The process of tooth whitening lightens the colour of a tooth. Tooth whitening can be achieved by either changing the intrinsic colour or by removing and controlling the formation of extrinsic stains. The chemical degradation of the chromogens within or on the tooth is termed as bleaching. Hydrogen peroxide (H2O2) is the active ingredient most commonly used in whitening products and is delivered as either hydrogen peroxide or carbamide peroxide.
Tooth discolouration and staining is primarily due to two sources of stain: intrinsic and extrinsic. In essence, tooth whitening primarily targets those intrinsic stains in which cannot be removed through mechanics such as a debridement (clean) or prophylaxis, in the dental office.
Coloured compounds from these sources are adsorbed into acquired dental pellicle or directly onto the surface of the tooth causing a stain to appear- Dental plaque, calculus, tobacco, betel, coffee, tea, etc.
