How Long Do Teeth Whitening Effects Last?
Teeth whitening 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.