Department of Restorative Dentistry, State University of Ponta Grossa, Av. General Carlos Cavalcanti, 4748, Ponta Grossa, Brazil.
Department of Pharmaceutical Sciences, State University of Ponta Grossa, Ponta Grossa, Brazil.
Clin Oral Investig. 2024 Jul 23;28(8):440. doi: 10.1007/s00784-024-05821-0.
To evaluate the decomposition rate of active hydrogen peroxide (HP) and bleaching efficacy during in-office bleaching using high-concentration HP gels with different pHs.
A randomized, parallel, double-blind controlled trial was conducted with 40 volunteers randomized into four groups (pH 5.4; pH 7.0; pH 7.7, and pH 8.0). During the first session in-office bleaching, approximately 0.01 g of the gel was collected and titrated with potassium permanganate to obtain the concentration of active HP and pH values were measured using an electrode. Bleaching efficacy was assessed using a spectrophotometer [∆E, ∆E, and WI], Vita Classical and Vita Bleachedguide scales [∆SGU]. The decomposition rate of HP concentration and pH values change were calculated using ANOVA one-way. The bleaching efficacy was assessed using two-way repeated measures ANOVA. Tukey's test was applied as a post-hoc test (p < 0.05).
All gels experienced decreasing HP concentration over time. pH 5.4 gel showed greatest reduction after 50 min (p < 0.001). pH 8.0 and 7.7 gels remained stable; pH 5.4 remained acidic, while pH 7.0 turned acidic (p < 0.001). No significant difference in bleaching degree was observed among gels. They all showed a similar and clinically important color change after two clinical sessions, remained stable 1-month post-treatment (p > 0.05).
All bleaching gels kept at least 70% of their HP content after 50 min, suggesting that there is a surplus of HP. They provided similar whitening efficacy 1-month after bleaching.
It is possible that lower HP concentrations may be equally effective in achieving desired results while reducing the potential for side effects.
RBR-35q7s3v.
评估不同 pH 值的高浓度 HP 凝胶在诊室漂白过程中活性过氧化氢 (HP) 的分解率和漂白效果。
采用随机、平行、双盲对照试验，将 40 名志愿者随机分为 4 组（pH5.4；pH7.0；pH7.7 和 pH8.0）。在第一次诊室漂白过程中，收集约 0.01g 凝胶，用高锰酸钾滴定以获得活性 HP 浓度，并用电极测量 pH 值。使用分光光度计 [∆E、∆E 和 WI]、Vita Classical 和 Vita Bleachedguide 量表 [∆SGU] 评估漂白效果。使用方差分析单向计算 HP 浓度和 pH 值变化的分解率。使用双因素重复测量方差分析评估漂白效果。应用 Tukey 检验作为事后检验（p<0.05）。
所有凝胶在一段时间后 HP 浓度均呈下降趋势。pH5.4 凝胶在 50 分钟后降幅最大（p<0.001）。pH8.0 和 7.7 凝胶保持稳定；pH5.4 保持酸性，而 pH7.0 变为酸性（p<0.001）。凝胶之间的漂白程度无显著差异。经过两个临床疗程后，它们都表现出相似的、具有临床意义的颜色变化，治疗后 1 个月保持稳定（p>0.05）。
所有漂白凝胶在 50 分钟后仍保持至少 70%的 HP 含量，表明 HP 仍有剩余。它们在漂白后 1 个月提供了相似的美白效果。
在降低副作用风险的同时，降低 HP 浓度可能同样有效，以达到预期效果。
RBR-35q7s3v。
