Teeth lose their earlier white shade and become discolored for various reasons, ranging from inevitable aging to ongoing exposure to dark-colored beverages and foods. People in the Middle Ages addressed the problem by filing their teeth down and applying damaging nitric acid, according to Chemical & Engineering News. Fortunately, dentists discovered the much safer and more effective teeth-whitening properties of peroxide in the 1970s, and hydrogen peroxide has since become a standard option for achieving whiter teeth.
Identification
Teeth-bleaching products available in the United States usually contain either hydrogen peroxide or carbamide peroxide. The second compound turns into hydrogen peroxide and other substances when mixed in a water-based liquid. However, carbamide peroxide is only about 33 percent as strong as hydrogen peroxide, according to the Consumer Guide to Dentistry, and it works slower than pure hydrogen peroxide as a result.
Types
Teeth whiteners that dentists and oral-health professionals apply often contain 15 to 35 percent hydrogen peroxide, according to the ADA. At-home bleaching kits, which you can obtain from a dentist or purchase over the counter in stores, typically contain lower-strength carbamide peroxide. For example, dentist-dispensed home-use whitening products with the ADA Seal of Acceptance--which means the product satisfies the ADA's requirements for effectiveness and safety--frequently have a 10-percent concentration of carbamide peroxide. That strength is comparable to a bleaching product with approximately 3.3 percent hydrogen peroxide.
Features
Teeth whitening with high-concentration hydrogen-peroxide products usually occurs in a dentist's office. The in-office procedure generally takes about 60 minutes and begins with the dentist or dental technician applying a protective substance or device, such as a rubber dental dam, to shield the patient's gums. The dentist or dental technician then applies a strong peroxide gel directly to the patient's teeth in several intervals that last about 20 minutes each. They may also direct a laser or light at the patient's teeth to speed up whitening. Patients with especially persistent tooth stains may need to either return for another in-office treatment or use a home whitening kit with lower-strength peroxide.
Considerations
Teeth-whitening products with hydrogen peroxide produce different results, depending on the type of discoloration involved. Such products are most effective on teeth with yellowish stains, followed by teeth with brownish stains, according to the Cleveland Clinic. If teeth have gray or purple stains, hydrogen peroxide may have little or no effect, and the compound may require a longer period of time to lighten teeth with blue-gray discoloration due to the antibiotic tetracycline.
Warning
Although they are often effective and safe when applied correctly, teeth-whitening products containing hydrogen peroxide do have associated risks. The Consumer Guide to Dentistry notes three potential complications of bleaching teeth with a substance containing hydrogen peroxide.
Approximately 50 percent of users experience gum irritation for several days, which generally goes away after discontinuing treatments or decreasing the concentration of hydrogen peroxide. Users may also develop sensitivity to pressure, temperature or touch, which typically disappears within a couple of days. Finally, individuals with certain tooth restorations, including crowns or veneers, may develop different-colored teeth. Such technicolor teeth are due to the fact that hydrogen peroxide does not alter the color of restorations, although nearby teeth become whiter.
References
- American Dental Association: Statement on the Safety and Effectiveness of Tooth Whitening Products
- Chemical & Engineering News: What's That Stuff? - Teeth Whiteners
- Cleveland Clinic: Effectiveness, Risks, Safety, and Other Frequently Asked Questions About Teeth Whitening
- Consumer Guide to Dentistry: Teeth Whitening - How Does Bleaching Work and What Does it Cost?
