Objectives: The objectives of this study were to compare the long-term shear bond strength of conventional adhesive on metal brackets with that of adhesive precoated brackets in vitro and to evaluate the amount of adhesive remnant on the tooth surface after debonding.
Materials and methods: A total of 90 maxillary permanent premolars were randomly divided into two groups. The samples in the first group were bonded with metal brackets using Transbond PLUS Color Change Adhesive (TP), and the samples in the second group were bonded with Flash-Free adhesive precoated brackets (APC FF). The bonding techniques were performed, according to the manufacturer's instructions. The samples from each group were randomly divided into three subgroups with different thermal cycles (n = 15). The shear bond strength (SBS) and adhesive remnant index (ARI) were measured and calculated.
Statistical analysis: Two-way ANOVA and Chi-square test were used to analyze the differences in the SBS and ARI between the groups, respectively.
Results: The means of the SBS of the APC FF subgroups were significantly lower than those of the TP subgroups, except in the 10,000 thermocycle subgroups. Chi-square test showed no statistically significant differences between the groups and subgroups. An ARI score of 1 was the predominant score in both groups.
Conclusions: This study found that the SBS of APC FF gradually increased with time and thermal aging did not affect the failure pattern.
The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/).