Capacity analysis of pigment removal of composite resin by hydrogen peroxide 35%

Abstract Objective Evaluate in vitro the ability to removal pigments of composite resin after application of hydrogen peroxide 35%. Material and method Concocted to-20 resin samples composed Opallis (FGM), A1 color, in circular metal matrix. The samples were divided into 4 groups (n = 5) the following coloring agents: distilled water (control), coffee, red wine and Coca-Cola®. In the staining, the samples were immersed in the solutions for 72 hours, with daily change of beverages. Proceeded to the application of 35% hydrogen peroxide gel (Whiteness HP Blue Calcium, FGM) in 3 sessions, one application of gel per session that remained in the samples for 40 minutes. Color measurements were made initially after staining after application of the peroxide and for 21 days using Vita Easyshade spectrophotometer. The data were submitted to two-way ANOVA and Tukey’s test (α = 0.05). Result Significant color change was observed in specimens after immersion in the solutions, except the control group. Hydrogen peroxide was capable of removing the stains, however the color did not return to the baseline in any of the staining groups, especially for the groups immersed in coffee. Conclusion Staining solutions can stain the composite resin. The application of 35% hydrogen peroxide can remove partially the staining, minimizing the color change produced by the staining solutions. However, the bleaching gel was not capable of removing all staining, especially for the coffee group.

摘要 目的：评估35%过氧化氢（hydrogen peroxide）应用后，复合树脂（composite resin）的体外脱色能力。
材料与方法：选用A1色的Opallis（FGM）复合树脂，使用圆形金属模具制备20个树脂样本。将样本分为4组（n=5），分别采用以下着色剂处理：蒸馏水（对照组）、咖啡、红酒及可口可乐®（Coca-Cola®）。染色过程中，将样本浸入对应溶液72小时，每日更换饮品。随后分3次应用35%过氧化氢凝胶（Whiteness HP Blue Calcium，FGM），每次凝胶在样本表面留存40分钟。使用维塔Easyshade分光光度计（Vita Easyshade spectrophotometer）分别于染色后、过氧化氢应用后以及21天后进行颜色测量。数据采用双因素方差分析（two-way ANOVA）及Tukey检验（Tukey’s test）进行统计学分析，显著性水平设定为α=0.05。
结果：除对照组外，其余各组样本经溶液浸泡后均出现显著色泽变化。过氧化氢可去除树脂表面污渍，但所有着色组的色泽均未恢复至基线水平，其中咖啡浸泡组的色泽恢复效果最差。
结论：各类着色溶液可使复合树脂发生染色。35%过氧化氢可部分去除污渍，减轻着色溶液引发的色泽变化，但该漂白凝胶无法完全清除所有污渍，尤以咖啡浸泡组最为显著。