A Comparative Study of Proliferative Activity within Odontogenic Cyst Epithelium : Radicular Cyst and Odontogenic Keratocyst

The purpose of this study was to investigate the reactivity of the epithelial linings of the two major types of odontogenic cyst (radicular cyst n=10, odontogenic keratocyst n=10) with a monoclonal antibody to proliferating cell nuclear antigen (PCNA). The PCNA expression was performed by using a labelled streptavidin biotin method on routinely processed paraffin sections. PCNA (+) cells were counted at the whole epithelial area which was confined in 100 basal cells. The following results were obtained : 1) The mean value of PCNA (+) cells in odontogenic keratocyst linings (43.5±30.23) was similar to that of radicular cyst linings (33.1±27.5). 2) There were significant (P<0.05) differences in suprabasal/basal PCNA (+) cell ratios between radicular cyst (0.14±0.18) and odontogenic keratocyst (2.89±2.79). 3) The number of PCNA (+) cells in both radicular cyst and odontogenic keratocyst was influenced by the degree of inflammation. 4) The number of PCNA (+) cells of radicular cyst in female was higher than that in male. 5) Clinically, the occurrence of odontogenic keratocyst was very common in the twenties and sixties, and this study demonstrated the similar peak frequency of PCNA (+) cell distribution in the same age groups.