Degradation of gel in tray whitening.

This article will address the breakdown or lowering of active bleaching agent concentration during use in the mouth. A greater than expected degradation occurs during the first 5 minutes followed by an exponential rate loss. Subjects have a large variation in degradation rates. After 2 and 6 hours there was 52% and 24% respectively, of the active agent present in a carbamide peroxide gel. The presence or absence of the pellicle did not affect the rate of degradation. The relationship of gel degradation to the whitening capability of a gel is yet to be determined.