Due to the multiple factors contributing to dentin demineralization and hypersensitivity among individuals, the effectiveness of the available treatments in the long term remains unclear. A recent study reported a simple strategy to potentially mimic natural remineralization with increased crystallization on the enamel caries using fluoride iontophoresis. Such an effect is also ideal for accomplishing dentin biomineralization and structural strength. This study aimed to investigate structural and compositional characteristics and permeability changes after fluoride iontophoresis with different polarities, cathodal iontophoresis (CIP), anodal iontophoresis (AIP), and the control without iontophoresis for the treatment of etched dentin under simulated pulpal pressure. The 24 premolars were divided into 3 groups: CIP, AIP, and topical application of 5% sodium fluoride (NaF) for 40 s. Relative to before treatment, iontophoresis with both polarities significantly decreased the permeability with a visible increase in occluding tubules containing crystal formation and growth throughout the dentin structure and depth. The CIP not only restored the etched dentin surface into a sound condition but also reinforced the dentin across the structure and depth by the synergistic effects of remineralization, increasing crystal formation and transformation toward the more crystalline structure of fluorohydroxyapatite. Following topical treatment, X-ray diffraction analysis and Raman spectra revealed a significant reduction in the crystal size and crystallinity associated with the raised B-type carbonate substitution into the hydroxyapatite compared with that in the sound dentin. The result was the first to reveal the ideal strategy to rapidly restore the etched dentin surface into a sound condition, including reinforcing the dentin across the structure and depth by the synergistic effects of decreasing permeability, increasing crystal formation, and transformation toward the more crystalline structure of fluorohydroxyapatite using the 5% NaF applied with the DC cathode iontophoresis. The technique is noninvasive and simple and deserves further development for clinical application.

中文翻译：

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氟化物离子电渗疗法后牙本质上的氟羟基磷灰石增加


由于导致牙本质脱矿和个体过敏的多种因素，现有治疗方法的长期有效性仍不清楚。最近的一项研究报告了一种简单的策略，可以通过使用氟化物离子电渗疗法增加牙釉质龋齿的结晶来模拟自然再矿化。这种效果对于实现牙本质生物矿化和结构强度也是理想的。本研究旨在探讨模拟牙髓压力下不同极性氟化物离子电渗疗法、阴极离子电渗疗法（CIP）、阳极离子电渗疗法（AIP）以及无离子电渗疗法对照处理酸蚀牙本质后的结构和成分特征以及渗透性变化。 24颗前磨牙分为3组：CIP、AIP和局部涂抹5%氟化钠（NaF）40秒。与治疗前相比，两种极性的离子电渗疗法均显着降低了渗透性，并且在整个牙本质结构和深度中包含晶体形成和生长的闭塞小管明显增加。 CIP 不仅使酸蚀的牙本质表面恢复到良好状态，而且通过再矿化、增加晶体形成和向氟羟基磷灰石的结晶结构转变的协同效应，在结构和深度上强化了牙本质。局部治疗后，X 射线衍射分析和拉曼光谱显示，与完好牙本质相比，与羟基磷灰石中 B 型碳酸盐取代量增加相关的晶体尺寸和结晶度显着降低。 该研究结果首次揭示了将酸蚀牙本质表面快速恢复到良好状态的理想策略，包括通过降低渗透性、增加晶体形成以及向更多晶体结构转变的协同效应，在结构和深度上强化牙本质使用 5% NaF 和直流阴极离子电渗法对氟羟基磷灰石进行分析。该技术无创、操作简单，值得进一步开发应用于临床。