7; Omnichroma remained within the moderate-match range. Conclusions: Both composites showed measurable, progressive discoloration. Omnichroma outperformed Transcend in color stability, a difference driven by its hydrophobic UDMA-based matrix and structural-color filler mechanism, also water sorption induced plasticization. Beverages producing similar ΔE₀₀ magnitudes can cause distinct chromatic shifts, supporting evidence-based material selection for patients exposed to acidic or chromogenic beverages.