The Influence of Bleaching Intensity and Laser Activation on the Durability of Selected Aesthetic Composites—An In Vitro Study

The aim of this study was to evaluate the effect of different bleaching protocols, including laser-assisted techniques, on the microhardness, surface roughness, and tribological resistance of selected light-cured composites. Three Estelite Universal Flow composites with different flow properties and G-aenial Universal Flo composites were tested. Each group underwent bleaching procedures using Opalescence agents at 10%, 16%, and 40% concentrations, with and without laser activation. Surface microhardness was assessed using the Vickers method, roughness was measured with 3D confocal laser microscopy, and friction coefficients and wear patterns were evaluated using tribological testing. All bleaching protocols resulted in reduced microhardness and increased surface roughness. The most significant changes were observed after treatment with 40% hydrogen peroxide. Laser application, particularly at 16% concentration of carbamide peroxide, helped to partially mitigate these effects in some materials. Bleaching procedures, especially those involving high peroxide concentrations, significantly deteriorated the surface properties of dental composites, which may have clinical implications for the patients.