Smoking and crevicular fluid levels of IL-6 and TNF-a in periodontal disease

Smoking is a well-documented risk factor for periodontal disease, although the mechanisms of its negative influence are not well understood. In the present study, the influence of smoking on the gingival crevicular fluid (GCF) content of the pro-inflammatory cytokines IL-6 and TNF-alpha was investigated in patients with moderate to severe forms of the disease. The study base consisted of 108 patients including 45 current smokers, 28 former smokers and 35 non-smokers. The median GCF sample levels of IL-6 and TNF-alpha were 5.0 pg/ml and 61.0 pg/ml, respectively, for current smokers, 13.0 pg/ml and 51.0 pg/ml, respectively, for former smokers, and 10.0 pg/ml and 12.0 pg/ml, respectively, for non-smokers. The differences between smoking groups with regard to IL-6 were not significant suggesting that the IL-6 content was not influenced by smoking. In contrast, the TNF-alpha content was significantly increased in current smokers as compared to non-smokers confirming our previous observations. The present results in patients with moderate to severe periodontal disease may indicate different mediator functions of IL-6 and TNF-alpha in response to smoking.