To break down stains and brighten the look of teeth, both PAP whitening and peroxide-based teeth whitening procedures employ oxidation.
Peroxides produce free radicals as part of this process. Free radicals rapidly attack organic molecules to minimize discoloration, but they can also cause sensitivity, gum irritation and demineralization.
PAP reacts similarly to dental stains, except that no free radicals are produced. This implies that the molecules that cause discolouration are safely broken down without causing sensitivity, discomfort, or harm.