Department of Restorative Dentistry, São Paulo State University, São José dos Campos, School of Dentistry, São Paulo, SP, Brazil.
Acta Odontol Scand. 2012 Mar;70(2):122-6. doi: 10.3109/00016357.2011.600704. Epub 2011 Jul 25.
The aim of this study was to assess the enamel microhardness treated with three in-office bleaching agents, containing 35% hydrogen peroxide with different acidity.
Bovine incisors were divided into three groups that received the following bleaching agents: Whiteness HP, Total Bleach and Opalescence Xtra. Three gel applications/10-min each, totaling 30-min of bleaching treatment, were made on the teeth and activated with a blue LED (1000 mW/470 nm) combined to a LASER (120 mW/795 nm) device (Easy Bleach-Clean Line). Vickers hardness (VH) was evaluated at baseline and after the bleaching procedure. The values of Hardness loss [HNL] (% reduction) were calculated. The two-sample t-test was used for comparison of the HNL of the three bleaching products (5% level of significance).
The Opalescence Xtra, which had the lowest pH value (pH = 4.30), showed a significant increase of HNL when compared with Total Bleach bleaching agent, which had the highest pH value (pH = 6.62).
The 35% hydrogen peroxide bleaching agents resulted in a reduction in surface enamel microhardness and bleaching with the most acid agent resulted in a significant enamel hardness loss compared to the less acid agent (4.30 vs 6.62). Strategies proposed to reduce the enamel loss after bleaching treatment may include the use of daily fluoride therapy, mouth rinsing (fluoride, milk and sodium bicarbonate solution), fluoride/bicarbonate dentifrices without abrasives, do not toothbrush immediately after bleaching, fluorides and calcium add to bleaching agents.
本研究旨在评估三种诊室用漂白剂处理后的牙釉质显微硬度，这些漂白剂均含有 35%浓度的过氧化氢，但酸度不同。
将牛切牙分为三组，分别用以下三种漂白剂处理：Whiteness HP、Total Bleach 和 Opalescence Xtra。每颗牙齿使用 3 次凝胶（每次 10 分钟），每次漂白处理 30 分钟，用蓝 LED（1000 mW/470nm）和 LASER（120 mW/795nm）设备（Easy Bleach-Clean Line）激活。在基线和漂白处理后评估维氏硬度（VH）。计算硬度损失[HNL]（%减少）的值。使用双样本 t 检验比较三种漂白产品的 HNL（5%显著性水平）。
Opalescence Xtra 的 pH 值最低（pH = 4.30），与 pH 值最高（pH = 6.62）的 Total Bleach 漂白剂相比，HNL 显著增加。
35%浓度的过氧化氢漂白剂会降低表面牙釉质的显微硬度，而使用最酸的制剂进行漂白会导致牙釉质硬度显著丧失，与使用酸性较低的制剂相比（4.30 与 6.62）。为了减少漂白治疗后牙釉质的损失，可以采用每日氟化物治疗、漱口（含氟、牛奶和碳酸氢钠溶液）、使用不含研磨剂的氟化物/碳酸氢盐牙膏、漂白后不要立即刷牙、在漂白剂中添加氟化物和钙等策略。
