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.”

Christie Brinkley's world-famous smile has graced the covers of countless magazines for over 30 years. In fact, in her own words from an interview with Dear Doctor magazine, the supermodel said, “I think my smile was really my passport to success in the modeling industry.” And while most of her smile's appeal comes naturally, Christie does give it a boost with good oral hygiene, regular dental checkups and tooth whitening. As Christie says, “When it comes to teeth, keep it as natural as possible. Do not go overboard on whitening. You want your teeth to compliment your face…your friends should not be required to wear sunglasses when you smile!”

Aside from some potential minor side effects such as tooth sensitivity, whitening teeth through bleaching is a relatively inexpensive way to brighten your smile conservatively and successfully. There are three common methods, as described below:

• An external or vital approach where “vital” (living) teeth are bleached through direct contact to the tooth's surface.
• An internal or non-vital approach where the tooth is whitened from the inside during a root canal treatment.
• A combination approach in which both internal and external bleaching techniques are used.

But what causes teeth to become discolored?

Tooth discoloration can be caused by a traumatic blow to your teeth resulting in nerve tissue (pulp) death. However, there can be many other causes: consuming or using products that stain the teeth such as coffee, tea, cola, tobacco products and red wine, to name just a few. Aging is another factor, as it results in changes in the mineral structure of the tooth as the enamel, the outermost layer, loses its beautiful and youthful translucency. Other causes include exposure to high levels of fluoride; tetracycline, an antibiotic, administered during childhood; inherited developmental disorders and jaundice in childhood; and tooth decay.

The good news is that we routinely brighten smiles through tooth whitening. To learn more about brightening your smile, continue reading the Dear Doctor magazine article “Teeth Whitening.” Or if you are ready to have your teeth professionally whitened, contact us today to schedule an appointment so that we can conduct a thorough examination and discuss your whitening treatment options. And if you want to read the entire feature article on Christie Brinkley, continue reading “The Secret Behind Christie Brinkley's Supermodel Smile.”

What causes stains on teeth?

Staining can occur on the outside surfaces of teeth and is caused by foods such as red wine, coffee, and tea, as well as by tobacco use. They can also be developmental, affecting the structure of the teeth due to excessive fluoride levels or from tetracycline antibiotics given during childhood to name a few. Changes in a tooth's enamel or dentin during tooth formation, or as teeth age, can also cause discoloration.

What is going on inside a tooth's structure that makes it look stained?

Most of a tooth's covering (95 percent) is composed of highly mineralized enamel. The crystals of enamel are contained in a framework, or matrix, of organic matter. Dentists believe that various organic compounds that get into this matrix can cause staining.

How do whiteners work?

Tooth whiteners or bleaches expose the teeth to a peroxide compound. This creates reactive oxygen that breaks down highly colored organic compounds within the tooth's sub-surface matrix, making the tooth look whiter, but without changing its internal structure.

What professional in-office whitening techniques are available?

During treatment, a high concentration of peroxide solution in the form of a gel is applied directly on the teeth, often with activation by a heat or light source. These systems use custom tailored trays fitted to an individual's mouth. Silicone barriers or protective gels are used to keep the peroxide gel away from the gums or sensitive membranes in the mouth.

How are professional home whiteners different?

Home whiteners involve a less concentrated solution of peroxide in a gel form. It is delivered to the tooth surface by a bleaching tray that is custom-made in your dentist's office. Over-the-counter whiteners such as whitening strips or paint-on formulas can also be used, but they take longer and they're not as effective — the more diluted solutions are used for safety.

Can toothpastes really whiten teeth?

Mild abrasives in toothpastes clean surface stains but cannot change the underlying tooth color or remove significant staining.

How long do the results last?

Usually, the results last from six months to two years, but effects will diminish over time. You can make them last longer by avoiding the foods and habits that cause staining.

Are teeth whiteners safe to use?

Teeth whitening products are safe if used according to our recommendations or the product manufacturer's directions. Peroxide products may be toxic if used in excess of recommended intervals and amounts.

Read more about teeth whitening in the article “Teeth Whitening, Brighter, Lighter, Whiter...” Contact us today to schedule an appointment or to discuss whether tooth whitening is right for you.