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A dentigerous cyst, also known as a follicular cyst, is an epithelial-lined developmental cyst formed by accumulation of fluid between the reduced enamel epithelium and the crown of an unerupted tooth. It is formed when there is an alteration in the reduced enamel epithelium and encloses the crown of an unerupted tooth at the cemento-enamel junction. Fluid is accumulated between reduced enamel epithelium and the crown of an unerupted tooth.
Dentigerous cysts are the second most prevalent type of after radicular cyst. Seventy percent of the cases occur in the mandible. Dentigerous cysts are usually painless. The patient usually comes with a concern of delayed tooth eruption or facial swelling. A dentigerous cyst can go unnoticed and may be discovered coincidentally on a regular radiographic examination.
The accumulation of fluid either between the reduced enamel epithelium and enamel or in between the layers of enamel organ seems to be the key to the formation of dentigerous cysts.
A potentially erupting tooth on an impacted follicle can obstruct the venous outflow, inducing rapid transudation of serum across the capillary walls.
Main suggested that this may exert pressure, causing the accumulation of fluid. On the contrary, Toiler suggested that the breakdown of proliferating cells of the follicle after impeded eruption is likely to be the origin of the dentigerous cyst. The breakdown products may result in increased osmotic tension, resulting in cyst formation.
The exact histogenesis of dentigerous cysts remains unknown, but most authors favor a developmental origin from the tooth follicle. In 1928, Bloch-Jorgensen suggested that the overlying necrotic deciduous tooth is the origin of all dentigerous cysts. The resultant periapical inflammation might spread to involve the follicle of the unerupted permanent successor, an inflammatory exudate ensued with resultant dentigerous cyst formation. He reported 22 cases of follicular cysts and stated that in each case a deciduous tooth or the remnants thereof was found in direct contact with the cyst cavity and that the related deciduous tooth always was diseased.
Azaz and Shteyer similarly suggested that the persistent and prolonged periapical inflammation caused chronic irritation to the follicle of the successors. This may trigger and hasten the formation of a dentigerous cyst developing around the permanent teeth. They reported five cases of dentigerous cysts which involved the second mandibular premolar in four children aged 8 to 11 years old. These children were referred for extraction of carious, nonvital primary molars with swelling of the surrounding soft tissue. Occlusal radiographs showed buccal expansion of bone at the affected site. The primary teeth were not in direct contact with the underlying dentigerous cyst.
It has been suggested that dentigerous cysts may be either extrafollicular or intrafollicular in origin. There were three possible mechanisms exist. Firstly, surrounding the crowns of affected teeth, the intrafollicular developmental dentigerous cysts may be formed. These cysts may be secondarily inflamed and infected as a result of periapical inflammation spreading from non vital deciduous predecessors. Benn and Altini (1996) claimed that this possibility was unlikely as all the cases reported were not associated with tooth impaction.
Secondly, radicular cysts developed at the apices of non vital primary teeth. These radicular cysts may fuse with the follicles of the unerupted successors, causing the eruption of the successors into the cyst cavity. This may result in the formation of extrafollicular dentigerous cyst. Shear regarded this to be exceptionally rare because radicular cyst is uncommon in the primary dentition.
The third possibility is that periapical inflammation could be of any source but usually from a non vital deciduous tooth spreading to involve the follicles of unerupted permanent successors. The inflammatory exudate causes separation of reduced enamel epithelium from the enamel with resultant cyst formation.
According to a study, 45.7 percent of dentigerous cysts involved mandibular third molar. On the other hand, only 2.7 percent of dentigerous cysts involved the maxillary premolar. Mourshed stated that the incidence of dentigerous cyst has been reported as 1.44 in every 100 unerupted teeth, so dentigerous cysts involving the premolars are rare.
Dentigerous cysts most commonly occur in the 2nd and 3rd decades of life. Males have been reported to be more prevalent than females with a ratio of 1.8:1. These cysts can also be found in young children and adolescents. The age of presentation of these cysts range from 3 years to 57 years with a mean of 22.5 years.
