Dentigerous cysts are a common type of fluid-filled sac that develops in the jawbone. These cysts are typically found around the crown of an unerupted or impacted tooth. The term “dentigerous” means “containing a tooth,” reflecting their association with unerupted teeth. They represent the second most common type of jaw (odontogenic) cyst.
What Are Dentigerous Cysts?
Dentigerous cysts are developmental cysts that form from the dental follicle, which is the tissue surrounding the crown of a developing tooth. Fluid accumulates between the crown of an unerupted tooth and the outer layer of enamel, leading to cyst formation. This process causes the dental follicle to expand, potentially preventing the tooth from erupting normally.
These benign cysts are typically fluid-filled sacs. They most frequently occur around impacted wisdom teeth (mandibular third molars), accounting for about 74% of cases in the lower jaw, and can also affect maxillary canines. While they can occur at any age, they are most often identified in individuals between 10 and 30 years old.
Recognizing Dentigerous Cysts
Dentigerous cysts are often discovered incidentally during routine dental X-rays because many small cysts do not cause any noticeable symptoms. A dental X-ray typically reveals a dark, circular area near the tooth, sometimes with a faint white semicircle around its outer border.
If a cyst grows larger, symptoms may become apparent. These can include swelling of the gums or jaw, pain, or tooth sensitivity. A growing cyst can also displace nearby teeth, leading to visible gaps or changes in tooth alignment, or cause numbness or tingling if it presses on nerves.
Diagnosis and Treatment
Dentists often identify these cysts during routine panoramic X-rays, where they appear as a well-defined, unilocular (single-chambered) radiolucency surrounding the crown of an unerupted tooth. For a more detailed assessment, especially for larger or complex cases, a CT scan or MRI might be used to differentiate the cyst from other jaw lesions and determine its exact size and relationship to surrounding structures.
Once identified, the primary treatment for dentigerous cysts is surgical removal, a procedure known as enucleation. This involves completely excising the cyst lining along with the associated unerupted tooth. This single-stage procedure is generally effective in eradicating the cyst and reducing the risk of recurrence.
For very large cysts, or in younger patients where preserving the associated tooth is desirable, an alternative approach called marsupialization may be considered. This procedure involves making an incision into the cyst, draining its fluid, and then stitching the cyst lining to the oral mucosa to create a pouch. This helps to decompress the cyst, reduce its size, and promote bone regeneration, sometimes allowing the associated tooth to erupt naturally or with orthodontic assistance.
Potential Risks and Outlook
If a dentigerous cyst is left untreated, it can expand and cause several complications. These include significant bone destruction, displacement of adjacent teeth, or resorption of their roots. Large cysts can also weaken the jawbone, potentially leading to a pathological jaw fracture.
While benign, there is a very rare risk of malignant transformation into certain types of jaw tumors, such as ameloblastoma or squamous cell carcinoma. This underscores the importance of proper diagnosis and complete removal. After successful surgical treatment, the prognosis is generally favorable, with recurrence being uncommon. Regular dental check-ups are important for early detection and to monitor healing, ensuring any potential issues are addressed promptly.