Color and translucency of finished and unfinished esthetic restorative materials after staining and bleaching

Purpose: To evaluate the effect of staining and bleaching on color and translucency of finished and unfinished nano-filled resin composite and giomer. Materials and methods: Twenty specimens (ten finished + ten unfinished) were fabricated from each material, then an initial color and translucency measurement was taken. Specimens were stained in coffee for 48 h at 37 °C, rinsed and dried. After which the second color and translucency measurement was taken. After in-office bleaching with 40% H₂O₂ Opalescence boost, a third color and translucency measurement was taken. CIE L system was used for measuring color change and translucency. Two-way ANOVA and paired t-test were used for statistical analysis at P ≤ 0.05. Results: After staining, all specimens showed clinically acceptable color change (ΔE ≤ 3.3) with no significant differences between groups. After bleaching, all specimens showed clinically unacceptable color change (ΔE > 3.3) and significant differences between finished & polished and unfinished groups (P = 0.024). Nano-composites recorded significantly higher translucency than giomer (P = 0.000) except after bleaching. In addition, the translucency of unfinished groups were significantly higher than finished & polished groups (P = 0.001). Conclusions: The tested materials responded similarly to staining and bleaching. High concentration bleaching increased color change and reduced translucency. Finishing & polishing restorative materials improves their resistance to color change after bleaching, but it adversely affects translucency.