Application Mode Affects Resin-Enamel Bond Strength of Universal Adhesives.

Objectives: To evaluate the effect of application mode on resin-enamel bond strength of four universal adhesives by means of microshear bond strength (μSBS) test.
Methods: The bonding procedure was performed on enamel of 80 extracted molars. The tested universal adhesives were: All-Bond Universal [ABU] (Bisco); G-Bond Plus/G-aenial Bond [GBP] (GC America); Prime&Bond Elect [PBE] (Dentsply) and Scotchbond Universal [SBU] (3M ESPE). The adhesive systems were applied with a microbrush under the manufacturer´s directions (etch-and-rinse [ER] and self-etch [SE] bonding strategy) and under sonic vibration mode (only for SE). After restorations were constructed, specimens were stored in water (37°C/24h) and the microshear bond strength tested (0.5 mm/min). The fracture pattern was evaluated by SEM. Data from each adhesive were analyzed with one-way ANOVA and Tukey’s test (α = 0.05).
Results: For all adhesives tested, higher μSBS were observed in the ER mode and SE sonic mode in comparison with SE mode (p < 0.05) (Table 1).
Conclusions: The sonic application mode at an oscillating frequency of 170 Hz increases the resin-enamel bond strength of universal adhesives when used in the self-etch bonding strategy.