Distribution of metallothionein in cigarette smokers and non-smokers in advanced periodontitis patients.

This study evaluated the effect of smoking on periodontal tissue in periodontal patients. Gingival biopsies were taken from the flap during periodontal surgery of 33 male patients with advanced periodontal disease (22 cigarette smokers; 11 non-smokers). Frozen sections were made immediately and used for hematoxylin-eosin and Giemsa staining, and for detection of metallothionein (MT), a free radical scavenger. The expression and distribution of MT in these sections was studied using monoclonal antibody and immunohistochemical staining. The smokers had a large number of infiltrate cells in the gingival epithelium compared with non-smokers. Moreover, samples from the smokers showed high levels of MT in the prickle cell layer of the epithelium. In the non-smokers, basal and prickle cell layers of the gingival epithelium also showed detectable MT. Smokers, however, had a higher metallothionein-positive cell ratio in the prickle cell layer as compared to non-smokers. This increased level of MT in smokers may reflect an attempt to defend against free radicals in the gingiva of smokers. These results suggest that inflammation is much greater in periodontal tissues of cigarette smoking periodontal patients than in non-smoking periodontal patients, and that the defense against free radicals is heightened in smokers' gingiva.