Integrated effect of fillers, monomers and bioactive ingredients on color stability of resin composites

Objectives: Resin composites containing surface pre-reacted glass (S-PRG) were introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physical-mechanical properties over time, including the color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites.Materials and Methods: Discs (n=5/group) of microhybrid, nanofilled, nanohybrid, and S-PRG-based nanohybrid composites with two opacities were prepared. Color (CIELab and CIEDE2000) was evaluated after aging in grape juice. The DC was analyzed by using Fourier Transform Infrared Spectroscopy before and after photopolymerization. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (PResults: In the color stabilityanalysis, the interaction between filler type and opacity was significant. S-PRG influenced color stability and DC.Conclusions: The nanohybrid resin composite presented favorable color stability and a greater DC, which is likely related to its organic content. S-PRG based nanohybrid resins require caution since its bioactive benefits depends on interaction with the environment that can be prone to impair color stability.Clinical Relevance: As color stability is mandatoryin specific regions, staining can jeopardize the esthetics of a resin composite. The use of nanohybrid composites with no or reduced BisGMA content and diluents may be more appropriate in these areas. Since materials containing S-PRG can offer relevant benefits, professionals need to balance their higher susceptibility to staining favoring other relevant properties.