1. Introduction Resin-based composites (RBCs) have been among the most common choices for restoring anterior and posterior teeth, mainly due to their high aesthetic properties, improved durability and success rate, and high patient acceptance. However, inadequate mechanical properties, polymerization shrinkage, plaque accumulation, and stainability are the major drawbacks of dental restorations [1,2,3]. The staining susceptibility of restorative materials is influenced by several factors.