Table 1.

Examples of commonly used whitening agents in products for home and professional use (in alphabetical order; the most efficient whitening agents are underlined) [12,17].

Whitening Agent	Mode of Action
Abrasives (e.g., hydrated silica, perlite, alumina) → Most important toothpaste ingredient for stain removal	Mechanical removal of extrinsic stains
Antiredeposition agents (e.g., polyphosphates, sodium citrate)	Prevention of the deposition of chromophores and inhibition of calculus formation where external stains could be incorporated
Calcium phosphates (e.g., hydroxyapatite)	Adhesion of white calcium phosphate particles on the tooth surface, and prevention of bacterial attachment/plaque-formation on the teeth
Colorants (e.g., blue covarine)	Shifting color absorption and reflection spectra from yellow to blue
Enzymes/proteases (e.g., papain, bromelain)	Support stain removal due to degradation of proteins (hydrolysis of peptide bonds)
Peroxides (e.g., hydrogen peroxide, calcium peroxide)	Oxidation of organic chromophores
Polyaspartate (e.g., sodium polyaspartate)	Inhibition of plaque-formation
Surfactants (e.g., sodium lauryl sulfate)	Removal of hydrophobic compounds from the tooth surface