6 Types of Tooth Whiteners
How it works: All toothpastes, whitening or not, contain detergents and mild abrasives that prevent plaque buildup and subsequent yellowing. But whitening pastes have an extra ingredient: a polishing agent called silica, which removes surface stains from the enamel (the outermost layer of the teeth).
The whitening effect: One to two shades, when used twice daily for a month. Lasts only as long as it is used.
Good to know: Look for the American Dental Association (ADA) Seal of Acceptance on the tube. With long-term use, products not approved by the ADA could wear down enamel, revealing a dark, unflattering layer of dentin below.
Average cost: $3 to $10 a tube. (Shown: Colgate Total Advanced Whitening toothpaste, $3.80 at drugstores.)