A cyst is a hollow lump filled with fluid, and a dentigerous cyst is a cyst which forms around the enamel crown of a tooth that has failed to erupt from the jaw. It is the second most frequently found type of odontogenic cyst, where odontogenic means something which is associated with tooth development. A dentigerous cyst, sometimes known as a follicular cyst, is typically benign, or non-cancerous.
In most cases, a dentigerous cyst causes no symptoms and is commonly discovered by accident on an X-ray. The cysts most often occur singly and around three-quarters are located in the lower jawbone. As they form around unerupted teeth, they are more likely to occur in association with those teeth which often become impacted, such as the wisdom teeth. These types of cysts are almost always found on adult, permanent teeth and very rarely in children. Both men and women may have them, and they are more commonly found in people who are in their twenties and thirties.
A dentigerous cyst is created when fluid builds up inside the developmental sac, or follicle, surrounding an unerupted tooth. The fluid accumulates after the enamel crown has finished forming, and the cyst ends up joined to the tooth at the point where the enamel meets the root. Although this type of cyst is typically small in size, large ones can develop and may cause movement of teeth or disrupt the jaw, possibly even causing a fracture in extreme cases. Occasionally a cyst may become infected. In very rare cases, one may transform into an ameloblastoma, a tumor which, although benign, causes a problem by growing and invading the tissues around it and must be surgically removed.
Although a dentigerous cyst may be recognized on an X-ray, unless it is very small it is usually removed surgically, together with the associated tooth. Even a small cyst is generally monitored for any increase in size. Once the cyst has been extracted, it can be examined microscopically to distinguish it from certain tumors which can mimic its appearance on an X-ray. These include the ameloblastoma and a type of cancer known as squamous cell carcinoma, which can occasionally arise from a dentigerous cyst. Usually, the cyst and tooth can be surgically extracted without any complications, and it is unlikely that the cyst will recur, apart from in rare cases where the removal has been incomplete.