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Odontogenic Keratocyst

 

 

 

Image Source: Recurrence of odontogenic keratocysts and possible prognostic factors: Review of 455 patients (researchgate.net)

Dentigerous/Follicular Cysts

Dentigerous (Follicular) Cysts are the second most commonly occurring odontogenic cysts after periapical cyst and the most common developmental cysts of the jaws. By definition, a dentigerous cyst is attached to the tooth cervix (enamel-cementum junction) and encloses the crown of the unerupted tooth.

image dentigerous cyst
Photograph: Dentigerous cyst surrounding the crown of right mandibular third molar and going upward in ascending ramus. [1]

Etiology and Pathogenesis of Dentigerous Cyst 

A dentigerous cyst originates from the enamel organ remnant or reduced enamel epithelium. The expansion of the dentigerous cyst is related to epithelial proliferation, release of bone-resorbing factors, and an increase in cyst fluid osmolality. 

Clinical Features of Dentigerous Cyst 

Dentigerous cysts are most commonly seen associated with third molars and maxillary Canines. The peak incidence of dentigerous cysts occurs between twenty to 40 years. Males have more predilection with a ratio of l.6 to 1.  

Dentigerous cysts are generally symptomless. The delayed eruption is the most common indication of dentigerous cyst formation. This cyst can achieve significant size, occasionally causes cortical bone expansion but rarely reaches a size that predisposes the patient to a pathologic fracture. 

Radiographically, a dentigerous cyst manifests as a well-defined, unilocular or sometimes multilocular radiolucency with corticated margins in attached with the crown of an unerupted tooth. The concerned unerupted tooth is mostly displaced. In the mandible the related radiolucency may extend superiorly from the third molar site into the ramus or anteriorly and inferiorly along the body of the mandible. In maxillary dentigerous cysts in the canine region, extension into the maxillary sinus or to the orbital floor may be seen.

image dentigerous cyst
OPG radiograph showing dentigerous cyst associated with right mandibular third extending in to the ramus and ascending body. [2}

Histopathology.

The cyst is lined by stratified squamous epithelium. In a noninflamed dentigerous cyst the epithelial lining is nonkeratinized. It remains approximately four to six cell layers thick. Sometimes, numerous mucous cells, ciliated cells, and rarely, sebaceous cells may be found in the lining of the epithelium. The epithelium-connective tissue junction is generally flat. But when secondary inflammation established, epithelial hyperplasia may be noted.

image histopathology of dentigerous cyst
Microscopic structure of Dentigerous cyst [4]

Differential diagnosis

When it is small, it is difficult to differentiate a dentigerous cyst from a large but normal dental follicle. When larger, the differential is essential that of lytic lesions of the jaw and includes:

  1. periapical cyst
  2. aneurysmal bone cyst
  3. ameloblastoma
  4. odontogenic keratocyst
  5. fibrous dysplasia
  6. Stafne cyst

Treatment

Removal of the associated tooth and enucleation of the soft tissue part is definitive therapy in most cases. When cysts affect significant portions of the mandible, exteriorization or marsupialization of the cyst is done to allow for decompression and subsequent shrinkage of the lesion followed by surgical enucleation. 

Ref:

  1. J Can Dent Assoc 2012;78:c59
  2. https://radiopaedia.org/cases/dentigerous-cyst-9
  3. https://www.pathologyoutlines.com/topic/mandiblemaxilladentigerous.html
  4. https://www.nature.com/articles/modpathol2016191

Periapical/Radicular Cyst

A cyst is defined as “an epithelial lined pathologic cavity”. The periapical/radicular cyst is an odontogenic cyst. The classification of the cysts can be seen HERE.t is important to read for ADC Exams or NEET MDS purpose.

Periapical/Radicular cyst

Periapical cysts are inflammatory cysts. Their epithelial lining originates from the odontogenic epithelium of the tooth buds that remains within periodontal ligaments (epithelial rests of Malassez) after completion of tooth maturation. Due to inflammatory response, the epithelial rests of Malassez start proliferating and provide cystic lining. (more…)

Dental Amalgam: SAQs for Viva Voce

SAQ 1. A patient arrives at your office and expresses concern about mercury from dental amalgam causing her harm. What will you tell this patient to reassure her about the safety of amalgam? 

ANSWER: 

You will tell about three facts of dental amalgam fillings:

(1) The mercury that is in an amalgam is not free and never released into the body. It is always tied up chemically in the dental amalgam matrix. The majority of bound mercury never leaves the dental amalgam mass. (more…)

Hepatitis B: Treatment & Prevention

Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (HBV). It can cause chronic infection and puts people at high risk of death from cirrhosis and liver cancer.

In the first part of the article, you have read the epidemiology, mode of transmission of Hepatitis B virus, its sign and symptoms, groups at risk, the relationship of HBV and HIV infection, and how the diagnosis is confirmed. In this part of the article, we shall discuss about its treatment and prevention.

If you want to read a short note on Hepatitis B in Indian context, read it HERE.

You can take a Mock test on Hepatitis B.

(more…)

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