National surveys have shown that on first meeting someone, the most observed parts of the body are the eyes and teeth (smile). Therefore, it should be no surprise that teeth whitening has grown to be a huge part of cosmetic dentistry. We hope the following helps you better understand your options and what results to expect. 

Treatment Options

There are different approaches to whitening teeth. Without a doubt, bleaching teeth is the most common means of whitening teeth and usually the first approach. This page will look into bleaching more in-depth, but there are other clinical options. 

Microabrasion is a low-cost alternative that involves removing the surface of teeth enamel using an abrasive disc. For superficial stains isolated on a few teeth, or rough teeth surfaces, this might be an option. Unfortunately, most stains run deep, and are generalized across all teeth. 

Veneers are another popular choice when bleaching fails to remove stains. Veneers involve removing the surface of a tooth, and cementing tooth-colored porcelain onto the tooth surface. Similarly, crowns, the final option, involve removing all sides of the tooth, leaving a central core on which porcelain jacket is cemented. Both veneers and crowns involve removing a significant amount of tooth structure though, and your dentist should only be considering them if bleaching is not a realistic option.

Bleaching vs. Whitening

Under FDA regulations, a product can only use the term "bleaching" when it is capable of whitening teeth beyond their natural color. On the other hand, the term "whitening" can be applied to any product that simply removes debris from teeth surfaces. Therefore "bleaching" can only be used for professional products that use peroxide chemicals, while even regular toothpaste can advertise itself as being a "whitening" product. Be aware of this advertising gimmick. 

To confound things further, many dentists refer to their bleaching products as being "whiteners" because they worry that the term "bleaching" may scare potential patients. Be alert though, most over-the-counter products at drugstores claim to be whiteners because they lack the active ingredient that truly bleaches teeth.

Types of Staining & Relevance

All discolored teeth are not the same. Different factors can cause discoloration, and knowing the cause gives you a better idea of whether bleaching is likely to work for you. Dentists attempt to classify stained teeth into either intrinsic or extrinsic stains. 

Examples of instrinsic staining: tetracycline banding (top), fluorosis (middle) and trauma to single tooth (bottom).

Extrinsic stains are the more common type. They largely appear on the surface of teeth as a result of long-term exposure to dark-colored beverages such as coffee, or smoking. While extrinsic stains can initially be brushed away, over time they become difficult to remove and require bleaching. Bleaching is largely effective with these teeth, and treatment is in the order of weeks, not months.

Intrinsic stains are formed from within the tooth and eventually appear on the outside. For example, trauma to a tooth can disrupt the blood flow to the inner pulp, and the tooth can appear black or darkened on the surface. Other causes of intrinsic stains include the use of tetracycline antibiotics as a child, normal aging, or excessive ingestion of fluoride. Each manifests differently on the tooth surface, but because the stains come from within, they are harder to bleach out. In the past, most dentists opted for veneers or crowns, but studies have shown bleaching can still be effective, but treatment is in the order of months.

For this reason, it is important to consult a dentist even if you plan on using an over-the-counter product to whiten your teeth. By explaining the cause of your teeth's discoloration, the dentist can give you a better understanding of whether whitening can work. As an example, certain tooth-colored fillings (composite fillings) blend in nicely to the surrounding tooth when they are first placed, but become discolored over time. Since the fillings are made of plastic and not tooth material, no amount of whitening products can change the color - a dentist would know to simply replace the filling instead. 

How Bleaching Works

Your teeth are composed of two layers: an outer layer of hard enamel and an inner layer of soft dentin. The enamel layer is largely composed of microscopic crystal rods, and is designed to protect the rest of the tooth from the effects of chewing, acidic foods and trauma. Unfortunately, this layer is relatively porous, and over time, staining agents work their way into the pores and bind crystal rods deep within the enamel. This reduces the "whiteness" of teeth and goes deeper than we think, so regular brushing cannot remove the discoloration. 

Fortunately, teeth bleaching products use chemicals that get down into the tooth enamel and set off a chemical reaction (oxidation) that breaks apart the staining compound while preserving the tooth structure itself. Most products use either carbamide peroxide or hydrogen peroxide (similar to chemicals used in bleaching hair). Carbamide products tend to be three times more concentrated than comparative hydrogen peroxide products because they are three times less effective. 

Bleaching Options

Example of in-office bleaching.

There are three treatment methods for bleaching teeth: in-office whitening, professionally dispensed whitening-kits and over-the-counter products. Each has its advantages and disadvantages, and cost varies among them.

In-office bleaching is the fastest and most effective means of whitening teeth. During a normal procedure, the dentist isolates your teeth and applies peroxide product directly on them, avoiding contact with the gums. Since it is being done in the supervision of a dentist, the peroxide concentration is far higher than the other options, and thus less time is required. The product may be used in combination with heat, a special light, and/or laser to accelerate the process. Results are seen in one, 30-60 minute treatment, but for more dramatic results, several appointments are needed. Some dentists even combine in-office treatments with dispensed whitening kits. In-office bleaching procedures are usually in the range of $400-500 per arch.
 

