Tooth decay, also known as caries or cavities, is an oral disease that affects many people. Unlike other diseases, however, caries is not life-threatening and is highly preventable, though it affects most people to some degree during their lifetime.

Natural bacteria live in your mouth and form plaque. The plaque interacts with deposits left on your teeth from sugary and starchy foods and produces acids. These acids damage tooth enamel over time by dissolving, or demineralizing enamel, which weakens the teeth and leads to tooth decay.

Foods containing carbohydrates (starches and sugars), such as soda pop, candy, ice cream, milk, and cake, and even some fruits, vegetables, and juices, may contribute to tooth decay.

The acids formed by plaque can be counteracted simply by saliva in your mouth, which acts as a buffer and remineralizing agent. Dentists often recommend chewing sugarless gum to stimulate your flow of saliva. However, though it is the body's natural defense against cavities, saliva alone is not sufficient to combat tooth decay. The best way to prevent cavities is to brush and floss regularly. To rebuild the early damage caused by plaque bacteria, we use fluoride, a natural substance that helps to remineralize the tooth structure. Fluoride is added to toothpaste to fight cavities. The most common source of fluoride is in the water we drink. Fluoride is added to most community water supplies and to many bottled and canned beverages.

If you are at medium- to high-risk for cavities, your dentist may recommend special high-concentration fluoride gels, mouthrinses or dietary fluoride supplements. Your dentist may also use professional strength anti-cavity varnish, or sealants ? thin, plastic coatings that provide an extra barrier against food and debris.

Because we all carry bacteria in our mouths, everyone is at risk for cavities. Those with a diet high in carbohydrates and sugary foods and those who live in communities without fluoridated water are likely candidates for cavities. And because the area around a restored portion of a tooth is a good breeding ground for bacteria, those with a lot of fillings have a higher chance of developing tooth decay. Children and senior citizens are the two groups at highest risk for cavities.

1. Cut down on sweets and between-meal snacks. Remember, it's these sugary and starchy treats that put your teeth at extra risk. Some research says certain foods, such as peanuts or sugar-free chewing gum, may be "friendly" to teeth. Eating these foods along with or after foods that contain carbohydrates may help to counter the effects of acids produced by bacteria. Drinking plenty of water can help wash away food particles. Of course, dentists encourage their patients to eschew these sugary snacks in favor of healthy alternatives.

2. Brush after every meal and floss daily. Cavities most often begin in hard-to-clean areas between teeth and in the fissures and pits ? the edges in the tooth crown and gaps between teeth. Hold the toothbrush at a 45-degree angle and brush inside, outside and between your teeth and on the top of your tongue. Be sure the bristles are firm, not bent, and replace the toothbrush after a few weeks to safeguard against re-infecting your mouth with old bacteria than can collect on the brush. Only buy toothpastes and rinses that contain fluoride (antiseptic rinses also help remove plaque) and that bear the American Dental Association seal on the package. Children under age 6 should only use a small pea-sized dab of toothpaste on the brush and should spit out as much as possible, because a child's developing teeth are sensitive to higher fluoride levels. Finally, because caries is a transmittable disease, toothbrushes should never be shared, especially with your children.

3. See your dentist at least every six months for checkups and professional cleanings. Because cavities can be difficult to detect, a thorough dental examination is very important. If you get a painful toothache, if your teeth are very sensitive to hot or cold foods or if you notice signs of decay like white spots, tooth discolorations or cavities, make an appointment right away. The longer you wait to treat infected teeth, the more intensive and lengthy the treatment will be. Left neglected, cavities can lead to root canal infection, permanent deterioration of decayed tooth substance and even loss of the tooth itself.