Dentigerous cysts (ovine odontogenic cysts) in sheep

Dentigerous cysts appear to be reasonably common near the mandibular incisors of sheep in New Zealand. Their aetiology, true prevalence, and, therefore, their economic significance, are not known at present. They appear as solitary swellings, grow slowly, and are lined by stratified squamous epithelium. Each example usually contains a single, unerupted tooth; however, the anatomical relationship of this tooth to the cyst wall differs from that in dentigerous cysts in humans. Moreover, as some do not contain an unerupted tooth, the term dentigerous is not entirely appropriate but is supported by common usage. Work is in progress to study these lesions further and to clarify their aetiology. There is no practical treatment.