Dentigerous Cysts

Dentigerous cysts are also referred to as follicular cysts of the jaw (FCJ) and they are the commonest of all non-inflammatory jaw cysts. These are benign and slow-growing cysts that are believed to be developmental in nature.

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Those most commonly affected are somewhere between the second and fourth decades of life, thus making the condition fairly uncommon in children and almost exclusive to secondary dentition. FCJs are the most common etiology associated with impacted tooth lucency around the peri-coronal area.

These cysts tend to form when there is fluid accumulation between the follicular epithelial cells and the crown of teeth that are developing or teeth that have not yet erupted. Young people and adults affected by FCJs are generally free of any pain and/or discomfort.

This is not the case, however, if the cyst becomes infected. Moreover, these cysts can enlarge, albeit asymptomatically, and cause the displacement and/or resorbing of neighboring dental and osseous tissues.

Characteristics of dentigerous cysts

These cysts can be observed with radiographic imaging and tend to be round in shape with well-defined margins and areas of lucency around the crown of the affected tooth. There appears to be a predilection for the third molars. As it pertains to their dimensions, FCJs may vary in size.

However, when they approach diameters of two or more centimeters, then they may cause enlargement in the area of the mandible affected. Furthermore, cysts that grow very large enough to cause mandibular expansion may present with less well-defined borders, because there may be areas where the bone density is uneven.  

Management

Diagnosis is done with the help of radiographic imaging. Panoramic radiographs show the lesions with their typical features. CT scans can also be done, but these essentially mirror what is brilliantly seen in a panoramic radiograph.

If there are atypical panoramic radiographic features, then an MRI may be done to help with distinguishing FCJs from other jaw cysts.These other cysts that could be part of the differential diagnosis include, but are not limited to, radicular cysts, odontogenic keratocysts, aneurysmal bone cyst and static bone cysts.

Treatment of dentigerous cysts involves extracting the tooth or teeth that are affected and the complete excision of the cystic lesion. If the cyst is very large and there is extensive damage to the bone tissue, then the bone must be adequately stabilized with metal plates, rods and/or screws and grafting may be conducted.

Some patients who are not fit for this type of surgical procedure may need to undergo marsupialization as an alternative. This is a surgical procedure that allows for the continuous drainage of the cyst after first cutting into it and suturing it in such a way that it remains open.

References:

1. https://www.ncbi.nlm.nih.gov/pubmed/20402321
2. https://radiopaedia.org/articles/dentigerous-cyst
3. http://europepmc.org/abstract/med/8419968