Sorption, solubility, and surface microharness of 3 nanohybrid resin composites after 60 days of water storage

Background and Aims: Microhardness, sorption, and solubility are useful predictors of a resin composite's clinical success. This study aimed to evaluate the effect of 60 days of water storage on the microhardness, sorption, and solubility of 3 commercial nanohybrid resin composites. Materials and Methods: Three nanohybrid composites were evaluated: GC Kalore (GC), Aura (SDI), and G-ænial Universal Flo Universal Flo (GC). Ten disc-shaped samples were prepared for each material. After baseline weight measurement, the specimens were stored in distilled water for a period of 60 days, and then in desiccators for another 60 days. Specimens were weighed at 24 hours, 7 and 60 days of water storage and desiccation. For the microhardness test, 24 were prepared for each material and divided into 6 groups based on storage media (dry and wet) and storage time (24 hours, 7 days, and 60 days). Specimens were tested by a digital Vickers microhardness tester after storage and data were analyzed using SPSS software. Results: G-ænial Universal Flo Universal Flo showed the highest sorption and solubility and the lowest microhardness after 60 days of water storage. GC Kalore showed lower sorption and solubility compared to Aura. Also GC Kalore had higher microhardness than Aura after 60 days of storage in water, while Aura had higher microhardness in dry storage. Conclusion: Composites with lower sorption and solubility showed higher microhardnss in wet conditions. Flowable composite resin showed the lowest microhardness and the highest sorption and solubility values. Therefore, the negative effect of water sorption and solubility on Surface microhardness should be considered in clinical decisions.