In vitro evaluation of self-etch bonding systems in orthodontics using cyclic fatigue

The objective of this study was to evaluate the bond strength of a self-etch bonding system using static and cyclic loading in both shear and tension methods. Bovine teeth (n=164) were distributed to either a self-etch or total-etch group. Static tensile (STBS), static shear (SSBS), cyclic tensile (CTBS) and cyclic shear (CSBS) bond strengths were measured. Mean STBS was 5.7(0.28) and 5.5(0.86), SSBS was 34.2(9.21) and 24.6(9.42), CTBS was 5.0(0.14) and 4.8(0.14) and CSBS was 24.0(0.65) and 18.9(1.08) MPa for the total-etch and self-etch systems respectively. Within each group, cyclic loading produced significantly lower bond strengths compared to its counterpart except in the SSBS group within the self-etch system. Material comparison showed a significant difference between the two techniques except the static tensile group. The total-etch system had higher bond strengths than the self-etch system. Results indicated that cyclic loading had a significant impact on the bond strength.