What Are Cavities (Tooth Decay)?

Tooth decay is caused by bacteria that normally dwell inside the mouth. These bacteria combine with food particles and mucus to form dental plaque, a sticky, colorless film that builds up on the teeth. The bacteria in plaque break down sugars to produce acids. Without proper oral hygiene, these acids may gradually erode the tooth’s hard protective layer of enamel, forming cavities.

Once the acids have penetrated the enamel, they can then attack the softer layers of tissue inside the tooth (the dentin and the pulp, which contain nerves and blood vessels), resulting in a toothache. Eventually, bacteria may invade the pulp, causing an infection that leaves the tooth vulnerable to a potentially dangerous abscess, characterized by severe pain and infection of the jaw. For this reason, tooth decay should be treated promptly.

Cavity - Masterfile Image

What Causes Tooth Decay?

  • Poor dental hygiene causes tooth decay.
  • Sugary or starchy foods and drinks may promote tooth decay.

Symptoms of Tooth Decay

  • Early decay has no symptoms
  • Increased tooth sensitivity to heat and cold
  • Toothache, especially after eating sweet or sour foods. Pain may grow more intense and persistent as decay worsens.
  • Bad breath and an unpleasant taste in the mouth
  • Darkening of the tooth surface

Cavity Prevention

  • Brush your teeth at least twice a day, using a soft bristle toothbrush and a fluoride toothpaste. Scrub with a gentle circular motion, then brush vertically, away from the gums. Brush your tongue too; it collects the same bacteria that stick to the teeth.
  • Floss daily. Ease the floss between the teeth, forming a crescent against one side of a tooth. Gingerly scrape up and down, from just under the gum line to the top of the teeth.
  • Fluoride mouth rinses offer additional protection.
  • Ask your dentist about the benefits of irrigation devices such as Waterpik or plaque removal devices such as Interplak.
  • Schedule a dental checkup at least once a year.
  • Chewing sugarless gum can increase salivation and help reduce the risk of tooth decay.
  • Limit your consumption of sugary drinks and sweet, starchy or sticky foods.
  • Do not use chewable vitamin C supplements, which can erode tooth enamel.

According to our sister publication, REMEDY's Healthy Living (Summer 2014), a good old-fashioned manual toothbrush, a little toothpaste and a couple of minutes are really all you need to brush your teeth well. But some people can benefit from using an electric toothbrush—per the experts at the University of California, Berkeley, Wellness Letter. If the following sounds like you, you may want to use an electric toothbrush:

  • You have a disability, such as arthritis, that limits your dexterity.
  • You scrub too hard when brushing, which can wear away the tooth's protective enamel covering. Some electric models remind you not to apply too much force.
  • You have orthodontic braces and need the extra cleaning power.

Diagnosis of Tooth Decay

  • A dental examination is performed.
  • Dental x-rays may be taken.

How to Treat Tooth Decay

  • For a toothache, use ice packs, aspirin or acetaminophen until you receive professional help. (Schedule an appointment with a dentist immediately.)
  • The decayed section of tooth will be removed and then filled with a metal alloy or plastic resin.
  • If a tooth is severely decayed and in danger of being lost, a root canal may be needed. The nerve and pulp of the tooth are removed leaving only the hollow tooth and roots. The cavity is then sterilized and filled with cement, and the tooth is fitted over with a metal or porcelain crown.
  • In the case of extensive decay or an abscess, extraction may be required if the tooth cannot be restored.

When to Call a Doctor

  • See a dentist regularly. Make an appointment promptly if you develop a toothache.


Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference

Simeon Margolis, M.D., Ph.D., Medical Editor

Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50

Our sister publication REMEDY's Healthy Living (Summer 2014)

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at HealthCommunities.com

Published: 04 Oct 2011

Last Modified: 04 Nov 2014