How does teeth whitening work?

There are a variety of products designed to whiten teeth and remove stains. From chewing gum to toothpaste, at-home whitening treatments to whitening procedures your dentist can perform, there are a plethora of options available to help you get a brighter smile quickly.

When it comes to whitening your teeth, the general formula to keep in mind is: length of time + dosage = desired result. The longer you use a tooth whitening product, the more effective the product will be. Also, the higher dose of a chemical agent that is in the product, the whiter your smile will be. However, if you have to choose between using a low-dose product for longer or a high-dose product for a shorter period of time, research indicates that the lower dose product used for a longer period of time leads to greater whitening results.

There are two types of stains on teeth: intrinsic stains and extrinsic stains.

Intrinsic stains are the stains that are found deep within the enamel and inside of the tooth itself. These stains may be caused by coffee, wine, tobacco, or other products that can permeate into the pores of your teeth to cause discoloration.

Extrinsic stains occur on the surface of teeth and are often newer than intrinsic stains. These stains can also be caused by coffee, wine, tobacco and other products that are known to cause discoloration.

There are different methods of addressing each of these stains.

Intrinsic Whitening Methods

Intrinsic whitening products usually use high doses of carbamide peroxide that can be administered at home or at a dentist's office. At-home whitening products may use a solution of up to 35% carbamide peroxide, which may cause tooth and gum sensitivity while the product is being used. No long-term sensitivity should occur.

Intrinsic whitening products include bleaching trays, gels, pens, and whitening strips, such as Crest Whitestrips, White&Go Teeth Whitening Pen, or All White whitening gel. These products are effective because the carbamide peroxide chemical solution breaks down into water and hydroxyl ions. During the process, the pores of the teeth are expanded. Hydroxyl ions bond to stain particles and break them down. The stains are, essentially, neutralized and washed away.

In order to be effective, most intrinsic whitening products should be used daily for two weeks. While in use, it is important to leave the whitening product on for the recommended period of time, which may be up to four hours. Swallowing a large amount of the solution could cause a health risk, so consult your physician immediately if this happens.

Extrinsic Whitening Methods

There are many popular extrinsic whitening tools, including whitening gum and toothpaste. Extrinsic methods remove surface stains from the teeth, which helps to brighten teeth, while simultaneously keeping the stains from working their way deeper into the teeth. However, these extrinsic whitening products are not designed to remove intrinsic stains. Instead, extrinsic products should be used to help maintain a whiter smile.

Extrinsic whitening products include Restore Remineralizing and Desensitizing Toothpaste, AllWhite Whitening Toothpaste, and the Oral-B® Vitality ProWhite toothbrush.

Note: There are some tooth discolorations that are caused by medical conditions, such as a dead nerve in the tooth, and medications, such as tetracycline. These discolorations may be difficult to remove with over-the-counter whitening products. Speak with your dentist to learn more about how to use tooth whitening products or for specific product recommendations.