Bond durability of four contemporary self-etching systems

Objectives: To evaluate the bonding performance of four commercial available self-etching systems stored in water for 24 hours, 3 months, 6 months and 12 months.

Methods: Four self-etching adhesives were employed in this study: Easy Bond (EB,3M ESPE, USA), G-Bond plus (GBp, GC Corporation, Japan), SE Bond (SE, Kuraray Medical INC. Japan) and Protect Bond (PB, Kuraray Medical INC. Japan). 32 human third molars without caries were separated into 4 groups with 8 teeth in each adhesive system. After bonding followed by the manufacture’s instruction, the teeth were build-up with resin composite (Clearfil AP-X) and being stored in 37 °C distilled water for 24 hours. The bonded specimens sectioned into 1.0 mm² sticks and storage into 37 °C distilled water again for 24h, 3m, 6m, and 12m. Micro-tensile bond strength (µTBS) test was performed, after different water-storage duration at a crosshead speed of 1mm/min. The obtained data were expressed as MPa and statistically analyzed by Games-Howell test and regression analysis (p<0.05).

Results: Regarding all-in-one adhesives, EB showed significant decrease in µTBS at all the storage durations. GBp indicated significant decrease after 12m storage in comparison with 24h. On the other hand, two 2-step self-etching systems expressed no decrease in µTBS during 12m water-storage.

Conclusions: Water could affect bonding performance of all-in-one system significantly, especially on HEMA-contained all-in-one system. 2-step self-etching systems might have consistent bonding performance comparing with that of all-in-one systems.