Post-Bleaching Polishing Effects on Composite Resins: Surface & Color Analysis

Objectives: The aim of this study is to evaluate the effect of polishing following bleaching treatment on the color stability and surface roughness of colored composite-resins.
Methods: Discs (10mm*2mm) were fabricated from Clearfil-Majesty-ES-2 (CME), Palfique-Estelite-Paste (PEP), Filtek-Z250 (Z250), Parafil (PF), Ruby-Comp-Nano (RC) composites (n=20) were polished with Kerr-Identoflex. Samples underwent initial roughness and color measurements (control), followed by immersion in coffee for 7 days. 40% Hydrogen Peroxide gel (Opalescence Boost PF) was applied for bleaching. Half of the samples in each group (n=10) were polished after bleaching. Then, the samples were immersed in coffee again for 7 days and third color and roughness measurements were made. Data were analyzed using one-way ANOVA and Tukey tests (p=0.05).
Results: Following bleaching, only the polished CME samples showed significantly lower surface roughness compared to the non-polished group. Among the polished composite resin groups, CME samples exhibited significantly higher roughness than other composites, except for Z250. No significant differences were found among the other composite resin groups. Non-polished samples in all composite-resins displayed higher surface roughness than polished ones, with no significant difference in color change. While non-polished samples showed no significant differences in color change, polished PF and Z250 samples demonstrated more discoloration compared to PEP and RC.
Conclusions: While polishing after bleaching was observed to reduce the surface roughness of composite-resins, no significant effect on color change was detected. However, surface roughness and color change varied depending on the content of the composite-resins.