Custom trays are filled with bleaching gel prior to placement.

Professionally dispensed whitening kits allow you to do the treatment at home, and the results are the same, or even better, than in-office bleaching, but take longer. For these products, the dentist takes an impression of your teeth and builds a clear custom tray that fits your teeth but avoids your gums. You are given the peroxide gel to take home, and every night, you place the gel into the tray and seat the tray in your mouth. The concentration of peroxide tends to be lower than in-office products, so treatment involves several weeks, but the results are preferred by most patients. Cost can range from $200 to $400 and depends on several variables.

Finally, over-the-counter products have become a rapidly growing field on their own. Products in this category include whitening strips, paint-on applicators, or one-size-fits-all mouth trays with gel - all found at local pharmacies. Most of these products whiten only the front teeth and ignore other teeth, and since they do not fit as well as dentist-made trays, the peroxide concentration is very low. This means that treatment needs to be in the order of months to really see the same results as the above two options. Many patients begin with these products because of their relatively low cost, and look toward dentist-directed treatments if they decide they need further whitening.

Patient Candidates & Contraindications

WIth any of the above bleaching methods, outcomes are best if you have extrinsic stains which are yellow-brown in color, across most of your teeth, and at the 2/3 tips of the teeth. Alternatively, a good outcome is harder if you have intrinsic stains which are grey-blue in color, isolated to a few teeth, and are at the 1/3 part of the tooth which is in contact with the gums. 

We recommend that the following patients avoid bleaching treatment: 

• children (we recommend no earlier than 14 years of age)
• pregnant or nursing mothers
• those with very sensitive teeth
• those with xerostomia (reduced saliva production)
• patients with gingivitis or poor oral hygiene

Expected Results

Shade guides allow for an accurate measurement of progress

To measure changes in teeth color, dentists often rely on shade guides. These are hand-held displays which show a range of teeth colors - the standard being Vitapan Classic Shade Guide. Most shade guides are arranged in some systematic manner, going from light to dark. Always remember to match your teeth color under natural light and when your teeth are wet or moist - otherwise you will have discrepancies.

Bleaching can occasionally lighten tooth color by nine or more shades, but most are likely see somewhere between a change of two to seven shades. The longer you bleach your teeth, the more dramatic the effect. Some patients are able to move up many shades by bleaching for several months. Always be aware of the negative effects of bleaching though as will be discussed shortly.

In general though, studies have shown that 66% of patients see a noticeable change after two weeks of using home-bleaching kits provided by the dentist. The proportion of people increased as bleaching time was extended. After 3 years, 60% of patients had fully retained their whiter smile. Teeth to not revert back to being stained on their own, but if you continue your former habits, teeth can once again become stained. 

Risks & Side Effects

If bleaching is conducted as directed, it is a safe procedure. However, you should be aware of the following risks:

• Sensitivity - By far, the greatest risk to bleaching is dental sensitivity to hot or cold foods following treatment. Mild tooth sensitivity is reported in upward of 25% of cases and if significant tooth sensitivity should occur, you should skip one or two days of bleaching as needed. Alternatively, speak to your dentist regarding using a product with a lower concentration of peroxide - this will lower the sensitivity, and your teeth can still be whitened, but the product will have to be used for a longer period of time. 

Sensitivity usually resolves on its own when the bleaching procedure has concluded. If only a week of treatment remains, it may be worthwhile to simply wait for treatment to commence. If there is over a month of treatment left, you may wish to consult your dentist. Some dentists recommend brushing with toothpaste containing potassium nitrate to alleviate the sensitivity (Sensodyne is one such product), but this is only a temporary solution.

• Irritated gums - Over half of those who use peroxide whiteners experience some degree of gum irritation resulting from the bleach concentration or from contact with the whitening trays. Such irritation typically lasts up to several days, dissipating after bleaching has stopped or the peroxide concentration lowered. Dental trays can be adjusted so that they fall short of the gums, and using less peroxide gel often equates to fewer chemicals reaching the gums. Speak to your dentist about both options.

• Uneven whitening - Teeth fillings, even if they were the color of your teeth to begin with, do not change color with bleaching. The same is true for veneers, crowns, and other dental restorations. As a result, your natural teeth may lighten in color, but these artificial teeth do not - resulting in technicolor teeth. Your dentist should be aware of these effects and you should be warned if it is relevant in your particular case. Such restorations may need replacing following bleaching.

Another common effect of teeth bleaching is uneven whitening of even natural teeth. Most often, the tips of teeth bleach first, and with continued use, the rest of the tooth follows. Some patients may even get white spots appear on their teeth during the process. With continued bleaching, these spots will blend in with the remaining portions of the tooth as the rest begin to lighten.

Additional Information

• Bleaching does not reduce the strength or structural stability of teeth - sensitivity is a concern though with prolonged use

• Bleaching has been proven to not cause the formation of any serious oral pathologies or cancers in humans

• Overnight wear of at-home bleaching products is recommended over usage during the day for greater results

• To maintain whitened teeth, it is advised that the patient stop smoking, and to sip dark-colored beverages through straws.