by EBSCO Medical Review Board
(Cavities; Dental Caries; Dental Decay)


Tooth decay is the destruction of tooth material, which includes:

  • Enamel—the hard outer surface of the tooth
  • Dentin—the second softer layer beneath the enamel
  • Pulp—the inside of the tooth that contains the nerve and blood supply
  • Root—the area of the tooth that holds it into the bone
Tooth Decay
Nucleus factsheet image
Copyright © Nucleus Medical Media, Inc.


Everyone has bacteria in their mouths. The bacteria eat sugars that are left on the tooth, which then creates acid. The acid and the bacteria form plaque on the teeth. This plaque clings to the teeth and holds the acid to the tooth. The acid wears away the tooth. Over time, the acid can lead to tooth decay.

Risk Factors

Everyone is at risk for tooth decay. Some things that may raise this risk are:

  • Having poor dental hygiene
  • Having high numbers of bacteria in the mouth
  • Not getting enough fluoride (some communities in the United States add fluoride to drinking water)
  • Taking medicines that contain sugar or cause dry mouth
  • Eating a diet that is high in sugar
  • Health problems that destroy tooth enamel, such as gastroesophageal reflux disease (GERD) or bulimia nervosa
  • Health problems that decrease the flow of saliva in the mouth, such as Sjogren syndrome
  • Poor nutrition
  • Having a family history of severe tooth decay
  • Giving babies a bottle between regular feedings or while in their crib


Problems may be:

  • Tooth sensitivity to hot or cold
  • Tooth discomfort after eating
  • Darkening of the tooth surface
  • Bad breath or a foul taste in the mouth
  • Throbbing tooth pain


The dentist will ask about your symptoms and health history. A dental exam will be done.

Images may be taken of the tooth and surrounding bone. This can be done with x-rays .


Sometimes tooth decay will repair itself. This is most likely if it is caught early.

Treatment for more severe decay includes:

  • A filling—Decay is removed and the hole is filled with a dental filling
  • Root canal—Pus and decayed tissue are removed from the inside of the tooth, then it is filled and sealed
  • Tooth removal—A tooth with severe decay is removed. It can be replaced with a partial bridge, denture, or tooth implant


To lower the risk of this problem:

  • Use a soft-bristled toothbrush and brush with fluoride toothpaste after meals or at least twice per day.
  • Floss every day.
  • Get regular dental check-ups and teeth and gum cleanings every 6 months. A dental sealant may also be applied to protect the teeth.
  • Eat a healthful diet that limits sugar and carbohydrates.
  • Chew gum with xylitol or sorbitol (may lower the risk of getting cavities)


Academy of General Dentistry 

Mouth Healthy—American Dental Association 


Canadian Dental Association 

The Canadian Dental Hygienists Association 


Fluoride for prevention of dental caries. EBSCO DynaMed website. Available at: Accessed September 16, 2021.

Statement on early childhood caries. American Dental Association website. Available at: September 16, 2021.

Tooth decay. National Institute of Dental and Craniofacial Research website. Available at Accessed September 16, 2021.

Revision Information