Objective The aim of this study is to evaluate the microhardness and surface roughness of two different bulk-fill composites polymerized with light-curing unit (LCU) with different polymerization times before and after the application of a home bleaching agent. Materials-Methods For both microhardness and surface roughness tests, 6 groups were prepared with bulk-fill materials (SonicFill, Filtek Bulk Fill) according to different polymerization times (10, 20, and 30 s). 102 specimens were prepared using Teflon molds (4 mm depth and 5 mm diameter) and polymerized with LCU. 30 specimens (n = 5) were assessed for microhardness. Before home bleaching agent application, the bottom/top (B/T) microhardness ratio was evaluated. After bleaching agent application, the microhardness measurements were performed on top surfaces. Roughness measurements were performed in 72 specimens (n = 12) before and after bleaching application. Additionally, for SEM analyses, two specimens from all tested groups were prepared before and after bleaching agent application. The data B/T microhardness ratio before bleaching was analyzed by two-way ANOVA and Tukey's HSD test. The data from the top surface of specimens' microhardness before and after bleaching were analyzed using Wilcoxon signed-rank test, Kruskal-Wallis, Mann-Whitney U tests. The data from surface roughness tests were statistically analyzed by multivariate analysis of variance and Bonferroni test (p < 0.05). Results The B/T microhardness ratio results revealed no significant differences between groups (p > 0.05). Comparing the microhardness values of the composites' top surfaces before and after bleaching, a significant decrease was observed exclusively in FB30s (p < 0.05). No significant differences in surface roughness values were observed when the groups were compared based on bulk-fill materials (p > 0.05) while the polymerization time affected the surface roughness of the SF20s and SF30s groups (p < 0.05). After bleaching, surface roughness values were significantly increased in the SF20s and SF30s groups (p < 0.05). Conclusion The clinicians should adhere to the polymerization time recommended by the manufacturer to ensure the durability of the composite material in the oral environment.

中文翻译：

---

聚合时间和家用漂白剂对散装复合材料显微硬度和表面粗糙度的影响：扫描电子显微镜研究

目的本研究的目的是评估两种不同的光固化单元（LCU）在不同聚合时间聚合的填充复合材料在使用家用漂白剂前后的显微硬度和表面粗糙度。材料-方法 对于显微硬度和表面粗糙度测试，根据不同的聚合时间（10、20 和 30 秒）用散装填充材料（SonicFill、Filtek Bulk Fill）制备 6 组。使用聚四氟乙烯模具（深度 4 毫米，直径 5 毫米）制备 102 个试样，并用 LCU 聚合。评估了 30 个样本 (n = 5) 的显微硬度。在家用漂白剂应用之前，评估底部/顶部 (B/T) 显微硬度比。应用漂白剂后，在顶面进行显微硬度测量。在漂白应用前后对 72 个样本（n = 12）进行了粗糙度测量。此外，对于 SEM 分析，在使用漂白剂之前和之后准备了来自所有测试组的两个样本。通过双向 ANOVA 和 Tukey 的 HSD 测试分析漂白前的数据 B/T 显微硬度比。使用 Wilcoxon 符号秩检验、Kruskal-Wallis、Mann-Whitney U 检验分析漂白前后试样顶面显微硬度的数据。通过多元方差分析和 Bonferroni 检验对表面粗糙度测试的数据进行统计分析 (p < 0.05)。结果 B/T显微硬度比结果显示各组间无显着差异（p > 0.05）。比较漂白前后复合材料顶面的显微硬度值，仅在 FB30 中观察到显着下降（p < 0.05）。当基于散装材料（p > 0.05）比较各组时，未观察到表面粗糙度值的显着差异，而聚合时间影响 SF20s 和 SF30s 组的表面粗糙度（p <0.05）。漂白后，SF20s 和 SF30s 组的表面粗糙度值显着增加（p < 0.05）。结论临床医生应遵守制造商推荐的聚合时间，以确保复合材料在口腔环境中的耐久性。05) 而聚合时间影响 SF20s 和 SF30s 基团的表面粗糙度 (p < 0.05)。漂白后，SF20s 和 SF30s 组的表面粗糙度值显着增加（p < 0.05）。结论临床医生应遵守制造商推荐的聚合时间，以确保复合材料在口腔环境中的耐久性。05) 而聚合时间影响 SF20s 和 SF30s 基团的表面粗糙度 (p < 0.05)。漂白后，SF20s 和 SF30s 组的表面粗糙度值显着增加（p < 0.05）。结论临床医生应遵守制造商推荐的聚合时间，以确保复合材料在口腔环境中的耐久性。