Objectives: The purpose of this research was to investigate the influence of 35% hydrogen peroxide on orthodontic bracket adhesion at zero hour, 24 hours, 7, 21 and 56 days after dental bleaching.
Materials and methods: Ninety bovine incisors were prepared for adhesion test and adhesive remnant index (ARI) determination. The 35% hydrogen peroxide was used as a bleaching agent and the Transbond XT as a bonding agent.
Results: Statiscally significant differences were observed between all the groups (p<0.001) and were observed in the comparison of zero hour and control group (p<0.001) and in the comparison of zero hour and 24 hours (p<0.001). ARI scores (0, 1, 2 e 3) also showed statiscally differences between all the groups (p=0.011) and at the comparison of all the test groups with the control: zero hour (p=0.001), 24 hours (p=0.009), 7 days (p=0.018), 21 days (p<0.001) e 56 days (p=0.004).
Conclusions: The shear bond strength values became significantly lower when the bracket was bonded immediately after bleaching and quickly returned to control level in 24 hours. In seven days, there was a slight increase that was not significant and recovered to normal values in the next weeks. Different patterns of fractures were observed in bleached enamel when ARI scores were analyzed. The control group showed a high frequency of 3 score and none of zero score, the opposite behavior was observed in the test groups.
Copyright © 2011 Società Italiana di Ortodonzia SIDO. Published by Elsevier Srl. All rights reserved.