Caries (tooth decay)
(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 containing the nerve and blood supply
- Root—the area of the tooth anchoring it in the bone
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 your teeth. It holds the acid to the tooth. The acid wears away the tooth. Over time, the acid can lead to tooth decay.
Everyone has the chance to develop tooth decay. Factors that may increase your chance of tooth decay include:
- Having poor dental hygiene
- Having high numbers of bacteria in the mouth
- Having an insufficient amount of fluoride (some communities in the United States add fluoride to the drinking water)
- Taking medication that contains sugar or causes dry mouth
- Eating a diet high in sugar
- Enamel erosion from gastroesophageal reflux disease (GERD) or bulimia nervosa
- Malnourishment (such as vitamin and mineral deficiencies)
- Having certain conditions that decrease the flow of saliva in the mouth, such as Sjogren syndrome
- For children: having parents or siblings with severe tooth decay
Babies are also at risk for developing cavities. Habits that can increase the risk include giving a bottle between regular feedings or while in bed at night.
Tooth decay may cause:
- 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, lingering pain in tooth
Tooth decay may be diagnosed over a period of time or at a single dental visit. This involves clinical examination as well as x-rays.
A dentist checks for tooth decay by:
- Asking about pain in the teeth
- Visually inspecting the surface of the teeth
Probing teeth with dental instruments to check for:
- Surface defects
- Taking x-rays of teeth
Sometimes tooth decay will repair itself. This is most likely if it is caught early.
Treatment for more severe decay includes:
When decay reaches the dentin, your dentist will treat it by:
- Numbing the tooth and surrounding tissue area
- Removing the decay with instruments
- Filling the hole with a dental filling; the filling can be silver or tooth colored
Tooth decay that reaches the pulp and/or root of the tooth is treated with a root canal:
- The tooth is numbed and a hole is drilled through the top of the tooth.
- Pus and dead tissue are removed from the tooth.
- The inside of the tooth and the root (nerve) canals are cleaned and filled with a permanent filling.
- The root (nerve) canal is sealed.
- A crown is placed on the tooth to protect it.
Tooth Extraction (Removal)
Tooth extraction may be necessary if:
- Tooth decay and/or tooth infection is too extensive for filling or root canal.
- A break or crack in the tooth that has allowed for decay is too severe to be repaired.
- An extensive infection exists between the tooth and gum.
If the tooth is removed, it will be replaced with a:
- Partial bridge
- Tooth implant
To help reduce your chance of tooth decay:
- Practice proper dental hygiene, including:
- Brushing teeth with fluoride toothpaste after meals or at least twice per day.
- Using a soft-bristled toothbrush or a powered toothbrush.
- Daily flossing between teeth and gums—Bacteria living between the teeth can only be removed with floss or interdental cleaners.
- Getting regular dental check-ups and teeth cleaning (usually every 6 months).
Limit the amount of sugar and carbohydrates you eat and drink, including:
- Sodas and other sweetened drinks
- Other sweets
- Rinse your mouth with water after eating sugars
- Replace your toothbrush every 3 to 4 months
- Avoid sugar-containing drinks (including fruit juices), especially in baby bottles
- Chew gum with xylitol or sorbitol (may reduce your risk of developing cavities)
Talk to your dentist about the use of a sealant. This is a protective plastic covering. It is applied to the chewing surfaces of teeth. Sealants usually last anywhere from 5-15 years.
Prevention is particularly important for children. Supplemental fluoride in early childhood can prevent early decay. The dose can be adjusted for the amount of natural or added fluoride in local water supplies. Fluoride can also be applied to permanent teeth as a long acting varnish. Re-varnishing is usually necessary at least twice yearly.
Academy of General Dentistry
Mouth Healthy—American Dental Association
Canadian Dental Association
The Canadian Dental Hygienists Association
Murdoch-Kinch CA, Mclean ME. Minimally invasive dentistry. J Am Dent Assoc. 2003;134(4):412-414.
Seal out tooth decay. National Institute of Dental and Craniofacial Research website. Available at http://www.nidcr.nih.gov/OralHealth/Topics/ToothDecay/SealOutToothDecay.htm. Updated August 2012. Accessed September 30, 2014.
Selwitz RH, Ismail AL, Pitts NB. Dental caries. Lancet. 2007:369(9555):51-59.
Statement on early childhood caries. American Dental Association website. Available at: http://www.ada.org/en/about-the-ada/ada-positions-policies-and-statements/statement-on-early-childhood-caries. Accessed September 30, 2014.
Tooth decay. National Institutes of Health website. Available at: http://report.nih.gov/nihfactsheets/ViewFactSheet.aspx?csid=129&key=T. Accessed September 30, 2014.
Twetman S. Consistent evidence to support the use of xylitol- and sorbitol-containing chewing gum to prevent dental caries. Evid Based Dent. 2009;10(1):10-1.
8/2/2012 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Khadra-Eid J, Baudet D, Fourny M, Sellier E, Brun C, François P. Development of a screening scale for children at risk of baby bottle tooth decay. Arch Pediatr. 2012;19(3):235-241.
5/17/2014 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Moyer VA, US Preventive Services Task Force. Prevention of dental caries in children from birth through age 5 years: US Preventive Services Task Force Recommendation Statement. Pediatrics. 2014;133(6):1102-1111.
7/15/2014 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Yaacob M, Worthington HV, et al. Powered versus manual toothbrushing for oral health. Cochrane Database Syst Rev. 2014;6:CD002281.
Last reviewed August 2015 by Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.