histopathological study of the effect of smoking on free gingiva in patients with moderate to severe chronic periodontitis

introduction: cigarette smoking is a risk factor for progression of periodontitis, which effects on the incidence, extent and severity of the periodontal disease and no other known factors can be harmful as much as smoking to the periodontal tissues. the purpose of this study was to determine clinical and histopathological effects of smoking on free gingiva in smokers and non-smokers with chronic periodontitis. materials and methods: biopsies were obtained from palatal gingiva of first and second molar of 72 patients with chronic periodontitis (36 smokers and 36 non-smokers). these samples were sent to the pathologic laboratory for microscopic examinations, and then the data were analyzed by spss version 21. results: histopathological examination showed that smoking increase the thickness of the outer and inner epithelium of free gingiva, collagenized connective tissue, and cal; and decrease the vascular density. conclusion: it seems that the reduction of the clinical signs of inflammation in the gingival tissue of smokers are because of changes in gingival epithelium and connective tissue due to smoking.