Odontogenic cysts – an overview

An odontogenic cyst is a pathological, epithelial-lined cavity containing fluid or semi-fluid which arises from the epithelial remnants of tooth formation. The 1992 World Health Organization (WHO) classification of odontogenic cysts is widely recognized and categorizes them as developmental or inflammatory in nature.1

Odontogenic cysts are often asymptomatic and therefore may expand to a large size before any clinical signs are noted and, as such, their presence is often an incidental finding on radiographic examination. These cysts may become increasingly obvious clinically as they increase in size, initially creating a bony hard swelling. As this gradually and slowly enlarges, the bony covering becomes increasingly thin, which clinically may be demonstrated on palpation by the classic ‘egg shell cracking’ as the thin bone gives way. As the lesion expands beyond its bony confines, it then becomes a fluctuant swelling. The slow expansion of the cyst usually causes displacement of related structures, such as the inferior alveolar bundle in the mandible and thus altered sensation is not a common feature of mandibular cysts. When altered sensation occurs, it can be an indication of infection or more aggressive pathology.