Illustrations: How a Tooth Decays


1. Healthy tooth

The healthy tooth has four different parts to it that are very important. The enamel is the hard outer surface of the tooth and the most highly mineralised substance in the body. The dentine is the softer layer beneath the enamel. The pulp chamber and root canals inside the dentine contain the nerves and blood vessels of the tooth and this pulp is the living part of the tooth. Covering the root surface of the tooth is a thin layer of cementum.

2. White spots

When exposed to sugars or carbohydrates in foods, some bacteria can make acid. The acid attacks the crystal-like substance in the tooth's outer enamel surface. This process, where the acid dissolves minerals from the enamel, is known as demineralisation. The first sign of demineralisation is a chalky white spot. At this stage, the decay process can be reversed using fluorides at home (toothpaste and mouthwash), and in the dentist's surgery, fluoride gel/foam or fluoride varnish can help the tooth repair itself.

3. Enamel decay

Demineralisation continues and the enamel starts to break down. Once the enamel surface is broken, the tooth can no longer repair itself. The cavity has to be treated and restored by a dentist.

stages of tooth dentin decay pictures - colgate au

4. Dentine decay

The decay reaches into the dentine, where it can spread and cause pain.

pulp involvement - cavity stages - colgate au

5. Pulp involvement

If decay is left untreated it will reach the tooth's pulp, where the nerves and blood vessels are found. The pulp will become infected and an abscess (a bacterial infection containing pus) will form, causing pain and possible further spread of infection.

This article is intended to promote understanding of and knowledge about general oral health topics. It is not intended to be a substitute for professional advice, diagnosis or treatment. Always seek the advice of your dentist or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment.

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Signs & Symptoms

Everyone develops plaque because bacteria are constantly growing in our mouths, which is not necessarily easy to see. Plaque that is not removed from around the gum line can cause inflammation and irritation to the gums around your teeth, leading to gingivitis (red, swollen, bleeding gums). If gingivitis is not treated, it can progress to periodontal disease and, possibly, tooth loss.

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Stop plaque in its tracks

Plaque is a sticky bacterial film that sticks to your teeth. When plaque is not removed through brushing and flossing, it turns into tartar. Try one of our toothpastes which reduces plaque and tartar build up.