Does the use of glycerin gel improve the color stability of composite resins?

Abstract Introduction The resin composite superficial layer not polymerized due to the presence of oxygen leads to clinical problems as color alteration by the absorption of pigments. Objective Evaluate the effect of different techniques to control the formation of the composite resin dispersion layer on the optical properties of a commercial composite. Material and method Resin composite Estelite Sigma specimens were made. The specimens were light-cured with the LED Bluephase G2 device (1200 mW/cm2 - 40 s). The groups were determined according to three different techniques: 1) no treatment (control); 2) light-curing through a glycerin gel layer on the surface; 3) polishing with abrasive discs after light-curing. The color stability (ΔE) and the translucency parameter were determined by the spectroscopy method (Easyshade Compact Vita) as a function of the CIELab parameter. The analyzes were performed immediately after photoactivation and repeated after 7 days of storage in water or 7 days in coffee. The results were submitted to ANOVA and Tukey test (α = 0.05). Result No difference was found for ΔE in groups aged in water. When stored in coffee, the control group had the highest value of ΔE while the polished group generated the lowest color change. The glycerin gel groups promoted intermediated results. The translucency parameter was not affected by the treatments tested. Conclusion: The glycerin-based gel layer minimizes the color change in those regions that the finishing and polishing instruments are difficult to access.

【摘要 引言】因氧气存在而未聚合的树脂复合材料（resin composite）表层，会因色素吸附引发色泽改变等临床问题。目的 评估不同控制复合树脂弥散层（composite resin dispersion layer）形成的技术，对市售复合树脂（commercial composite）光学性能的影响。材料与方法 制作Estelite Sigma树脂复合材料试件，采用LED Bluephase G2光固化设备（功率密度1200 mW/cm²，光照时长40 s）完成光固化。根据处理方式分为三组：1）空白对照组（不作任何处理）；2）在试件表面涂布甘油凝胶层后进行光固化；3）光固化完成后使用研磨盘进行抛光。采用分光光度法结合Easyshade Compact Vita设备，依据CIELab色彩参数测定试件的颜色稳定性（ΔE）与半透明度参数。检测分别在光固化后即刻开展，并在去离子水储存7天、咖啡溶液储存7天后重复进行。所有实验数据采用单因素方差分析（ANOVA）与Tukey检验进行统计学分析，检验水准设定为α=0.05。结果 经去离子水储存的各组试件ΔE值无统计学差异。在咖啡溶液中储存时，对照组ΔE值最高，抛光组的颜色变化幅度最低，甘油凝胶组的检测结果介于两者之间。本研究所采用的三种处理方式均未对半透明度参数产生显著影响。结论 甘油基凝胶层可有效减少修复体难以进行修整抛光区域的色泽变化。