Evaluation of surface roughness and hardness of newer nanoposterior composite resins after immersion in food-simulating liquids

Introduction: Restorative resins during their prolonged use are exposed to variety foods and beverages are subjected to wear, degradation, and staining resulting in failure of restoration and require replacement. This study is aimed to evaluate surface roughness and hardness of five commercially available posterior resin composites following exposure to various food-simulating liquids (FSLs). Materials and Methods: Specimens were immersed in distilled water, ethanol, citric acid, and air and later examined using a profilometer, scanning electron microscope for the surface profiles. Hardness was measured by Vickers Hardness test. Statistical Analysis: Results were subjected to two-way ANOVA and Tukey's multiple Post hoc test. Results: There were significant differences in results among the composite resin tested. Inter comparison between materials after treating with FSLs, clear fill majesty (CFM) and Z350 showed better hardness values under the influence of ethanol, followed by Ever X, Tetric Evo Ceram and Sure fill SDR. None of the composites were unaffected by air compared to FSLs. Citric acid had reduced the hardness of CFM and had caused surface roughness on Sure fill SDR and Tetric Evo Ceram. Distilled water reduced hardness of CFM and SureFil SDR. EverX was not affected by any of the FSL either in hardness or surface roughness properties. All composites showed surface irregularities in all media. Ethanol and water had almost similar effect on all composites. Conclusions: Differences in hardness and surface roughness are due to different composition of resin matrix and different filler particles in all composite resin material tested.