Impact of bracket displacement or rotation during bonding and time of removal of excess adhesive on the bracket–enamel bond strength

Abstract

Objective: This study investigated the the influence of bracket displacement or rotation during fixation and the time of excess adhesive removal from around the bracket on bond strength to enamel. Methods: Stainless steel brackets were bonded to the buccal faces of bovine incisors using Transbond XT® adhesive resin. The teeth were divided into five groups (n = 20). In the control group, no displacement or rotation of the bracket was carried out. In the Displac-A group, excess adhesive was removed after the bracket was displaced 2 mm incisally. In the B-Displac group, excess adhesive was removed before the bracket was displaced incisally. In the Rotat-A group, excess adhesive was removed after the bracket was rotated 45°. In the B-Rotat group, excess adhesive was removed before the bracket was rotated. Photoactivation was carried out on the lateral sides of the bracket. A shear test was conducted 10 min after fixation using a knife-edged chisel. Bond strength data were analysed using ANOVA and Fisher’s test (5%). The adhesive remnant index (ARI) was scored under magnification. ARI data were analysed using the Kruskal–Wallis test (5%). Results: No significant differences were detected among the Control, Displac-A, Rotat-A and B-Rotat groups. The B-Displac group showed lower bond strength than all of the other groups, except Displac-A. No significant differences were observed in ARI scores across groups. Conclusions: Displacements of the brackets during fixation did not seem to affect the enamel bond strength when excess adhesive is removed after the final positioning of the bracket.

Keywords:

• Bonding
• displacement
• excess adhesive
• rotation
• shear strength