Bleaching does not work on crowns, fillings, or bonding. If one of your front teeth consists of any type of artificial surface, you may need additional dental work after the bleaching to make sure colors match.
Products can cause temperature sensitivity, gum inflammation, soreness and discoloration of the gum and inner lips. “While […] sensitivity usually goes away quickly on discontinuation of product use, the inconvenience of such unpleasant side-effects may serve as a deterrent to continued use,” says Bornfeld. “This is significant, since the whitening effect of these products is temporary, and their use must be repeated to maintain whitening. In my experience, many patients use these products once or twice, and eventually lose interest.”
Results are not permanent. Professional work can last for many years, but OTC products usually require that you repeat the process every six months or so. Smokers and heavy coffee drinkers may need more frequent “touchups.”
Results depend greatly on the color of the teeth before using the product. Stains caused by smoking, coffee, or use of tetracycline (antibiotic) can easily lighten up to five shades with the use of strips or gels. Grey stains, such as those caused by pigments inside the tooth rather than outside discoloration, may not respond well to OTC bleaching products and may require professional help.
Experts also recommend avoiding no-name bleaching kits and buying only well-known brands with a history of dental products. “OTC bleaching products are unregulated, and as such present some danger of faulty formulation,” says Bornfeld. “This can introduce any of a number of risks-- whether one of over-concentrated product, unsanitary product, or extraneous ingredients that may provoke irritation or allergy.”
All tooth decay, to the smallest cavity, should be dealt with before bleaching is attempted.
Pregnant or nursing women should avoid these products.