Polishing, Not Bleaching, Best Improves Coffee-Stained dental Composite Restorations: Study

A new study published in the journal of BMC Oral Health showed that the optical appearance and surface characteristics of bleach-shade dental composite resins were negatively impacted by coffee stains.

Bleach-shade composite resins are becoming increasingly used in modern cosmetic dentistry to replicate the exceedingly brilliant look of chemically whitened teeth. However, the long-term clinical effectiveness of these restorations is strongly reliant on retaining their original color stability, whiteness, and structural integrity in a dynamic dental environment. Surface treatment processes, including various finishing and polishing protocols, play an important part in establishing these physical characteristics. Inadequate surface smoothness immediately accelerates extrinsic staining, reduces apparent whiteness, and increases surface roughness, promoting plaque formation. As a result, doctors must understand how different surface treatments impact these composites in order to improve restoration regimens and achieve long-term cosmetic results. This study assessed how various surface treatment methods affected the bleach-shade composite resins' color stability, whiteness index, and surface roughness during coffee immersion.

Four bleach-shade composite resins and one multi-shade (Filtek Z250 A2) composite resin were used to create 300 examples (n = 60 per material). The specimens were divided into six groups (n = 10) at random: Group 1 (OptraGloss one-step polishing), Group 2 (Nova Twist two-step polishing), Group 3 (Whiteness HP bleaching), Group 4 (bleaching plus one-step polishing), Group 5 (bleaching plus two-step polishing), and Group 6 (control). For twelve days, every specimen was submerged in a coffee solution. Color and roughness [Ra] measurements were taken at baseline (t0), following staining (t1), and following surface treatments (t2). The CIEDE2000 method (∆E00) was used to compute color differences, and the CIELAB-based WID formula was used to estimate whiteness index (WID) values. Kruskal-Wallis, Dunn, and robust ANOVA tests were used for statistical analysis (p < 0.05).

All specimens showed reduced WID values and clinically unsatisfactory ΔE00 values at the t1 time point.

The Brilliant and A'chord groups had the greatest WID values (p < 0.05), whereas the Asteria group showed the strongest color stability at t1.

Ra rose in the bleaching groups at the t2 time point, while the one-step polishing group had the lowest Ra levels (p < 0.05).

Overall, coffee exposure degraded the optical and surface characteristics of bleach-shade composite resins. Bleaching alone had little efficacy; however, polishing enhanced cosmetic effects while retaining therapeutically acceptable surface qualities. Material-dependent variations were found among the tested composites.

Reference:

Kutlu, İ., & Fi̇dan, M. (2026). Effects of surface treatment methods on the color stability, whiteness, and surface roughness of bleach-shade composite resins. BMC Oral Health. https://doi.org/10.1186/s12903-026-09186-6