DISTRIBUTION OF PORPHYROMONAS-GINGIVALIS AND TREPONEMA-DENTICOLA IN HUMAN SUBGINGIVAL PLAQUE AT DIFFERENT PERIODONTAL POCKET DEPTHS EXAMINED BY IMMUNOHISTOCHEMICAL METHODS

Localization of Porphyromonas gingivalis and Treponema denticola in di fferent areas of subgingival plaque from advanced adult periodontitis patients was studied immunohistochemically using sensitive immunogold- silver staining and immunoelectron microscopy. Fourteen periodontally diseased teeth were extracted without damaging the subgingival plaque, fixed, and embedded. The subgingival plaque samples were sectioned ac cording to four different pocket depths (0-2 mm, 2-4 mm, 4-6 mm and gr eater than or equal to 6 mm). Serial thin sections were stained using specific antisera to P. gingivalis or T. denticola and then with secon dary antibody labelled with colloidal-gold. Cells of both P. gingivali s and T. denticola were predominantly found in subgingival plaque loca ted at depths of more than 4 mm in periodontal pockets. T. denticola c ells were found in the surface layers of subgingival plaque, and P. gi ngivalis were predominant beneath them. However, in the deeper subging ival plaque, the coexistence of P. gingivalis and T. denticola was obs erved. The present findings suggest that P. gingivalis and T. denticol a play important roles in the pathogenicity of periodontal disease and provide the useful information for elucidating the pattern of coloniz ation of microorganisms in the periodontal pocket.