Oral probiotic Weissella cibaria improves halitosis and reduces periodontal pathogens: a randomized, double-blind, placebo-controlled trial

Halitosis is closely linked to periodontal inflammation and affects oral health–related quality of life. This randomized trial investigated the effects of Weissella cibaria CMU (OraCMU) on halitosis in adults with gingivitis and early (Stage I–II) periodontitis. Eighty adults were enrolled in a randomized, double-blind, placebo-controlled trial and assigned to OraCMU (n = 40) or placebo (n = 40). Participants consumed two slow-dissolving tablets daily for 8 weeks. The primary endpoint was change in total Volatile sulfur compounds (VSCs) from baseline to week 8. Secondary outcomes included organoleptic test (OLT), bad breath improvement (BBI), gingival index (GI), bleeding on probing (BOP), probing depth, plaque index, and oral health impact profile-14 (OHIP-14). Multiplex quantitative real-time PCR was performed at baseline and week 8 to quantify nine periodontopathogens and to derive the periodontal pathogen index (PPI) and PPI level. The OraCMU group showed a significantly greater reduction in total VSC (primary endpoint) at week 8 than the placebo group (P = 0.001). Secondary outcomes favored OraCMU for OLT (P = 0.015) and BBI (P = 0.045). Periodontal indices (GI and BOP) improved more in the OraCMU group at week 8 (P = 0.0035 and P = 0.030, respectively). qPCR showed lower levels of Porphyromonas gingivalis, Prevotella intermedia, and Treponema denticola in the OraCMU group at week 8 (P = 0.001, P = 0.046, and P = 0.005), along with lower PPI and PPI level (P = 0.005 and P = 0.002). OHIP-14 improved within the OraCMU group (P < 0.05) but did not differ between groups (P > 0.05). Eight-weeks of W. cibaria CMU supplementation reduced major halitosis indices and improved periodontal pathogen levels in adults with gingivitis/incipient periodontitis. Longer-term studies, including post-intervention follow-up, are needed to assess the sustainability of the effects. Clinical Research Information Service (CRIS), KCT0009810, registered 27 September 2024, retrospectively registered.