High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial

Abstract Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient’s sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients’ perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.

摘要 研究目的：本项单盲随机平行临床试验，旨在评估37%过氧化脲（carbamide peroxide, CP）应用于诊室内牙齿漂白时的漂白效果与患者自述的牙齿敏感度，并与35%过氧化氢（hydrogen peroxide, HP）的临床效果进行对比。
材料与方法：将40例患者随机分配至两组，分别接受两次诊室内牙齿漂白治疗，所用漂白剂分别为35%过氧化氢（HP）或37%过氧化脲（CP）。于每次漂白治疗期间及治疗后24小时内，评估每位患者的牙齿敏感度水平。分别于每次治疗后1周、末次治疗后30天，采用分光光度计（spectrophotometer）评估漂白效果。此外，记录牙齿漂白操作及其效果对患者关于笑容改观的主观感知的影响。计算敏感度的绝对风险与相对风险。敏感度水平数据采用曼-惠特尼检验（Mann-Whitney test）或t检验（T-test）进行分析，颜色评估数据则采用双向重复测量方差分析（two-way repeated measures ANOVA）进行分析。
结果：使用过氧化脲（CP）可将牙齿敏感度的发生风险与严重程度降至接近零，但两种漂白剂的敏感度差异在术后24小时便不复存在。过氧化氢（HP）组的漂白效果更为显著，这主要源于其对牙齿红染与黄染的改善效果更佳。受试者认为过氧化氢（HP）的牙齿漂白效果更优，过氧化脲（CP）组的牙齿敏感度更低，但两种操作的舒适度并无显著差异。
结论：本研究中，37%过氧化脲（CP）可有效降低牙齿敏感度，但漂白效果稍逊一筹。不过两种漂白剂均获得了较高的患者满意度。