Objective: To determine color stability of nanofilled and suprananofilled resin composites subjected to different polishing systems after immersion in coffee solution.
Materials and Methods: Nanofilled (Filtek Z350 XT Universal) and suprananofilled (Palfique Omnichroma) resin composites were polished after polymerization, except for control groups, with three-step (Enamel Plus Shiny), two-step (Super-Snap X-treme) or one-step (OneGloss) polishing systems after polymerization. The baseline color was recorded using spectrophotometer (Vita Easyshade V), samples were stored in coffee solution for 14 days, then color change was calculated using (CIEDE2000) and statistically analyzed using two-way ANOVA test and post hoc pairwise comparisons.
Results: There was a significant interaction between type of composite resin and polishing protocol on color change. For the control samples, the discoloration in nanofilled samples was significantly higher than suprananofilled ones. For both types of composites, there was a significant difference between samples polished by different protocols.
Conclusions: 1. Unfinished and unpolished suprananofilled composite obtains less color change than the nanofilled composite. 2. The three-step polishing provide the least color change in both types of resin composites, yet comparable with the two-step system in the nanofilled composite. 3. Immersion of composite in coffee colorant showed apparent alterations in all tested groups.