How do bleaching toothpastes work?

Commercial bleaching products designed for home use include gel, chewing gum, mouthwash and toothpaste.
In general, the toothpastes made specifically for bleaching achieve this objective by removing and preventing the formation of extrinsic (surface) stains.
The key ingredient in bleaching toothpastes is an abrasive substance to which other ingredients with chemical or optical effects are added.