Teeth whitening is the treatment most commonly requested of cosmetic dentists. There are a variety of whitening or bleaching treatments available to suit every preference, time frame, and budget.

Teeth whitening treatments can be done in the dental office over a few one-hour bleaching sessions. Whitening using bleaching kits purchased at the drugstore can also be done at home. A survey showed that 15 percent of the American population has tried teeth whitening. The cosmetic procedure usually results in moderate to significant improvement in the brightness and whiteness of a person’s smile. It is important to note that teeth whitening is not a permanent solution and needs some upkeep for a long lasting effect.

Bleaching vs. Whitening

The term “whitening” is used when restoring a tooth’s surface color by getting rid of stains and dirt. This means that a whitener includes products that clean, such as toothpaste. Since most people would rather use the term whitening than bleaching, whitening has become more widely used, even when addressing products that contain bleach. The FDA allows the use of the term “bleaching” only to address procedures resulting in teeth whiter than their natural color. Only products that contain bleach (hydrogen peroxide or carbamide peroxide) do the trick.

Tooth Enamel

The enamel on our teeth give off the sparkling white color that we originally have. Tooth enamel is made up of microscopic crystalline rods. It is the material that protects our teeth from the acids and sugar in the foods we consume, our activities of chewing and grinding, as well as from effects of trauma. As the years go by the enamel is worn down, becoming more transparent so that the dentin is revealed. Dentin composes the core material of the tooth and is yellow in color.

As our teeth perform their functions, micro-cracks appear in the enamel while the dentin stays intact. These micro-cracks slowly fill up with debris and are gradually stained. In time, the appearance of the teeth becomes dull and yellowed.

Teeth whitening removes the debris and stains but does not treat the cracks in the enamel. The exposed cracks are either quickly re-mineralized by saliva, or are filled up again with organic debris.

Types of Tooth Stains

There are two types of staining relating to the teeth: extrinsic staining and intrinsic staining.
Extrinsic stains form on the surface of the teeth as a result of contact with dark-colored beverages, foods, and tobacco, and routine wear and tear. Extrinsic stains may be minor and superficial, easily removed with brushing and dental cleaning. Stubborn extrinsic stains can be removed with tooth bleaching. If they are not dealt with early on, stubborn extrinsic stains may infiltrate the dentin and become embedded.

Intrinsic stains form on the interior of teeth. Possible causes of intrinsic stains are aging, trauma, contact with minerals (like tetracycline) during tooth formation, and excessive intake of fluoride. It was thought several years ago that intrinsic stains were too resistant to be removed with bleaching. These days, cosmetic dentists consider even deep-set intrinsic stains removable with take-home teeth whitening treatment that is maintained and supervised over a period of months or even a year.

Causes of Tooth Stains

Initial color: People’s initial natural tooth color may range from yellow-brownish to greenish-grey. As we age, our inherent color intensifies. In most cases, yellow-brownish teeth are more responsive to bleaching than greenish-grey teeth.

Translucency and thinness: These are genetic traits that people inherit and become more pronounced with age. Teeth that are less translucent and thicker have the benefit of seeming lighter in color. They also are more responsive to bleaching, compared to more translucent teeth. Your front teeth are typically thinner and contain less of the pigment that is required for bleaching. Cosmetic dentists believe that transparency is the only circumstance that cannot be adjusted by any form of teeth whitening.

Age: As you age, the whiteness of your teeth declines due to regular wear and tear and the buildup of stains. Teenagers’ teeth tend to be very responsive to whitening treatments and will show immediate, significant results. In your twenties, teeth-whitening may need a little more effort as the teeth begin to appear slightly yellow. By your forties, your teeth look more brown in color and may require greater maintenance. By your fifties, the stains that have accumulated and penetrated into the dentin can prove difficult (but not impossible) to eliminate.

Smoking habits: Intrinsic stains form and reside on the teeth from the nicotine, eventually penetrating the dentin with brownish deposits.

Eating habits: Food and beverages that are deep in color, such as carrots, oranges, coffee, cola, and red wine cause prominent staining with habitual intake. Moreover, foods that are high in acid content, like citrus fruits and vinegar, cause erosion of the enamel.

Drugs / chemicals: Excessive intake of fluoride causes fluorosis, in the form of small white streaks to black and brown stains on the teeth. Use of tetracycline at a young age while teeth are still forming produces dark grey or brown ribbon stains which are very difficult to eliminate.

Trauma: Falls and other injuries can result in substantial cracks in the teeth, which accumulate large amounts of stains and debris.

Grinding: Teeth grinding can produce cracking in the teeth at a micro level. It is most often caused by stress, and can result in the darkening of the edges of the teeth.

Whitening Shades

The outcome of teeth whitening treatments is subjective, varying substantially from person to person. Discuss your expectations with your dentist before the procedure, to obtain a reasonable idea of the results and avoid disappointment.