These cysts are commonly single lesions. Bilateral and multiple dentigerous cysts are very rare although they have been reported. Bilateral or multiple dentigerous cysts have been reported in Maroteaux-Lamy syndrome, cleidocranial dysplasia and Gardner's syndrome In the absence of these syndromes, the occurrence of multiple dentigerous cysts is rare. Sometimes multiple dentigerous cysts are suggested to be induced by prescribed drugs. The combined effect of Ciclosporin and a calcium channel blocker is reported to cause bilateral dentigerous cyst
Dentigerous cyst is potentially capable of becoming an aggressive lesion. The possible sequelae of continuous enlargement of dentigerous cyst are expansion of the alveolar bone, displacement of teeth, severe root resorption of teeth, expansion of buccal and lingual cortex and pain.
Potential complications are development of cellulitis, deep neck infection, ameloblastoma, epidermoid carcinoma or mucoepidermoid carcinoma.
Pathologic analysis of the lesion is important for the definitive diagnosis even though radiographs provide valuable information.
One or several areas of nodular thickening may be seen on the luminal surface in the gross examination of the fibrous wall of a dentigerous cyst. Careful examination of these areas microscopically is mandatory to rule out the presence of early neoplastic change.
As the dental follicle surrounding the crown of an unerupted tooth usually is lined by a thin layer of reduced enamel epithelium, this may render it difficult to distinguish a small dentigerous cyst from a normal or enlarged dental follicle based on microscopic features alone. (2015). 9781455770526 ISBN 9781455770526
The cyst-to-crown relationship presents several radiographic variations which are explained as follows:
The radiographic distinction between an enlarged dental follicle and a small dentigerous cyst can be difficult and fairly arbitrary. Generally, any pericoronal radiolucency that is greater than 3–4 mm in diameter is considered suggestive of cyst formation.
Some dentigerous cysts may result in considerable displacement of the involved tooth. Infrequently, a third molar may be displaced to the lower border of the mandible or into the ascending ramus. On the other hand, maxillary anterior teeth may be displaced into the floor of the nasal cavity, while other maxillary teeth may be displaced through the maxillary sinus to the floor of the orbit. Furthermore, larger cysts can lead to resorption of adjacent unerupted teeth. Some dentigerous cysts may also grow to considerable size and produce bony expansion that is usually painless, unless secondarily infected. However, any particularly large dentigerous radiolucency should clinically be suspected of a more aggressive odontogenic lesion such as an odontogenic keratocyst or ameloblastoma. For this reason, biopsy is mandated for all significant pericoronal radiolucencies to confirm the diagnosis.
The role of CT (computerized tomography) imaging in the evaluation of cystic lesions has been well-documented. CT imaging aids to rule out solid and fibro-osseous lesions, displays bony detail, and provides precise information about the size, origin, content, and relationships of the lesions.
On CT imaging, a mandibular dentigerous cyst appears as a well-circumscribed unilocular area of osteolysis that incorporates the crown of a tooth. Displacement of adjacent teeth may be seen and they may be partly eroded. Dentigerous cysts in the maxilla often extend into the antrum, displacing and remodeling the bony sinus wall. Large cysts which may project into the nasal cavity or infratemporal fossa and may elevate the floor of the orbit can be noted on CT imaging. In the mandible, buccal or lingual cortical expansion and thinning are noted. (2025). 9780323087926, Mosby. ISBN 9780323087926
On MR imaging, the contents of the cyst display low to intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. The tooth itself is a zone of signal void. The lining of the cyst is thin with regular thickness and may show slight enhancement after contrast injection.
The prognosis for the dentigerous cyst is excellent, and recurrence is rare. This is related to the exhausted nature of the reduced enamel epithelium, which has differentiated and formed tooth crown enamel before developing into a cyst. Nevertheless, several potential complications must be considered. The possibility that the lining of a dentigerous cyst might undergo neoplastic transformation to an ameloblastoma has been well-documented. Mourshed showed that 33% of ameloblastomas arose from the epithelial lining of a dentigerous cyst. Although undeniably this can occur, the frequency of such neoplastic transformation is low. In addition, a squamous cell carcinoma may rarely arise in the lining of a dentigerous cyst. Transformation from normal epithelial cyst lining to SCC is due to chronic inflammation. It is likely that some intraosseous mucoepidermoid carcinomas develop from mucous cells in the lining of a dentigerous cyst. Malignancy in the cyst wall is usually unexpected at the time of presentation and the diagnosis is usually made following enucleation. Jagged or irregular margins with indentations and indistinct borders are considered to be suggestive of possible malignant change. Due to the potential for occurrence of an odontogenic keratocyst or the development of an ameloblastoma or, more rarely, mucoepidermoid carcinoma, all such lesions, when excised, should be submitted for histopathologic evaluation.
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