Bertacci Angelica, Lucchese Alessandra, Taddei Paola, Gherlone Enrico F, Chersoni Stefano
1 School of Dentistry, Department of Biomedical and Neuromotor Sciences (DiBiNeM), University of Bologna, Bologna - Italy.
J Appl Biomater Funct Mater. 2014 Dec 30;12(3):240-7. doi: 10.5301/jabfm.5000179.
The aim of this study was to evaluate enamel acid-induced structural changes after 2 different treatments, by means of Raman and infrared (IR) spectroscopy analyses, and to correlate these findings with permeability measured as fluid discharge from outer enamel.
Two different treatments were investigated: 10 enamel slices were etched with 15% hydrochloric acid (HCl) for 120 seconds and 10 slices with 37% phosphoric acid gel (H3PO4) for 30 seconds, rinsed for 30 seconds and then air-dried for 20 seconds. Powders of enamel treated as previously described were produced. Replicas of enamel subjected to the same treatments were obtained to evaluate the presence of fluid droplets on enamel surface.
Raman and IR spectroscopy showed that the treatment with both hydrochloric and phosphoric acids induced a decrease in the carbonate content of the enamel apatite. At the same time, both acids induced the formation of HPO42- ions. After H3PO4 treatment, the bands due to the organic component of enamel decreased in intensity, while they increased after HCl treatment. Replicas of H3PO4 treated enamel showed a strongly reduced permeability. Replicas of HCl 15% treated samples showed a maintained permeability. A decrease of the enamel organic component, as resulted after H3PO4 treatment, involves a decrease in enamel permeability, while the increase of the organic matter (achieved by HCl treatment) still maintains enamel permeability.The results suggested a correlation between organic matter and enamel permeability. Permeability was affected by etching technique and could be involved in marginal seal, gap and discoloration at the enamel interface, still causes of restoration failure.
本研究旨在通过拉曼光谱和红外（IR）光谱分析评估两种不同处理后牙釉质酸诱导的结构变化，并将这些发现与从牙釉质外层测量的液体排出量所表示的渗透性相关联。
研究了两种不同的处理方法：10片牙釉质切片用15%盐酸（HCl）蚀刻120秒，10片用37%磷酸凝胶（H3PO4）蚀刻30秒，冲洗30秒，然后风干20秒。制备了按上述方法处理的牙釉质粉末。获得了经过相同处理的牙釉质复制品，以评估牙釉质表面液滴的存在情况。
拉曼光谱和红外光谱显示，盐酸和磷酸处理均导致牙釉质磷灰石中碳酸盐含量降低。同时，两种酸均诱导形成HPO42-离子。经H3PO4处理后，牙釉质有机成分产生的谱带强度降低，而经HCl处理后则增加。经H3PO4处理的牙釉质复制品显示渗透性大幅降低。经15%HCl处理的样品复制品显示渗透性保持不变。如H3PO4处理后所显示的，牙釉质有机成分的减少涉及牙釉质渗透性的降低，而（通过HCl处理实现的）有机物增加仍保持牙釉质渗透性。结果表明有机物与牙釉质渗透性之间存在相关性。渗透性受蚀刻技术影响，可能与牙釉质界面处的边缘封闭、间隙和变色有关，这些仍是修复失败的原因。
