Cavities are decayed areas of your teeth that develop into tiny openings or holes. Cavities, also called tooth decay or caries, are caused by a combination of factors, including not cleaning your teeth well, frequent snacking and sipping sugary drinks.

What is it?

  • Cavities are decayed areas of your teeth that develop into tiny openings or holes. Cavities, also called tooth decay or caries, are caused by a combination of factors, including not cleaning your teeth well, frequent snacking and sipping sugary drinks.
  • Cavities and tooth decay are one of the most common health problems around the world. They're especially common in children, but anyone who has teeth can get cavities, including infants and older adults.
  • If cavities aren't treated, they get larger and the decay can cause a severe toothache, infection, tooth loss and other complications. Regular dental visits and good brushing and flossing habits go a long way toward preventing cavities and tooth decay.


The signs and symptoms of cavities and tooth decay vary depending on the extent and location of the cavity. When a cavity is just beginning, you may not have any symptoms at all.

But as the decay gets larger, it may cause such signs and symptoms as:

  • Toothache
  • Tooth sensitivity
  • Mild to sharp pain when eating or drinking something sweet, hot or cold
  • Visible holes or pits in your teeth
  • Pain when you bite down
  • Pus around a tooth


Cavities are caused by tooth decay, which is a process that occurs over time.

  • Plaque forms. Your mouth, like many other parts of your body, naturally contains many types of bacteria. Some of these bacteria thrive on food and drinks that contain sugars and cooked starches, also known as fermenting carbohydrates. When these carbohydrates aren't cleaned off your teeth, the bacteria can convert them into acids. The bacteria, acids, food particles and saliva then form into dental plaque — a sticky film that coats your teeth. If you run your tongue along your teeth, you can feel this plaque several hours after you've brushed. The plaque is slightly rough and is more noticeable on your back teeth, especially along the gumline.
  • Plaque attacks. The acids in plaque attack minerals in the tooth's hard, outer surface, called the enamel. This erosion causes tiny openings or holes in the enamel — cavities. Once spots of enamel are worn away, the bacteria and acid can reach the next layer of your teeth, called dentin. This layer is softer and less resistant to acid than is enamel.
  • Destruction continues. As tooth decay continues, the bacteria and acid continue their march through the layers of your teeth, moving next to the pulp, or the inner material of the tooth. The pulp contains nerves and blood vessels. The pulp becomes swollen and irritated from the bacteria. The bone supporting the tooth also may become involved. When a cavity and decay is this advanced, you may have severe toothache pain, sensitivity, pain when biting or other symptoms. Your body also may respond to these bacterial invaders by sending white blood cells to fight the infection. This may result in a tooth abscess.

Risk factors

Cavities are one of the most common worldwide health problems, and everyone who has teeth is at risk of getting them. But some factors increase the risk that you'll get a cavity or develop tooth decay. These risk factors include:

