Effect of Delayed Exposure to Staining Agents on the Color Stability and Translucency of Esthetic Resin Composites

To evaluate the effect of delayed exposure to staining agents and resin composite type on the discoloration and translucency changes of esthetic resin composites.

Five resin composites (Asteria, Tokuyama; Brillant EverGlow, Coltene; GC A'chord; Harmonize; and Filtek Ultimate, 3M ESPE) were tested. Disc specimens (n = 10 per subgroup) were polymerized, polished, and exposed to coffee, red wine, or cigarette smoke either immediately (IE), after 1 day (D1), or after 7 days (D7) post-polymerization, while specimens immersed in distilled water served as the control group. Color parameters (CIEDE2000) were recorded at baseline and after 1, 7, and 28 days, as well as following repolishing, using a clinical spectrophotometer and color difference (ΔE ₀₀) was calculated. Translucency parameter change (ΔTP) between baseline and 28 days was calculated. Data were analyzed by three-way repeated-measures ANOVA and Bonferroni tests (α = 0.05).

Resin composite type, colorant, and exposure timing significantly affected ΔE ₀₀ values (p < 0.05). IE and D1 exposure groups demonstrated higher color change values than D7 exposure groups. Cigarette smoke produced the highest ΔE ₀₀ and ΔTP values, while Asteria showed the greatest resistance to staining. Repolishing reduced ΔE ₀₀ but did not restore baseline appearance.

Delaying exposure to staining agents for at least 7 days after polymerization enhances the color stability of resin composites. Clinical guidance on avoiding early staining exposures and selecting stain-resistant materials may improve long-term esthetic outcomes.