The effect of long–term heavy smoking on gingival crevicular fluid IL–4 levels in chronic periodontitis

Objective: the aim of this study was to evaluate the influence of long–term and heavy smoking on the gingival crevicular fluid (gcf) interleukin (il)–4 (il–4) levels in chronic periodontitis patients. material-method: the study population included 126 non–smoker (ns) and long–term and heavy smoker (s) chronic periodontitis patients and 17 non–smoker healthy controls. the ns and s groups were divided into three subgroups according to the probing depth (pd) categories: a: pd ≤ 3 mm, b: pd= 4–5 mm, c: pd > 5 mm. for each individual, clinical data were recorded. results: all of the ns subgroups had higher il–4 concentrations than the control group (p<0.05). however in the s a– and b– subgroups, il–4 levels were found lower than those in the control group (p<0.05). the ns a– and b– subgroups showed significant negative correlations between il–4 and gingival inflammation symptoms (p<0.05). discussion: our study has supported our hypothesis that long–term and heavy smoking impairs the local immune response in periodontitis patients.