Clinical Comparison of Dissolving and Non-dissolving Marketed Whitening Strips

Objective. This randomized, examiner-blinded, parallel design clinical trial compared efficacy of two marketed whitening strips. Methods. 55 subjects were randomly assigned to one of two whitening treatments: Listerine Whitening® Quick Dissolving Strips worn twice a day until completely dissolved for 14 days (dissolving strips) or Crest® Whitestrips® Premium Plus containing 10% hydrogen peroxide and worn 30 min twice a day for 10 days (non-dissolving strips). Whitening efficacy was measured objectively from CIELAB digital measurements at Baseline, Day 8, Day 11 and Day 15, and product safety was assessed via subject interviews and oral examination conducted at each visit. Whitening response was compared at each visit and at the end-of-treatment (Day 15 for the dissolving strips vs. Day 11 for the non-dissolving strips) using the analysis of covariance method. Results. The study participants ranged in age from 19 to 71, and 64% of subjects were female. The two groups were well-balanced with respect to the Baseline tooth color. At each study visit, the non-dissolving strip group demonstrated significantly greater tooth color improvement (p ≤ 0.0006) relative to the dissolving strip group. At the end-of-treatment, use of dissolving strips resulted in adjusted means of -1.35 for Δb* and 0.95 for ΔL*, while the use of non-dissolving strips resulted in adjusted means of -2.12 for Δb* and 1.72 for ΔL* with treatment differences being highly significant (p < 0.0005). In addition, the non-dissolving strip group demonstrated significantly greater (p < 0.02) tooth color improvement (both Δb* and ΔL*) at Day 8 compared to the dissolving strip group at day 15. No adverse events were reported in any of the treatment groups. Conclusion. Use of the 10% hydrogen peroxide non-dissolving strips resulted in significantly greater tooth whitening relative to that of the dissolving whitening strips.