Effects of carbonated beverages on resin composite stability

Purpose: To evaluate the effect of four distinct carbonated beverages on the color stability of two resin composites, microhybrid and nanofilled, from the same manufacturer but with different inorganic filler compositions and different finishing and polishing methods. Methods: A total of 150 specimens were prepared in microhybrid (n= 75) and nanofilled (n= 75) resin composites, with the color shade A2E. The samples, subdivided into groups (n = 25), underwent different surface treatments: G1, a sequence of sandpaper discs; G2, universal polishing paste; and G3, disc sequence, and polishing paste. Subsequently, the samples were immersed in five solutions: Coca-Cola, Fanta Orange Soda, Guarana. Antarctica, Sprite, and distilled water (as the control group) (n= 5). Photographic images were taken at four times: baseline and after immersion for 7, 15, and 30 days. Color change was calculated with computerized image analysis using the Commission Internationale de l'Eclairage (CIE) L* a* b* values. Color change variations by time, beverage type, and polishing were calculated by ANOVA followed by Tukey's test for differentiation (P <= 0.05). Student's t-test was used for differentiation of inorganic loads (P <= 0.05). Color variation was significant at Day 30 when compared to Day 7 (P= 0.000) and Day 15 (P= 0.004). Results: There was no significant difference between the finishing and polishing methods. When compared to other soft drinks, Guarand presented statistical significance. There was no significance between nanofilled and microhybrid resins (P= 0.239). Soft drink type and immersion time influenced the color stability of resin composites. Inorganic fillers, as well as finishing and polishing methods, did not influence color change.