Dentigerous Cyst
- defined as an odontogenic cyst that surrounds the crown of an impacted tooth; caused by fluid accumulation between the reduced enamel epithelium and the enamel surface, resulting in a cyst in which the crown is located within the lumen.
- most common ; about 20% of all jaw cysts ; about 10% of impacted tooth form a dentigerous cyst
- almost always permanent tooth involved; rarely deciduous tooth involved
Clinical Features:
- always associated initially with the crown of an impacted, embedded or unerupted tooth
- most common sites of this cyst are the mandibular and maxillary third molar and maxillary cuspid areas, as these teeth are most commonly impacted
- mostly solitary; bilateral and multiple cysts are usually found in association with a number of syndromes including cleidocranial dysplasia and Maroteaux–Lamy syndrome.
- potentially agressive; due to continuous enlargement of the cyst, may result in expansion of bone with subsequent facial asymmetry, extreme displacement of teeth, severe root resorption of adjacent teeth and pain
- usually, no pain or discomfort associated with the cyst unless it becomes secondarily infected
Radiographic Features
- radiolucency associated in some fashion with an unerupted tooth crown is observed
- may be confused with the enlarged dental follicle; histologically identical
- normal follicular space is 3–4 mm, a dentigerous cyst can be suspected when the space is more than 5 mm
Three radiological variations may be observed:
Central - crown is enveloped symmetrically
Lateral - results from dilatation of the follicle on one aspect of the crown
Circumferential - results when the follicle expands in a manner in which the entire tooth appears to be enveloped by the cyst
Histologic Features
- no characteristic microscopic features which can be used reliably to distinguish the dentigerous cyst from the other types of odontogenic cysts
- usually composed of a thin connective tissue wall with a thin layer of stratified squamous epithelium lining the lumen
- unless secondarily infected, rete pegs are absent
- varying numbers of islands of odontogenic epithelium seen ( also seen in normal dental follicles )
- inflammatory cell infiltration of the connective tissue is common
- in cysts exhibiting inflammation, Rushton bodies, which are peculiar linear, often curved, hyaline bodies with variable stainability which are of uncertain origin, questionable nature and unknown significance, are seen within the lining epithelium
- content of the cyst lumen is usually a thin, watery yellow fluid, occasionally blood tinged
Treatment
- depends upon the size of the lesion - smaller lesions totally removed surgically, larger cysts are often treated by insertion of a surgical drain or marsupialization as larger cysts involve serious loss of bone and there is potential of fracturing the jaw if complete surgical removal is attempted
- recurrence relatively uncommon
Potential complications
Besides recurrence, following complications may occur:
- development of an ameloblastoma
- development of epidermoid carcinoma
- development of a mucoepidermoid
