ABSTRACT
This chapter explores the scientific basis behind the tooth whitening treatments available and how the whitening gels whiten the teeth. The oxygen and free radicals establish their primary mechanism of action in tooth whitening by penetrating through the porosities of the enamel prism to the dentin. The tooth whitening gels in the form of hydrogen peroxide were originally used as treatments to reduce the swelling of the gingivae after orthodontic treatment. The higher the concentration of hydrogen peroxide, the faster the gel moves into the tooth. The science of whitening has shown that the movement of the whitening agent is directly related to the anatomy and internal structure of the tooth. As the tooth dehydrates, the dehydration effect and the pattern of dehydration can be noted; this will give some indication of the whitening potential of the tooth. The dehydration line may not disappear and the teeth will have a two-tone effect after whitening.