Shade guides are available to help determine the shade of white that is most natural for you. The broad range of tooth colors in the shade guides also measure before-and-after tooth color. Made up of 16 shades, the Vitapan Classic Shade Guide is most often the standard used in dental offices. It names the shades and divides them into four color groups according to darkness. It is common to observe tooth color lighten by two to seven shades after the bleaching procedure is done.

Teeth Whitening Options

A person wishing to whiten his or her teeth has three major options presented here. All three are based on differing concentrations of peroxide and vary in application times.

In-Office Whitening

Visiting your dentist to accomplish whitening procedures has the advantage of dramatic effects within a short period of time. Your dentist will first protect your gums with a paint-on rubber barrier. He or she will then carefully apply a relatively high-concentration peroxide gel to your teeth. The gel will stay on your teeth for several 15 to 20 minute intervals, adding up to one hour (at most). Should the stains on your teeth prove resistant after the session, your dentist may suggest that you return for one or more additional teeth-whitening sessions. Alternatively, your dentist may recommend a home-use system to continue with the whitening procedure. On average, in-office whitening sessions cost $650 each.

Professionally Dispensed Take-Home Whitening Kits

Many dentists believe that professionally dispensed take-home whitening kits have the potential to produce the most significant results in the long term. Take-home kits contain custom-made bleaching trays that are designed like mouth guards, which are used to apply a lower concentration of peroxide gel. Depending on the concentration of peroxide, the gel may stay on the teeth for a period of anywhere from one hour to overnight. The cost of a take-home teeth whitening kit ranges from $100 to $400.

Over-the-Counter Whitening

Over-the-counter teeth-whitening treatments present the most affordable and convenient method of bleaching the teeth. A whitening kit that can be found at your local drugstore contains a gel with a peroxide concentration that is lower than that of the professionally dispensed take-home whiteners. The kit may include either a one-size-fits-all tray, whitening strips, or paint-on applicators. Typically, only a few of the front teeth are treated, unlike custom-made trays that whiten the whole set of teeth. The cost of over-the-counter whitening ranges from $20 to $100.

Hydrogen Peroxide vs. Carbamide Peroxide

There are two kinds of peroxide or bleaching agents that may be used in teeth-bleaching. Your dentist will probably use hydrogen peroxide, which is more powerful and acts in a shorter time. Concentrations used in whitening gels range from about 9 to 40 percent. Carbamide peroxide has about a third of the strength of hydrogen peroxide and is the preferred chemical in at-home whitening treatments.

Maintaining Your Whiter Smile

To prolong the durability of newly whitened teeth, here are some suggestions:

  • Maintain the whitening treatment either at home or by dental visits, according to the instructions given by your dentist.
  • Practice exceptional dental hygiene, making sure to brush and floss daily.
  • Avoid consumption of dark-colored foods and drinks for a period of at least one week after whitening.
  • Use a straw when drinking dark-colored beverages to prevent staining of teeth.

Teeth Whitening Risks

While teeth whitening treatments are considered generally safe when instructions are followed, particular risks arise in the use of the products. Firstly, sensitivity to touch, pressure, and temperature may result, especially after treatment with a high concentration of peroxide. Some people experience shooting pains in the middle of their front teeth that occur spontaneously. Sensitivity typically lasts no longer than one or two days, but may continue for up to a month in some cases. Using a toothpaste that contains potassium nitrate may alleviate this problem. You are more at risk for sensitivity if you have major cracks in your teeth, gum recessions, or poor tooth restorations. Interestingly, it has been observed that redheads are also at greater risk.

Another risk of teeth whitening procedures is gum irritation. More than 50 percent of users of teeth-whiteners experience irritation lasting up to several days. Gum irritation is due to the bleach concentration or contact with the trays, and may be reduced if the concentration is lowered.

Note that dental restorations including crowns, veneers, and bonding are not affected by bleach and will keep their default color while the surrounding teeth are whitened.

Additional Cautions

Here are some additional points to consider when you are deciding whether to undertake teeth-whitening. If you intend to have ceramic restorations, cosmetic bonding, or porcelain veneers on your teeth, they should be placed only after at least two weeks following whitening. This is important for a few reasons. Firstly, it will ensure that the restoration is properly bonded and that the functionality of the tooth is restored to its greatest potential.

In addition, whitening results are not completely observed until approximately two weeks after bleaching. You want to be sure the shade of your restoration matches that of your newly whitened teeth. If you already have tooth-colored restorations in place, they may need to be replaced after your whitening treatment.

Another point to consider is that no amount of bleaching will result in teeth that appear unnaturally white. It is also a challenge to bleach the yellow color of the root surfaces that appear in people with recessed gums. Finally, pregnant or nursing women should not undergo teeth whitening. The possible effects of swallowed bleach on the baby is yet unknown.