A histological study of odontogenic cysts formed following mouse molar tooth transplantation.

The enamel organs of subcutaneously transplanted mouse molar teeth undergo cyst formation and present a model for the study of the pathogenesis of development odontogenic cysts. Maxillary molars extracted from 10-day-old C57B1 mice were grafted subcutaneously into adult mice of the same strain. The grafts were recovered between 2 and 50 days after operation and routinely prepared for histological examination. After initial degeneration, the enamel organ took the form of a squamous epithelium in which after 5 to 6 days squamous hyperplasia took place. Cystic degeneration within the epithelium produced cavities lined with a thick parakeratotic stratified squamous epithelium which resembled the lining of an epidermoid implantation cyst. As the cysts enlarged the lining changed in appearance to a thin squamous non-keratinized epithelium. Similar features have been described in other experimentally produced cysts and in some odontogenic cysts in humans. Their different morphology may arise frominteraction betwen the surrounding connective tissue with epithelium at different stages of development.