The teeth bleaching industry has seen massive growth

The teeth bleaching industry has seen massive growth since its onset in the late 1980s when the first in-office bleaching light was used. Today, there's a plethora of procedures and products sold within dental offices—and retail stores—for whitening. Entrepreneur Magazine estimated that total revenue from dental whitening services in 2011 was $11 billion. As dental practitioners, not only do we have to understand the demand from the consumer, but the effectiveness and safety of these products.

For the most part, all of these products have hydrogen peroxide or carbamide peroxide (hydrogen peroxide and urea) as active ingredients. Dental Burs Whitening occurs when carbamide peroxide and hydrogen peroxide freely pass through all parts of the tooth. These peroxides break down into oxygen radicals, which migrate between enamel prisms, breaking down any discolored molecules that result in tooth discoloration. Tooth structure is unaltered; it's the internal tooth color that's simply made lighter.
Whitening methods
The methods of whitening generally fall into four groups:

Power whitening or laser whitening—when a power source is used to activate whitening gel. It's an in-office application of a highly concentrated hydrogen peroxide mixture applied with some method of isolation that protects the cheeks, lips and gums. For some brands—such as Zoom! Dental Handpiece or BriteSmile—an intense light is used to activate certain chemicals in the whitening gel, to enhance absorption. The effectiveness of the light has come under scrutiny in the past—whether the light actually plays a role in the whitening process or is just “bells and whistles” used for marketing purposes. Note: Power whitening has been offered in both whitening centers and in kiosks at shopping malls. This process should only be done under the supervision of a licensed dentist.

Take-home whitening with custom-made bleaching trays. Custom-fitted mouthguards—which are mostly worn while sleeping—allow the patient to apply different strengths of hydrogen or carbamide peroxide from 1 hour up to 8 hours each use. This goes on for a period of time—usually weeks—depending on the color the patient is starting from. Generally the high concentration translates into faster whitening, but also increased sensitivity.

Tray containing whitening gel—which is also applied by the patient. These trays are generally available at pharmacies and supermarkets, and are featured on the Web and infomercials.

Toothpaste containing some form of the peroxide in its formulation.