Color stability of conventional and bulk fill composite resins

ABSTRACT Objective: This study compared the color stability of different dental composite resins after prolonged exposure to a coffee solution. Methods: Sixty-four cylindrical discs (10 mm diameter x 2 mm thickness) were prepared using 8 different dental composite resins (n=8, per group). The specimens were first immersed in artificial saliva for 24 h followed by immersion in a coffee solution for 14 days. The assessment of chromatic variation (ΔE) was performed with the aid of a Vita Easyshade Advanced spectrophotometer (VITA Zahnfabrik, Bad Sackingen, Germany). The color of each specimen was calculated based on the L*, a* and b* coordinates of the CIELab system. Results: Grandio SO had the lowest average chromatic variation (ΔE=7.77) after immersion in coffee solution. Durafill VS, Grandio and Z350 XT (ΔE=8.58; ΔE=9.52; ΔE=10.39, respectively) showed similar chromatic variation, with no statistical difference in relation to Grandio SO. However, the other dental composite resins evaluated showed statistically higher values of ΔE compared to Grandio SO, and Enamel HRi (ΔE=20.56) demonstrated the highest chromatic variation. Conclusion: The Bulk Fill and hybrid composite resins from the same manufacturer (Micerium, Avegno, Italy) showed greater chromatic variation than the other composite resins tested. Grandio SO (Voco, Cuxaven, Germany) had the lowest ΔE variation.摘要 目的：本研究旨在比较不同牙科复合树脂经咖啡溶液长期浸泡后的色彩稳定性。方法：采用8种不同的牙科复合树脂制备64个圆柱形试件（直径10 mm，厚度2 mm），每组n=8。首先将试件置于人工唾液中浸泡24小时，随后转移至咖啡溶液中浸泡14天。使用Vita Easyshade Advanced分光光度计（VITA Zahnfabrik，德国巴登-扎金根）对色度变化值（ΔE）进行评估。基于CIELab色彩系统的L*、a*、b*坐标计算各试件的颜色参数。结果：Grandio SO经咖啡溶液浸泡后的平均色度变化值最低（ΔE=7.77）。Durafill VS、Grandio及Z350 XT的色度变化值分别为8.58、9.52、10.39，三者色度变化相近，与Grandio SO无统计学差异。其余受试牙科复合树脂的ΔE值均显著高于Grandio SO，其中Enamel HRi的色度变化值最高（ΔE=20.56）。结论：来自同一制造商（Micerium，意大利阿韦尼奥）的大块充填型（Bulk Fill）及混合型复合树脂的色度变化值高于其余受试复合树脂。Grandio SO（Voco，德国库克斯哈文）的ΔE变化值最低。