Comparative Evaluation of the Effect of Different Beverages on Color Stability of Two Single-Shade Composite Resins:...

Background Color stability is a critical property for the long-term success of aesthetic composite restorations. Recently introduced single-shade composite resins, such as Omnichroma (Tokuyama Dental, Tokyo, Japan) and Vittra APS Unique (FGM Dental Group, Joinville, Santa Catarina, Brazil), exhibit a chameleon effect that enhances shade matching. However, their resistance to staining from commonly consumed beverages remains inadequately explored. Aim The aim of this in vitro study was to comparatively evaluate the effect of different commonly consumed beverages on the color stability of two single-shade composite resins: Omnichroma and Vittra APS Unique. Materials and methods This in vitro study included 96 composite disc specimens (n=48 per material), fabricated with standardized dimensions (10 mm diameter and 2 mm thickness). Specimens of each material were divided into four subgroups (n=12) based on immersion media: artificial saliva, turmeric solution, tea, and soft drinks. Baseline color measurements were recorded using a spectrophotometer based on Commission Internationale de l'Eclairage (CIELAB) parameters (L*, a*, b*). Samples were immersed in the respective beverages for 28 days, simulating long-term clinical exposure. Post-immersion color measurements were obtained, and color change (ΔE) was calculated. Statistical analysis was performed using the Shapiro-Wilk test, Wilcoxon signed-rank test, and Mann-Whitney U test, with significance set at p<0.05. Results All specimens exhibited statistically significant color changes after immersion in the tested beverages (p<0.05). Among the tested solutions, turmeric demonstrated the highest staining potential, followed by tea, while soft drinks exhibited the least discoloration. In artificial saliva, Omnichroma showed a significantly higher color change (ΔE=17.37±2.79) compared to Vittra APS Unique (ΔE=10.58±0.11) (p<0.001). In contrast, turmeric caused significantly greater discoloration in Vittra APS Unique (ΔE=30.00±4.69) than in Omnichroma (ΔE=18.60±2.47) (p<0.001). Similarly, tea resulted in higher color change in Vittra APS Unique (ΔE=17.80±4.38) compared to Omnichroma (ΔE=5.98±1.39), indicating increased susceptibility to staining. Soft drinks caused relatively minimal discoloration, with no statistically significant difference between the two materials (p>0.05). Overall, Vittra APS Unique demonstrated greater susceptibility to staining in highly pigmented solutions, whereas Omnichroma exhibited comparatively better color stability under similar conditions. Conclusion Within the limitations of this in vitro study, both single-shade composite resins were affected by exposure to staining beverages. Turmeric showed the greatest staining effect, followed by tea, while soft drinks had minimal impact on color stability. Omnichroma demonstrated superior resistance to discoloration compared to Vittra APS Unique in highly staining environments. These findings have important clinical implications in guiding the selection of restorative materials, particularly in patients with dietary habits that predispose restorations to staining.