A cyst is a sac of tissue that has either fluid or soft material inside it. Dental cysts can form at the tip of the roots of dead teeth. They can also form around the crowns (and roots) of buried teeth. Most cysts form because the teeth they are associated with have died (infection or trauma). Others form because of a mistake in the way the teeth have developed (including being unable to grow into the mouth properly). Rarely, dental cysts are part of a genetic syndrome that has other symptoms (eg Gorlin's syndrome).

Dental cysts can cause several problems but some remain undetected for months or even years. Many cause problems when:-

• They become infected (causing pain and/or swelling);
• They slowly replace some bony tissue (they can weaken the jaws),
• They press against other teeth and structures;
• They prevent the normal function of the teeth and mouth tissues.

Treatment for a cyst is its excision or removal by small surgical procedure performed under local anaesthesia. Cysts in the mouth are most commonly seen around impacted wisdom teeth, but can also be seen around any other teeth which may have failed to erupt in the mouth. These cysts and the impacted teeth are removed in the same procedure. Large cysts require more detailed or extensive surgery, which may or may not require bone reconstruction.