SUMMARY

Several theories have been put forward concerning the origin of the neoplastic epithelium in ameloblas-toma. Because of the doubt on the possible origin of ameloblastomas from cells with odontogenic potentiality, the aim of the present was to observe the development and growth pattern of odontogenic epithelium and tooth germs in tissue culture. Fourteen molar tooth germs consisting enamel organ and dental papilla of fourteen days old mouse embryos were cultured in a medium on millipore filters. THWP 0.45 m porosity and 25 ± 5 m thin. Cultivation was terminated at 21st day. Explants were embedded in cellulose-paraffin for histology. After 2 days cultivation, the epithelial outgrowth of enamel organ was observed, and 2 days later was visible structure resembled the pattern of the dental lamina often seen in ameloblastomas. Histological sections of specimens showed that the outer epithelium has differentiated into a lamellar-like structure and the enamel organ has similar pattern of the ameloblastoma. Formation of microcysts and continued formation of epithelial buds was observed. Tissue culture studies of mouse embryo tooth germs and enamel organ demostrated epithelial proliferation from the borders of odontogenic epithelium and the formation of lamellar-like structure observed in ameloblastomas. This study offers additional experimental evidence that ameloblastomas orginate from epithelium with odontogenic potentiality