Hydrolytic Degradation of Resin Composites Under Different Immersion Media

Objectives: The aim of this study was to evaluate in vitro the hydrolytic degradation of two bulk-fills resins (XTra Fil, VOCO; Tetric EvoCeram Bulk Fil, Ivoclar Vivadent) and two self-adhering resin composites (Vertise Flow, Kerr; Fusio Liquid Dentin, Pentron Clinical) compared to Filtek Z250 (3M ESPE) as control group.
Methods: Seventy-five cylindrical specimens (7 x 1mm) were desiccated and immersed into distilled water, artificial saliva, and 0.1 M lactic acid for 180 days (n=5). Specimens were weighed after 7, 14, 21, 28, 90, and 180 days at 37±1^oC, after which they were desiccated again. The sorption and solubility (μg/mm³) were calculated based on ISO 4049. Data were analyzed through Kruskal Wallis and Mann Whitney test. The statistical significance for all tests was considered as p<0.05.
Results: Self-adhering resin composites Vertise Flow and Fusio Liquid Dentin showed respectively higher sorption values independently of the solution (62.55 and 50.81μg/mm³ in water, 67.26 and 50.46μg/mm³ in saliva, 64.98 and 59.86μg/mm³ in latic acid). Self-adhesive Vertise Flow also had the greater solubility value in water (22.18μg/mm³) and Fusio Liquid Dentin had the greater value in latic acid (65.87μg/mm³) but in saliva, XTra Fil showed the higher solubility values (22.13μg/mm³).
Conclusions: The self-adhering resin composites had higher hydrolytic degradation, while the bulk-fill behaved similarly to or more than the control group. The storage environment influenced the final characteristics of each material tested.