Tooth Whitening
The most common bleaching systems for intrinsic stain are based on hydrogen peroxide (H2O2) or one of its precursors, carbamide peroxide, and they can be used alone or in combination with an activating agent such as heat or light. Vital bleaching can be performed by applying the bleaching agents externally to the teeth, and non-vital bleaching is performed internally, by introducing the same agents into the pulp chamber. Both methods aim to change the body colour of the tooth by bleaching chromagens, which are largely contained in the dentine. [Sulieman, 2003]
During vital bleaching the pigment molecules in enamel and dentin are oxidized directly by peroxide and by active oxygen species generated during its breakdown to produce the whitening effect.
The whitening mechanism of carbamide peroxide is ultimately identical, as carbamide peroxide dissolves to form H2O2 and urea. The H2O2 can then react as described above.
