Effect of whey protein beverages on surface roughness of a packable resin composite

Objective: This study aimed to analyze the effect of whey protein beverages on the surface roughness of a packable resin composite restorative material.Methods: Twenty disc-shaped specimens were prepared from a resin composite (Ivoclar Te-Econom Plus). The specimens were divided into two equal groups (n=10) and subjected to different immersion media, as follows: Group 1: Whey-1 solution (BigMuscles Essential Whey) and Group 2: Whey-2 solution (Muscletech Nitro Tech 100% Whey Gold). Each whey solution was prepared by mixing 25 g of the corresponding whey powder into 250 ml of water. The samples were immersed in the respective solutions for 10 minutes daily for 14 days. The surface roughness of each composite specimen was analyzed pre- and post-immersion using a stylus profilometer. The average surface roughness value (Ra) of each specimen was recorded in µm at each interval. The data were subjected to statistical analysis using SPSS software 26.0. Wilcoxon signed-rank test and Mann-Whitney U test were used for statistical analysis. P-values less than 0.05 were considered significant.Results: Both groups exhibited a significant increase in surface roughness values after immersion in whey protein drinks (P= 0.045 for group 1 and P=0.038 for group 2). The mean post-immersion Ra value was significantly greater in group 2 (0.402 ± 0.328) compared to group 1 (0.302 ± 0.167) (P=0.048). Conclusions: Both types of whey protein beverages significantly increased the surface roughness of a packable resin composite. These results imply that exposure to whey protein beverages may adversely affect the surface roughness of composite restorations.