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

Tooth Decay

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Tooth decay, also known as caries, is caused by bacteria interacting with food particles left on the surface of the tooth. Bacteria feed on the sugars in the food and produce acids. These acids and bacteria combine to form a sticky substance called plaque. Plaque clings to your teeth and gives the acids a chance to eat away at the protective enamel of the tooth, eventually causing tooth decay. The process is reversible in the early stages through intake of calcium, phosphate, and fluoride.

Risk Factors

All of us carry bacteria in our mouth which make us susceptible to tooth decay.

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

  • Poor dental hygiene
  • High numbers of bacteria
  • Insufficient fluoride
  • Frequent use of medications containing sugar or causing dry mouth
  • Diet high in sugars
  • Malnutrition, including vitamin and mineral deficiencies
  • Medical conditions, such as Sjogren's syndrome]]> , that decrease the flow of saliva in the mouth
  • Children whose caregivers or siblings have severe caries have a greater chance for dental caries



Symptoms include:

  • 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 or caries is diagnosed by monitoring over a period of time. 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:
    • Sensitivity
    • Pain
    • Softness
    • Surface defects
  • Taking x-rays of teeth


Sometimes tooth decay that is stopped before it reaches the dentin (second layer of the tooth) will repair itself.

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

Root Canal

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)

]]>Removal of the tooth]]> is required 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
  • A denture
  • A tooth implant

If you are diagnosed with tooth decay, follow your dentist's instructions .


Measures that help prevent and stop tooth decay include:

  • Proper dental hygiene, including:
    • Brushing teeth with fluoride toothpaste after meals or at least twice per day
    • Daily flossing between teeth and gums. Bacteria living between the teeth can only be removed with floss or interdental cleaners.
    • Regular dental check-ups and teeth cleaning
  • Limiting the amount of sugar and carbohydrates you eat and drink, including:
    • Honey
    • Sodas
    • Candy
    • Cakes
    • Cookies
    • Other sweets
  • Rinsing your mouth with water after eating sugars
  • Replacing your toothbrush every 3 to 4 months
  • Avoiding sugar-containing drinks (including fruit juices), especially in nursing bottles, and careful brushing can help prevent childhood tooth decay

Talk to your dentist about the use of a sealant, a protective plastic covering which is applied to the chewing surfaces of teeth. This is the location where initial tooth decay starts. Sealants usually last anywhere from 5 to 10 years.

Prevention is particularly important for children, especially after the permanent teeth come in. Supplemental fluoride in early childhood (with dose adjustment for the amount of natural or added fluoride in local water supplies) can prevent early caries. Fluoride can also be applied to permanent teeth as a long acting “varnish,” though revarnishing is usually necessary at least twice yearly