Mary Warner
Patient demand for tooth whitening has been on the increase for several years, bolstered by the availability of a wide variety of nonprescription whitening toothpastes and strips.
Whitening treatments include dental office bleaching procedures, dentist-supplied products for use at home, and nonprescription whiteners. All three methods use the same chemical agents: carbamide peroxide or hydrogen peroxide in various strengths.
Products used in traditional whitening in the dentist’s office as well as products supplied by dentists for use at home are FDA-approved. However, nonprescription whitening products are classified as cosmetics rather than drugs because of the low levels of peroxides they contain and are not evaluated by FDA. The American Dental Association (ADA) has indicated that it has repeatedly asked FDA to regulate nonprescription whitening products, but FDA has declined to do so.
Not all stains are alike
Tooth discoloration is typically classified as extrinsic, intrinsic, or a combination of both types.
Extrinsic stains typically result from tobacco use, exposure to iron or copper, or the consumption of highly pigmented foods (e.g., dark fruits) or beverages (e.g., red wine, coffee, tea, or cola drinks).
Intrinsic stains, on the other hand, occur inside the tooth and are commonly caused by genetic disorders, fluorosis, tetracycline use in childhood, prolonged use of chlorhexidine mouthwash, or aging, during which the enamel becomes more translucent and thinner, which allows the yellower dentin to show through and the overall tooth color to darken.
Although the in-office method has the advantage of being a faster one-time treatment due to the use of a stronger bleaching agent and accelerator light, most extrinsic stains can be effectively removed using OTC whitening products over a more extended time period. Dentists can also provide professional-strength bleaching gel for use at home using custom-fitted mouth trays. These products are unable to effectively remove intrinsic stains, however, which experts consider nearly impossible to remove when using an external whitening procedure. Some intrinsic stains can be removed with a procedure that uses carbamide peroxide, hydrogen peroxide, or sodium perborate to provide internal bleaching, but results are not guaranteed.
Whitening agents
A variety of toothpastes, whitening strips, and gels painted directly on teeth or delivered in trays are available directly to patients. Bleaching compounds in these products are peroxide-based and typically contain carbamide peroxide or hydrogen peroxide at lower concentrations than those used in a dental office.
Whitening toothpastes primarily rely on abrasives such as silica or charcoal to remove extrinsic surface stains, although some have a low level of peroxide (3–5%) to lighten the color of the tooth. Most whitening strips rely primarily on peroxide to bleach the teeth, though at a lower concentration (generally 6–14%) than professional products. Whitening gel pens contain either 3% hydrogen peroxide or up to 10% carbamide peroxide, which breaks down to about the same 3% hydrogen peroxide in the mouth.
What to tell your patients
Per ADA, patients who have tooth-colored restorations (including crowns or implants) should be aware that only natural teeth will be affected by the bleaching agent and treatment could result in color differences between natural teeth and restorations, which will not change color.
Patients may wish to choose toothpastes and whitening strips that bear the ADA Seal of Acceptance, indicating that the company has demonstrated that the product meets ADA Seal Program requirements for safety and effectiveness when used as directed. Caution patients to avoid do-it-yourself tooth whitening processes, such as using acid-containing fruits, vinegar, or swishing coconut oil in the mouth (known as oil pulling), as none of these methods has been proven to whiten teeth. Patients who suffer from temporary tooth sensitivity or gingival inflammation, the most common adverse effects of tooth whitening, should visit their dentist for professional advice. ■