Evaluation of a 6% hydrogen peroxide tooth-whitening gel on enamel microhardness after extended use.

Objectives: To evaluate the effects of a 6% hydrogen peroxide tooth whitener, Xtra White, on sound human enamel microhardness in vitro after an extended and exaggerated simulated 8 weeks of product use.

Method And Materials: Polished human enamel specimens were prepared and baseline microhardness and color measurements determined. The enamel specimens were exposed to a fluoride-containing toothpaste for 30 seconds and then exposed to water, Xtra White, a control carbopol gel containing no hydrogen peroxide, or a carbonated beverage (each group, n = 8) for 20 minutes.