Department of Restorative Dentistry, Faculty of Dentistry, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil.
Metallurgical and Materials Engineering Program, COPPE, Rio de Janeiro, RJ, Brazil.
Indian J Dent Res. 2020 Nov-Dec;31(6):924-929. doi: 10.4103/ijdr.IJDR_791_19.
The side effects of bleaching products are still incompletely known.
This work aims to evaluate the effects of bleaching regimens on colour variation, microstructure, roughness, composition and nanohardness of human dental enamel until 8 weeks.
: Twenty teeth were cross-sectioned to obtain eighty enamel fragments (50 × 50 mm) divided into four groups: CN (control Negative-artificial saliva), CP10 (10% carbamide peroxide), HP10 (10% hydrogen peroxide), and WS (whitening strips-10% hydrogen peroxide).
Roughness (atomic force microscopy-AFM and 3-D surface scanning), morphology (confocal laser scanning microscopy-CLSM and AFM), hardness and elastic modulus (nanoindentation), and composition (Raman microspectroscopy) were analysed before the therapy and after 4 and 8 weeks. Colour measures were performed weekly.
: Two-way ANOVA with repeated measures (P < 0.05).
Bleaching stabilizes after 3 weeks for HP10 and after 4 weeks for CP10 and WS. Roughness evaluation showed statistical difference for HP10 after 8 weeks for Sa and Sq, for HP10 and WS after 4 weeks and for CP10 after 8 weeks. The same occurred for hardness and elastic modulus. The morphological evaluation demonstrated the most significant effects after 8 weeks of treatment for HP10 and WS. Composition analysis revealed modifications in peaks related to the organic content spectra (protein) with an increase in detection after 4 weeks, followed by a decrease after 8 weeks.
HO-based products caused morphological and compositional alterations on enamel.
漂白产品的副作用仍不完全清楚。
本研究旨在评估漂白方案对人牙釉质颜色变化、微观结构、粗糙度、成分和纳米硬度的影响，直至 8 周。
将 20 颗牙齿横切成 80 个牙釉质碎片（50×50mm），分为 4 组：CN（对照阴性-人工唾液）、CP10（10%尿素过氧化物）、HP10（10%过氧化氢）和 WS（美白条-10%过氧化氢）。
在治疗前和治疗后 4 周和 8 周，用原子力显微镜（AFM）和三维表面扫描法测量粗糙度，用共聚焦激光扫描显微镜（CLSM）和 AFM 测量形貌，用纳米压痕法测量硬度和弹性模量，用拉曼微光谱法测量成分。每周进行颜色测量。
采用双向重复测量方差分析（P<0.05）。
HP10 组在治疗 3 周后、CP10 组和 WS 组在治疗 4 周后漂白稳定。8 周后，HP10 组的 Sa 和 Sq、4 周后 HP10 组和 WS 组以及 8 周后 CP10 组的粗糙度评估有统计学差异。硬度和弹性模量也有同样的情况。8 周治疗后，HP10 和 WS 组的形态评估显示出最显著的影响。成分分析显示，与有机成分谱（蛋白质）相关的峰在治疗 4 周后增加，8 周后减少。
基于 HO 的产品会导致牙釉质形态和成分的改变。
