A study of effects of mouthwash on the human oral mucosae: with special references to sites, sex differences and smoking.

In recent years, the use of mouthwash has become widespread as a part of routine oral hygiene. However, there have been no fundamental studies on the influence of mouthwashes on the human oral mucosae. One hundred and twenty-five subjects (50 males and 75 females) were selected for this study. The effects of mouthwash was assessed with the use of exfoliative cytological and cytomorphometric analyses of smears obtained from clinically normal upper labium and cheek mucosae before mouthwashing, 30 s, 10 min and 1 h after mouthwashing. The independent variables examined were oral site, sex and smoking (smokers versus never-smokers). In all subjects and sites, the appearance rate of exfoliated cells stained by light green SFY decreased just after mouthwashing, and the rate after 1 h was lower than that of the untreated controls. The oral mucosae of smokers were more irritated action by mouthwashing than that of the never-smokers. Even after 1 h, decreases in the nuclear and cytoplasmic areas of cells and increases in inflammatory cells were observed. In conclusion, the use of mouthwash was so inflamed the human oral mucosae that more attention should be paid when it is used daily in oral hygiene.