Bacterial adherence to gingival epithelial cells of rats with naturally occurring gingivitis

Bacterial adherence to gingival cells was compared in rats with spontaneous gingivitis (SUS rat) and in control rats (RES rat). In the SUS rat, the number of adherent bacteria in gingival cells changed according to the progression of gingival inflammation. There was a correlation between the change of the number of adherent bacteria, progress of inflammation and pH in the pocket. In the RES rat, the number of adherent bacteria was constant and very small. In the adherence assay, adherence of Bacteroides intermedius to epithelial cells was dependent on the pH. Adherence of B. intermedius was better than that of other species. B. gingivalis and B. macacae showed good adherence but B. levii showed poor adherence. Adherence to the epithelial cells of the SUS rat was always better than that of the RES rat. These results were supported by scanning electron microscopic studies.