Argyrophilic nucleolar organizer regions (AgNORs) in mucosal epithelium under experimental denture bases in rats

The purpose of this study was to evaluate changes in the argyrophilic nucleolar organizer region (AgNOR) counts in mucosal epithelium induced by continuous or intermittent compressive pressure exerted through experimental denture bases and to examine the relationships between the AgNOR count, histopathological changes and the intensity of the pressure under denture bases. Continuous or intermittent compressive pressure exerted through the denture bases was applied to the hard palate of the molar region in rats. A morphometric analysis of AgNORs was performed in denture-supporting tissue 3 days and 1, 2, 4, 8, 12 and 20 weeks after the denture insertion. From the results of this study, it was found that non-pressure contact of the denture bases with palatal tissues did not change the AgNOR count. The AgNOR count was decreased by continuous or intermittent compressive pressure, and then recovered to almost the same level as with the non-pressure contact at 20 weeks following a decrease of the pressure. The AgNOR counts in the epithelium under the denture bases were revealed to be related to the histopathological changes in the denture-supporting tissues and the intensity of the pressure under the denture bases.