Toker H, Akpinar A, Aydin H, Poyraz O. Influence of smoking on interleukin-1beta level, oxidant status and antioxidant status in gingival crevicular fluid from chronic periodontitis patients before and after periodontal treatment. J Periodont Res 2012; 47: 572577. (C) 2012 John Wiley & Sons A/S Background and Objective: The aim of this study was to evaluate the impact of smoking on the relationship between interleukin-1 (IL-1 beta) and oxidation in patients with periodontitis and response to nonsurgical periodontal therapy. Material and Methods: Data were obtained from 30 patients with generalized chronic periodontitis (15 smokers and 15 nonsmokers) and from 10 periodontally healthy controls. IL-1 beta level, total oxidant status (TOS) and total antioxidant status (TAS) were recorded in gingival crevicular fluid. Probing depth, clinical attachment level, gingival and plaque indices and bleeding on probing were also measured. The gingival crevicular fluid and clinical parameters were recorded at baseline and 6 wk after periodontal treatment. Results: The study showed statistically significant improvement of clinical parameters in both smokers and nonsmokers after periodontal treatment. Moreover, the baseline IL-1 beta levels were significantly higher in smokers compared with nonsmokers (p < 0.05). After periodontal treatment, the IL-1 beta levels were significantly reduced in both smokers and nonsmokers (p < 0.05). There were no significant differences in TOS and TAS between periodontitis patients and healthy controls at baseline and 6 wk after periodontal treatment. The level of IL-1 beta in gingival crevicular fluid was positively correlated with TOS in both smokers and nonsmokers. Conclusions: Periodontal treatment improved the clinical parameters in both smokers and nonsmokers. The results confirm that periodontal therapy has an effect on IL-1 beta levels in gingival crevicular fluid, but not on TOS and TAS.