Ferreira Artemisa Fernanda Moura, Perez Flávia Maria de Moraes Ramos, Limeira Júnior Francisco de Assis, de Moura Mirella de Fátima Liberato, de Sousa Frederico Barbosa
Master Program in Dentistry, Health Sciences Center, Federal University of Pernambuco, Av. Prof. Moraes Rego 1235, 50670-901 Recife, Pernambuco, Brazil.
Department of Morphology, Health Science Center, Federal University of Paraiba, Cidade Universitária, 58051-900 João Pessoa, Paraiba, Brazil.
Arch Oral Biol. 2016 May;65:52-8. doi: 10.1016/j.archoralbio.2016.01.016. Epub 2016 Jan 29.
To test the hypothesis that changes in enamel component volumes (mineral, organic, and water volumes, and permeability) are graded from outer to inner enamel after a short bleaching procedure.
Extracted unerupted human third molars had half of their crowns bleached (single bleaching session, 3 × 15 min), and tooth shade changes in bleached parts were analyzed with a spectrophotometer. Ground sections were prepared, component volumes and permeability were quantified at histological points located at varying distances from the enamel surface (n=10 points/location), representing conditions before and after bleaching.
Tooth shade changes were significant (p<0.001; 95% CI=-1/-8; power=99%), and most of the enamel layer was unaffected after bleaching, except at the outer layers. Multiple analysis of covariances revealed that most of the variance of the change in enamel composition after bleaching was explained by the combination of the set of types of component volume (in decreasing order of relevance: mineral loss, organic gain, water gain, and decrease in permeability) with the set of distances from the enamel surface (graded from the enamel surface inward) (canonical R(2)=0.97; p<0.0001; power>99%).
Changes in enamel composition after a short bleaching procedure followed a gradient within component volumes (mineral loss>organic gain>water gain>decrease in permeability) and decreased from the enamel surface inward.
验证以下假设：在经过短时间漂白程序后，牙釉质成分体积（矿物质、有机物和水的体积以及渗透性）的变化从牙釉质外层到内层呈梯度变化。
提取未萌出的人类第三磨牙，将其牙冠的一半进行漂白（单次漂白，每次15分钟，共3次），并用分光光度计分析漂白部分的牙齿颜色变化。制备磨片，在距牙釉质表面不同距离的组织学位点（每个位置n = 10个点）定量分析成分体积和渗透性，以代表漂白前后的情况。
牙齿颜色变化显著（p<0.001；95%置信区间=-1/-8；检验效能=99%），除外层外，漂白后牙釉质层的大部分未受影响。多变量协方差分析显示，漂白后牙釉质成分变化的大部分方差可由成分体积类型集（按相关性降序排列：矿物质流失、有机物增加、水增加和渗透性降低）与距牙釉质表面的距离集（从牙釉质表面向内分级）的组合来解释（典型R(2)=0.97；p<0.0001；检验效能>99%）。
短时间漂白程序后牙釉质成分的变化在成分体积内呈梯度变化（矿物质流失>有机物增加>水增加>渗透性降低），并从牙釉质表面向内递减。
