Bond failure of gingivally offset mandibular premolar brackets: A randomized controlled clinical trial

Abstract

The purpose of this randomized controlled clinical trial was to examine the clinical bond failure rate of gingivally offset mandibular premolar brackets and compare it with that of standard mandibular premolar brackets. Eighty-three patients were enrolled in this trial. A total of 240 brackets--120 standard and 120 offset--were bonded in a split-mouth design. Ten standard brackets and 1 offset bracket debonded during the trial period. Survival times were analyzed by using the Kaplan-Meier nonparametric test, and comparisons between bracket types were made with the Mantel-Haenszel log rank test. These tests showed that the failure rate between the bracket types was statistically significant (P <0.0058). Gingivally offset mandibular premolar brackets have a lower bond failure rate than standard mandibular premolar brackets.