How to Use It: Chew 2-3 times a day as you would any other gum.
Results: No studies have been done to study efficacy.
Drawbacks: None, especially if you chew gum anyway.
Professional opinion: “I am unaware of any reliable studies that deal with this question,” says Bornfeld. “My personal observation, intuition, and experience with what it takes to keep teeth clean tell me they do not. Also, just as is the case with toothpastes, there is no effect on the intrinsic coloration of the teeth from the use of whitening chewing gums; if a change in intrinsic color is how you define the term "whiten," then most assuredly these gums do not work.”
Brush-on Gels
Cost: $15 to $20
Sample Brands: Colgate’s Simply White and Simply White Night, Crest’s Night Effects
How to Use: As the name implies, these products are designed to be brushed or “painted” on the tooth a minimum of twice a day and a maximum of four, depending on the bleaching concentration of the product. The pain-on gel then dries to form a film. No food or drinks should be consumed for at least 30 minutes after application.
Results: With a peroxide concentration of only three percent (six for overnight products), results are minor. To give you a straightforward comparison, professionally applied bleach whiteners offer concentrations of up to 35 percent. It is also hard to avoid friction of the lips or saliva against the teeth, which means the products dilutes fairly quickly.
Drawbacks: Although easy to use, it requires frequent re-applications.
Professional opinion: “These products cannot maintain contact between enamel surfaces and a sufficient amount of active bleaching material for a sufficient period of time, and are less effective than tray/strip systems,” says Bornfeld.