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

目标。本研究的目的是1)阐明一步法自酸蚀粘结剂(1-SEA)的风干时间与溶剂挥发度(ED)之间的关系；2)评价ED对粘结剂极限微拉伸强度(UTS)的影响。方法：研究方法。用重量法测定了3种1-SEA：iBond(Heraus Kulzer)、G键(GC)和S3键(Kuraray)在0、5和10s风干后的ED。然后，评估了胶粘剂在0、5和10s风干的ED下的UTSS。结果。EDS随风干时间的延长而增加。对于粘接剂之间的比较，iBond的ED最大，其次是G键和S3键。对于UTS，较长的风干时间会导致较大的UTS。在胶粘剂之间的比较中，S3 Bond(含HEMA胶粘剂)的UTS大于其他两种粘结剂(不含HEMA胶粘剂)。意义重大。风干对脱除1-SEA中的溶剂并获得更大的UT有显著的效果。因此，对于界面处牢固硬化的粘合层，通过彻底、强烈的风干来尽可能多地去除溶剂可能是至关重要的。

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.