Whitening is a process where the tooth discolouration is 'whitened' to a lighter shade. It removes the staining agent through chemical means. It is a safe procedure when carried out under professional supervision. Treatment results usually depend on the severity of the discolouration. Both vital (i.e. live) and non-vital teeth (e.g. tooth with root removed) can be bleached and may take several visits to complete. It is not effective on dental restorations such as amalgam fillings, metal or porcelain crowns, etc.
Teeth can discolour for various reasons. The dentist will recommend the most ideal method based on your oral condition after an in-office examination to establish the cause and nature of your tooth discolouration, as well as provide you with more information on the various types of whitening procedures available, duration & frequency of treatment.
Click here for more information from the British Dental Bleaching Society.