The ADA is the largest and oldest national dental association and has been helping consumers make smart, educated choices about dental products for decades. So what do they have to say about teeth whitening?

In 2008, they released an official statement on whitening, called the ADA Statement on the Safety and Effectiveness of Tooth Whitening Products.

Here are some of the main takeaways:

• Whitening is achieved either by bleaching with peroxide—which works on stains caused by both genetics and lifestyle choices like diet—or by a polishing/chemical agent that removes surface stains only.
• Dental products are dispensed 1) by dentists in the dental office, 2) by dentists for at-home use, or 3) over the counter.
• The ADA recommends consumers choose a whitening product only after consulting with their dentist.
  
• The most common side effect of bleaching is tooth sensitivity and occasional gum irritation. Gum irritation is usually caused by an ill-fitting bleaching tray. Both conditions are temporary.