Tobacco smoking and periodontal disease : some clinical, microbiological and immunological aspects

Abstract: The main aim of the thesis was to evaluate the influence of smoking on the inflammatory response in periodontal disease. The overall study population included 347 patients: 224 men and 123 women, aged between 31-86 years, with moderate to severe periodontal disease. Paper I concerned patients surgically treated and the patients in Papers II-V were considered untreated for periodontal disease. By means of a lavage method, gingival crevicular fluid (GCF) samples were collected from diseased sites. Culture and checkerboard DNA-DNA techniques were used for the identification of subgingival bacteria. TNF-[alpha], IL-6, IL- I [beta], IL- 1 ra, IgA and IgG were determined with ELISA, albumin with immunoelectrophoresis and total protein with the BCA method. Albumin and total protein were used as references for standardizing of the volume and were not observed to have any associations with smoking. A main finding was the association of smoking with an elevated TNF-[alpha] level in GCF, and there was a tendency towards higher levels of TNF-[alpha] along with an inferior therapeutical outcome in maintenance patients. The observation of GCF levels of IL-6, IL-1[beta] and IL-1ra respectively, revealed no significant differences between smokers and non-smokers. A notable finding was that the IL-1ra GCF concentration was approximately 1000-fold that of TNF-[alpha] IL-6 and IL-1[beta] respectively. The studied immunoglobulins were not observed to have any association with smoking. Cigarette smokers among patients with periodontal disease did not differ from non-smoking patients regarding the periodontopathogenic bacteria P. gingivalis, P. intermedia, P. nigrescens, B. forsythus, A. actinomycetemcomitans, F. nucleatum, T. denticola, P. micros, C. rectus, E. corrodens, S. noxia and S. intermedius. In regions assigned for surgery, a decrease of pocket depth was observed irrespective of smoking. Furthermore, an increase of bone height was observed. However, the gain of bone was less favourable among smokers, compared to non-smokers. Main conclusions: TNF-[alpha] is associated with an elevated GCF level in smokers with periodontal disease. In contrast, the GCF levels of IL-6, IL-1[beta] and IL-1ra in similarity with those of albumin, total protein, IgG and IgA have no association with smoking. Further-more, smoking has no association with several of the periodontopathogenic bacteria.