Effect of solvent in 1-step self-etching adhesives on degree of conversion and long-term durability

Objective.本研究的目的是1）澄清一步自酸蚀胶粘剂（1-SEA）的空气干燥时间与溶剂蒸发度（艾德）之间的关系; 2）评估艾德对胶粘剂的极限微拉伸强度（UTS）的影响。方法.通过重量分析法测定三种1-SEA、iBond（Heraus kulzer）、G-BOND（GC）和S3 BOND（kuraray）在0、5和10秒空气干燥后的艾德。然后，评价在相当于0、5和10秒空气干燥的艾德下的粘合剂的UTS。结果ED随着风干时间的延长而增加。对于粘合剂之间的比较，iBond显示出最大的艾德，其次是G-BOND和S3 BOND。关于UTS，较长的风干时间导致较大的UTS。在粘合剂之间的比较中，S3 BOND（含HEMA的粘合剂）显示出比其他两种粘合剂（不含HEMA的粘合剂）更大的UTS。意义空气干燥对去除1-SEA中所含的溶剂并获得较大的UTS具有显著效果。因此，通过彻底的强力空气干燥尽可能多地去除溶剂对于界面处牢固硬化的粘合剂层可能是至关重要的。

Objective. The objectives of the present study were 1) to clarify the relationship between the duration of air-drying for one-step self-etch adhesives (1-SEA) and evaporation degree (ED) of solvents, and 2) to evaluate the effect of ED on the ultimate micro-tensile strength (UTS) of the adhesives. Methods. The ED of three 1-SEA, iBond (Heraus kulzer), G-BOND (GC) and S3 BOND (kuraray), after 0, 5 and 10 sec air-drying was decided by gravimetric method. After that, the UTSs of the adhesives at ED equivalent to 0, 5 and 10 sec air-drying were evaluated. Results. EDs were increased by extension of air-drying time. As for the comparison between the adhesives, iBond showed the largest ED, and followed by G-BOND and S3 BOND. Regarding UTS, longer air-drying time resulted in larger UTS. In comparison between the adhesives, S3 BOND (HEMA containing adhesive) showed larger UTS than the other two adhesives (HEMA-free adhesives). Significance. Air-drying had a significant effect to remove solvents included in 1-SEAs and to achieve larger UTS of them. Hence, it might be crucial to remove solvents as much as possible by thorough, strong air-drying for firmly hardened adhesive layer at the interface.