How to Use: Polyetheylene (a type of transparent plastic) strips coated with hydrogen peroxide are stuck on the teeth twice a day, 30 minutes at a time, for 14 days. Each strip is used only once and then discarded. The bleaching concentration is higher than in most products (up to 10 percent) and because it’s condensed on one side of the strips (the one that touches the tooth), contact with saliva does not interfere or diminishes the bleaching process.
Results: Teeth can whiten up to five shades if the strips are used properly and for enough time.
Drawbacks: The strips only cover the six front teeth. As with other bleaching methods, it can cause gum irritation and teeth sensitivity.
Professional opinion: “As opposed to brush-on gels, strips can hold a greater amount of bleaching product, and protect it from dilution and dispersal from saliva and lip/cheek/tongue movements,” says Bornfeld. “Of the OTC products, the Crest WhiteStrips can achieve comparable levels of whitening as the professional systems, but the patient must use proper technique and must persevere longer to get the same level of whitening.”
How to Use: Carbamide peroxide gels are placed on a plastic dental tray, which is then inserted in the mouth and worn for 30 minutes twice a day. The tray helps the gel stay in constant contact with the teeth for enough time to allow the bleach to penetrate the tooth’s surface.
Results: Teeth can whiten 2 to 5 shades.
Drawbacks: Uncomfortable. Can cause uneven whitening of the teeth. The major problem is that the shelf life of the product is very short. “All bleaching systems, whether over the counter or professional, rely on some type of oxygenating bleach,” says Bornfeld. “What distinguishes them is the way they are transported, stored, dispensed, and disposed. All these chemicals are quite unstable, and have a very short shelf life. Professional systems are shipped to dental offices in refrigerated canisters, which permit higher and more reliable concentrations of product.”
Professional opinion: “Professional systems are best-- conventional bleaching trays and gel that are provided by the dentist and taken home by patients to use over a one-or two-week period, and repeated as necessary,” says Bornfeld.