A cyst is an abnormal sac which forms in the body and is filled with a gas, liquid or solid substance. An oral cyst is generally filled with liquid, and can form anywhere in the mouth, including the bones, lips, tongue, throat, or salivary glands. These are generally painless and usually less than one inch (2.54 cm) wide. An infected, or abscessed cyst, becomes red, swollen and painful.
The most common kinds of oral cysts are periapical cysts, caused by infections in the pulp of the tooth, and dentigerous cysts, usually formed by impacted wisdom teeth. While these are benign, dentists generally recommend removal to prevent the cyst from spreading and damaging nearby bones or teeth. The removal can usually be done in an office with local anesthesia, though a large cyst may require more extensive surgery to reconstruct any bone which has been displaced or damaged.
It is common for an oral cyst to grow next to a dead root or nerve. If a tooth nerve has died, dentists recommend a root canal, which removes the nerve. During this procedure, the dentist fills in the space formed by the removal of the nerve, which helps to prevent cyst formation.
A cyst which grows in the jawbone is called an ondontogenic cyst. These are usually painless unless infected, and are not noticed until they become large enough to cause a bulge in the jawbone. Dentists generally recommend removing ondontogenic cysts, however, because they tend to grow and can weaken or break the jaw and damage nearby teeth. These can also be removed in a dentist office under a local anesthesia as long as the cyst is not large enough to have caused significant bone damage.
A mucocele, or mucus retention oral cyst, is a common and harmless occurrence. This can be caused by an injury or irritation of the tissue of the mouth, tongue or lips, such as biting the inside of the mouth or tongue, sucking the lip between the teeth, or piercing the tongue or lip. They are generally painless and often rupture spontaneously and heal without treatment. If the cyst is irritating, or if it grows or refuses to rupture, it should be seen by a dentist who can drain or remove it.
An oral cyst is not cancerous; however, it is important to have a dentist examine any cyst which forms and lingers for a period of time to confirm that it is indeed a cyst and not a tumor. Most cysts can be observed visually unless it is located inside of a bone structure, in which case a dental x-ray is required. The dentist may perform a traditional biopsy, which involves removing a small amount of tissue, or a needle biopsy, which uses a needle to extract some of the fluid from the cyst. The tissue or fluid is then sent to a lab to confirm that the structure is indeed a benign cyst.
If the cyst is persistent, uncomfortable, or situated in a place that may cause damage to the teeth or bones, it is highly recommended that it be removed. In the case of a mucus cyst, the dentist will generally try draining the sac and waiting to see if the cyst dissolves on its own. There is a tendency for these cysts to reoccur, so routine check-ups are recommended to monitor the site.