From Yahoo! News- First off, why do teeth stain? The color of teeth darkens with age, from food and drinks such as coffee and tea, and from cavities. In-office and take-home teeth whitening are designed to work against stain caused by age and diet. The 2 types of whiteners are surface whiteners and bleaches. Surface whiteners include whitening toothpaste or gum. These products use abrasives on the teeth to remove stain.
Bleaches are the preferred method for whitening and should be administered under a dentist's care. Bleaching products can be offered in one dose at the dentist office or several doses at home. Many over the counter products work very well, but they are lower doses of bleach than offered in the dental office.
You should definitely talk to your dentist if you are interested in whitening because whitening may not be recommended due to tooth sensitivity, cavities, or your dentist may simply recommend a whitening product you did not know about. Remember to limit your intake of drinks that stain teeth after whitening to prolong your beautiful results.