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A dental cavity is a hole in your tooth caused by dental caries. Dental caries is also known as decay. It is caused by the bacteria in plaque. The bacteria produce acid that progressively destroys the tooth’s enamel and subsequently the underlying dentine.

Plaque is a sticky pale yellow film that naturally develops on the teeth. It contains hundreds of different bacteria (commonly streptococcus mutans), food, saliva and other natural substances. It forms mainly in the pits and fissures of back teeth, in-between the teeth and near the gum line.

For decay to develop there are four factors which are required:

  • 1. Susceptible tooth
  • 2. Bacterial plaque
  • 3. Food
  • 4. Time

The normal resting pH of the mouth and plaque is approximtaley 6.8. This is neutral (i.e. neither acid nor alkaline).  When a susceptible tooth is exposed to frequent intakes of sugar and carbohydrates, the bacteria present in plaque produce lactic acid. This will then cause the pH level in the mouth to drop. When it reaches 5.5 (known as critical pH), an acid attack occurs.

Tooth decay occurs in five stages:

  • 1. Acid from plaque dissolves the mineral in hard enamel. This is known as demineralisation. Saliva contains bicarbonate ions which have a buffering effect, therefore neutralising the acid; if no more sugar is consumed the pH returns to normal. This is known as remineralisation.
  • 2. However, if remineralisation does not occur, decay spreads through the enamel and an initial break in the enamel is formed.
  • 3. Decay spreads to the dentine and destroys it more rapidly than enamel because it is softer.
  • 4. If left untreated and the pulp cavity is reached, the pulp becomes inflamed and pain occurs. This is called pulpitis
  • 5. The pulp will die and the tooth will become non-vital. An abscess will then form and the tooth will then need root canal treatment.

By visiting the dentist for regular examinations, it is possible to diagnose early signs of decay and treat it accordingly. If left untreated then root canal treatment or even extraction may ultimately be required.

If you are worried that you might have a cavity or you haven’t been for your 6 monthly check-up, please click here to book an appointment with your dentist.

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