Bond Strength of Scotchbond1 Applied with Electric Impulses: Voltage Influence

Methods: Thirty non carious extracted human molars were selected for the study. Middle dentin was exposed and standard smear layer was created. Specimens were then randomly and equally assigned to three groups. SB1 was applied on the etched dentin substrate in accordance with the wet bonding technique using the electric device set at 6 V (group 1)or at 9 V (group 2) or without electric impulses (i.e. following manufactures' instructions) (group 3). 4 mm composite build-up was created. Specimens were sectioned and processed for microtensile test. Results were calculated in MPa. ANOVA and Multiple Range (LSD) tests were applied.

Results: Mean and standard deviation of microtensile bond strength values for SB1 applied under the influence of electric impulses at 6 V (group 1) and at 9 V were respectively 31.9±9.1 MPa and 29.6±9.0 MPa. Control specimens showed values of 17.3±6.3 MPa. SB1 showed a statistically significant increase if applied with the electric device (p<0.05), while no difference was found between the tested voltages.

Conclusions: The use of electric field created by the device for the application of dental bonding systems increases microtensile bond strength irrespective to the voltage if compared with control application technique. We speculated that the electric flow may increase adhesive impregnation due to substrate modifications induced by the electric field or by a direct interactions with the adhesive monomers. How much the electric device contributes to improve the in vivo bonding efficacy should be further investigated.