Genotoxic potential of 10% and 16% Carbamide Peroxide in dental bleaching

Dental bleaching has become one of the most frequently requested esthetic treatments in dental offices. Despite the high clinical success observed with this procedure, some adverse effects have been reported, including a potential for developing premalignant lesions, root resorption and tooth sensitivity, especially when misused. The aim of this study was to evaluate the genotoxic response using a micronucleus (MN) assay, after the application of two concentrations of carbamide peroxide. Thirty-seven patients were divided into two groups and randomly received either a 10% carbamide peroxide (CP) (19) or a 16% carbamide peroxide (18) concentration for 21 days in individual dental trays. Gingival margin cells were collected immediately before the first use (baseline), and then 15 and 45 days after baseline. The cells were placed on a histological slide, stained by the Feulgen technique, and evaluated by an experienced blinded examiner. One thousand cells per slide were counted, and the MN rate was determined. The two groups were analyzed by the Wilcoxon rank-sum test and the Kruskal-Wallis equality-of-populations rank test. A slight increase in MN was observed for both groups, in comparison with the baseline, at 15 days. However, no difference was observed between the two groups (10% and 16%), at either 15 or 45 days (p = 0.90). When bleaching is not prolonged or not performed very frequently, bleaching agents containing carbamide peroxide alone will not cause mutagenic stress on gingival epithelial cells.

牙齿漂白现已成为牙科诊所中患者最常要求的美学诊疗项目之一。尽管该操作临床疗效优异，但已有研究报道其存在部分不良反应，包括可能诱发癌前病变、牙根吸收以及牙齿敏感，尤其在不当使用的情况下。本研究旨在通过微核（micronucleus, MN）试验，评估两种浓度过氧化脲（carbamide peroxide）应用后引发的遗传毒性反应。共纳入37例患者并随机分为两组，通过定制牙科托盘分别施加10%过氧化脲（CP，19例）或16%过氧化脲（18例），持续干预21天。分别于首次干预前（基线）、基线后15天及45天收集龈缘细胞。将细胞涂布于组织切片上，采用福尔根（Feulgen）染色法进行染色，由一名盲法经验丰富的检查者完成评估。每张切片计数1000个细胞，计算微核率。采用Wilcoxon秩和检验与Kruskal-Wallis多样本秩检验对两组数据进行统计分析。结果显示，相较于基线水平，两组在15天时微核数量均出现轻微升高；但在15天及45天两个时间点，10%与16%浓度组间均未观察到显著差异（p=0.90）。本研究表明，若非长期或高频使用，仅含过氧化脲的牙齿漂白剂不会对龈缘上皮细胞产生诱变应激。