IADR Abstract Archives
Evaluation of Bonding Layer Durability of HEMA-Free 2-Step Self-Etch Adhesive
Objectives: Generally, 2-step self-etch adhesives have high bond strength because of its thick bonding layer. 2-step self-etch adhesives comprise PRIMER and BOND. BOND which has a hydrophobic composition plays a role in forming thick and strong bonding layer. However, adhesives have been formulated with HEMA to obtain compatibility with tooth substance, this may tend to have negative impact on bonding layer durability due to its hydrophilicity. Our new 2-step self-etch adhesive “G2-BOND Universal” comprises “1-PRIMER” and “2-BOND”, both of which are HEMA-free composition. The purpose of this study was to find impact of HEMA-free composition on long-term bonding layer durability by evaluating physical properties of bonding layer after 1-year immersion in water.
Methods: Two adhesives were selected for analysis, 2-BOND from G2-BOND Universal (GC, G2B), BOND from Clearfil SE BOND 2 (Kuraray, SE2) which is known to be formulated with HEMA. These materials were evaluated by flexural strength test and water absorption test. The specimens for both tests were prepared with reference to ISO 4049:2019 (n=5). These specimens were soaked in water at 37 degreeC for 1 day and 1 year respectively. Flexural strength test was conducted by using universal testing equipment (Shimazu). Water absorption test was conducted by measuring the weight of specimens before and after soaking. All results were analyzed by Tukey’s test (p<0.05)
Results: G2B showed significantly higher flexural strength and lower water absorption than SE2 after 1-year soaking.
Conclusions: On 1-year soaking in water, G2B exhibited higher flexural strength and lower water absorption. In contrast, SE2 exhibited lower flexural strength and higher water absorption because the hydrophilicity from HEMA caused water absorption easily. Therefore, it is expected that G2B, which has HEMA-free composition, has high long-term durability of bonding layer after treatment, which can be clinical advantages.
Methods: Two adhesives were selected for analysis, 2-BOND from G2-BOND Universal (GC, G2B), BOND from Clearfil SE BOND 2 (Kuraray, SE2) which is known to be formulated with HEMA. These materials were evaluated by flexural strength test and water absorption test. The specimens for both tests were prepared with reference to ISO 4049:2019 (n=5). These specimens were soaked in water at 37 degreeC for 1 day and 1 year respectively. Flexural strength test was conducted by using universal testing equipment (Shimazu). Water absorption test was conducted by measuring the weight of specimens before and after soaking. All results were analyzed by Tukey’s test (p<0.05)
Results: G2B showed significantly higher flexural strength and lower water absorption than SE2 after 1-year soaking.
Conclusions: On 1-year soaking in water, G2B exhibited higher flexural strength and lower water absorption. In contrast, SE2 exhibited lower flexural strength and higher water absorption because the hydrophilicity from HEMA caused water absorption easily. Therefore, it is expected that G2B, which has HEMA-free composition, has high long-term durability of bonding layer after treatment, which can be clinical advantages.