ABSTRACT Objective: The aim of this study was to investigate the influence of smoking on both the oral malodor and
oral microbiome in smokers compared with a control group of non-smokers. Methods: The study population consisted of 37 patients with complete data for oral malodor, periodontal
condition, and oral health behavior. The number of bacteria was determined by real-time PCR analysis. Results: Levels of hydrogen sulfide in smokers (n=9) were significantly higher than those from non-smokers
(n=28). The mean numbers of total bacteria, Fusobacterium nucleatum and Campylobacter rectus recovered in
saliva were significantly higher in smokers. In addition, a multiple linear regression analysis showed that
smoking influenced oral microbiome. Bacteria in tongue coatings from 21 patients with no tongue cleaning
habit were also investigated. The detection rates of F. nucleatum and C. rectus per total bacteria in smokers
were 3.03% and 0.60%, respectively, this correspond to approximately 5 fold the rates detected in nonsmokers.
The number of F. nucleatum and C. rectus also showed positive correlation coefficients with all
volatile sulfur compounds (VSC) values. Conclusions: The results of this study suggest that smoking promotes colonization of periodontopathogenic
bacteria in tongue coatings and influences oral malodor by increasing the amount of VSC.