Teeth Whitening

How Long Do Teeth Whitening Effects Last ?


Teethwhitening is not permanent. People who expose their teeth to foods and beverages that cause staining may see the whiteness start to fade in as little as one month. Those who avoid foods and beverages that stain may be able to wait one year or longer before another whitening treatment or touch-up is needed.


The degree of whiteness will vary from individual to individual depending on the condition of the teeth, the level of staining, and the type of bleaching system used.

At-Home Teeth Whitening vs. Dentist-Supervised Teeth Whitening


There are differences between whitening teeth at home and having them bleached in a dentist’s office, including:


  • Strength of bleaching agent. Over-the-counter products and dentist-supervised at-home products usually contain a lower strength bleaching agent, with about a 10% to 22% carbamide peroxide content, which is equivalent to about 3% hydrogen peroxide. In-office, professionally applied tooth whitening products contain hydrogen peroxide in concentrations ranging from 15% to 43%.
  • Mouthpiece trays. With dentist-supervised at-home bleaching products, your dentist will take an impression of your teeth and make a mouthpiece tray that is customized to exactly fit your teeth. This customization allows for maximum contact between the whitening gel, which is applied to the mouthpiece tray, and the teeth. A custom-made tray also minimizes the gel’s contact with gum tissue. Over-the-counter whitening products also contain a mouthpiece tray, but the “one-size-fits-all” approach means that the fit will not be exact. Ill-fitting trays can irritate the gum and soft tissue by allowing more bleaching gel to seep onto these tissues. With in-office procedures, the bleaching agent is applied directly to the teeth.
  • Additional protective measures. In the office setting, your dentist will apply either a gel to the gum tissue or use a rubber shield (which slides over the teeth) prior to treatment to protect your gums and oral cavities from the effects of the bleaching. Over-the-counter products don’t provide these extra protective measures.
  • Costs. Over-the-counter bleaching systems are the least expensive option, with in-office whitening being the costliest.
  • Supervised vs. unsupervised process. Dentist-supervised at-home bleaching and in-office treatments offer additional benefits compared with over-the-counter procedures. First, your dentist can perform an oral exam and consider your complete medical history, which can be helpful in determining if bleaching is an appropriate course of treatment based on the type and extent of stains, and the number and location of restorations. Your dentist can then better match the type of stain with the best treatment, if appropriate, to lighten those stains. With dentist-supervised bleaching procedures, your dentist will likely want to see you a couple of times to ensure you are following directions, to make sure the customized tray is fitting properly, to inspect the gums for signs of irritation, and to generally check on how the teeth whitening process is proceeding. With over-the-counter bleaching products, you are on your own.

Risks Associated With Teeth Whitening


The two side effects that occur most often with teeth whitening are a temporary increase in tooth sensitivity and mild irritation of the soft tissues of the mouth, particularly the gums. Tooth sensitivity often occurs during early stages of the bleaching treatment. Tissue irritation most commonly results from an ill-fitting mouthpiece tray rather than the tooth-bleaching agent. Both of these conditions usually are temporary and disappear within one to three days of stopping or completing treatment.


If you do experience sensitivity, you can reduce or eliminate it by:


  • Wearing the tray for a shorter period of time (for example, two 30-minute sessions vs. two 60-minute sessions).
  • Stop whitening your teeth for two to three days to allow teeth to adjust to the whitening process.
  • Ask your dentist or pharmacist for a high fluoride-containing product, which can help remineralize your teeth. Apply the fluoride product to the tray and wear for four minutes prior to and following the whitening agent.
  • Brush teeth with a toothpaste made for sensitive teeth. These toothpastes contain potassium nitrate, which helps soothe the teeth’s nerve endings.

>Whitening Product Safety


Some whitening products dispensed through dentists’ offices as well as professionally applied (in-office) bleaching products have received the American Dental Association (ADA) Seal of Acceptance, which indicates that the product has met ADA guidelines for safety and effectiveness. Currently, only dentist-dispensed home-use products containing 10% carbamide peroxide and office-applied products containing 35% hydrogen peroxide have received the ADA Seal of Acceptance. Over-the-counter bleaching products are not endorsed by the ADA, because the organization believes that professional consultation is important to ensuring safe and effective use.


No whitening products using lasers are on the ADA’s list of accepted products. Several whitening toothpastes that are available in drugstores have received the ADA Seal of Acceptance. For a list of specific toothpastes that have gained the ADA’s Seal of Acceptance, visit www.ada.org.


It should be noted that not all manufacturers seek the ADA’s Seal of Acceptance. This is a voluntary program that requires considerable expense and time on the part of a manufacturer. Just because a product does not have the ADA Seal of Acceptance does not necessarily mean that the product is not safe and effective. You can be assured, however, that products that do carry the seal meet the ADA’s standards for safety and effectiveness when used as directed.


Teeth whiteners are not drugs and therefore are not regulated by the FDA.


Tips to Consider When Choosing an Over-the-Counter Whitening Kit


  • Try to select a teeth whitening kit that allows some customization of the mouthpiece. Some kits come with a mouthpiece that can be molded to some degree. These are better than others that come with a standard mouthpiece.
  • Try to gain the opinion of others who may have already tried the kit you are considering.
  • If at any time you experience a prolonged change in the color of your gums or an increased tooth sensitivity to hot or cold foods and beverages, stop wearing the mouthpiece and see your dentist immediately.