Options abound for consumers in search of brighter, whiter smiles, from dentist-supervised procedures, to bleaching spas and over-the-counter whitening kits, which are available from drug stores and over the Internet. But consumers should exercise caution, warns the Academy of General Dentistry (AGD).

Of particular concern to dentists are companies that sell professional-strength bleaching materials, which are intended for use only under a dentist's supervision, directly to the public via the Internet, late-night infomercials and shopping-mall kiosks. "Consumers have no way of knowing what they are getting when they buy bleaching products from these sources," says AGD spokesperson Myron J. Bromberg, DDS.

While bleaching is safe, it requires a dentist's supervision to ensure proper results. Not only may an over-the-counter product not work well enough, says Dr. Bromberg, but it might work too well. "There is a wide range in results when using these products without supervision," he says. "If a bleaching agent is too strong, or used for too long, teeth can wind up with an unnatural, frosty look."

Proper whitening depends upon the use of a custom-made bleaching tray, which only a dentist can properly fit. Some Internet companies sell the materials to make your own bleaching tray. But only dentists should use these materials. Without supervision and expertise, these materials can cause damage to existing dental work. "As with any dental procedure, bleaching should always be done under the supervision of a dentist," says Dr. Bromberg.