Clinical response of three direct-to-consumer whitening products: strips, paint-on gel, and dentifrice

Abstract

A randomized, examiner-blind, parallel-group, 3-week clinical trial evaluated the efficacy and safety of 3, popular, direct-to-consumer whitening products: a paint-on gel, a whitening dentifrice, and whitening strips. Both the paint-on gel (18% carbamide peroxide) and the whitening strips (6% hydrogen peroxide) were peroxide-based systems, while the dual-phase whitening dentifrice incorporated surface cleaning agents and sodium fluoride, but contained no peroxide. Treatment consisted of twice-daily use over 3 weeks following label instructions, except that strips were applied only during the first 14 days as per the manufacturer's instructions. Tooth color was measured on the maxillary anterior teeth from polarized digital images. Safety was assessed by examination and subject report. A total of 48 healthy adults were randomized, and 42 completed 1 or more post-baseline visits. For the primary efficacy variable delta b*, the adjusted mean +/- standard error reduction in yellowness was -0.06 +/- 0.131 for the dentifrice with no peroxide and -0.21 +/- 0.109 for the 18% carbamide peroxide paint-on gel, compared with -2.53 +/- 0.244 for the whitening strip control. Only the strip group exhibited significant (P < 0.0001) delta b* improvement. Between-group comparisons demonstrated significant and improved whitening for the strip treatment compared with the whitening dentifrice or paint-on peroxide gel, as evidenced by the more than 2-unit improvement in delta b* at week 3. Regardless of the parameter (delta b*, delta L*, delta a*, or delta E*), this represented a significant (P < 0.0001) color improvement for the whitening strips relative to both of the comparative treatments. There were no significant differences in color improvement for the 18% carbamide peroxide paint-on gel used for up to 3 weeks continuously, compared with normal brushing with a dual-phase whitening dentifrice. All products were well tolerated, with no subjects discontinuing treatment early because of adverse events. In head-to-head testing conditions, 14-day use of the 6% hydrogen peroxide whitening strips resulted in superior improvement in tooth color compared with either of the experimental controls.