Shear Bond Strength of Three Light-Cured Orthodontic Adhesives

Abstract

Objective: The purpose of this study was to compare shear bond strength (SBS) and adhesive remnant index (ARI) of three light-cured orthodontic adhesives.Methods: Sixty upper human premolars were randomly divided into three groups of 20 teeth each. Stainless steel brackets were bonded to the specimens with two different color-change adhesives (Grengloo and Green Glue) and a control (Transbond XT), according to manufacturer’s instructions. After bonding for 24 hours, a universal testing machine was used to apply an occlusal shear force directly to the enamel/bracket interface at a speed of 0.5 mm/min. The ARI scores were evaluated for each debonded tooth. Mean SBS values were analyzed statistically using the Welch robust analysis of variance and the Games-Howell post hoc statistic. Chi-square test was used to determine significant difference in the ARI scores.Results: There was statistical difference in the mean SBS of the three groups (P<.001). The lowest value was obtained from the Green glue (14.88 MPa), which significantly differed from the Grengloo (29.25 MPa) and the Transbond XT (28.03 MPa) group. Chi-square comparison for the ARI indicated that there was significant difference (P=.018) between the groups. Mixed failure patterns were observed for all materials.Conclusion: Although Green glue yielded lower SBS values than Grengloo and Transbond XT, it was sufficient for orthodontic and biting forces in clinical practice.