A laboratory trial was conducted to evaluate post-treatment color improvement following bleaching with 2.6% hydrogen peroxide containing tooth-whitening strip.
Hydroxyapatite tablet(HPT) was made by compressing and sintering 2.5 g hydroxyapatite powder. HPTs were embedded in epoxy resin except active surface. This active surface was stained using Stookey´ s methods. Bleaching materials were 2.6% hydrogen peroxide strip, 5.3% hydrogen peroxide strip(Crest® Whitestips), 2.6% hydrogen peroxide solution, and placebo strip without hydrogen peroxide. HPTs were allocated to each bleaching materials by matching on color grade. After HPTs were treated for 30 minutes at 37t and washed and dried, color was measured by Colorimeter CR 321(Minolta, Japan).
The efficacy was evaluated by comparing delta L* and delta E*ab values of HPTs surface at baseline and each repeated steps.
There was no change of L* value in placebo strip. Each delta L* and delta E*ab values of 2.6% hydrogen peroxide strip, 5.3% hydrogen peroxide strip(Crest® Whitestips), and 2.6% hydrogen peroxide solution was increased significantly compared to baseline and placebo strip, respectively (P ( .05). There was no significant change in delta L* and delta E*ab values among 2.6% hydrogen peroxide strip, 5.3% hydrogen peroxide strip(Crest® Whitestips), and 2.6% hydrogen peroxide solution.
Whitening effect of 2.6% hydrogen peroxide strip was fairly high compared to 5.3% hydrogen peroxide strip in this in vitro experiment, but further in vivo experiment is needed to prove its efficacy.
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