Kakaboura A, Eliades G, Palaghias G
Research Center for Biomaterials, Athens, Greece.
Dent Mater. 1996 May;12(3):173-8. doi: 10.1016/s0109-5641(96)80017-0.
An experimental method was used to assess the glass ionomer and resinous character in three "dual-cure" (Fuji II LC, Photac-Fil, Variglass) and a "triple-cure" (Vitremer) resin-modified glass ionomer restoratives to evaluate their acid-base and free-radical setting mechanisms.
Four groups (A-D) of three specimens (5 x 4 x 1 mm) were prepared from each material and subjected to the following treatments: A: mixing; B,C: mixing, 60 s irradiation, 20 min dark/dry storage; and D: mixing, 20 min dark/dry storage and then 60 s irradiation. Micro-multiple internal reflectance FTIR spectroscopy was used to determine: 1) the curing efficiency of the products immediately after irradiation; 2) the effect of irradiation 20 min after dark/dry storage on the curing efficiency; and 3) the extent of the acid-base reaction on irradiated and non-irradiated specimens after 20 min dark/dry storage.
The curing efficiency immediately after irradiation was determined from the percentage of residual double bonds which ranged from 33-50% for these materials. Irradiation after 20 min dark/dry storage significantly reduced curing efficiency in all the products, except Variglass. The latter showed no acid-base reaction under the conditions of this study. Non-irradiated specimens after the dark storage period demonstrated higher carboxylate yields compared to their irradiated analogues. Non-irradiated specimens from Vitremer had the highest carboxylate yield and a curing efficiency of approximately 50% residual double bonds.
Photopolymerization seemed to greatly reduce the acid-base reaction during the early setting stages of resin-modified glass ionomer restoratives. The free-radical formation rates are slower than those achieved by chemically initiated polymerization, but they produce adequate conversion and high carboxylate salt yields. This study demonstrated an experimental model for identification and characterization of the acid-base reaction in water-containing resinmodified glass ionomer restoratives.
采用实验方法评估三种“双固化”（富士II LC、光固化玻璃离子水门汀、VariGlass）和一种“三固化”（Vitremer）树脂改性玻璃离子修复材料的玻璃离子体和树脂特性，以评估其酸碱和自由基固化机制。
从每种材料制备四组（A-D）三个样本（5×4×1毫米），并进行以下处理：A：混合；B、C：混合，60秒照射，20分钟黑暗/干燥储存；D：混合，20分钟黑暗/干燥储存，然后60秒照射。采用显微多重内反射傅里叶变换红外光谱法测定：1）照射后立即测定产品的固化效率；2）黑暗/干燥储存20分钟后照射对固化效率的影响；3）黑暗/干燥储存20分钟后照射和未照射样本上酸碱反应的程度。
照射后立即测定的固化效率由残余双键百分比确定，这些材料的残余双键百分比范围为33%-50%。黑暗/干燥储存20分钟后照射显著降低了所有产品的固化效率，但VariGlass除外。在本研究条件下，后者未显示酸碱反应。黑暗储存期后的未照射样本与照射后的类似样本相比，羧酸盐产率更高。Vitremer的未照射样本羧酸盐产率最高，残余双键固化效率约为50%。
光聚合似乎在树脂改性玻璃离子修复材料的早期固化阶段极大地减少了酸碱反应。自由基形成速率比化学引发聚合慢，但能产生足够的转化率和高羧酸盐产率。本研究展示了一种用于识别和表征含水性树脂改性玻璃离子修复材料中酸碱反应的实验模型。
