Antiseptic mouthwashes as a potential strategy for controlling oral dysbiosis: Antimicrobial effect against opportunistic pathogens.

OBJECTIVES

Oral dysbiosis is increasingly recognized as a clinically relevant condition associated with oral diseases, systemic complications, and the emergence of antimicrobial-resistant microorganisms. Antiseptic-containing mouthwashes are widely used as adjunctive, non-antibiotic tools in oral hygiene; however, comparative data on their activity against dysbiosis-associated microorganisms and their clinical efficiency at formulation-relevant concentrations remain limited.

METHODS

In this study, the antimicrobial activity of commercially available mouthwashes containing octenidine dihydrochloride (OCT), chlorhexidine digluconate (CHX), polyhexamethylene biguanide (PHMB), and cetylpyridinium chloride (CPC) was evaluated against Gram-positive and Gram-negative bacteria and Candida spp. associated with oral dysbiosis. Minimum inhibitory concentrations (MICs) were determined by broth microdilution and expressed both as product dilutions and active compound concentrations. Clinical relevance was assessed using the Clinical Efficiency of MIC (CEMIC) index.

RESULTS

OCT-containing mouthwashes demonstrated the lowest MIC and CEMIC values and the most consistent antimicrobial activity against all tested microorganisms. CHX-based formulations showed high activity against Gram-positive bacteria and Candida spp. but were markedly less effective against Gram-negative pathogens. PHMB exhibited lower antimicrobial potency; however, its CEMIC values indicated clinical efficiency at formulation-relevant concentrations.

CONCLUSIONS

The results demonstrate in vitro antimicrobial activity of antiseptic mouthwashes against microorganisms associated with oral dysbiosis and suggest that they may have potential as non-antibiotic adjuncts, although this requires clinical validation.

CLINICAL SIGNIFICANCE: This study demonstrates that antiseptic mouthwashes, particularly those containing octenidine, chlorhexidine and polyhexanide, effectively control oral dysbiosis at commercial concentrations. By using the CEMIC index, our findings provide evidence-based guidance for non-antibiotic oral care, reduce antimicrobial resistance risk, and support improved oral health.