COMPOSITION OF PLAQUE-ASSOCIATED LESIONS IN THE GINGIVA AND THE PERI-IMPLANT MUCOSA IN PARTIALLY EDENTULOUS SUBJECTS

The purpose of the present investigation was to study characteristics of the plaque associated lesions in the gingiva and the adjacent perii mplant mucosa sampled from the same subjects. 20 partially edentulous patients (12 female and 8 male, 30-60 years of age) volunteered to par ticipate in the study. They had all been treated for moderate to advan ced periodontal disease. Edentulous regions had been restored with imp lants. The restorative therapy had been completed 6-24 months prior to soft tissue biopsy. Samples of gingival tissue (GM) and periimplant m ucosa (PIM) from an ''interproximal surface'' of one tooth site and on e implant site of the same jaw were harvested. One portion of the biop sy was embedded in EPON(R), stained in PAS and toluidine blue and used for histometric and morphometric analyses. The 2nd portion of the bio psy was snap frozen in liquid nitrogen. lj sections, about 5 mu m thic k, were prepared in a cryostat and used for immune histochemical stain ing. The analysis of the sections included determination of the size o f the lesions as well as assessments of various cells and cell markers . In all samples of both PIM and GM discrete infiltrates of inflammato ry cells (ICT) were found in the connective tissue lateral to the junc tional epithelium. The ICT of PIM occupied on the average 0.17+/-0.14 mm(2) of the soft tissue, while the corresponding lesion in GM occupie d an area that was 0.25 mm(2)+/-0.21 mm(2) large. The density of CD19 positive cells was 7 times higher in GM than in PIM (3.7 versus 0.5) w hile the densities of CD3 positive cells were 7.5 (GM) and 4.7 (PM) re spectively. The density of PMN elastase positive cells was about 3 tim es higher in GM than in PIM (3.7 versus 1.2). Care must be exercised w hen these differences are interpreted. It is possible that a prolonged exposure of the implant site to the oral environment may induce both qualitative and quantitative changes of the infiltrate in PIM.