Dental bleaching with 16% carbamide peroxide improves dental color aesthetics, although it may temporarily increase enamel susceptibility to pigmentation. Beverages such as coffee, red wine, and dark soft drinks contain compounds that promote staining. This study evaluated their effect on dental color stability after bleaching.

This was an in vitro experimental study that assessed the degree of pigmentation in 60 extracted human teeth subjected to dental bleaching with 16% carbamide peroxide. The samples were divided into a control group and three experimental groups exposed to coffee, dark soft drink, and red wine. Color measurements were taken before bleaching, after bleaching, and after immersion in the beverages using digital spectrophotometry (VITA Easyshade® V). Color change was analyzed using the ΔE_BLEACH and ΔE_STAIN parameters. Data were tested for normality and compared using ANOVA or non‑parametric tests. This design allowed evaluation of post‑bleaching susceptibility to pigmentation under controlled conditions.

The statistical analysis showed that all four groups began with similar chromatic conditions, which allowed subsequent changes to be attributed to bleaching and beverage staining. The bleaching protocol was effective in all samples, with ΔE values close to 12 and no statistically significant differences among groups. Subsequently, exposure to chromogenic beverages produced clear changes in the L, a, and b coordinates, confirmed by descriptive analyses, plots, and ANOVA. These variations demonstrated that each beverage affects enamel brightness and hue differently.

When directly comparing pigmentation between Measurement 2 and Measurement 3, Coca‑Cola showed the highest ΔE_STAIN, followed by red wine and coffee, while the control group remained stable. Results indicated that Coca‑Cola produces stronger darkening and yellowing, red wine increases the red component, and coffee produces moderate changes. ANOVA confirmed highly significant differences among beverages. Overall, the data established a clear chromatic trajectory and concluded that Coca‑Cola has the greatest post‑bleaching staining potential.

The analysis confirmed that all groups started with similar dental colors, ensuring comparability. After bleaching, the chromatic change was uniform and showed no significant differences among groups. The staining stage did show marked differences, with Coca‑Cola producing the greatest pigmentation, followed by red wine and coffee. The L*, a*, and b* parameters showed distinct behaviors depending on the beverage, with more abrupt changes in the experimental groups. Overall, time and chromogenic beverages were determining factors in the final variability of dental color.