Odontogenic cysts and tumours

A cyst is a pathological cavity lined by epithelium and have accumulation of fluid or gaseous content which is not pus.

Dentigerous or follicular cyst

This is a type of odontogenic cysts that are of developmental origin that involve the crown of a unerupted or partially erupted tooth. The cavity of the cyst is lined by epithelial cells derived from the reduced enamel of the unerupted tooth. The pressure from the erupting tooth may obstruct the venous flow, which results in exudate between the reduced enamel epithelial cells and the crown of the tooth.

In other words, this is a cyst which surrounds the crown of a unerupted tooth.

Odontogenic keratocyst

Rare, benign but aggressive cyst which affects the posterior mandible. It usually presents in patients around their 30s.

Periapical cyst (or radicular cysts or inflammatory cyst)

The most common type of odontogenic cysts and is found in 75 % of cases of cysts in the oral cavity. These cysts surround the apex of the root of a tooth and occur mostly in the anterior region of the maxilla.

Dental caries and trauma to the teeth can lead to pulpal necrosis, which will form the cyst from the epithelial cells’ rests.

Its more common in men and in individuals between 20 and 60 years.

Odontogenic tumors

The tumors are derived either from odontogenic epithelium (ameloblast), ectomesenchyme or both.

When from ameloblast, it’s called an ameloblastoma. It doesn’t cause any chondroid or osseous differentiation, but its cystic and infiltrates local tissue. However, its slow growing.

Odontomas are arisen from epithelium but show deposition of enamel and dentin. The tumor can be either hard or soft.