Safety and efficacy of a 2-hour whitening strip

Objectives: To evaluate the safety and whitening efficacy of a 9.5% H2O2 high adhesion whitening strip worn for 2 hours once daily relative to a 10% H2O2 whitening strip marketed control. Methods: This was a randomized, examiner-blinded, parallel group, clinical trial. Twenty-nine subjects were assigned to treatment with either a 9.5% H2O2 high adhesion whitening strip worn 2 hours once daily for 8 days (Procter & Gamble) or 10% H2O2 whitening strip (Crest Whitestrips Premium, Procter & Gamble) worn 30 minutes once daily for 8 days. Safety (oral exams and subject interviews) and efficacy (L*a*b*) measurements were obtained at Baseline, Day 3, Day 5, and Day 9. Comparisons to Baseline were investigated using a paired-difference t-test and treatment groups were compared using the ANCOVA at a two-sided 0.05 level of significance. Results: At each post-treatment visit, both treatment groups provided significant (p<0.02) yellowness reduction (Db*) and lightness improvement (DL*) relative to Baseline. At each post-treatment visit, the 2-hour strip group provided significantly (p<0.02) greater improvement in b* and L* color parameters relative to the 30-minute strip group. Tooth sensitivity and oral irritation were the most common adverse events in the study. Tooth sensitivity was reported by 29% of subjects in the 2-hour strip group and 13% of subjects in the 30-minute strip group. No subject discontinued treatment due to an adverse event. The majority (89%) of adverse events were classified as mild in severity. The occurrence of adverse events was similar in both groups. Conclusion: Use of 2-hour 9.5% H2O2 whitening strips resulted in greater whitening efficacy when compared to a marketed 30-minute whitening strip control under the recommended protocol. This study was supported by Procter & Gamble.