Peroxide degradation kinetics of a direct application percarbonate bleaching film

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.

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.

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.