Teeth Bleaching – Types, Risks and benefits

teeth bleaching

Reviewed By:
Andrew M. Sicklick, D.D.S.

Summary

Bleaching is a cosmetic procedure to whiten the teeth with peroxide. This changes the natural color of the teeth and removes both surface and deep stains. The degree of color change that occurs during bleaching depends on the types of stains present, the peroxide dose, the amount of time on the teeth and how frequently it is performed. Some areas, including artificial crowns, veneers and the roots of the teeth, cannot be whitened by bleaching.

Teeth gradually yellow as they age. Specific types of stains or discolorations also occur and respond differently to bleaching. Extrinsic stains are superficial stains extending no deeper than the enamel of the tooth. Intrinsic stains are deeper stains in the dentin of the tooth. A tooth may also become discolored after a root canal treatment. Age-related and extrinsic stains typically bleach much faster than intrinsic stains.

Several different bleaching options are available. During in-office bleaching, a dentist applies a 15 percent to 35 percent hydrogen peroxide gel or paste to the teeth. During at-home dentist-supervised bleaching, the patient uses a molded mouthpiece to apply the bleaching agent. Many over-the-counter bleaching products are also available. However, the American Dental Association (ADA) recommends that patients consult their dentists before using any bleaching products, including over-the-counter products. Internal bleaching involves chemicals that are placed inside a tooth that has undergone a root canal treatment.

Before bleaching, a dental examination is necessary to help determine if the patient is a good candidate and what treatments are best. Any existing cavities will need to be filled. If the patient will be using an at-home treatment, a mouthpiece will be made. The dentist may request a follow-up after treatment to evaluate the success and to check for gum (gingiva) irritation or tooth sensitivity. Bleaching tends to last for about one to five years, depending on the patient’s personal habits.

Professional bleaching is a safe procedure that does not tend to cause serious problems. According to the American Academy of General Dentistry (AAGD), it is successful in at least 90 percent of patients. Side effects of bleaching include tooth sensitivity and gum irritation. They tend to go away when the treatment is completed.

About teeth bleaching

Bleaching is whitening teeth with peroxide to change the natural color of teeth. Teeth naturally yellow as they age and whitening is a cosmetic procedure that can temporarily change the color. Yellowed or slightly discolored teeth can be perfectly healthy.

Tooth enamel contains pores, which allow external stains to penetrate. Bleaching alters the light-absorbing or light-reflecting quality of teeth. In general, yellow stains bleach more rapidly than gray stains. Some areas, including artificial crowns or veneers and the roots of the teeth, cannot be whitened by bleaching.

The degree of color change that may occur depends on the types of stains present, the strength of the chemicals, the amount of time bleach remains on the teeth and how frequently it is used. Many dentists recommend bleaching gradually, until patients find the preferred shade. Teeth are not naturally pure white and bleaching to intensely white shades may look unnatural. For a natural look, teeth should be bleached no whiter than the whites of the patient’s eyes.

Different types of stains or discolorations respond variably to bleaching. These different types of discolorations include:

  • Extrinsic stains. Superficial stains that extend no deeper than the tooth enamel. These stains may be caused by smoking, beverages (e.g., coffee, tea, cola, red wine) or foods (e.g., tomato sauce). Overall, these stains tend to respond very well to bleaching.
  • Intrinsic stains. Deeper stains that develop in the dentin of the tooth. These may be caused by certain chemicals or medications (e.g., excessive fluoride, tetracycline) used in childhood when the teeth are developing. The use of the antibiotic tetracycline during pregnancy can also stain a child’s developing teeth. These stains may cause a gray discoloration. They may bleach very slowly or not respond to bleach.
  • Age-related stains. During the aging process the teeth become stained due to both extrinsic and intrinsic factors. The enamel becomes thinner with age and dentin becomes slightly yellow. This discoloration may be visible through the enamel, which is translucent. These stains tend to respond well to bleach.
  • Stains from root canal treatments. A tooth may become discolored after a root canal treatment. These stains require a different method of treatment than others, but tend to bleach well when this treatment is used.

