Posted by Dr. Abeyta on May 7 2013, 11:00 PM
The outer layer of teeth is composed of a substance called enamel. Enamel is porous, meaning that it absorbs stains from foods and drinks. Teeth whitening is the process of removing stains from the enamel.
Teeth whitening products contain peroxide, which penetrates the enamel and breaks up the stains. As a result, the stains are lifted off the surface of the teeth.