Effects of in vitro erosion on surface texture, microhardness, and color stability of resin composite with S-PRG fillers

Objectives To evaluate the effect of acid erosion on different physical properties of resin composite with S-PRG (surface pre-reacted glass) fillers, by conducting simulations of intrinsic and extrinsic sources. Materials and methods Cylindrical samples (Ø6 vs. 2 mm) of a conventional nanohybrid resin composite (Forma, Ultradent) and of a nanohybrid resin composite with S-PRG filler (Beautifil II, Shofu) were exposed to erosive cycling (5 days), based on ( n =12) remineralizing solution (control); 0.3% citric acid (pH=2.6); or 0.01 M hydrochloric acid (pH=2). Roughness (Ra), microhardness (KHN), and color (CIEL*a*b*, CIEDE2000, and Vita scale (SGU)) factors were analyzed at the initial and final time points, and the general color changes (Δ E ab , Δ E 00 , ΔSGU) were calculated. Final images were obtained using scanning electron microscopy (SEM). The data were evaluated by generalized models, Mann-Whitney, Wilcoxon, Kruskal-Wallis, and Dunn tests ( α =0.05). Results Regarding KHN, there was no difference between the groups or the time periods ( p = 0.74). As for Ra, there was a significant increase in the Ra of both composites after cycling with hydrochloric acid, but only the resin composite with S-PRG filler showed a change in Ra after cycling with citric acid ( p = 0.003). After cycling with citric and hydrochloric acid, the highest Ra values were found for the resin composite with S-PRG filler ( p < 0.0001), corroborating the result of images (SEM) indicating loss of filler and porosities in this material. The resin composite with S-PRG filler showed higher Δ E ab and Δ E 00 , in addition to more negative ΔSGU values and lower L * values after exposure to both acids, compared to the control ( p < 0.05). Conclusion The acidic conditions altered the roughness and color stability of the materials tested, pointing out that the resin composite containing S-PRG filler showed greater degradation of its physical properties than the conventional resin composite. Clinical relevance Bioactive materials are relevant, considering that their properties interact with dental hard tissues; however, the S-PRG-based resin composite showed greater degradation under acidic conditions than the conventional resin composite.