Abstract
Aims: To determine the effect of an antioxidant agent on the tensile bond strength values of metal brackets bonded with to human enamel after bleaching. Materials and Methods: Thirty two sound human maxillary and mandibular premolars extracted for orthodontic reasons were collected. All teeth had undamaged buccal enamel, no caries and no pre-treatment with any chemicals. They were then stored in a solution of 0.1 % thymol before the experiment. Results: In the present study, we found that , tensile bond strength in group of direct bonding after bleaching was lower than other groups when compared with control group and the difference was significant at level p< 0.05 . The present investigation confirmed that waiting for a period of 7 days after bleaching is sufficient to obtain ade-quate tensile bond strength for clinical conditions. There was significant difference in tensile bond strength when the brackets that underwent direct bonding and ethanol with control group. No signifi-cant difference in tensile bond strength was observed when compared with the bracket immersed in a distilled water & with control bracket. Conclusions: In the present study we found that , tensile bond strength in group of direct bonding after bleaching were the lowest than other groups and when com-pared with the control group, the difference is significant. There was a significant difference in tensile bond strength when comparing the group that underwent direct bonding with control group.
