Effect of peroxide concentration and brushing on whitening clinical response

This clinical trial compared the effects of hydrogen peroxide concentration and toothbrushing on clinical response to vital bleaching. Tooth bleaching was accomplished with a flexible, polyethylene strip coated with a hydrogen peroxide bleaching gel worn for 30 minutes twice daily over a 14-day period. A total of 36 subjects were randomized to 1 of 3 treatment groups: 5.3% hydrogen peroxide strip plus prebrushing, 6.5% hydrogen peroxide strip plus prebrushing, or 6.5% hydrogen peroxide strip without prebrushing. Two groups brushed with regular anticavity toothpaste immediately before bleaching, while the other group performed ad libitum brushing only. Tooth color was measured over a 14-day period using digital images of the anterior dentition. Over the 14-day treatment period, all 3 strip groups experienced highly significant (P < 0.001) whitening as evidenced by decreased yellowness (delta b*) and increased brightness (delta L*), as well as composite color change (delta E*) relative to baseline. Keeping brushing constant, the 6.5% hydrogen peroxide strip plus prebrushing group experienced a 31% to 60% improvement in whitening relative to the 5.3% hydrogen peroxide standard. Keeping concentration constant at 6.5% hydrogen peroxide, the prebrushing group experienced a directional 5% to 33% improvement in whitening relative to no prebrushing. All treatments were generally well tolerated. This study demonstrates that for strip-based delivery, increasing hydrogen peroxide concentration to 6.5% results in a significant improvement in efficacy with few tolerability trade-offs.