Oral cysts are pouches of tissue, typically less than one inch across, that enclose fluid made up of a clear blood component called serum. Often, the fluid in a cyst is sterile. However, the sac may also become infected and fill up with pus. An infected cyst is referred to as an abscess. Other types of abnormal (but non-cancerous) tissue growth are also called cysts. Oral cysts can affect any of the tissues in the mouth including:
- Mucosal lining of the lips, cheeks and oral cavity
- Tooth roots
- Jaw bone
- Salivary glands
Types of Oral Cysts
Oral and dental cysts come in many varieties. Here are the four most common:
- Periapical Cyst (also called a Radicular Cyst) – This type of dental cyst forms at the base of a tooth as a side effect of untreated tooth pulp infection and nerve death. Infectious material from the inside of the tooth leaks out into the surrounding tissue, causing inflammation and resulting in cyst formation. The cyst itself may or may not develop into an abscess.
- Dentigerous Cyst – This is a dental cyst that forms near or over the crown of an unerupted wisdom tooth. If the cyst grows too near the second molar, it may cause the root of that molar to be reabsorbed into the body. A large dentigerous cyst may move nearby teeth out of alignment. In extremely rare cases, cysts on wisdom teeth have been linked to the development of oral cancer.
- Odontogenic Cysts – These are various dental cysts (in addition to the periapical and dentigerous cysts already listed) that may occur in the jawbone. An odontogenic cyst often causes no symptoms until it has grown quite large. By that time, it may show up as a visible bulge or bump on the jaw. Left untreated, the cyst may continue to grow, weakening the jaw and causing damage to nearby teeth. Rarely, a cyst may become infected, swollen and painful. The infection may spread to other areas of the body. A very small percentage of these cysts may become cancerous and metastasize to other areas of the body.
- Mucocele (Mucous Cyst) – This is a cyst affecting the soft tissue in the mouth such as the tongue, inner cheek or lip. They form in response to irritation or trauma to the tissue. Unlike other oral cysts, these usually resolve on their own. The exceptions are epulis (gum) and ranula (floor of the mouth) cysts that can cause significant discomfort and are typically removed surgically.
Symptoms of Oral Cysts
Dental cysts that are infected may be painful, red and swollen. However, those that are not infected often cause no noticeable symptoms. Unless they become large enough to cause a lump that can be seen or felt, they are usually only detected on x-rays or other diagnostic scans. An oral cyst in the mucosal lining of the mouth may appear as a blister or lesion.
Treatment of Oral Cysts
Your dentist will need to determine what, if any, risk factors are associated with your dental cyst prior to recommending treatment. This may involve taking additional x-rays to discover the size and extent of the cyst (especially to see if it may cause problems with the nearby teeth). Your dentist will also examine the cyst to check for signs of infection. A biopsy may need to be done to confirm that the mass is a cyst and not a tumor. Fluid or lining from the cyst is sent to a dental pathology lab for microscopic examination to check for abnormal cells. With large cysts in the jaw bone, CT scans or an MRI may be used to plan treatment.
Small cysts that are not causing any symptoms may not require immediate treatment. However, since cysts can grow bigger over time, early removal is often advisable to prevent structural damage to the mouth and teeth. If the cyst is abscessed, antibiotics are prescribed to stop the infection. Depending on the size and location of the cyst, the most effective treatment is usually surgical removal. If the cyst is simply drained, it may fill up again. In fact, many cysts do tend to recur. So, the goal is to remove the entire membranous sac along with its contents. This gives the surrounding tissue a chance to heal and fill in the space left by the cyst. In rare cases, a bone graft may be used to fill the gap left after the removal of a large cyst in the jawbone.