  • Tooth location. Tooth decay most frequently occurs in the back teeth — the molars and premolars. These teeth have lots of grooves, pits and crannies. Although these grooves are great for helping chew food, they can also collect food particles. These back teeth are also harder to keep clean than your smoother and more accessible front teeth. As a result, plaque can build up between these back teeth and bacteria can thrive, producing acid that destroys the enamel.
  • Certain foods and drinks. Some foods and drinks are more likely than others to cause decay. Foods that cling to your teeth for a long time, such as milk, ice cream, honey, table sugar, soda, raisins and other dried fruit, cake, cookies, hard candy, breath mints, dry cereal and chips, are more likely to cause decay than are foods that are easily washed away by saliva.
  • Frequent snacking or sipping. When it comes to your teeth, the amount of sugary snacks you eat is less important than when you eat them. If you frequently snack or sip sodas, acid has more time to attack your teeth and wear them down. This is also why parents are encouraged not to give babies bottles filled with milk, formula, juice or other sugar-containing liquids at bedtime. The beverage will remain on their teeth for hours and cause erosion — often called baby bottle tooth decay. If you're nursing or feeding an infant formula, talk to your baby's doctor about how to prevent early tooth decay. If you have a toddler who's transitioning from the bottle, don't let him or her wander around drinking from a "sippy" cup.
  • Not brushing. If you don't clean your teeth after eating and drinking, plaque builds up, eroding your teeth.
  • Bottled water. Adding fluoride to public water supplies has helped decrease tooth decay by offering protective minerals for tooth enamel. But today, many people drink bottled or filtered water that doesn't contain fluoride, and they may miss out on the protective benefits of fluoride. On the other hand, some bottled water may contain added fluoride, and if your drinking water also contains fluoride, babies and children could then get too much fluoride. Talk to your child's dentist about the amount of fluoride he or she may be getting and check ingredient labels on your bottled water.
  • Older age. An increasing number of older adults still have their natural teeth. However, over time, teeth can wear down and the gums may recede, making teeth more vulnerable to tooth decay and cavities. Older adults also may use more medications that can reduce the saliva flow, increasing the risk of tooth decay.
  • Receding gums. When your gums pull away from your teeth, plaque can form on the roots of your teeth. Tooth roots are naturally covered with a coating called cementum, but the cementum is quickly lost when the root surface is exposed. The underlying dentin is softer than enamel and can become decayed more easily, leading to root decay.
  • Dry mouth. Dry mouth is caused by a lack of saliva. Saliva has an important role in preventing tooth decay. It washes away food and plaque from your teeth. Minerals found in saliva help repair early tooth decay. Saliva also limits bacterial growth and neutralizes damaging acids in your mouth.
  • Weak or rough dental fillings. Over the years, dental fillings can become weak and begin to breakdown, or the edges can become rough. Either of these situations can allow plaque to build up more easily and make it harder to completely remove plaque.
  • Eating disorders. Anorexia and bulimia can lead to significant tooth erosion and cavities. Stomach acid from vomiting, for instance, washes over the teeth and erodes the enamel. Eating disorders can also interfere with saliva production. In addition, some people with eating disorders may sip soda or other acidic drinks throughout the day, which creates a continual acid bath over the teeth.
  • Heartburn. Gastroesophageal reflux disease (GERD), acid reflux and heartburn can cause stomach acid to flow into your mouth, wearing away the enamel of your teeth. If your dentist notices enamel loss and doesn't think this loss is caused by grinding your teeth, consult your physician to see if gastric reflux is the cause. Untreated reflux can cause significant tooth damage that is costly to correct.
  • Close contact. Some harmful, decay-causing bacteria in the mouth can be passed from one person to another by kissing or sharing eating utensils. Parents or even child care providers may pass along harmful bacteria to infants and children, for example.
  • Certain cancer treatments. Having radiation to your head or neck areas can increase the risk of getting cavities by changing the saliva produced in the mouth, which allows more cavity-producing bacteria to thrive.


Cavities and tooth decay are so common that you may not take them seriously. And you may think that it doesn't matter if children get cavities in their baby teeth. However, cavities and tooth decay can have serious and lasting complications, even for children who haven't yet gotten their permanent teeth.

Complications may include:

  • Pain
  • Tooth abscess
  • Tooth loss
  • Broken teeth
  • Chewing problems
  • Serious infections

In addition, when cavities and decay become very painful and severe, they can interfere with daily living. The pain may prevent you from going to school or work, for instance. If it's too painful or difficult to chew or eat, you may lose weight or have nutrition problems. If cavities result in tooth loss, it may affect your self-esteem. In rare cases, an abscess from a cavity can cause serious or even life-threatening infections when not properly treated.


Types of cavitiesYour dentist usually can detect tooth decay easily. He or she will ask about tooth pain and sensitivity. Your dentist will examine your mouth and teeth and may probe your teeth with dental instruments to check for soft areas. You may also have dental X-rays, which can show the extent of cavities and decay. Your dentist will also be able to tell you specifically which of the three types of cavities you have — smooth surface, pit and fissure, and root.

