A Narrative Review on the Impact of ENDS Use on Clinical, Inflammatory and Microbiological Periodontal-Related...

Background/Objectives: The increasing prevalence of electronic nicotine delivery systems (ENDS) has prompted questions regarding their effects on periodontal health. While the detrimental impacts of cigarette smoking are well-established, the periodontal implications of ENDS use remain poorly understood. This narrative review aimed to evaluate current evidence comparing periodontal parameters, inflammatory markers, and oral microbiome composition among ENDS users, cigarette smokers, and non-smokers. Methods: A structured literature search was conducted in PubMed (January 2009-May 2026) following a PICO question: "What is the impact of ENDS, compared to cigarette smoking and non-smoking, on periodontal health?" Clinical studies reporting on periodontal health parameters (plaque index, bleeding on probing, probing depth, and clinical attachment loss), inflammatory markers (e.g., IL-1β, IL-6, TNF-α), and microbial composition were included. Due to methodological heterogeneity across studies, meta-analysis was not feasible, necessitating narrative synthesis. Results: Across studies, clinical periodontal findings in ENDS users were heterogeneous and did not consistently resemble those of either cigarette smokers or non-smokers. In contrast, ENDS use was consistently associated with alterations in inflammatory profiles and oral microbiome composition, characterized by selective changes in specific inflammatory cytokines rather than uniform inflammatory upregulation, as well as shifts towards microbial communities linked to periodontal inflammation. Notably, these biological alterations were not uniformly reflected in traditional clinical periodontal indices. Conclusions: ENDS use is associated with heterogeneous clinical findings and inflammatory and microbial alterations that suggest ENDS is a distinct exposure rather than a predictable intermediate between smoking and non-use. This review, to our knowledge, is the first to integrate clinical, inflammatory, and microbiome outcomes and highlights the limitations of relying solely on clinical parameters to assess the impact of ENDS on periodontal health. It also underscores the need for well-designed longitudinal studies to clarify the periodontal implications of ENDS use.