Clinical trial comparing whitening strips to a carbamide peroxide potassium nitrate tray system

Objective: Several factors may impact bleaching-related sensitivity, including peroxide concentration, contact time, delivery system, use of desensitizing agents and others. This randomized clinical trial was conducted to evaluate the clinical response of a low peroxide bleaching system with a desensitizing agent relative to a marketed control. Methods: Balancing for baseline color and age, 34 healthy adult volunteers were randomized to one of two marketed bleaching systems. Subjects received either 5% carbamide peroxide bleaching gel + potassium nitrate in a custom tray or 6.0% hydrogen peroxide bleaching strips. Daily contact time was 6-8 hours for the tray system compared to 1 hour for the strip system, following manufacturers instructions. Whitening was measured objectively using digital image analysis to assess L*a*b* after 7 days. Results: The predominantly female (85%) and non-smoking (91%) study population ranged from 21-47 years of age. Both treatments yielded a statistically significant (p < 0.01) whitening benefit with respect to reduction in yellowness (Db*), as well as secondary endpoints (DL* and DE*). The strip group experienced greater color improvement on average for all color parameters in the study. After 7 days treatment, mean Db* was –1.20 in the strip group and –0.68 in the tray group, with these groups differing significantly (p=0.03). Tooth sensitivity was reported by 13% of subjects using the hydrogen peroxide strips, compared to 22% of subjects using the carbamide peroxide potassium nitrate tray system. No subjects discontinued treatment early due to an adverse event. Conclusion: The 6.0% hydrogen peroxide whitening strip system had greater whitening and less tooth sensitivity compared to the 5% carbamide peroxide potassium nitrate tray system.