In vitro evaluation of the color stability of flowable composites with various filler content

Objective: It was aimed to comparatively evaluate the color stability of four different flowable composite resins with different filler content [Supreme (Filtek Supreme XTE Flowable), Bulkfill (Filtek Bulk-Fill Flowable), Estelite (Estelite Universal Medium Flow), GaenialFlo (G-aenial Universal Flo)], subjected to three beverages (water, coffee, tea) after two different finishing and polishing procedures (OptiDisc, Pogo). Material and Methods: A total of 120 disc-shaped (6mm diameter x 2mm thickness) samples were prepared by allocating 30 samples in each flowable composite resin group. The samples in each flowable composite resin group (n=30) were divided randomly into two subgroups according to the finishing-polishing system to be used and polished with Optidisc or Pogo. All samples were kept in distilled water in an incubator at 37°C for 24 hours and then initial color measurements were performed quantitatively using a contact-type spectrophotometer. After initial color measurements, the samples were divided into 3 subgroups according to the beverages and kept in the distilled water, coffee or tea in an incubator for 7 days. The ΔE values expressing the color change were calculated by using the CIE Lab system and placing the mean L, a, b, values obtained from the measurements into the formula ΔE=[(ΔL)2 +(Δa)2 +(Δb)2]1/2. Three-way Analysis of Variance and post-hoc Tukey HSD tests were used for statistical analysis of mean ΔE values at a significance level of p<0.05. Results: The main factors of the flowable composite resin material type, beverage and polishing system had a statistically significant effect on color change (p<0.001). The groups kept in tea or coffee showed a significantly higher color change compared to the control groups in water (p<0.05). However, no significant difference was found between the groups kept in tea and coffee (p>0.05). The groups polished with Pogo showed significantly higher color change compared to Optidisc groups (p<0.05). The highest and lowest color changes were obtained in Supreme and Estelite flowable composite resin materials, respectively (p<0.05). Estelite did not reveal any clinically unacceptable discoloration under any circumstances. Conclusion: Within the limitations of the study, Estelite presented the highest color stability among all flowable composite resin materials Keywords: Flowable Composite Resin, Color Analysis, Color Stability, Spectrophotometer.