Evidence to infer the causal association between tobacco use and health consequences have been investigated recently for oral diseases. The aim of present review is to clarify underlying mechanisms regarding effects of tobacco use on oral microorganisms comprehensively. Electronic searches of relevant articles were conducted with a standardized search strategy in the last 10 years. Overall, 1099 papers were extracted. The studies that addressed the relationship between tobacco and oral microorganisms were included. After reading the titles and abstracts, 121 papers were deemed appropriate for the present review. These studies addressed periodontal pathogens, and other microorganisms included HPV, Candida species, Streptococcus mutans, and peri-implant microorganisms. Dysbiosis of periodontal microbiome in smokers has been demonstrated by observational and intervention studies. Smoking cessation is shown to be beneficial in terms of compositional changes of subgingival and peri-implant microbiomes. Studies utilizing cigarette smoke extract and indicators of virulence have suggested a benefit regarding the functional changes of subgingival microbiomes for quitters. The effects of nicotine exposure on growth and metabolism of S. mutans were observed in a dose dependent manner. The potential role of tobacco use on HPV infection requires clarification with large sample studies. Potential effects of exposure to tobacco smoking were reported on accumulation of pathogenic bacteria on oral apparatus for orthodontic treatment, denture, and titanium for oral implant. In conclusion, further studies are warranted to examine impact of tobacco intervention for healthier mouth ecosystem on the full achievement of the interventions in dental settings.

Funding:
This study was supported by Pfizer Global Medical Grant #35621681.