E-cigarettes, Oral Microbiome, and Periodontal Disease Risk: A Narrative Review of Pathogenic Mechanisms

Introduction. Electronic nicotine delivery systems (ENDS) are global alternatives to tobacco, particularly popular among adolescents. Although they are marketed as a smoking cessation aid, their long-term impact on the oral cavity remains unclear. This review synthesizes current knowledge regarding the impact of ENDS on oral microbiota composition and periodontal disease risk. Methods. The literature search covering 2015–2025 was conducted using terms: e-cigarettes, oral microbiome, periodontal disease and aerosol toxicity. Eligible peer-reviewed studies addressed aerosol properties, microbial shifts, periodontal outcomes or pathogenic mechanisms. Brief description of the state of knowledge: ENDS aerosols containing nicotine and humectants (PG/VG) decompose into toxic carbonyls and reactive oxygen species (ROS). Vaping induces xerostomia, oxidative stress, and pH alterations, triggering rapid microbial dysbiosis. In this state, bacteria utilize PG/VG as a carbon substrate, favoring anaerobic taxa. Aerosols inhibit beneficial commensals while enhancing the virulence and biofilm formation of S. mutans and S. aureus. Host immune defenses are compromised through reduced cytokine secretion, leading to impaired bacterial clearance and greater probing depths. Conclusions. The use of E-cigarette disrupts oral homeostasis, promoting pathogenic biofilms and chronic infl ammation. This unique dysbiotic state, coupled with DNA damage, significantly elevates the risk of aggressive periodontal disease and potential oral malignancy. However, marked methodological and product heterogeneity underscores the urgent need for well-controlled, longitudinal human clinical investigations.