Whitening can only lighten your existing tooth colour. For a change to specific chosen shade veneering is another option. Whitening also works on natural teeth. It will not work on any type of 'false’ teeth. This includes dentures, crowns and veneers. If dentures are stained or discoloured, it may be worth visiting the dentist and asking him or her to clean them. Stained veneers, crowns and dentures may need replacing. Again, ask your dentist.