Roberts Howard, Berzins David, Nicholson John
Dental Biomaterials Research, College of Dentistry, University of Kentucky, Lexington, KY 40536, USA.
Graduate Dental Biomaterials, School of Dentistry, Marquette University, Milwaukee, WI 53233, USA.
Materials (Basel). 2022 Jan 21;15(3):807. doi: 10.3390/ma15030807.
The complex role of water in glass ionomer cement (polyalkenoate) dental restorative materials has been studied, but much of the present understanding concerning water balance within these materials is based on very early studies and short-term experiments. This study evaluated the nature of the water species of six conventional and four resin modified glass ionomer restorative materials over 3 years using thermogravimetric analysis techniques. Materials were prepared, placed in crucibles, and stored in physiologic phosphate buffered saline and evaluated at 24 h, 1 week, and then at 1, 3, 6, 9, 12, 18, 24, 30 and 36 months. All materials demonstrated a significant increase in unbound water percentage content but except for the resin modified materials, the enthalpy required to remove the unbound water species did not significantly change over 36 months. Also, bound water content percentage and removal enthalpy was established at 24 h, as no significant increase was noted in both bound water content and removal enthalpy over the course of this evaluation. This study suggests that unbound water species may increase with time and is loosely held except for the resin modified materials. Protective coatings placement and re-evaluation are prudent to prevent unbound water loss.
水在玻璃离子水门汀（聚烯烃酸酯）牙科修复材料中的复杂作用已得到研究，但目前关于这些材料内水平衡的许多认识是基于非常早期的研究和短期实验。本研究使用热重分析技术，在3年时间里评估了六种传统玻璃离子修复材料和四种树脂改性玻璃离子修复材料中的水种类性质。制备材料，将其置于坩埚中，储存在生理磷酸盐缓冲盐水中，并在24小时、1周以及1、3、6、9、12、18、24、30和36个月时进行评估。所有材料的游离水百分比含量均显著增加，但除树脂改性材料外，去除游离水种类所需的焓在36个月内未发生显著变化。此外，在24小时时确定了结合水含量百分比和去除焓，因为在此评估过程中结合水含量和去除焓均未显著增加。本研究表明，除树脂改性材料外，游离水种类可能随时间增加且结合松散。放置保护涂层并重新评估对于防止游离水损失是明智的。
