Comparative Antimicrobial and Antibiofilm Activity of Antiseptics and Commercial Mouthwashes Against Porphyromonas gingivalis ATCC 33277

<b>Background:</b><i>Porphyromonas gingivalis</i> is one of the most prevalent periodontal pathogens, involved in the development of periodontitis, deep caries, pulpitis, endodontic infections, and peri-implantitis. Antiseptics are commonly used in the treatment of oral diseases, but their effectiveness against <i>P. gingivalis</i> remains only partially understood. This preliminary study investigated antimicrobial and antibiofilm activity of eight pure antiseptics: boric acid (BA), chlorhexidine (CHX), ethacridine lactate (ET), hydrogen peroxide (H₂O₂), octenidine (OCT), polyhexanide (PHMB), potassium permanganate (KMnO₄), and sodium hypochlorite (NaOCl), as well as five commercial rinses containing these agents, against periopathogen <i>P. gingivalis</i> ATCC 33277. <b>Methods:</b> Minimal inhibitory concentrations (MICs) were determined using the broth microdilution method. The Clinical Efficiency of MIC (CEMIC) was subsequently calculated. Antibiofilm activity was evaluated using the crystal violet method, LIVE/DEAD fluorescence assay and by measuring biofilm thickness with digital microscopy in combination with the author's Python-based application Biofilm Thickness Analyzer. <b>Results:</b> OCT, CHX, PHMB and ET showed the strongest activity against <i>P. gingivalis</i>, in both its planktonic and biofilm forms. H₂O₂ and BA had variable MIC efficacy and moderate antibiofilm activity. In contrast, NaOCl and KMnO₄ demonstrated the weakest activity or no significant effect against <i>P. gingivalis</i>. <b>Conclusions:</b> The results have a translational dimension, supporting the potential clinical relevance of the selected compounds. However, this study was conducted strictly in vitro on a single strain under monomicrobial biofilm conditions. Therefore, while the findings suggest that mouthwashes containing OCT, CHX, and PHMB may be effective against <i>P. gingivalis</i>, their actual clinical efficacy in the treatment and prevention of oral diseases remains to be confirmed in in vivo studies.