Odontogenic neoplasms in Wistar rats treated with N-methylnitrosourea.

Odontogenic lesions developed in the jaws of six of eighty-one Wistar rats following a single intravenous injection of the alkylating agent, N-methylnitrosourea (MNU). The superficial and deep portions displayed significant differences in both prevailing tissue components and the degree of maturation and induction. In superficial portions, there was a preponderance of well-differentiated mature dental tissues, whereas in deeper portions, nests of less-differentiated, primitive-appearing epithelium predominated. These findings suggest that experimental odontogenic lesions were derived from two distinct sources: surface oral epithelium and enamel organ of the perpetually erupting mandibular incisor tooth. When stimulated by MNU, each source apparently exhibits different potential for odontogenic differentiation.