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Tooth decay


Tooth decay is one of the most common diseases globally, and if you have teeth, you are not immune to it. Decay is caused by bacteria that live on sugar and produce acids that create tiny holes in tooth enamel and exposed tooth root surfaces. Direct exposure to acids commonly present in certain foods and drinks also causes tooth decay.

Left untreated, tooth decay progresses into the next layer of the tooth called dentin , which is softer and less resistant to acids. When this happens, your tooth may become more sensitive.

Tooth decay in pits and fissures

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Tooth decay in pits and fissures

Without proper treatment, decay will progress into the inner portion of your tooth, the pulp, where nerves and blood vessels reside. Mouth bacteria irritate the pulp tissues, and the pulp can become infected and start to swell. Because tooth enamel is hard, the swollen tissues have no room to expand, and pressure builds inside the tooth. The pressure compresses the tooth nerves, resulting in pain. In severe cases, the infection can progress into your jawbone, leading to tooth loss (edentulism) and other medical and dental issues. In rare cases, dental infections can become life-threatening.

Tooth decay can also develop under dental sealants and other restorations such as fillings , inlays , onlays , or crowns .

You can drastically lower your risk of tooth decay with proper nutrition, good oral hygiene, and at-home or professional treatments.

Tooth decay is believed to be caused by a strain of bacteria that uses sugars, starches, and proteins in your saliva to produce acids and enzymes to form plaque that attacks tooth enamel and exposed tooth roots . Acids from food and drink can also directly cause cavities. If you do not remove plaque from your teeth at least once a day and reduce the level of acids after eating or drinking by brushing , flossing , or using oral rinses, the plaque will eventually harden into tartar (calculus). Tartar creates a shielded environment that protects bacteria. It can only be removed by a dentist.

You and your dentist need to know if you are at a higher risk for tooth decay to take the steps required to reduce your risk. Regular dental checkups that include open and honest discussions with your dentist about your habits, ongoing exposure to fluoride , and good oral hygiene help reduce the risk of tooth decay. If you do fall into a high-risk population, your dentist will provide recommendations based on guidelines from the American Dental Association (ADA).

Some of the factors that may put you or a family member into a higher-risk population for tooth decay include:

  • Poor oral hygiene and/or infrequent dental treatment.
  • High levels of cavity-causing bacteria in your mouth.
  • Inadequate ongoing exposure to fluoride.
  • A family history of poor dental health.
  • Recent tooth decay.
  • Failing, poorly placed, or poorly shaped restorations.
  • Large or multiple tooth-surface fillings .
  • Teeth with deep pits and fissures or cracks.
  • Exposed root surfaces.
  • Active orthodontic treatment .
  • Weakened enamel due to demineralization or genetic abnormalities.
  • A poor diet.
  • Alcohol use.
  • Drug use .
  • Past or present eating disorders .
  • Special needs that may affect proper oral hygiene .
  • Dry mouth (xerostomia).
  • Chronic use of antihistamines, antianxiety medications , antidepressant medications, or any other medications that cause chronic dry mouth.
  • Prolonged nursing and/or evidence of baby bottle syndrome.
  • Cancer treatment.

When tooth decay begins to form, you may not notice any signs or symptoms, but as it progresses, you may experience:

  • Black, brown, or white stains on your teeth.
  • Visible pits or holes in your teeth.
  • Sensitivity to hot, cold, or sweets.
  • Toothache .
  • Pain when biting.

If you have any of these symptoms, make an appointment with your dentist to have your teeth checked for decay. It's also important to maintain regular dental exams and professional tooth cleanings even when you are not experiencing symptoms.

Your dentist can diagnose some tooth decay by a visual inspection. However, some decay can be difficult or impossible for your dentist to visually detect if it develops between your teeth or in the deep pits and fissures of your teeth.

  • Your dentist will use an instrument to probe the pits and fissures of your teeth. If the instrument sticks in your tooth, it may indicate that the base of the pit or fissure has been softened by tooth decay.
  • Detection dye or a staining solution may be used to help identify decay. The dye also helps your dentist identify and remove tooth decay that would have been more difficult to detect visually.
  • Your dentist can also diagnose tooth decay by taking and examining dental X-ray (radiograph) images, which show decay in the enamel and tooth roots as darker areas.
  • Some dentists may use a laser tooth decay detection device.
  • The use of high-intensity light may be useful for detecting decay in some areas of the teeth.

Preventing tooth decay

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Preventing tooth decay

It is almost always possible to prevent the development of cavities. Here are some of the things you can do to prevent tooth decay:

  • Reduce or eliminate contributing factors.
  • Maintain good oral hygiene.
  • Avoid frequent snacking (eating or drinking) unless you brush your teeth afterward.
  • Maintain good nutrition.
  • Brush with fluoride toothpaste and drink fluoridated water.
  • Use an oral antibacterial rinse or fluoride-enriched mouthwash.
  • Avoid dry mouth (xerostomia) by sipping on water or by chewing xylitol-based gum.
  • Get regular dental exams , professional tooth cleanings , and fluoride treatments .
  • Sealants .

A goal of dentistry is to use the most effective treatment methods while maintaining as much original tooth structure as possible. There are several dental procedures used to treat tooth decay that should be explored to achieve this goal.

  • Some early tooth decay can be reversed by tooth remineralization treatment such as fluoride varnish.
  • Dental photographs and dental X-ray (radiograph) images are useful for monitoring areas prone to tooth decay.
  • Depending on the severity of the decay, restoring decayed teeth may involve fillings , inlays , onlays , crowns , or tooth removal (tooth extraction).
  • Tooth decay that reaches the inner pulp may require root canal therapy to eliminate the bacteria and reduce swelling .

Sometimes the procedures required to restore a natural tooth effectively would be overly expensive. It may be less costly if the tooth is removed and replaced. This is especially true if there is a low probability of keeping the natural tooth healthy over the long-term, even if efforts are made to save it. While tooth removal may be a less costly option in the short-term, it's important to understand that removing a tooth without replacing it has implications that could lead to greater dental and medical issues over time.

Author: Symbyos staff, go2dental staff
Medical review: Thomas J. Greany DDS
Last medical review: March 6, 2021
Last updated: June 2, 2021