Treatments and drugs

Treatment of cavities depends on how severe they are and your particular situation. Treatment options include:

  • Fluoride treatments. Fluoride is a mineral that helps prevent cavities and helps teeth repair themselves. If your cavity is just getting started, a fluoride treatment may be able to help restore enamel. Professional fluoride treatments contain more fluoride than what's found in over-the-counter toothpaste and mouth rinses. Fluoride treatments may be in a liquid solution, a gel, foam or varnish that is brushed onto your teeth or placed in a tray that fits over your teeth. Each treatment takes a few minutes. Your dentist may suggest having periodic fluoride treatments.
  • Fillings. A filling is material that replaces decayed areas of your teeth. Fillings, sometimes called restorations, are the main treatment option when the decay has progressed beyond the initial enamel-erosion process. Your dentist drills away the decayed material inside your tooth. The gap is then filled to restore the tooth shape. Fillings are made of various materials, such as tooth-colored composite resins, porcelain, or combinations of several materials. Silver amalgam fillings contain a variety of materials, including small amounts of mercury. Some people don't like using mercury fillings because they fear possible adverse health effects. While some medical studies have shown these fillings to be safe, they remain controversial.
  • Crowns. If you have extensive decay or weakened teeth, you may need a crown rather than a filling to treat your cavity. The decayed area is drilled away. A crown is then fit over the remaining portion of tooth. Crowns are made of gold, porcelain or porcelain fused to metal.
  • Root canal. When decay is severe and reaches the inner material of the tooth, you may need a root canal. In this procedure, the pulp of the tooth is removed and then replaced with a filling.
  • Tooth extractions. A severely decayed tooth may need to be removed entirely. Having a tooth extracted can cause the other teeth in your mouth to move, so if possible, consider getting a dental implant to replace the missing tooth.


Good oral and dental hygiene can help prevent cavities and tooth decay. Follow these tips to help prevent cavities:

  • Brush after eating or drinking. Brush your teeth at least twice a day and ideally after every meal, using fluoride-containing toothpaste. To clean between your teeth, floss or use an interdental cleaner. If you can't brush after eating, at least try to rinse your mouth with water.
  • Rinse your mouth. If your dentist feels you are at higher risk of developing a cavity, he or she may recommend that you use a fluoridated mouth rinse.
  • Visit your dentist regularly. Get professional tooth cleanings and regular oral exams, which can help prevent problems or spot them early. Your dentist can recommend a schedule that's best for your situation.
  • Consider dental sealants. A sealant is a protective plastic coating that's applied to the chewing surface of back teeth — sealing the grooves in the teeth most likely to get cavities. The sealant protects tooth enamel from plaque and acid. Sealants can help both children and adults. The Centers for Disease Control and Prevention strongly recommends sealants for all school-age children. Sealants last up to 10 years before they need to be replaced, though they need to be checked more frequently to assure they're still intact.
  • Drink some tap water. Adding fluoride to public water supplies has helped decrease tooth decay significantly. But today, many people drink bottled water that doesn't contain fluoride.
  • Avoid frequent snacking and sipping. Whenever you eat or drink something other than water, you help your mouth create acids that destroy your tooth enamel. If you snack or drink throughout the day, your teeth are under constant attack.
  • Eat tooth-healthy foods. Some foods and beverages are better for your teeth than others. Avoid foods that get stuck in grooves and pits of your teeth for long periods, such as chips, candy or cookies. Instead, eat food that protects your teeth, such as cheese, which some research shows may help prevent cavities, as well as fresh fruits and vegetables, which increase saliva flow, and unsweetened coffee, teas and sugar-free gum, which wash away food particles.
  • Consider fluoride treatments. Your dentist may recommend a fluoride treatment, especially if you aren't getting enough fluoride naturally, such as through fluoridated drinking water. In a fluoride treatment, your dentist applies concentrated fluoride to your teeth for several minutes. You can also use fluoridated toothpaste or mouthwash.
  • Ask about antibacterial treatments. Some people are especially vulnerable to tooth decay, because of medical conditions, for instance. In these cases, your dentist may recommend special mouth rinses or other antibacterial treatments to cut down on harmful bacteria in your mouth.

Check with your dentist to see which methods are best for you.