Clinical response of maxillary and mandibular teeth following use of 6.5% hydrogen peroxide whitening strips

Objective: In traditional tray-based bleaching systems, increasing peroxide concentration is reported to impact on both whitening effectiveness and tolerability. This research summarizes the clinical response following use of a higher concentration whitening strip system. Methods: Data from three single center, parallel group, randomized clinical trials were pooled to assess the clinical response following extended use of a 6.5% hydrogen peroxide whitening strip. The study population consisted of teens and adults who underwent tooth bleaching (maxilla and mandible) twice daily for up to a 4-week period. Digital images of the 12 maxillary and mandibular anterior teeth were collected at baseline, and again throughout the study period to measure L*a*b* color change. Longitudinal analysis was used to estimate response over the treatment period. Results: The 101 study subjects exhibited considerable diversity with respect to age (11-56 years), ethnicity (49% non-white) and gender (59% female). For the primary response variable, change in yellowness (Db*), color improvement was evident after 1 week and continued through week 4. Mean changes in b* (SE) were -1.78 (0.13), -2.43 (0.16), -2.72 (0.28) and -3.12 (0.17) at Weeks 1, 2, 3 and 4 respectively. At each time point, color improvement differed significantly from baseline (p < 0.0001). The higher concentration strips were generally well-tolerated, with minor tooth sensitivity (33%) and oral irritation (31%) representing the most commonly reported events associated with treatment. Conclusion: This research involving a diverse population demonstrates that use of a 6.5% hydrogen peroxide whitening strip results in significant color improvement over a 4-week period.