Objective:The purposes of the present animal experiment were to investigate the histogenesis of odontogenic keratocyst. Methods:A total of 17.5-day-old C3Hmouse embryos were removed from pregnant females and placed in 2% bovine serum in Hanks solution. Under a dissecting microscope, the mandibular first molar tooth germs with the dental lamina and oral epithelia were cut from these embryos. The following 3 kinds of graftswere prepared, including recombinantof the dental lamina and dental papilla, recombinant of the oral epithelium and dental papilla, and tooth germ. Three-month-old syngenic male mice were anaes- thetized by intraperitoneal injection of pentobarbital sodium and these grafts were transplanted under the left renal subcapsular spaces of the mice at the rate of one graft per capita. The graftswere harvested at times ranging from 1 to 24 weeks andwere fixed in 10% neutral buffer formalin and demineralized in 5% formic acid at4efor12 h. The specimenswere processed forhistologi- cal examination. Serial sections were made, stained with hematoxylin and eosin, examined using a light microscope.Results: Three kinds of graftsgrewinto cysts lined by parakeralinized ororthokeratinized stratified squamous epithelia. The histopathological features of these cysts were the similar to those seen in the odontogenic keratocyst of human. Of these 58 cases of grafts, kerato- cyst-like lesions were formed in 41 cases and, dental tissue formation were found in 45 cases.Conclusion:These results suggest that the dental lamina, the oral epithelium and external enamel epithelium of enamel organ are the sources of the odontogenic kera- tocyst. The dental lamina and the oral epithelium, when recombinantwith the dental papilla, have compensatory potential of dental tissue formation.
