Cisto Dentígero


Resumo
  • Bem definida / unilocular / frequentemente corticada.
  • Uniformemente radiolúcida.
  • Arredondada ou oval / simetricamente circunda a coroa / 5 milímetros a vários centímetros de tamanho. Associated com a coroa de um dente não erupcionado.
  • Pode causar deslocamento / reabsorção / expansão.
  • Normalmente adolescentes, 20-40 anos / relação de 1,6 entre homens e mulheres


Diagnóstico diferencial

Cisto Dentígero


Sinônimo / Acrônimo

Cisto Folicular


Definição

É um cisto que se forma a partir do acúmulo de líquido entre o epitélio reduzido do esmalte e a coroa de um dente incluso e adere-se ao colo do dente na junção amelocementária.


Aspectos Clínicos 

O cisto dentígero é o segundo mais comum cisto odontogênico, após os cistos radiculares.
Os dentes mais envolvidos são, em ordem decrescente de frequência de ocorrência, os terceiros molares, os caninos e os segundos pré-molares.

O cisto dentígero pode formar-se em redor dos dentes supranumerários, sendo comumente encontrados em torno mesiodens.
Normalmente não há sintomas associados a cisto dentígero. O atrazo de erupção pode indicar a possibilidade de um cisto. Um cisto dentígero pode expandir causando assimetria facial. Tal como acontece com outros cistos, o cisto dentígero expande a cortical externa mais do que a cortical interna. Pode envolver outros dentes à medida que expande. O termo cisto de erupção é usado para um cisto que envolve a coroa de dente irrompido.


Radiographic Features

Well-defined unilocular radiolucency associated with the crown of an unerupted tooth. If the cyst become infected the cortex may be absent. The cyst attaches at the cementoenamel junction. It can appear round in shape or eccentric if the cyst develops from the lateral aspect of the follicle. Dentigerous cyst in mandibular third molars can expand to occupy the ramus area which represents an area of least resistance to cyst expansion. It causes displacement of the affected tooth in an apical direction and adjacent teeth in lateral direction. Inferior displacement of the inferior mandibular canal is also possible. Dentigerous cysts associated with maxillary teeth can grow into the maxillary sinus space and may not be discovered till late. The cyst is unlikely to cause resorption of apices of adjacent teeth.


Differential Diagnosis

The lining epithelium when examined histologically cannot be used alone to differentiate the cyst; the diagnosis depends on finding the attachment of the cyst to the CEJ. It is always hard to differentiate between a small dentigerous cysts and hyperplastic follicle. It is more likely to be a cyst if there are signs of tooth displacement and evidence of bone expansion. Usually the size of a normal follicle ranges is less than 5 mm. If the space size exceeds 5 mm, then it is more likely to be a dentigerous cyst. If we are still uncertain whether it is a cyst of hyperplastic follicle, we can wait for 6 months and re-evaluate the area and see if there are signs of enlargement or any influence on surrounding structures.

The differential diagnosis can include also keratocystic odontogenic tumor (KCOT), ameloblastic fibroma, and a cystic ameloblastoma. KCOT has less expansion than dentigerous cyst and less likely to cause root resorption, and may attach more apically instead of at the cementoenamel junction. If there is no internal structure, then it is harder to differentiate dentigerous cysts from ameloblastic fibroma or cystic ameloblastoma. There are other lesions that have similar appearance like adenomatoid odontogenic tumor (AOT) as it also surrounds the crown of the involved tooth. However, adenomatoid odontogenic tumor usually has internal structure which can help to differentiate between the two entities. If there is an apical radiolucency associated with the root apex of a deciduous tooth, it can give the false impression of a dentigerous cyst. A thorough examination of the tooth is necessary.


Treatment

Surgical removal of the cyst alone or along with the associated tooth is carried out. If the cyst is large then marsupialization can be done before the surgical removal. Whenever a diagnosis of a dentigerous cyst is made, the possibility of it containing mural ameloblastoma should also be considered; thus a biopsy is imperative and must always be done to confirm the final diagnosis and eliminate other diseases.


