Comparison of Color Stability Between Single-Shade and Conventional Composite Resins Following Immersion in Staining Solutions of Coffee, Cola, and Distilled Water

Background: This in vitro study aimed to compare the color stability and the effect of polishing on single-shade and conventional resin-based composite after immersion in commonly consumed beverages over certain time intervals. Material/Methods: We prepared 120-disc specimens using 2 universal single-shade and 2 conventional composite resins (n=30) and then each group was divided into 3 groups of solutions (n=10/solution): distilled water, coffee, and cola. To mimick the clinical situation, polishing with the Soflex system was performed. Color stability measurement was recorded for every specimen after 1 week (T1), 1 month (T2), and after polishing (T3) after immersion in staining solutions. Color stability was assessed by using the clinical spectrophotometer (Color-Eye 7000A, Greta Macbeth, USA). Data were analyzed using SPSS Version 25, and comparisons between groups were made with the value of significance kept under 0.05 (P>0.05). Results: Color changes after 1 week, after 1 month, and after polishing showed a high significant difference in all parameters (L, a and b) as P value <.05. Pair-wise comparison was done using the Mann-Whitney test, which confirmed the significant difference between coffee vs (distilled water vs cola) in all parameters (L,a,b) (P>0.05). Conclusions: Within the limitation of this in vitro study, it can be concluded that the different solutions used affected the color stability of all the different composites used, with the coffee solution showing greater color change than cola and distilled water. Additionally, polishing may affect the composite surface's quality, which suggests that polishing can change the color of composite resins.