Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, SE-405 30 Gothenburg, Sweden.
J Dent. 2010 Jan;38(1):72-81. doi: 10.1016/j.jdent.2009.09.006.
In this study, morphological and chemical changes in teeth enamel exposed to alkaline agents, with or without surfactants, have been investigated. In addition, chemical effects of the organic surface layer, i.e. plaque and pellicle, were also investigated.
The present study was conducted using several techniques: Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM).
From XPS-measurements, it was found that exposure to alkaline solutions resulted in a massive removal of carbon from the tooth surface, and that the addition of surfactants increased the rate under present conditions. Based on the results from the FTIR-analysis, no substitution reactions between phosphate, carbonate and hydroxide ions in the enamel apatite could be detected. From a minor SEM-analysis, degradation and loss of substance of the enamel surface was found for the exposed samples. From XRD-analysis, no changes in crystallinity of the enamel apatite could be found between the samples.
The findings in this study show that exposure to alkaline solutions results in a degradation of enamel surfaces very dissimilar from acidic erosion. No significant erosion or chemical substitution of the apatite crystals themselves could be discerned. However, significant loss of organic carbon at the enamel surface was found in all exposed samples. The degradation of the protective organic layer at the enamel surface may profoundly increase the risk for caries and dental erosion from acidic foods and beverages.
本研究调查了暴露于碱性剂、有或没有表面活性剂的牙釉质的形态和化学变化。此外，还研究了有机表层（即菌斑和牙垢）的化学效应。
本研究使用了几种技术：傅里叶变换红外光谱（FTIR）、X 射线光电子能谱（XPS）、X 射线衍射（XRD）和扫描电子显微镜（SEM）。
从 XPS 测量结果发现，暴露于碱性溶液会导致牙齿表面大量去除碳，并且在目前条件下添加表面活性剂会增加这种去除速率。基于 FTIR 分析的结果，在牙釉质磷灰石中磷酸盐、碳酸盐和氢氧化物离子之间没有检测到取代反应。从少量的 SEM 分析中发现，暴露的样品的牙釉质表面发生了降解和物质损失。从 XRD 分析来看，暴露组样本的牙釉质磷灰石的结晶度没有变化。
本研究的结果表明，暴露于碱性溶液会导致牙釉质表面的降解，与酸性侵蚀非常不同。没有发现磷灰石晶体本身有明显的侵蚀或化学取代。然而，在所有暴露的样本中都发现了牙釉质表面有机碳的大量损失。牙釉质表面保护性有机层的降解可能会极大地增加酸性食物和饮料引起龋齿和牙侵蚀的风险。
