Effects of using a new protective sealant on the bond strength of orthodontic brackets

This study determines the effect of applying a new protective sealant to the enamel surface on the shear bond strengths of orthodontic brackets. Sixty teeth were randomly divided into three groups. In group 1 (control), the brackets were bonded to the etched teeth using the regular sealant. In group 2, the sealant was replaced with Pro Seal and light cured as recommended by the manufacturer; the brackets were then placed, and the adhesive was light cured. In group 3, Pro Seal was applied, the bracket with the adhesive was placed on the tooth, and both Pro Seal and the adhesive were cured simultaneously. The purpose of this modification was to reduce one of the steps during the bonding procedure. A shear force was applied at the bracket-tooth interface using a Zwick Universal Test Machine. The results of the analysis of variance (F-ratio = 1.35) indicated that the shear bond strengths of the three groups were not significantly different (P = .267) from each other. The mean shear bond strength of the control group was 4.9+/-2.1 MPa. The mean shear bond strength for teeth coated with Pro Seal and light cured followed by application and light curing of the adhesive was 4.8+/-2.3 MPa, and the mean for the teeth coated with Pro Seal and then bracket placed followed by simultaneous light curing of the sealant and the adhesive was 4.0+/-1.5 MPa.