If you want striking results, it takes a bleach to affect the surface of the tooth. You can spray bleaches on, brush them on, or wear bleach-filled plastic trays that resemble athletic mouth guards. Though makers claim their products whiten teeth up to seven shades or more, dentists say they often aren't that effective, rarely work on tough stains such as ones caused by the use of the antibiotic tetracycline, and won't whiten dental work. But the peroxide can irritate and damage the gums if left on too long, and some of these products contain acids that can corrode enamel, dentists warn. But bleaching-kit makers argued that hydrogen peroxide has long been safely used as a mouthwash or to cleanse wounds.
Users boil the plastic and then fit it to the teeth by biting it.
A dentist can regularly check patients for problems, make sure they are using the product correctly, and determine if gum disease or other dental problems make whitening dangerous. Natural White Inc. says few consumers have complained. Gord Lorimer, vice president of North American sales and marketing, thinks dentists may be worried about a loss of revenue. Perhaps, but bleaching isn't as helpful to your teeth as brushing them. Brush as usual.