Purpose: To evaluate in a randomized, double-blind, placebo-controlled clinical trial the initial, cumulative and sustained whitening with a brush-applied, peroxide-based, overnight tooth whitener.
Methods: 50 adults were randomized to Crest Night Effects, a 19% sodium percarbonate gel that dries to form an adherent film, or a placebo gel without any peroxide source. The treatments were brush-applied at night, and removed the next morning with normal toothbrushing. Subjects were evaluated biweekly during the 6-week treatment period to evaluate initial and cumulative color change, and again, 4 weeks after completion of treatment to evaluate color relapse. Efficacy was determined by evaluating reduction in tooth yellowness (delta b*), increase in tooth brightness (delta L*) and overall change relative to white (delta W*) from standardized digital images. Tolerability was assessed by examination and interview conducted at treatment and post-treatment visits.
Results: Relative to baseline, the 19% sodium percarbonate film group had significantly (P < or = 0.013) whiter teeth after 2 weeks overnight use. For maxillary teeth, delta b* and delta L* means (SD) were: -1.35 (0.858) and 1.06 (0.886), respectively. For mandibular teeth, delta b* and delta L* means (SD) were: -1.27 (0.903) and 0.56 (0.790), respectively. Relative to placebo, the 19% sodium percarbonate group was significantly (P < 0.005) better than placebo for delta b*, delta L*, and delta W*. There was a cumulative benefit with additional treatment, as evidenced by significant (P < 0.0001) improvement in mean delta b* after the initial 2 weeks of treatment. Approximately 90% of the 6-week cumulative color improvement was still evident after 4 weeks post-treatment. Tooth sensitivity (20% of the peroxide group) represented the only adverse event with increased occurrence over placebo, and these events were mild and fully resolved during/after treatment.