Objectives: This randomized, parallel group, single centre clinical trial was conducted to evaluate the safety and compare the whitening efficacy for an extended wear of an experimental 9.5% H₂O₂ high-adhesion whitening strip, relative to a marketed 10% H₂O₂ control strip.
Methods: Twenty-nine eligible adult volunteers were randomly assigned to either a treatment series with an experimental 9.5% H₂O₂ high-adhesion whitening strip at home for 2h, once a day, for 8 days; or a marketed 10% H₂O₂ whitening strip for 30 min, on a similar daily regimen. Tooth color/whitening progression was recorded under standardized lighting conditions at baseline, day 3, day 5, and day 9, via digital imaging. Outcomes were reported using the CIELAB system. Usage safety was also assessed at each follow-up visit. Whitening efficacy for each group was investigated using a paired-difference t-test. The treatment groups were compared among each other using the analysis of covariance, with the baseline value and age as the covariates.
Results: Both treatment groups demonstrated statistically significant mean color improvement from baseline for b* (yellow ness) and L* (lightness) at each post-baseline visit. In addition, the 2-h high-adhesion strips demonstrated significantly greater improvement in b* and L* relative to the 30-min strip group at each follow-up visit.
Conclusions: The 2-h regimen for the 9.5% H₂O₂ high-adhesion whitening strip was more efficient for tooth whitening than the 30-min regimen of 10% H₂O₂ whitening strip. Both treatments were well tolerated and the use of the test products during the study time frame was considered safe.
Clinical relevance: Extending the daily wear time of whitening strips can improve the efficacy of the treatment and ultimately shorten the length of the treatment without any significant adverse effects.
Keywords: Clinical trial; Hydrogen peroxide; Vital bleaching; Whitening.
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