MIB-1 expression in odontogenic epithelial rests, epithelium of healthy oral mucosa and epithelium of selected odontogenic cysts. An immunohistochemical study.

The aim of this study is to investigate the proliferative potential of rests of odontogenic epithelium found in follicles of unerupted teeth, epithelium of oral mucosa and epithelial linings of various odontogenic cysts. MIB-1 expression was studied in the rests of odontogenic epithelium (n=10), healthy oral mucosa (n=10), odontogenic keratocysts (n=10) and other odontogenic cysts (n=10) using an avidin-biotin peroxidase technique on paraffin sections. The number of positively stained cells was counted on 10 representative areas of epithelium using a x40 objective. The average number of MIB-1 positive cells in each group was calculated. No MIB-1 positive cells were seen in the rests of odontogenic epithelium. The mean numbers of MIB-1 positive cells detected within the epithelium of oral mucosa, and of radicular and dentigerous cysts were similar. The number of MIB-1 positive cells was found to be increased in the presence of marked inflammatory cell infiltration. The highest number of MIB-1 positive cells was seen in the keratocysts. These findings suggest that removal of an unerupted tooth to prevent the possibility of neoplastic transformation of rests of odontogenic epithelium is not a justifiable rationale.