[Effects of application methods of self-etching adhesives on resin-dentin bonding].

Objective: To investigate the effects of application time and rubbing action of self-etching adhesives on resin-dentin bond strength and interface morphology in vitro.

Methods: Caries-free human third molars were wet ground to expose dentin surface. Three self-etching bonding agents were applied with varying application time and with/without rubbing. The microtensile bond strength and interface morphology were evaluated.

Results: When etching time was shortened, normal and prolonged, the bond strength was bonding agent 1 (Adper Prompt): (16.30 +/- 2.59), (23.13 +/- 2.56), (22.28 +/- 2.83) MPa, bonding agent 2 (Xeno III): (15.17 +/- 6.07), (34.50 +/- 3.64), (24.87 +/- 7.01) MPa, bonding agent 3 (Clearfil SE Bond): (29.92 +/- 3.32), (42.21 +/- 6.28), (41.07 +/- 3.93) MPa. When etching was applied with and without rubbing, the bond strength was bonding agent 1 (23.13 +/- 2.56), (12.53 +/- 3.73) MPa, bonding agent 2 (23.98 +/- 3.86), (34.50 +/- 3.64) MPa, bonding agent 3 (48.37 +/- 4.95), (42.21 +/- 6.28) MPa.

Conclusions: Shortening application time decreased bond strength of self-etching adhesives, while prolonging application time did not increase bond strength of self-etching adhesives. Not all self-etching adhesives applied with rubbing showed increased bond strength to dentin, which is product-dependent. Manufactures' instructions should be followed to achieve optimum bonding.