Bonding to previously bleached teeth

Some authors have reported a decrease in the bond strength of restorative composite resin to previously bleached enamel. Since there has been an increase in the number of adult patients seeking orthodontic treatment, this study was undertaken to determine whether the act of bleaching would somehow affect the bonding of orthodontic brackets to enamel surfaces. Sixty extracted premolar teeth were divided into 6 groups of 10, for comparison of the shear/peel bond strength of orthodontic brackets to enamel using light-cured composite resin cement and a resin-modified glass-ionomer cement. For each material, one group of teeth was used for bonding to unbleached enamel, and the other two for bonding to enamel at 24 hours and 14 days after bleaching. The experimental method simulated clinical procedures as closely as possible. No significant difference in the shear/peel bond strength was found between the bleached and the unbleached groups. It was concluded, therefore, that at-home bleaching with Nite Lite does not affect the shear/peel bond strength of light-cured composite resin and resin-modified glass-ionomer cements used for bracket bonding.