Some effects of periodontal therapy on local and systemic immunological parameters

The aim of the present investigation was to study the effect of nonsurgical periodontal therapy on some local (gingival) and systemic host defense characteristics in subjects with advanced periodontal disease. 16 individuals with advanced periodontal disease were recruited. Following a clinical examination, the 3 deepest interproximal sites in the upper and lower premolar- or molar segments were selected for further analysis. Samples from the subgingival microbiota were obtained from the pocket of the selected sites and were prepared for a microbiological examination. The gingival tissue at one of the selected sites was also biopsied. Each excised soft tissue specimen was snap frozen and prepared for immunohistochemical analysis. A sample of peripheral blood was obtained from each individual and prepared for immunohistochemical analysis. Following the baseline examination, all 16 patients received periodontal therapy including oral hygiene instruction and scaling and root planing. Re-examinations regarding the clinical parameters were performed, the subgingival microbiota harvested from the sampling sites and one gingival biopsy was collected at 12 months and 24 months, respectively, among the selected sites. Samples of peripheral blood were obtained from the subjects at the 24-month re-examination. It was demonstrated that non-surgical periodontal therapy effectively reduced symptoms such as gingivitis and probing pocket depth in the subject sample and improved the overall probing attachment level. The treatment applied also markedly reduced (i) the total number of micro-organisms present in selected gingival pockets as well as (ii) the relative proportions of A. actinomycetemcomitans, P. gingivalis and P. intermedia of the subgingival microbiota. The improved clinical condition was, in addition, accompanied by a substantial reduction in the size of the inflammatory lesion (P-ICT) which in the soft tissue samples harvested at baseline was found to reside lateral to the pocket epithelium. Also qualitative alterations occurred in the lesions. Hence, following therapy (i) both the density of CD19 positive cells and the proportion of CD3 positive cells expressing TCR Vbeta genes were reduced in the P-ICT. while (ii) the overall relative number of CD3 positive cells remained unchanged. In conclusion, non-surgical periodontal therapy markedly changed the size and composition of the plaque associated lesion in the gingival tissue but apparently failed to affect the relative distribution of lymphocyte subsets in peripheral blood.