The In Vitro Effect of Isotonic Sports Drinks on Color Variation and Thickness of A Material Used for Sport Mouthguards

This in vitro study aimed to evaluate the effect of isotonic sports drinks (Gatorade) on color variation and thickness of ethylene-vinyl acetate (EVA). White thermoformed EVA blocks (n = 60) were prepared and randomly allocated into five groups (n = 12): reverse osmosis water (G1-control, transparent/colorless), isotonic passion fruit flavor (G2-yellow drink), isotonic citrus flavor (G3-orange drink), isotonic strawberry with passion fruit flavor (G4-red drink), and isotonic grape flavor (G5-purple drink). The specimens were submerged in their respective liquids/drinks for each group and incubated at 37°C for 28 consecutive days. The liquids/drinks were replaced every 24 h. Color variation (ΔE_ab) and thickness (mm) were evaluated using a digital spectrophotometer and a digital micrometer, respectively, at baseline and after 7, 14, 21, and 28 days. ΔE_ab was calculated using the CIEL*a*b* system. Statistical analysis for both independent and dependent data was performed (α = 5%). Regarding color variation, G2 and G5 showed significant changes in ΔE_ab values after 21 and 28 days (p < 0.05), respectively. After 21 days, G2 became less clear and more pigmented towards the blue and red coordinates, with a reduction in L* (p < 0.001) and b* (p < 0.001), and an increase in a* (p < 0.001). After 28 days, G5 became pigmented towards the red and blue coordinates, with no significant change in L* (p > 0.05), but a reduction in b* (p = 0.021) and an increase in a* (p < 0.001). The thickness did not vary in relation to time or isotonic flavor/drink (p > 0.05). Isotonic drinks may cause changes in the color of EVA depending on the exposure time and the color of the isotonic drink consumed.