Color Stability Under Challenge: Effects of Thermo-Aging and Mouthrinse Exposure on Anterior Teeth and Esthetic Composites

Objective: The aim of this study is to comparatively evaluate how the color stability of different esthetic composite resins and natural anterior teeth is affected after exposure to thermal aging and various mouthrinse solutions. Materials and Methods: A total of 96 extracted permanent anterior teeth were prepared with Class V cavities on the buccal surfaces and restored using three different esthetic composite resins: G-aenial Anterior (GC Corp., Tokyo, Japan), SOLARE X (GC Corp., Tokyo, Japan), and Estelite Sigma Quick (Tokuyama Dental Corp., Tokyo, Japan). The palatal surfaces of the same teeth were used as a natural enamel reference. Following restoration, all specimens underwent thermal aging for 10,000 cycles between 5 °C and 55 °C. Subsequently, the samples were immersed for 24 hours in four different mouthrinse solutions: 0.12% chlorhexidine solution (Kloroben, Drogsan, Türkiye), an antiseptic and anticavity formulation (Listerine Total Care, Johnson & Johnson, USA), a zinc-containing mouthrinse (Listerine Total Care Stay White, Johnson & Johnson, UK), and distilled water (control group). Color measurements were performed using a VITA Easyshade Advance 4.0 spectrophotometer, and color differences were calculated according to the CIEDE2000 (ΔE₀₀) formula. Results: Color changes were observed in all composite materials after thermal aging and exposure to mouth-rinse solutions. Specimens exposed to chlorhexidine-containing solutions exhibited significantly greater discoloration compared with the control group (p < 0.050). Statistically significant differences in color stability were also found among the materials (p < 0.050). Conclusion: Within the limitations of this in vitro study, chlorhexidine-containing mouthrinse caused the highest color change, while material type significantly influenced color stability.