Placebo-controlled Clinical Trial of 4-week Whitening Strip Treatment: Initial and Sustained Response

Objective: A randomized, double blind clinical trial was conducted to evaluate 4-week use of whitening strips or placebo strips. Methods: After balancing for baseline shade, 60 healthy adults were treated with 6% hydrogen peroxide whitening strips or placebo twice daily for four weeks. Subjects were evaluated at end-of-treatment to assess initial color change, and at 3 and 6 months post-treatment to assess color retention. Tooth shade (Vita Lumin) was measured on maxillary anterior teeth, while gingivitis (GI) and plaque (PlI) scores were collected from the Ramjford teeth. Results: Between-group comparisons demonstrated a highly significant (p < 0.0001) 7.3 shades improvement for the whitening strips at end-of-treatment compared to placebo. This shade improvement persisted throughout the post-treatment period, with the whitening strips exhibiting highly significant (p < 0.0001) 6.6 shades and 6.5 shades improvement relative to placebo at the Month 3 and Month 6 examinations. There were no between-group differences in GI or PlI scores, as both groups improved during active treatment. Four weeks treatment was generally well tolerated. Adverse events in both groups were limited to minor tooth sensitivity and oral irritation, and no subjects modified or discontinued treatment early because of discomfort. Conclusion: Four weeks use of 6% hydrogen peroxide whitening strips yielded significant mean shade improvement at end-of-treatment and post-treatment. (The research was supported by The Procter & Gamble Co.)