Effects of whitening mouthwashes on color change of a resin composite.

PURPOSE: To evaluate the effect of whitening mouthwashes with different active ingredients on the color change (ΔE₀₀) of a stained resin composite. METHODS: A total of 70 resin composite samples (G-aenial Anterior) with dimensions of 8 х 2 mm were prepared. The samples were immersed in coffee for 14 days to simulate time-dependent color change, then randomly assigned into seven groups (n=10). Listerine Advanced White (LAW), Splat White Plus (SWP), Colgate Optic White (COW), Colgate Plax White + Charcoal (CPC), Global White Charcoal Extra Whitening Mouthwash (GWE), R.O.C.S Black Edition Whitening Mouthwash (ROC), and distilled water (DW) were used over a 12-month period. Color measurements were performed at baseline, after staining, and after 1 month, 3 months, 6 months, and 12 months of use. RESULTS: Resin composite exhibited discoloration exceeding the 50:50% acceptability threshold (AT) (ΔE₀₀: 1.8) after 14 days of coffee immersion. Group, immersion period, and their interaction significantly affected the ΔE₀₀ values (P< 0.001). All whitening mouthwashes except SWP reduced the color change on resin composite below the AT, while COW achieved this level after 1 month of use, LAW and CPC after 3 months of use, and GWE and ROC after 12 months of use. The effectiveness of whitening mouthwashes in improving the color of stained resin composite varies depending on the formulation of the whitening mouthwash and immersion time. All whitening mouthwashes except SWP were effective in improving the color of resin composite. CLINICAL SIGNIFICANCE: The color improvement effect of whitening mouthwashes on resin composite may be affected by the specific formulation and duration of use of whitening mouthwash.