Bleaching is not permanent and usually needs to be repeated. The whiter color may last for up to five years, depending on how much care is taken to avoid new stains.Bleaching is not recommended for some patients and for specific dental areas. The roots of the teeth may become exposed due to receding gums, but they cannot be bleached. People with periodontal disease, worn tooth enamel and sensitive teeth are not good bleaching candidates because bleach can irritate sensitive tissue such as the gums. Pregnant women and those who are breast-feeding should not have bleaching because the effect of bleach on a developing fetus or nursing infant is unknown.

Types and differences of teeth bleaching

There are many different methods available for bleaching teeth. All of the teeth may be bleached at once, or some of the teeth may be bleached. In fact, a single tooth may be bleached to closely match the surrounding teeth in a process called selective bleaching.

Bleaching can be either external or internal. During external bleaching, chemicals are placed on the surface of the tooth. Options for external bleaching include:

  • In-office bleaching. A dentist applies a 15 percent to 35 percent hydrogen peroxide gel or paste to the teeth. Currently, all of these bleaching agents have the American Dental Association Seal of Acceptance. In-office bleaching can be expensive but it provides the fastest results. It often can be completed in about one hour, although in some cases multiple treatments may be needed. Some dentists may use light, heat or a laser as well. It is believed that light or heat speeds up the bleaching process, but some studies refute these claims. The American Dental Association (ADA) has not recognized the use of lasers or light with the seal of acceptance, because studies demonstrating the effectiveness of the procedure have not yet been completed.
  • At-home dentist-supervised bleaching. Patients use a mouthpiece molded for their teeth to apply the bleaching agent at home. The dentist provides the custom fit mouthpiece, bleaching agent, instructions for use and monitors the process with regular appointments. Currently, all of the bleaching agents used in this process that have the ADA Seal of Acceptance use a 10 percent carbamide peroxide gel. The mouthpiece is lightweight enough to be worn comfortably and is often thin enough to talk or work while wearing it.
  • Over-the-counter products. Many over-the-counter whitening products are also available. However, the ADA recommends that patients consult their dentists about the use of over-the-counter products. Over-the-counter mouthpieces are not custom-fitted and may cause leaking and potential swallowing of the bleaching agent. This can irritate the gums and reduce the bleaching effectiveness. Overuse can damage the teeth, gums and mouth.

Some products are available that do not actually bleach the teeth, but can remove some surface stains. One widely used example is over-the-counter whitening toothpaste. Mild abrasives are present in nearly all toothpastes to help remove some surface stains. “Whitening” toothpastes remove more stains through the use of chemicals or polishing agents. However, toothpaste can only remove some surface stains.

In internal bleaching, chemicals are placed by the dentist inside the root canal of a discolored tooth that had previously undergone root canal treatment and no longer has a live nerve. This is known as non-vital whitening. The dentist places a whitening agent inside the tooth for several days.

Before the teeth bleaching procedure

A dental examination is necessary to help determine if the patient is a good candidate for bleaching and what treatments are best. This examination will include a dental history focusing on the factors that may have caused the stains. The dentist may also photograph the teeth before bleaching to help monitor the treatment’s progress. People with gum disease and worn tooth enamel, and pregnant women are not good candidates.

A dental hygienist will clean the teeth in preparation for the bleaching treatment. Any cavities will usually need to be filled beforehand. If whitening agents penetrate through decayed areas in the tooth, they can damage the tooth nerve.

If the patient will be using an at-home treatment, a mouthpiece will be made. The dentist will make an impression of the teeth. This impression will be sent to a dental laboratory, where the mouthpiece is custom-made to fit the patient’s mouth. The dentist will also provide the bleaching agent or a prescription for the agent and give the patient instructions for use.

