You don’t have to be born with perfect teeth to have a bright smile. Tooth whitening, or bleaching, can usually erase stains and discoloration that occur over time.
How effective is bleaching — and is it safe? Should you use over-the-counter products or go to your dentist? To find out, we talked to Sandra Burkett, D.D.S. She is a former instructor in clinical dentistry at Columbia University College of Dental Medicine.
QCan all stains be removed?
AMost of the time, yes, but not always. “Extrinsic” stains can be removed easily with a bleaching agent. This kind of discoloration occurs on the outer layer of the tooth. It can be stained by such things as drinking coffee, tea or red wine, smoking or even eating a lot of spaghetti sauce.
Sometimes the inner structure of the tooth becomes darker or yellowed. This is called an “intrinsic” stain. Intrinsic stains are more difficult to remove. Some can’t be removed at all. For example, tetracycline (an antibiotic) can cause intrinsic staining. This happens when it is used by children under 8 or women in the last half of their pregnancies. These are times when permanent teeth are developing in a child or fetus. These stains cannot be removed by bleaching.
Fluorosis is a cosmetic dental condition caused by overexposure to fluoride during tooth development. Bleaching can’t always remove fluorosis marks either. Mild to moderate fluorosis causes white lines, streaks or spots. Whitening can make these less obvious. In more severe cases of fluorosis, however, the teeth can become pitted and have brown, gray or black spots. Bleaching will not work in these cases.
Some stains are caused by nerve or blood vessel damage, usually as a result of some trauma. Root canal therapy may be necessary to prevent permanent staining. Even so, the tooth may darken. If external bleaching does not remove the stain, a bleaching agent can be applied to the inside of the tooth. Another option is to cover the tooth with a veneer or a crown.
A third type of stain is called “age-related.” It’s a combination of intrinsic and extrinsic factors. As we age, the dentin (the inner portion of the tooth) gets slightly yellow. The outer part of the tooth (enamel) gradually becomes thinner over time. This allows the yellow dentin to show through.
Yellow stains are the easiest to remove with bleaching. Gray or black stains tend to be more difficult. Generally, new stains are easier to remove than old ones.
QHow white will my teeth get?
AWell, that depends. Professional whitening (in-office or at home) can make your teeth up to seven shades whiter. Your dentist will show you “shade cards” that are similar to those used for choosing paint. You can choose which one is best for you.
If you use an over-the-counter product at home, choose carefully to ensure it is safe, effective and reliable. For example, you can look for a product accepted by the American Dental Association. Follow the directions carefully. Over-the-counter products will not produce the dramatic improvements you can get through a professional. Excess exposure to OTC bleaching products can cause sensitivity in your teeth.
There’s been a trend in recent years toward whiter, brighter teeth. The shades that were popular a few years ago seem somewhat dingy by comparison.
It is important to think about which shade most flatters you and not how white your teeth can get. Keep in mind that your habits also dictate how white your teeth will be. Your whitening results will last longer if you don’t smoke and don’t drink coffee or tea. Occasional touch-ups may be needed to maintain the shade you want. This should be done with professional direction.
QDo I have to bleach all my teeth?
ANo. It’s possible for you to have one or a select number of teeth bleached to match the surrounding teeth. However, this should only be done professionally.
QI had a root canal and now the tooth looks dark. Can bleaching help?
AWhen a tooth has been darkened because of root canal therapy, a bleaching agent can be applied to the inside of the tooth. This is known as non-vital whitening. In this situation, the middle of the tooth (the pulp chamber) is cleaned out. A bleach-soaked cotton ball is placed into the cavity. It stays in place for about a week and then is replaced with a fresh one. Eventually the tooth will bleach from the inside out.
QWhy should I pay more for in-office bleaching when I can do it at home?
AFor uniform results, in-office bleaching is best. Before starting a whitening program, your cosmetic dentist will determine the health of your teeth and mouth. He or she will remove any surface stains and deposits. Treatment will be customized to your particular needs. Your dentist also will advise you if you need to change your daily oral care routine, to help maintain the results.
Professional in-office whitening is also more convenient. This is because the bleaching agents are stronger than those in over-the-counter products. Your teeth will get much whiter in 60 to 90 minutes. Some people may need two or three visits. Others can get good results in a single session.
Some in-office treatments use a light to activate the whitening agent. This process is more efficient. Teeth can get many shades whiter using the light.
In-office whitening also avoids the use of trays, so you will not swallow any of the whitening agent.
QAre over-the-counter products effective?
APeroxide-based over-the-counter products can be effective at whitening your teeth. The ingredients in home kits aren’t very concentrated, however. This means it may take several weeks to get good results.
Over-the-counter whitening products tend to cost less than having your teeth whitened by a dentist. However, they aren’t ideal.
Some over-the-counter whitening kits contain mouthpieces that won’t fit snugly around your teeth. As a result, some parts of the teeth may be covered by the bleaching agent, while some parts may not. This results in uneven covering and bleaching. The bleaching ingredient also may leak out from the mouthpiece. This can irritate the gums and other soft tissues.
If you decide to use an over-the-counter product, consult with your dentist first. The dentist can offer advice, and can make a mouthpiece that fits. This will help you to get the best results from the OTC product.
QWhat about whitening toothpastes?
AWhitening toothpastes can help the teeth remain cleaner and therefore look whiter. However, the stronger toothpastes rely on abrasion. This can damage the teeth. When you use an abrasive on the outer layer of the teeth, the “newer” layer looks whiter. But this process causes the teeth to lose shine and luster over time.
These toothpastes do not actually whiten or change the shade of your teeth. They simply help to prevent stains from sticking to your teeth. Results will take some time, and the change won’t be very visible. Whitening toothpastes can help to preserve the results of professional in-office or at-home whitening.
Before you choose whitening toothpaste, be sure to look at the product’s ingredients. Some toothpastes have less abrasive materials. Ask your dentist for advice before you make a decision.
QHow much does whitening cost?
AIn-office whitening is the most expensive. It usually costs between $300 and $750.
A less costly approach may be to use the home-bleaching kit offered by your dentist. The cost of home bleaching will run about $250 to $450. This includes the materials and consultations with your dentist.
QHow long does bleaching last?
AIf you take good care of your teeth, and follow your dentist’s directions for care, you can expect the results to last one to three years. You can maintain your white teeth even longer if you don’t smoke, chew tobacco, or drink a lot of coffee or tea.
QI’ve had previous dental work on my front teeth. Will that be a problem?
ANot necessarily, although it does complicate things. The bleaching agents that are used to whiten teeth don’t affect tooth-colored fillings or other materials, such as porcelain crowns. After bleaching, these areas may appear darker than the surrounding teeth. However, sometimes the repair work is whiter than the natural teeth. In these cases, the whitened natural teeth will blend better with the repaired teeth.
QAre there any side effects?
AYou are unlikely to have any serious effects from whitening. However, some people feel mild tooth sensitivity after bleaching. Gums also can get irritated. A prescription fluoride gel can reduce the sensitivity, but most people don’t need it. The sensitivity usually goes away within a few days.
Irritation of gums or other soft tissues in the mouth is more of a problem with over-the-counter bleaching kits. That’s because the bleaching agents may leak around the edges of the mouthpiece.
Women should avoid tooth whitening during pregnancy. The effects of bleaching agents on fetal development are unknown.