Two-week Clinical Trial Comparing an 18% Carbamide Peroxide Paint-on Gel with Hydrogen Peroxide Whitening Strips
I. MAGNUSSON1, M.L. BARKER2, and R.W. GERLACH2, 1 University of Florida, Gainesville, USA, 2 The Procter & Gamble Company, Mason, OH, USA
Objective: This study evaluated the clinical response of a new, peroxide-containing paint-on gel relative to a marketed control having a similar pre-treatment peroxide concentration.
Methods: 32 adults were randomized to Colgate® Simply WhiteTM, an 18% carbamide peroxide paint-on liquid in an applicator bottle, or Crest® Whitestrips®, a 6.0% hydrogen peroxide gel on a whitening strip. Participants were supplied with the manufacturers usage instructions specifying twice daily 30-minute treatment. Efficacy was measured objectively as L*a*b* color change using digital images of the maxillary anterior teeth after 1 & 2 weeks treatment.
Results: All subjects made all visits, and were included in the analysis. Week 1 adjusted means and standard errors for Db* (yellowness) were –0.3 ± 0.12 for the paint-on group compared to –1.6 ± 0.12 for the strip group, while lightness/brightness (DL*) means were 0.3 ± 0.18 and 1.7 ± 0.18 in the paint-on and strip groups, respectively. Outcomes were consistent after 2 weeks, with 94% of strip users and 25% of paint-on users experiencing at least a 1-unit improvement in b*.
All (100%) of strip users and 19% of paint-on users had at least a 1-unit improvement in lightness at Week 2. Between-group comparisons showed highly significant (p < 0.0001) greater color improvement for the strip group compared to the paint-on gel. For Db*, DL* and the composite measures DE* and DW*, one week use of whitening strips resulted in significant (p £ 0.0001) color improvement relative to that seen following two weeks use of the paint-on gel. Both treatments were well tolerated.
Conclusion: One week use of 6.0% whitening strips resulted in superior whitening compared to two-weeks use of an 18% carbamide peroxide paint-on liquid. (This research was sponsored by The Procter & Gamble Co.)