During the teeth bleaching procedure

What occurs during the bleaching procedure depends on the type of procedure. These procedures include:

  • In-office bleaching. This may take from 30 to 90 minutes to perform and may require several appointments. However, it can be accomplished in a single one-hour appointment for certain patients. A protective gel or rubber dam is placed over the gums to protect them from the bleaching agent, which is then applied to the teeth. In some cases, light, heat or a laser may be used on the bleaching agent to speed up the bleaching process.
  • At-home, dentist-supervised bleaching. The first application may be done at the dental office. The dentist can demonstrate the proper use of the product and the patient can ask questions. The mouthpiece is filled with the bleaching agent and is then worn in the patient’s mouth. The mouthpiece may be worn for about 30 minutes to a few hours each day, or it may be worn overnight.

    At-home treatment may take up to several weeks. More severe stains take longer to bleach than lighter stains. In general, wearing the mouthpiece overnight requires less treatment time. The patient will need to return to the dentist’s office regularly to monitor progress and check for any signs of problems, such as gum irritation.
  • Non-vital whitening. A process to whiten teeth that have undergone root canal treatment. This whitening occurs from the inside out. The material used to fill the tooth’s root canal (called gutta percha) is removed and a whitening agent is put in its place. This agent remains inside the tooth for several days before it is removed and the gutta percha is replaced.

After the teeth bleaching procedure

The dentist usually requests a follow-up visit a few days after treatment is completed to evaluate the success and to check for gum (gingiva) irritation or tooth sensitivity. In some cases, bleaching may be combined with other cosmetic procedures. For example, a veneer may be applied to a tooth that did not bleach well.

Bleaching tends to last for about one to five years, depending on the patient’s lifestyle habits that may restain the teeth. A touch up can be performed to maintain the brighter appearance of the teeth. If the patient used at-home, dentist-supervised whitening, the same mouthpiece may be able to be used. This can reduce the cost of the treatment. Retreatment usually does not take as long as the first treatment.

Risks and benefits of teeth bleaching

Bleaching is a safe procedure that does not tend to cause serious problems. According to the American Academy of General Dentistry (AAGD), it is successful in 90 percent of patients. There is typically at least a two-shade improvement, measured by a dentist’s tooth shade guide. The rate of success depends on many factors, including the types of stains present, patient compliance with treatment and the type of product used. Discolorations caused by excessive fluoride and the antibiotic tetracycline may not be as responsive to bleaching. Artificial materials, such as crowns and veneers, are not affected by bleaching. The roots of the teeth, which may be exposed due to receding gums, are also not affected by bleaching.

Side effects of bleaching include tooth sensitivity and gum (gingiva) irritation. They tend to go away when the treatment is completed. However, a prescription gel may be recommended to help reduce tooth sensitivity. When over-the-counter bleaching agents are used without the supervision of a dentist, there is the risk of overuse. Overuse can cause irreversible damage to the teeth and/or gums.

Bleaching is not for all patients. People who are allergic to peroxide should not have their teeth bleached, because the bleaching agent contains peroxide. Women who are pregnant or breastfeeding should postpone treatment until delivery and after any breastfeeding is complete. It is not known how the bleaching agents may affect a fetus or breastfeeding infant. It is also recommended that children under the age of 16 avoid bleaching. Children are likely to experience much more tooth sensitivity because the pulp of the tooth has not fully matured. Bleaching may not be appropriate for people with sensitive teeth, gum disease or worn tooth enamel.

Questions for your doctor regarding teeth bleaching

Preparing questions in advance can help patients have more meaningful discussions regarding their treatment options. Patients may wish to ask their doctor the following bleaching-related questions:

  1. Am I a good candidate for bleaching?
  2. Are my gums healthy enough to withstand teeth bleaching?
  3. What type of bleaching is best for me?
  4. Would you recommend any over-the-counter products?
  5. How much whiter are my teeth likely to become?
  6. How long will this treatment take?
  7. How long may I expect to maintain whiter teeth?
  8. How can I avoid staining my teeth in the future?
  9. Would I benefit from any other cosmetic procedures, as well?
  10. Should I make an appointment for a follow-up?
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