Argyrophilic nucleolar organizer regions (AgNORs) in odontogenic myxoma (OM) and ameloblastic fibroma (AF)

Ten cases of odontogenic myxoma (OM) and six cases of ameloblastic fibroma (AF) were subjected to comparative analysis by the AgNOR technique, in orde r to determine a possible difference in cell proliferation index between th ese lesions. The mean AgNOR number of the mesenchymal component of AF was c ompared with its epithelial component and the difference was not found to b e statistically significant. The mean AgNOR index of the AF group was signi ficantly higher than that of the OM group. Moreover, the mesenchymal compon ent of AF demonstrated increased AgNOR numbers compared with that of OM (P < 0.05). These results suggest that the epithelial and mesenchymal componen ts of AF may have similar cell proliferative activity. However, the cell pr oliferative index of this lesion seems to be higher than that of OM.