What Is a Cavity?

A cavity is a small hole in your tooth that occurs when the hard outer layer of the tooth, called enamel, is damaged. Although you might not notice a cavity forming at first, it can eventually cause pain. In more serious cases, a cavity can result in a dental procedure called a root canal

Cavities are a common dental problem. In fact, about 91% of Americans over the age of 20 have experienced a cavity. However, with proper oral hygiene and regular dental visits, they’re often preventable. 


Teeth are covered in a relatively thick layer of enamel, a protective coating. Enamel is made mostly from minerals—including calcium—which form hard crystals to protect the blood vessels and nerves in the tooth. Since enamel isn't living, it's not able to repair itself.

That's problematic, since tooth enamel is constantly under attack. Your mouth is full of all sorts of bacteria, which are always forming plaque, a sticky film, on your teeth. When you eat foods that contain sugar, these bacteria produce acid that can damage your tooth enamel. Over time, that damage can lead to the formation of a cavity. 

Symptoms and Diagnosis

Cavities are hard to detect at first, because you won’t notice any symptoms when they’re just forming.  That’s why regular dental checkups every six months are important. At these checkups, dentists can check for early cavities by looking at your teeth, touching them, and using x-rays. 

As your cavity grows deeper into your tooth, it could reach the sensitive blood vessels and nerves in your tooth.  That’s when you’re likely to start experiencing symptoms. The symptoms of cavities include:

  • A toothache
  • Pain when you bite
  • Tooth sensitivity to temperature, including sharp pain when eating hot or cold foods or drinks
  • Discoloration of the tooth, or a noticeable hole

Who Gets Cavities?

In America, almost everyone will get a cavity at some point in their lives. However, the people most at risk for cavities are people who are very young or people over 50. Babies and young children who drink from bottles are at increased risk because their teeth are exposed to carbohydrates and sugar from bottles overnight.

On the other hand, older people are at risk because they more often have receding gums. As the gum recedes, it can expose the root of the tooth, which is not covered in enamel, but a softer substance. This can make it easier for cavities to form. 

In addition to those two demographics, there are other risk factors that can increase your likelihood of cavities. People with these conditions are at increased risk for tooth decay:

  • Dry mouth. Saliva helps to wash away plaque, so people who don’t have enough saliva because of medical conditions or medication are more likely to have cavities. 
  • Reflux. The acid that enters the mouths of people with reflux can deteriorate tooth enamel. 
  • Eating disorders. Eating disorders can change saliva production, and frequent vomiting can bring stomach acid into the mouth and deteriorate enamel. 


Although cavities are common, they’re also preventable. Taking these steps can help reduce your risk for cavities:

  • Brush your teeth two times a day, for two minutes, with fluoride toothpaste. 
  • Floss
  • Minimize sugary snacks and drinks, which can spur plaque to produce acid.
  • Avoid frequent snacking so that your teeth aren’t constantly exposed to acids that are made when you eat. 
  • Visit a dentist regularly to help catch tooth decay early. 


The treatment for your cavity will depend on how early it is detected. If you catch the cavity early, your dentist may be able to prevent further damage by using fluoride treatments. This helps the enamel to repair the minerals that have been depleted by plaque formation. 

However, cavities often require other treatments to make sure that the damage to your tooth does not get worse. This includes: 

  • Fillings: The dentist drills the damaged enamel and fills it in with synthetic material. This prevents further damage to the tooth, since the filling protects your tooth in the same way that enamel does.
  • Root canal: A root canal is needed when a cavity has gone all the way through the enamel to the pulp, which is the material inside your tooth surrounding the blood vessels and nerves. During this procedure, a dentist cleans the root of the tooth, removing any decay. You leave with a temporary filling, and later return for a permanent filling or crown, depending on how much of the tooth you’ve lost. 
  • Tooth pulling: If the damage to your tooth from a cavity is severe, your dentist may advise you to have the tooth extracted. In this case, you should use a bridge or implant to fill the space that the tooth has left, so that your other teeth don’t move into the space. 

An Early Warning Sign for Tooth Decay

Cavities are tricky to catch early since they don’t have symptoms. However, there is one early warning sign of tooth decay: White spots appearing on the tooth. These show the spots where minerals in the enamel—the main building blocks of this protective layer—have been depleted. 

If you notice white spots, especially in children, you can speak with your dentist about how to prevent the spots from developing into cavities. Taking these steps may help:

  • Brush properly, twice a day, with a fluoride toothpaste. Talk to your healthcare provider about using supplemental fluoride, like a fluoride mouth wash, especially if you do not typically drink from public water supply, which contains fluoride. 
  • Reduce the number of sweets and snacks that you or your child is eating.
  • Avoid eating or drinking after brushing your teeth and before bed. 
  • Consider dental sealants. This is a thin plastic layer that covers the grooves of the molars, making them less likely to trap food particles and plaque. 

A Word From Verywell

You may feel ashamed if you get a cavity, but remember: Cavities are extremely common and nothing to be embarrassed about. The normal function of our mouths means that most of us will get cavities occasionally. 

Finding out about a cavity early can help you avoid pain and keep treatment simpler. Going to the dentist every six months, even if you're nervous, can help with that. Since oral health is linked to overall health, taking care of your teeth is an important part of taking care of yourself!

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Dental Association. New CDC statistics show need for increased access to dental care, with a greater emphasis on preventing disease.

  2. American Dental Association. Tooth.

  3. National Institute of Dental Craniofacial Research. Tooth decay

  4. American Dental Association. Cavities. 

  5. American Dental Association. Baby bottle tooth decay.

  6. National Institute of Dental and Craniofacial Research. The tooth decay process: how to reverse it and avoid a cavity.

By Kelly Burch
Kelly Burch is has written about health topics for more than a decade. Her writing has appeared in The Washington Post, The Chicago Tribune, and more.