Influence of cigarette smoking on oral microbiota in patients with recurrent aphthous stomatitis.

Recurrent aphthous stomatitis (RAS) is a common recurrent ulcerative disease of the oral mucosa which is closely related to oral microbial composition. However, the specific effect and the mechanism of smoking in RAS are unclear. In this study, 16S rRNA sequencing technology was used to compare the differences in saliva microbial community between 28 non-smoking healthy controls (NSctrl), 31 non-smoking RAS patients (NSras), and 19 smoking RAS patients (Sras). The results showed that the bacterial community diversity in patients with RAS (NSras and Sras) was lower than that of NSctrl. The microbial community in smoking-associated RAS is less diverse and distinct from that of non-smokers. The RAS groups have higher abundance of , , and and lower abundance of , , , , , and at the genera level. A significantly different abundance of , , , , , and was observed between the Sras and the NSras group. Notably, there was a significant difference in many species from the genus and between the NSras and the Sras group. Further, the relative abundance of several taxa is correlated with smoking age or frequency, including , , , and at the genera level, and , , , , , , , and at the species level. Among patients with RAS, smoking aggravated the pathways of respiration and human pathogens. Our results suggest that smoking is closely related to changes in the oral microbiota, which may contribute an opposite effect to the pathogenesis of RAS. This study provides new insight and theoretical basis for the cause and pathogenesis of RAS and better prevention and treatment.