Teeth whitening is the use of bleaching agents to lighten the colour of teeth. The normal colour of tooth enamel (the hard outer surface of each tooth) varies, with most teeth ranging from off-white to light yellow. Teeth may be discoloured by various factors including:
Teeth discoloured by surface stains or age usually respond best to whitening treatment.
Only your dentist is qualified to assess you correctly and, if applicable, provide you with a bleaching treatment to ensure the best results for you.
Various professional whitening treatments are available. Your dentist will discuss the best treatment for you depending on factors including your dental history, the causes of your tooth discolouration and the degree of discolouration. Sometimes, the dentist may suggest a combination of treatments.
Light-activated and laser bleaching:
Your dentist protects your lips and gums with rubber seals or gel, then applies a bleaching agent to tooth surfaces. A high-intensity light or a laser is shone into your mouth to quicken the whitening process. This bleaching takes about one hour to complete in a single session.
Multiple sessions may be needed or may need to be augmented with the tray method of application.
Your dentist takes a mould of your teeth to make plastic trays that have a custom fit, then gives you tubes of bleaching gel and instructions. You may wear the gel-filled trays at home anywhere between an hour and overnight. Most people will need to wear the mouth trays every day for two to four weeks.
*(excerpt from ADA Teeth Whitening pamphlet)