Effect of tooth enamel staining by coffee consumption during at-home tooth bleaching with carbamide peroxide

Abstract Introduction Obtaining the result expected during tooth bleaching requires a correct diagnosis of the type of staining presented. The causes of tooth staining differ depending on the etiological factor. Objective To assess the color change caused by the immersion of bovine teeth in coffee solution during at-home tooth bleaching using a 16% carbamide peroxide gel. Material and method Thirty-three sound bovine teeth were assigned to three groups of eleven teeth each: 1 – Teeth bleached (TB) four hours per day for 21 days; 2 – TB four hours per day for 21 days and immersed in coffee solution immediately after tooth bleaching; 3 – TB four hours per day for 21 days and immersed in coffee solution four hours after the end of tooth bleaching. Immersed in coffee was performed for 15 minutes and tooth color was assessed before the start of the bleaching procedure and after 21 days with an intraoral spectrophotometer. Test Shapiro-Wilk was used to assess homoscedasticity and data were submitted to one-factor Analysis of Variance (ANOVA) and Tukey’s test (p <0.05). Result The color change observed in group 1 (5.76 ± 2.74)A was not statistically different from group 2 (8.83 ±5.11)A, which was immersed in coffee solution immediately after tooth bleaching, and from group 3, which was immersed in coffee solution four hours after tooth bleaching (8.20 ±3.71)A. Conclusion Coffee did not interfere with the tooth bleaching results, regardless of the time after the procedure. Hence, diet restrictions are not necessary during tooth bleaching.

摘要
引言：要获得牙齿漂白的预期效果，需对现存的牙齿着色类型作出准确诊断。牙齿着色的病因因致病因素不同而存在差异。
目的：评估使用16%过氧化脲凝胶开展居家牙齿漂白时，牛牙浸泡于咖啡溶液后所产生的颜色变化。
材料与方法：选取33颗健康完整的牛牙，分为3组，每组11颗：1组：每日进行牙齿漂白（Teeth bleached，TB）4小时，持续21天；2组：每日进行牙齿漂白（Teeth bleached，TB）4小时共21天，且在漂白操作结束后立即浸泡于咖啡溶液；3组：每日进行牙齿漂白（Teeth bleached，TB）4小时共21天，且在漂白操作结束4小时后浸泡于咖啡溶液。所有浸泡操作均持续15分钟。分别于漂白操作开始前及21天后，使用口内分光光度计评估牙齿颜色。采用夏皮罗-威尔克（Shapiro-Wilk）检验评估方差齐性，数据采用单因素方差分析（Analysis of Variance，ANOVA）及图基（Tukey）检验进行分析（p<0.05）。
结果：第1组的颜色变化值为5.76±2.74，与第2组（8.83±5.11，漂白后立即浸泡咖啡溶液）及第3组（8.20±3.71，漂白后4小时浸泡咖啡溶液）均无统计学差异。
结论：无论漂白后间隔时长如何，咖啡均不会对牙齿漂白效果产生干扰。因此，牙齿漂白期间无需进行饮食限制。