To evaluate the effect of vital tooth bleaching agent and alcohol pretreatment on dentin bonding, flat dentin windows were produced on the buccal side of the crowns of fifty-five extracted, human premolars. A bleaching gel, Opalescence® with 10% of carbamide peroxide (Ultradent Product, USA) was daily applied on the teeth of three experimental groups for six hours for 10 consecutive days, while teeth of a control group were not bleached. After 6 hours of bleaching gel application, the specimens were washed and stored in saline until the next day application. After application of One-step® dentin bonding agent (Bisco, USA), Z-250® resin (3M-ESPE, USA) was bonded to dentin with a mount jig. Shear bond strength was measured with an Instron machine (Type 4202, Instron Corp., USA) after 24 hours. The results were analyzed using one-way ANOVA and Duncan's multiple range test at
Immediate bonding group showed significantly lower bond strength than un-bleached control group (
Ethanol-treated group showed significantly higher bond strength compared to immediate bonding group (
There were no significant difference in shear bond strength between the 2-week delayed bonding group and the ethanol-treated group (
In the condition of the present study, it seems that alcohol pretreatment after bleaching procedure can reduce the adverse effect of vital bleaching agent on dentin bonding.
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