A cyst is a hollow lump filled with fluid, and a dentigerous cyst is a cyst that forms around the enamel crown of a tooth that has not erupted from the jaw. It is the second most common type of odontogenic cyst, where odontogenic means something that is associated with tooth development. A dentigerous cyst, sometimes known as a follicular cyst, is usually benign or noncancerous.
In most cases, a dentigerous cyst causes no symptoms and is commonly discovered by accident on an x-ray. The cysts most often occur alone, and about three quarters are found in the lower jaw. As they form around unerupted teeth, they are more likely to occur in association with those teeth that are often impacted, such as wisdom teeth. These types of cysts are almost always found in permanent and adult teeth and very rarely in children. Both men and women can get them, and they are most commonly found in people in their twenties and thirties.
A dentigerous cyst is created when fluid accumulates within the developmental sac, or follicle, that surrounds an unerupted tooth. The fluid collects after the enamel crown has finished forming, and the cyst ends up attached to the tooth at the point where the enamel meets the root. Although a dentigerous cyst is typically small in size, large ones can develop and cause movement of the teeth or disrupt the jaw, possibly even causing a fracture in extreme cases. Occasionally a cyst can become infected. In very rare cases, one can transform into an ameloblastoma, a tumor that, although benign, causes a problem by growing and invading the surrounding tissues and must be removed surgically.
Although a dentigerous cyst can be recognized on an x-ray, unless it is very small, it is usually removed surgically, along with the associated tooth. Even a small cyst is usually checked for any increase in size. Once the dentigerous cyst is removed, it can be examined microscopically to distinguish it from certain tumors that can mimic its appearance on an X-ray. These include ameloblastoma and a type of cancer known as squamous cell carcinoma, which can occasionally arise from a dentigerous cyst. The cyst and the tooth can usually be removed surgically without complications, and the cyst is unlikely to recur, except in rare cases where removal has been incomplete.