Peroxide degradation kinetics of a direct application percarbonate bleaching film

Abstract

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.