Cavities are the result of tooth decay, which occurs when specific types of bacteria produce acid that destroys the tooth’s enamel and its underlying layer, the dentine.

Signs & Symptoms

Three possible symptoms of a cavity are toothache, tooth sensitivity to sweet, hot or cold foods or drinks, or pain when chewing.


Many different types of bacteria live in our mouths and build up on the teeth in a sticky film called dental plaque. When we eat and drink, these bacteria create acids, which can dissolve the protective layer of tooth tissue beneath the retained plaque. The acid removes minerals from the enamel, which if left untreated can cause a cavity. Decay begins in the outer part of the tooth (the enamel) and as the enamel is broken down the decay can go deeper into the dentine and can eventually reach the nerve (pulp) of the tooth.


Your dentist can identify and reverse the early signs of decay, white spot lesions, with preventative measures and can diagnose cavities by examining the tooth surface. An x-ray may be necessary to see if the cavity has gone from the enamel into the dentine or pulp of the tooth.


There are a variety of ways to help prevent cavities which include:

  • Brushing and flossing daily; this will help reduce the amount of dental plaque and bacteria in your mouth.
  • Eating sugary or starchy foods less often during the day to help reduce the frequency of tooth-damaging acid in your mouth. Using fluoride toothpaste, which strengthens teeth, as well as fluoride treatments applied by the dental practitioner or using fluoride supplements, such as rinses, as recommended by the dental practitioner.
  • Using antibacterial mouth rinses to reduce the levels of bacteria that cause cavities.
  • Chewing gum that contains xylitol; this can help decrease bacterial growth.


In adults, dental practitioners can apply sealants on molars that have early signs of tooth decay, as long as the decay has not broken through the enamel. Once the enamel has been irreversibly compromised, your dental practitioner will have to fill the tooth. In more serious cases, where the decay has reached the tooth pulp, a root canal filling may be necessary.

In children, both baby molars and permanent molars can be sealed. Dentists can also apply fluoride varnish on both primary and permanent teeth to protect them from decay.


If left untreated, a cavity will cause the tooth to break down significantly. Eventually, uncontrolled decay may destroy the tooth completely. There is also the risk of developing an infection called an abscess where the infection spreads beyond the root of the tooth.

Related Conditions

Cavities are a result of poor oral hygiene which results in dental plaque building up on the tooth surfaces. Specific bacteria in plaque cause decay. Some types of bacteria in plaque, which are retained near the gum line, cause gum disease. This is a condition that your dental practitioner and periodontist can help treat.

Don’t brush off your oral health

Brushing your teeth twice a day will help keep your smile healthy.