Antimicrobial Activity of Mouthwashes Against Gingival Bacteria

Abstract

Gingivitis is a common inflammatory oral disease caused primarily by the accumulation of dental plaque and associated bacterial pathogens. Mouthwashes are widely used as adjunctive agents for controlling oral microorganisms and preventing periodontal disease progression. This study aimed to evaluate the antibacterial activity of different mouthwash formulations, including Cariax Chlorhexidine DG Fluoride (0.12%), Perio Chlorhexidine DG (0.20%) with 0.1% cetylpyridinium chloride (CPC), 3% hydrogen peroxide (H₂O₂), and nystatin, against gingival-associated bacterial pathogens. The antimicrobial effects of the tested formulations were evaluated against Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, and Escherichia coli using the disc diffusion method. Sterile filter paper discs impregnated with the tested agents were used to determine inhibition zones. The results demonstrated that 3% hydrogen peroxide exhibited the strongest antibacterial activity against all tested bacterial isolates, producing the largest mean inhibition zones against P. aeruginosa (23 mm), S. aureus (41 mm), S. epidermidis (25 mm), K. pneumoniae (29 mm), and E. coli (25 mm), with statistically significant differences compared with other agents. Chlorhexidine formulations showed moderate antibacterial activity, with the 0.20% concentration generally producing greater inhibition than the 0.12% formulation. As expected, nystatin, included as an antifungal negative control, showed no an antibacterial activity against the tested bacterial species. These findings indicate that 3% hydrogen peroxide has strong in vitro antibacterial potential against common gingival pathogens, while chlorhexidine remains an effective antimicrobial agent with prolonged activity. Further clinical studies are required to confirm the effectiveness of these formulations in patients with gingivitis and periodontal disease.