クラスII MOD バルク充填レジンコンポジット修復物の水分貯蔵によるマイクロリーケージへの影響：in vitro評価

To evaluate and compare the effect of 6-month water storage on the marginal microleakage of class II MOD cavities restored with two different bulk-fill resin composites (sculptable and no-cap flowable) and a conventional resin composite.A total of 60 sound freshly extracted mandibular molars, each with a standardized class II MOD cavity, were assigned into three main groups according to the restorative material used as follows: bulk-fill resin composite (SimpliShade, Kerr), no-cap flowable bulk-fill resin composite (G-aenial Bulk Injectable, GC), and conventional resin composite (Neo Spectra ST LV, Dentsply Sirona). Each group was further divided into two subgroups (n = 10) based on the water-storage time: 24 hours (immediate) and 6-month water storage (aged). All specimens were thermocycled 5,000 times between 5°C ± 2°C and 55°C ± 2°C, then immersed in 2% basic fuchsin dye for 24 hours. The specimens were longitudinally sectioned, and the amount of dye penetration was evaluated using stereomicroscope under 25× magnification. The results were analyzed by non-parametric Kruskal-Wallis, Mann-Whitney, and Wilcoxon signed-rank tests. The level of significance was set at p <0.05.Both bulk-fill resin composites exhibited significantly lower microleakage scores than conventional resin composite (p <0.05). However, 6-month water storage significantly increased the microleakage for all tested groups.Water storage has a negative impact on the marginal microleakage regardless of the type of the restoration.