HashemiKamangar Sedighe Sadat, Jafari Soheil, Rouhaninasab Marzieh
Department of Restorative Dentistry, Dental Research Center, Dental School, Tehran University of Medical Sciences, Tehran, Iran.
Department of Aesthetic and Restorative, Dental School, International Campus, Tehran University of Medical Sciences, Tehran, Iran.
Dent Res J (Isfahan). 2023 Jun 27;20:67. eCollection 2023.
Despite the improvements in optical properties of composite resins, their color stability is still a matter of concern. This study aimed to assess the curing time and intensity and polishing technique on color stability of bleach-shade composite resins.
In this , experimental study, 128 discs (1 mm × 8 mm) were fabricated from two composite resins. The specimens fabricated from each composite were assigned to 8 subgroups ( = 8) based on the curing time and intensity and polishing with polishing points or discs. After polishing, the color parameters of specimens were measured by EasyShade spectrophotometer according to the CIEL* ab color system. The specimens were then immersed in tea solution, and their color parameters were measured again. Color change (ΔE) was calculated and analyzed at 0.05 level of significance. SPSS 25 was used for data analysis. Univariate four-way ANOVA was applied to assess the effects of composite type, curing time, curing intensity, and technique of polishing on ΔE of composite resins. Since the interaction effects were significant, subgroup analysis was performed by -test. The level of significance for this test was set at 0.05.
The effects of curing intensity and polishing technique were significant on ΔE ( < 0.05). Filtek Z350 XBW composite specimens polished by polishing points experienced lower color change than those polished with discs. The minimum ΔE of Gradia XBW composite was recorded in specimens that underwent high-intensity curing for 20 s and were polished with polishing points while the maximum ΔE was recorded in specimens that underwent high-intensity curing for 20 s and were polished with discs.
In all groups except on (Filtek, polishing with Disk, curing time = 20 s), high-intensity curing and polishing with polishing points were more effective and caused lower color change compared with low-intensity curing and polishing with discs.
尽管复合树脂的光学性能有所改善，但其颜色稳定性仍是一个令人关注的问题。本研究旨在评估固化时间、强度和抛光技术对漂白色调复合树脂颜色稳定性的影响。
在本实验研究中，用两种复合树脂制作了128个圆盘（1毫米×8毫米）。根据固化时间、强度以及使用抛光点或圆盘进行抛光，将每种复合树脂制作的标本分为8个亚组（每组n = 8）。抛光后，根据CIELab*颜色系统，用EasyShade分光光度计测量标本的颜色参数。然后将标本浸入茶溶液中，再次测量其颜色参数。计算颜色变化（ΔE）并在0.05的显著性水平上进行分析。使用SPSS 25进行数据分析。应用单因素四向方差分析来评估复合树脂类型、固化时间、固化强度和抛光技术对ΔE的影响。由于交互作用显著，通过t检验进行亚组分析。该检验的显著性水平设定为0.05。
固化强度和抛光技术对ΔE有显著影响（P < 0.05）。用抛光点抛光的Filtek Z350 XBW复合树脂标本的颜色变化低于用圆盘抛光的标本。Gradia XBW复合树脂的最小ΔE记录在经过20秒高强度固化并用抛光点抛光的标本中，而最大ΔE记录在经过20秒高强度固化并用圆盘抛光的标本中。
除一组（Filtek，用圆盘抛光，固化时间 = 20秒）外，在所有组中，与低强度固化并用圆盘抛光相比，高强度固化并用抛光点抛光更有效，且颜色变化更小。
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