10% Hydrogen peroxide whitening strips: evidence from 14 clinical trials

Objectives: This meta-analysis summarizes an extensive clinical trials database collected as part of the development of a very thin peroxide gel whitening strip system to ascertain factors that contributed to clinical response. Methods: There were 13 different clinical trials in the inclusive analysis. In each study, subjects used a flexible polyethylene, whitening strip coated with a very thin 10% hydrogen peroxide bleaching gel twice daily for 30 minutes over a 1-week period. Efficacy was measured objectively from digital images of the anterior teeth to determine tooth color change in CIELAB units (b* yellowness, L* lightness, and a* redness). Results: The sample included 280 subjects ranging in age from 18-81 years. Age and baseline tooth color were positively-correlated. The regression of tooth color on age demonstrated a slope (SE) of 0.038 (0.0073) b* units and -0.093 (0.0095) L* units per year. Tooth color improved over the 7-day usage period, with 99% of subjects exhibiting 2-parameter (Db* & DL*) color improvement. After adjusting for random study effects, the overall mean (SE) Db* and DL* were –1.94 (0.11) and 1.90 (0.08), respectively, with each differing significantly (P< 0.0001) from baseline. Age and baseline tooth color were significantly (P < 0.002) related to whitening (Δb* & DL*). Minor tooth sensitivity (18%) and oral irritation (20%) represented the most common adverse events. Conclusions: This meta-analysis of 13 randomized clinical trials showed the 10% hydrogen peroxide whitening strips to be safe and effective across a broad population, with baseline color and age representing significant determinants of whitening response.