Influence of surface coating sealer on resin composite water absorption and discoloration: An in vitro study

Purpose: This in vitro study evaluated the efficacy of surface coating sealer (SCS) in reducing the amount of water absorption and stain formation in resin composites. Methods: To evaluate the amount of water sorption, 40 stainless steel round molds (n=10 per composite) were filled with Filtek Supreme XTE; Venus Diamond; Clearfil Majesty ES-2; Gradia Direct Anterior. Groups were further divided into two subgroups (n=5) according to the presence/absence of SCS (Easy Glaze,VOCO). Their masses were measured at baseline and reweighed at 1,4,12and20 weeks. For staining evaluation, 48 composite resin discs, 2 mm thick, were obtained with the same composites and SCS was applied on a single surface of each sample. After baseline color assessment, samples were immersed in vials containing 5 mL of six different staining solutions. Color evaluation was performed again after 1,4,12and20 weeks. Three-way ANOVA was performed to evaluate either differences in weight gain and color changes (p<0.05). Results: A significant protective action of SCS (p<0.001), but not of the composites (p=0.366) was found. Differences in weight and color change were not influenced by the resin composite, but uniquely by the presence of the coating on the surface of the samples. SCS are well-established materials for polishing and protecting composite restorations from water sorption and color changes. Different staining solutions can still produce different effects on composite resins.