Effect of energy drinks on microhardness of silorane and dimethacrylate-based composite resins

Introduction: Increased consumption of energy drinks has raised concerns about their effects on dental restorations. This study assessed the effects of two energy drinks on the surface microhardness of methacrylate and silorane-based composites after 1-week and 1-month periods. Materials & Methods: In this in-vitro study, 90 cubic samples were prepared from Filtek P90, Filtek Z250 and Filtek Z350 XT composite resins. Vickers hardness test was performed to measure the baseline surface microhardness for each specimen. Ten randomly selected samples from each composite material were then immersed in one of the two sports drinks (Red Bull and Hype) or artificial saliva (control). Surface microhardness was re-evaluated after 1 week and 1 month of immersion. The data were evaluated using ANOVA via post-hoc Tukey tests and repeated measure test (α=0.05). Results: Surface microhardness of all composites were significantly decreased in energy drinks in both evaluation periods (P<0.001). In artificial saliva, microhardness was significantly increased after 1 week and decreased after 1 month of immersion (P< 0.001). After 1 month, the lowest microhardness changes were observed in Filtek Z350 XT composite. (18% and 14% reduction in Hype and Redbull respectively). Differences between energy drinks were significant for Z350 XT composite only after 1 week (P=0.01) and for Z250 composite after 1 week and 1 month (P=0.020 and P< 0.001 respectively). Conclusion: Hype and Red Bull energy drinks can affect the surface hardness of composite resins depending on their characteristics and exposure time.