Teeth whitening works by essentially bleaching the enamel. Tooth whitening products contain either hydrogen peroxide or carbamide peroxide that work by fragmenting the stain, making the color less concentrated and resulting in brighter teeth.

It is important to note, that whitening is not suitable for all types of discoloration. Only natural teeth can be bleached. Whitening will not work on caps, veneers, crowns or fillings and will also not correct discoloration, or medication. Yellow teeth will probably bleach well whereas brown teeth or those with gray tones may not respond as well, if at all.