Teeth whitening isn’t permanent. It can last from a few months to up to 3 years – it varies from person to person.
The whitening effect won’t last as long if you smoke or drink red wine, tea or coffee, which can all stain your teeth.
Teeth whitening doesn’t work on dentures, crowns, fillings or veneers.
No matter what treatment you use, there’s a chance your gums will be sensitive to the chemicals used in teeth whitening, particularly if you already have sensitive teeth. There’s also a chance of burns to gums and some of the whitening kits used at home can harm tooth enamel.