Effect of whitening mouthrinses on the fluorescence of a nanohybrid composite resin

The pursuit of brighter smiles has led to the frequent use of whitening mouthrinses. However, their effects on the optical properties of restorative materials remain poorly understood. Fluorescence, which is responsible for reproducing the vitality of natural teeth, may be compromised by the continuous contact of these products with composite resins, potentially affecting long-term esthetics. In this context, the present study aimed to evaluate the influence of different whitening mouthrinses on the fluorescence of a nanohybrid composite resin through computer-assisted analysis of digital images. Fifty discs of nanohybrid composite resin (Luna) were fabricated and randomly allocated into five groups (n = 10) according to the immersion solution: distilled water (control), Colgate Luminous White Charcoal, Listerine Whitening Extreme, Colgate Luminous White, and Colgate Plax Ice Infinity. The specimens were immersed in the solutions for 30 minutes per day and stored at 37 °C for 24 hours between measurements. Digital photographs were obtained at each interval and analyzed for fluorescence in the blue channel of the RGB system using the mColor Meter application (MacOS). All groups showed a significant reduction in fluorescence over time (p < 0.001). Between 60 and 90 days (T2–T3), no statistical differences were observed for most groups, suggesting stabilization of the effect. It can be concluded that whitening mouthrinses affect the fluorescence of composite resin, promoting a progressive decrease up to approximately 60 days, which may compromise the optical stability of restorations subjected to prolonged exposure to these solutions.