Understanding and preventing cavities | MouthHealthy - Oral Health Information from the ADA

Cavities: What are They and How Do We Prevent Them?

By Caitlin Rosemann A.T. Still University - Missouri School of Dentistry and Oral Health

A.T. Still University - Missouri School of Dentistry and Oral Health

Did you know tooth enamel is the hardest substance in the human body?  Enamel is the protective outer layer of our teeth. Bacteria in our mouths use the sugar we eat to make acids which can wear away this protective layer, forming a cavity. Once enamel is gone, it does not grow back. This is why your dentist and dental hygienist are always telling you to brush with fluoride toothpaste and clean between your teeth! You can learn more about cavities and how to prevent them below.

What Is a Cavity?

 A cavity is a hole in your tooth. A cavity in an early stage can look like a white spot, which can be healed. Over time, it will look like a brown or black spot. Cavities can be tiny or big. Cavities can form in many places, but they often form on the tops of your teeth where you bite and in between your teeth where food gets stuck. Cavities that are not fixed can cause sensitivity, pain, infections, and can even cause you to lose your teeth. The best way to keep your teeth and keep them healthy is to prevent cavities.

What Causes Cavities?

 Do your teeth ever feel “fuzzy” after a meal? Do you notice when you brush and floss this fuzzy feeling goes away? When we don’t brush and floss the bacteria and foods we eat build up and form a sticky substance called plaque (plak).

Throughout the day, bacteria feed off the foods we eat.  When we eat or drink sugar, the bacteria in our mouths use it to live and make acid. This acid stays on our teeth and attacks the outer surface of our teeth. Over time, the acid wears down our teeth, causing a cavity.

To understand how a cavity forms, let’s look at what makes up a tooth. Enamel is the outside hard covering that protects our teeth. Below the enamel is the dentin. Dentin is not as hard as enamel. This makes it easier for cavities to spread and get bigger. Below the dentin is the pulp. The pulp is where the nerves and blood supply for the tooth live.

Image of cavity process.

If a cavity is not fixed, the bacteria can travel from the enamel to the dentin and can reach the pulp. If the bacteria from the cavity get into the pulp, it becomes an infection.

Dental infections can be serious and life-threatening if not treated. See your dentist right away if you notice any of the following:

  • Swelling on your face or in your mouth
  • Redness in or around your mouth
  • Pain in your mouth
  • Bad taste in your mouth

Who Is At Risk For Cavities?

Children, teens, and adults can all be at risk for getting cavities. You might be at increased risk if you:

  • Snack between meals
  • Eat sugary foods and drinks
  • Have a personal and/or family history of cavities
  • Have cracked or chipped teeth
  • Take medications that cause dry mouth
  • Have had head or neck radiation therapy

How Are Cavities Treated?

Cavities should be treated by a dentist. A dentist is trained to see cavities. A cavity in an early stage can be repaired with fluoride. If the cavity is deeper, the only fix may be for dentist to remove the cavity and fill the area with a silver or white colored material. If a tooth has a large cavity, it might need more complicated treatment.

How Do I Reduce My Risk of Cavities?

  • Drink water with fluoride
  • Brush with fluoride toothpaste 2 times a day
  • Stay away from sugary foods and drinks, like candies and soda. Don’t sip or eat on them all day. If you are going to eat or drink things that are sweet do so at meal times.
  • Limit sweet snacks between meals
  • Clean between your teeth daily
  • Visit your dentist regularly
  • Sealants can be placed on back teeth to better protect them from bacteria causing cavities in the grooves.


American Dental Association. (N.d.). Abscess (toothache). Retrieved from https://www.mouthhealthy.org/en/az-topics/a/abscess

American Dental Association. (N.d.). Cavities. Retrieved from https://www.mouthhealthy.org/en/az-topics/c/cavities

Centers for Disease Control and Prevention. (N.d.). Dental caries (tooth decay). Retrieved from https://www.cdc.gov/healthywater/hygiene/disease/dental_caries.html

Delta Dental. (N.d.). Preventing Tooth Decay. Retrieved from  http://oralhealth.deltadental.com/22,DD39

National Institute of Dental and Craniofacial Research. (2018, July). The tooth decay process: how to reverse it and avoid a cavity. Retrieved from