In-use comparative kinetics of professional whitening strips: peroxide recovery from strips, teeth, gingiva, and saliva.

A clinical trial was conducted to evaluate the peroxide degradation and dilution kinetics of Crest Whitestrips Supreme, a whitening strip carrying a low, fixed amount of a 14% hydrogen-peroxide bleaching gel. Crest Professional Whitestrips--a 6.5% hydrogen-peroxide strip with a well-established clinical efficacy and safety profile--served as the positive experimental control. A total of 17 healthy adults were enrolled in the crossover study (subjects used both products, and each product was used 4 times by each person). Test strips were applied to the maxillary arch, after which hydrogen-peroxide concentration was measured on the strip, teeth, gingiva, and in saliva over a 60-minute period using standard analytical methods. Treatments were compared at individual time points, and overall using the area-under-the-curve (AUC) calculation of total hydrogen-peroxide exposure (concentration over time). For the higher-concentration strip, hydrogen-peroxide concentration from the strip and teeth samples dropped initially at the 5-minute sampling point, then slowly declined over time. At 30 minutes--the nominal treatment time for these 14% hydrogen-peroxide strips--the median hydrogen-peroxide concentration was 6.2% on the strips and 4.4% on the teeth. In contrast, the gingival and salivary hydrogen-peroxide concentrations were already low and/or below the level of detection by 5 minutes, and remained low throughout the sampling period. Treatments generally differed (P < .001) with respect to hydrogen-peroxide concentrations on the strip and teeth, but not on the gingiva or in the saliva. AUC cumulative measurements through 60 minutes demonstrated 77% higher hydrogen-peroxide levels on teeth for the 14% hydrogen-peroxide strip compared to the 6.5% hydrogen-peroxide strip. This research demonstrates the feasibility of vital bleaching with an exceedingly thin layer of 14% hydrogen-peroxide gel, with little gingival or salivary hydrogen-peroxide exposure.

Peroxide degradation kinetics of a direct application percarbonate bleaching film.

PURPOSE: To evaluate the hydrogen peroxide (HP) degradation kinetics of a 19% sodium percarbonate (5.3% HP released) direct application bleaching gel on the tooth surface and in saliva during use. METHODS: This was a single center, 14 subject trial, where both maxillary and mandibular teeth were treated. Peroxide concentrations in the tooth scraping sample were determined at 10 minutes, 30 minutes, 1 hour, 2 hours, and 4 hours. Peroxide concentrations in the saliva were determined at 5, 10, 20, 30, and 60 minutes after test product application. RESULTS: The median peroxide concentrations on the teeth at 10 minutes, 30 minutes, 1 hour, 2 hours, and 4 hours of daytime wear were 4.7, 3.5, 1.5, 0.3 and 0.1% respectively, demonstrating significant substantivity of peroxide on the tooth surface. In contrast, the median peroxide concentrations in the saliva at 5, 10, and 20 minutes of daytime wear were very low; 0.001, 0.0001 and 0.0001% respectively. By 30 minutes, median salivary concentrations of peroxide were below the limit of detection (0.00007%). A comparison was made to previously reported data from other peroxide degradation studies with strips, trays and a paint-on tooth bleaching product.