When you have your teeth bleached in a dental office, the results almost seem like magic. Let's push aside the magician's cape and see what is really happening in professionally-applied, in-office tooth whitening.

How do teeth become discolored?
A tooth's enamel covering is mostly composed of mineral crystals. At a microscopic level, you can see a framework or matrix of organic (living) matter interspersed between the crystals of enamel creating a very irregular surface capable of retaining stains. Chromagenic (color generating) organic compounds can become part of this organic matrix resulting in tooth staining. They can be bleached without affecting the mineral structure of the tooth's enamel.

As people get older and their teeth wear, the enamel loses its youthful translucency and the underlying layer, called dentin, thickens and becomes more yellow. Such changes to the actual tooth structure are called intrinsic staining. Other causes of intrinsic discoloration are exposure to high levels of fluoride or tetracycline antibiotic administration during childhood, tooth decay, or root canal problems, among others. Discoloration can also be caused by external staining from certain foods, drinks, or tobacco products. Such surface stains are called extrinsic staining.

Behind the Magic
Materials used for tooth bleaching are hydrogen peroxide and carbamide peroxide. Peroxides are commonly used as bleach, and you may have seen them used as hair bleaches, for example. Hydrogen peroxide is a strong oxidizing agent that attacks the organic molecules responsible for tooth discoloration, bleaching them until they lose their color. Carbamide peroxide also contains urea, which is a compound that permits the peroxide to remain in contact with the teeth for longer amounts of time without harming them.

Often called power bleaching, the in-office technique uses a high concentration of peroxide solution (35-45% hydrogen peroxide), placed directly on the teeth in the form of a gel. A heat or light source may enhance the peroxide release. The gel is applied with trays custom fitted to your mouth, and specific barriers are applied to protect sensitive gum tissue from the solution. Results show teeth becoming up to ten shades lighter in about an hour.

In-office bleaching under the supervision of my staff and me is recommended if you have severely stained teeth, and particularly if you are about to have veneers or crowns made. It's a way to rediscover the pearly translucency of your youthful smile.

Contact us today to schedule an appointment to discuss your questions about tooth bleaching. You can also learn more by reading the Dear Doctor magazine article “Teeth Whitening.”

If you have discolored teeth, the cause is often staining on the enamel surfaces from foods, beverages, or smoking. But tooth discoloration may also originate deep within the root of a tooth. Sometimes this happens to a tooth that had to have earlier root canal treatment because of injury or decay.

In such cases the living pulp tissue and its blood vessels and nerves had to be removed from the root canals, resulting in the death of the dentin layer, which makes up most of the tooth's body. Over time this caused the dentin to darken. The color may come from remains of blood that was left in the tissue, or from filling materials left in the root canal that are showing through.

Since these stains are caused internally (intrinsic) and not on the outside of the tooth (extrinsic) they must be whitened from the inside. This is usually done by putting a bleaching agent into the empty chamber from which the pulp was removed. Usually the bleaching agent is a substance called sodium perborate.

When it is mixed with a solution of hydrogen peroxide, sodium perborate slowly bleaches the color from the tooth's internal material. It is considered to be safe and reliable for this use.

The work begins by taking x-ray images to make sure that the root canal is correctly sealed and the bone is healthy. After this, we will make a small hole in the back of the tooth through which the root canal space will be cleaned. The root canal space will be sealed and the bleach will be applied in a putty-like form and sealed off from the rest of your mouth. Every few days this procedure will be repeated until the bleaching reaches the desired level.

At this point a tooth-colored composite resin will be used to seal the small hole that was made in the dentin to insert the bleach. After the tooth has reached the level of whiteness that matches it to your other teeth, veneers or crowns must sometimes be used to repair the surface if it is chipped or misshapen, for example.

Contact us today to schedule an appointment to discuss your questions about whitening internally discolored teeth. You can also learn more by reading the Dear Doctor magazine article “Whitening Traumatized Teeth.”

Having a whiter, brighter smile can do wonders for improving self-confidence, career opportunities, and interpersonal relationships, as demonstrated in numerous scientific studies. In fact, according to a poll conducted on behalf of the American Academy of Cosmetic Dentistry (AACD), the following was revealed:

• 99.7% of Americans believe a smile is an important social asset.
• 74% feel an unattractive smile can hurt chances for career success.
• 50% of all people polled were unsatisfied with their smile.

These statistics demonstrate why you should have a solid understanding about any cosmetic procedure — even teeth whitening — before making your decision to proceed. To help you ensure that you have the facts, we created the following list of questions.

• Am I a good candidate for tooth whitening?
• How much will the entire process cost?
• Does my insurance cover the cost (or any portion of the cost)?
• How does teeth whitening work?
• Is bleaching teeth safe?
• Will the bleaching agents damage tooth enamel?
• Can whitening treatments make my teeth sensitive?
• How does your professional bleaching differ from home whitening?
• What type of bleach and strength will you use?
• How long can I expect the results to last?
• What will the bleach do to my gums, filings, crowns, veneers, and/or bridgework?

Please note that we may cover most or all of these questions during your initial consultation; however, we encourage you to bring this list with you to ensure you get the answers you need so that you can make the best decision. To learn more now, continue reading the Dear Doctor article, “Teeth Whitening: Brighter, Lighter, Whiter....” Or, you can contact us to discuss your questions or to schedule an appointment.