Abstract
INTRODUCTION: The oral cavity harbors over 700 bacterial species, and disruption of this balance can lead to periodontitis, which has been linked to systemic conditions including respiratory disease. METHODS: In this longitudinal clinical trial, 57 never-smoking adults with stage I-II periodontitis underwent full-mouth periodontal disinfection. Airway resistance and subgingival plaque sampling (analyzed by shotgun metagenomics) was measured at baseline and six weeks after therapy. RESULTS: Periodontal treatment significantly improved clinical periodontal parameters, and was associated with reductions in airway resistance. Microbiome analysis showed a shift from periodontitis-associated taxa, including Prevotella, Porphyromonas, and Tannerella, toward health-associated species such as Actinomyces oris, and Rothia dentocariosa. Higher airway resistance was associated with a greater relative abundance of periodontitis-associated bacteria. DISCUSSION: Together, findings suggest that periodontal therapy promotes a healthier oral microbiome and is associated with improved lung function in non-smokers with no prior lung disease.