Bleaching and desensitizer application effects on shear bond strengths of orthodontic brackets.

OBJECTIVE

To evaluate the effects of bleaching and desensitizer application on shear bond strengths of orthodontic brackets.

MATERIALS AND METHODS

Forty-eight extracted human premolar teeth were randomly assigned to 4 groups of 12 each. The first group of teeth was bleached with a 35% hydrogen peroxide office bleaching agent. The second group was bleached the same as the first group and UltraEZ desensitizer was applied. No bleaching procedures were applied on the third and fourth groups. UltraEZ desensitizer alone was applied to teeth in the third group. The fourth group served as control. Orthodontic brackets were bonded with a LC (light cure) composite resin and cured with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a Universal testing machine.

RESULTS

The results showed that bleaching, bleaching plus desensitizer, and desensitizer procedures significantly reduced the bonding strengths of the orthodontic brackets (P < .05, P < .001, and P < .01, respectively). No statistically significant difference was found between bleaching, bleaching plus desensitizer, and desensitizer groups (P > .05).

CONCLUSIONS

Because bleaching and desensitizer application significantly affected shear bond strengths of orthodontic brackets on human enamel, they should be delayed until the completion of orthodontic treatment.