Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
Dental Physical Sciences, Barts and the London School of Medicine and Dentistry, Institute of Dentistry, Queen Mary University of London, London, UK.
Sci Rep. 2021 Aug 3;11(1):15734. doi: 10.1038/s41598-021-95279-x.
This study investigated the interaction of borate ions released from surface pre-reacted glass ionomer (S-PRG) fillers with the biological apatites of enamel and dentin using solid-state (SS) magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy analysis. We further evaluated the effect of borate ions on the pH change. Bovine enamel and dentin powder were submerged in S-PRG eluate (with borate ion concentration of 100 mM) for 3 h, then washed with deionized water (DW). The dried enamel and dentin specimens were used for B SS-NMR and Fourier transform infrared spectroscopy (FT-IR) analysis. Enamel and dentin blocks were treated with three solutions: DW (control), S-PRG eluent and borate solution (100 mM). The treated samples were submerged in the demineralization solution and the pH was measured using a pH meter daily for 6 days. The surfaces of the enamel and dentin blocks were then observed using field emission scanning electron microscopy (FE-SEM). SS-NMR analysis revealed the presence of adsorbed borate ions in the enamel and dentin samples in a tetra-coordinated form. The pH results demonstrated an increase in pH values in the S-PRG and borate groups. SEM images showed that the surfaces of the control group were demineralized, whereas the surfaces of the S-PRG and borate groups were intact. These results concluded that borate ions could be adsorbed to enamel and dentin in the tetra-coordinated form. Borate ions possess a buffer capacity which may help to protect the tooth structure against acid attacks and promote remineralization.
本研究采用固态（SS）魔角旋转核磁共振（MAS-NMR）光谱分析，研究了表面预反应玻璃离子（S-PRG）填料释放的硼酸根离子与牙釉质和牙本质生物磷灰石的相互作用。我们进一步评估了硼酸根离子对 pH 值变化的影响。将牛牙釉质和牙本质粉末浸泡在 S-PRG 洗脱液（硼酸根离子浓度为 100 mM）中 3 小时，然后用去离子水（DW）冲洗。干燥后的牙釉质和牙本质标本用于硼的 SS-NMR 和傅里叶变换红外光谱（FT-IR）分析。牙釉质和牙本质块用三种溶液处理：DW（对照）、S-PRG 洗脱液和硼酸溶液（100 mM）。处理后的样品被浸泡在脱矿溶液中，每天使用 pH 计测量 pH 值，持续 6 天。然后使用场发射扫描电子显微镜（FE-SEM）观察牙釉质和牙本质块的表面。SS-NMR 分析表明，在牙釉质和牙本质样品中，硼酸根离子以四配位形式存在。pH 值结果表明 S-PRG 和硼酸组的 pH 值升高。SEM 图像显示，对照组的表面脱矿，而 S-PRG 和硼酸组的表面完整。这些结果表明，硼酸根离子可以以四配位的形式吸附到牙釉质和牙本质上。硼酸根离子具有缓冲能力，可以帮助保护牙齿结构免受酸的攻击，并促进再矿化。