Case Reports


CASE 1»


CASE 2»


CASE 3»


CASE 4»
Cone Beam CT ReportHISTORY: A 68-year-old white male was referred for a Cone Beam CT scan. The alveolar nerve was exposed during the surgery but without damage.


FINDINGS: A well-defined radiolucent lesion is associated with the crown of impacted right lower molar. The lesion shows slight bucco-lingual expansions and thinning of cortical borders especially the lingual cortical border as seen on the cross-sectional image. The tooth is horizontally impacted and in close proximity to the mandibular canal.


IMPRESSION: The radiographic features of the lesion are most consistent with a cyst. A dentigerous cyst would be on the top of the differential diagnosis list since the lesion is associated with the crown of an impacted tooth. Other possible lesions would include keratocystic odontogenic cyst and mural ameloblastoma.
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Cone Beam CT ReportHISTORY: A 13-year-old female patient was referred for a Cone Beam CT evaluation of a radiolucent area associated with her impacted #6.


FINDINGS: There is a well-defined radiolucent lesion associated with the crown of horizontally impacted right maxillary canine. The lesion extends from the crown of the tooth inferiorly. There is slight lingual and buccal expansion in the cortical borders. The lesion exhibits smooth partially corticated margins. The impacted tooth is situated at the level of the floor of the nose and the apex of the tooth extends slightly into the right maxillary sinus. There are signs of soft tissue thickening in the sinus floor. The retained primary tooth #c shows slight root resorption.


IMPRESSION: This is classic appearance of a dentigerous cyst. Although in a differential diagnosis we would include keratocystic odontogenic cyst and mural ameloblastoma; however, those are less likely.



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Cone Beam CT ReportHISTORY: A 10-year-old female patient was referred for a Cone Beam CT evaluation of an expansile lesion in the left mandibular premolar area.


FINDINGS: Mixed dentition is present which is consistent with patient age. There is a well-defined radiolucency that extends from distal of unerupted #22 to the buccal of #19 and it extends from the furcation of #19 till the mental foramen. The lesion is hydrostatic, corticated, and expansile. There is thinning of buccal cortex. Lesion dimensions are 27 mm length x 13 mm width x 14 mm height. The lesion has caused displacement of roots #22 and #21. There is no evidence of root resorption. The follicular space of #20 and #22 are indistinguishable from the lesion. The lesion does not seem to displace the mandibular canal although it surrounds the mental foramen. It is noteworthy that lingual aspect of the lesion appears to intersect the CEJ areas of both #20 and #21..


IMPRESSION: The hydrostatic character of this lesion corresponds well with a cyst. The association of the CEJ(s) of unerupted premolar teeth and buccal expansion are consistent with a dentigerous cyst. KCOT would also be included in the differential. A benign odontogenic tumor is possible but unlikely.

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Cone Beam CT ReportHISTORY: A 22-year-old female patient was referred for a Cone Beam CT evaluation of a radiolucency of the 3rd molar area and ramus of the left mandible.


FINDINGS: There is a well-defined and partially corticated rounded radiolucent lesion extends from the distal aspect of #18 to the middle of the ramus area. There are also signs of expansion and thinning of buccal and lingual cortices. The lesion involves the lower margin of horizontally impacted #17 and it extends to the level of the mandibular canal. The lesion is in close proximity to the mandibular canal and the distinction seems to disappear in some parts of the lesion (cross-sections 7-10).


IMPRESSION: The hydrostatic form and homogenous radiolucency of this lesion is consistent with cyst. The scalloped margin and localized expansion of the buccal ramus cortex is more consistent with a benign tumor. Association with partially impacted #17 suggests an odontogenic origin. A differential would include:

  1. keratocystic odontogenic tumor
  2. unicystic ameloblastoma
  3. dentigerous cyst

Biopsy is indicated.



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