Diseases & Conditions


Dental Caries (Tooth Decay)

Diseases & Conditions


What is dental caries?

Dental caries or tooth decay is the breakdown of the outer layer of the teeth (enamel) by bacteria. The bacteria convert the sugar from the food into acids which dissolves the minerals in the enamel. This leads to erosion of the enamel, eventually forming cavities and tooth decay.1 Dental caries usually occurs in children between 6 to 11 years and adolescents aged 12 to 19 years.1 9 out of 10 adults over the age of 20 have some sort of tooth-root decay.2


What causes dental caries?

The formation of cavities occurs over time and is caused by tooth decay. It begins with plaques build-up on the teeth that breakdown the teeth surface.3

  • Plaque forms: Consumption of foods high in sugar helps the bacteria in the mouth to convert carbohydrates into energy they need, producing acid in this process. A bacterial plaque will be formed adhering to the teeth above the gum line.
  • Plaque attacks: The acid first softens the enamel by dissolving the minerals, forming a hole in the tooth. The bacteria then attack the softer layer underneath the enamel, leading to cavity formation and tooth decay.
  • Destruction continues: If left untreated, the bacteria affect the inner layers of the teeth containing the nerves, resulting in tooth pain.


What are the symptoms of dental caries?

Signs of tooth decay may not appear until it has reached an advanced stage. Symptoms mainly include toothache, tooth sensitivity, spots on teeth, bad breath and unpleasant taste in mouth.3


What are the risk factors of dental caries?

The main risk factors for dental caries include:4


Eating food that stick to the teeth for a long time such as milk, honey, soda etc.

Frequent consumption of snacks or soda.

Tooth location:

Teeth at the back of the mouth have more grooves and pits where food gets stuck, thus increasing bacterial activity and enamel erosion.

Insufficient fluoride:

Fluoride provides protection against cavity formation. Inadequate exposure to fluoride can therefore increase the risk of caries.

Brushing habits:

Not brushing teeth immediately after food consumption contributes to tooth decay.

Dry mouth:

Saliva protects the teeth from demineralization. Therefore low salivary flow in the mouth leaves the teeth susceptible to the bacteria.


Cavities are more common in younger and older people.


Gastroesophageal reflux disease can cause acid to leak backwards from the stomach to the mouth wearing away the enamel of the teeth.


How is dental caries diagnosed?

Regular dental check-ups help to detect tooth decay. If a problem is suspected, the dentist will take an X-ray.


How is dental caries treated?

Treatment of dental caries depends on the severity of the condition and may include:5

  • Fluoride treatments: Fluoride therapy consists of liquid, gel, foam or varnish brushed into the teeth to protect them from dental caries. This therapy works best if the cavity is just being started.
  • Fillings: The standard treatment for a tooth cavity is to drill out the decay and fill the cavity with resins, porcelain or a combination of different materials.
  • Crowns and root canals: If the tooth decay is extensive then a crown or root canal treatment may be needed. Crowns are custom-fitted coveting that replaced the entire natural crown of the tooth. Root canals consist of removing the diseased tooth pulp and replacing it with a filling.
  • Tooth extraction: If the tooth is severely damaged an extraction is needed.


How can dental caries be prevented?

Dental caries can be prevented by:1

  • Using fluorides through water fluoridation, fluoride toothpaste
  • Healthy eating habits: reducing the consumption of sugars, limit snacking
  • Maintaining oral hygiene: brushing twice a day, flossing, regular visits to dentists



  1. Centres for Disease Control and Prevention http://www.cdc.gov/healthywater/hygiene/disease/dental_caries.html (Accessed November 10, 2015)
  2. Dye BA, Tan S, Smith V, Lewis BG, Barker LK, Thornton-Evans G, Eke PI, Beltrán-Aguilar ED, Horowitz AM, Li CH. Trends in oral health status, United States, 1988-1994 and 1999-2004. Vital Health Stat 11. 2007; (248):1-92.
  3. Tooth decay (Tooth decay) http://www.nhs.uk/conditions/Dental-decay/Pages/Introduction.aspx (Accessed December 22, 2015)
  4. http://www.mayoclinic.org/diseases-conditions/cavities/basics/risk-factors/con-20030076 (Accessed November 10, 2015)
  5. Cavities/tooth decay (Treatments and drugs)

http://www.mayoclinic.org/diseases-conditions/cavities/basics/treatment/con-20030076 (Accessed December 22, 2015)