Do whitening toothpastes work?

Dear Self-Portrait with White Teeth and Sasha,

The number of whitening products has exponentially expanded in recent years. From toothpaste to gels to strips and lasers, those looking for a way to perk up those pearly whites have many decisions to make. 

A tooth has several different layers that can become discolored for various reasons. Things we eat and drink change the color of our teeth because the outermost layer of our teeth (enamel) contains pores that can "hold" these stains. Some products, such as tea, coffee, wine, and cigarettes, stain teeth more than others. The innermost part of our teeth, called dentin, yellows naturally over time. Certain medications or excessive use of fluoride can also cause the dentin layer to yellow. Because whitening toothpastes can only affect the outer enamel layer, they do not affect yellowing of the inner dentin layer. In fact, sometimes whitening toothpaste can make inner-layer discoloring more noticeable.

Whitening toothpastes may contain strong abrasives or chemicals that can remove some stains on the outermost layers of a tooth. While these whitening toothpastes may be somewhat effective in removing stains from the outermost layer of your teeth, they can destroy tooth enamel in the process, particularly if used for extended periods of time. No toothpaste or treatment has been proven effective for discoloration on the inner layers of your teeth.

Daily brushing (with non-whitening toothpaste) and flossing minimize discoloration, as can professional cleaning at your dentist's office. Dentists also recommend rinsing your mouth with water after having wine, coffee, or other potentially staining foods. If you decide you want to further whiten your teeth, dentists may recommend a number of different treatments. These procedures are fairly safe as long as your dentist follows particular safety guidelines. You can find more information on teeth whitening from the American Dental Association. Some of the treatments include:

• Tooth whitening. The dentist molds a custom-fitted bleaching tray to be worn over the teeth for a few hours daily for a brief length of time. The tray contains mild whitening gel that seeps into the outer and middle layers of your teeth. Similar products can also be purchased over the counter for use at home and may consists or trays, strips, or gels. 
• Microabrasion. This is a cosmetic dental procedure that uses an abrasive and a mild acid to remove white and brown spots on the enamel. 
• Bonding. An enamel-like material is applied to the tooth's surface and then it is sculpted. After hardening, it is polished and results are immediate. This technique can also repair chipped or damaged teeth. 
• Porcelain veneers. Thin shells of porcelain are glued onto the outer surface of the front teeth. A small amount of tooth enamel needs to be removed from the teeth to make room for the veneer. 
• Crowns. These are recommended for those with a damaged tooth. A significant part of the tooth structure has to be removed to place a crown.

Bottom line? Talk with your dentist. Everyone's teeth yellow over time, so talking with your dentist will help you figure out what options make sense for you. Consult your own dentist, a nearby dental school associated with a university, or your own health care provider for a referral.

Smiling?