In Vitro Antibacterial and Antibiofilm Effects of Antiseptics and Mouthwashes on Streptococcus mutans.

BACKGROUND

Streptococcus mutans is a key etiological agent of dental caries, and its ability to form biofilms significantly increases resistance to antimicrobial agents. This study evaluated the activity of selected oral antiseptics against both planktonic and biofilm forms of S. mutans.

METHODS

Seven pure antiseptic compounds and nine commercially available mouthwashes were tested. Minimal inhibitory concentrations (MICs) were determined using a microdilution method, and their clinical relevance was assessed using the Clinical Efficiency of MIC (CEMIC) index. Antibiofilm activity was evaluated using a crystal violet assay and by measuring biofilm thickness using 3D microscopy and the Biofilm Thickness Analyzer application.

RESULTS

The highest antibacterial and antibiofilm activity was observed for octenidine (OCT), chlorhexidine (CHX), and polyhexanide (PHMB), as well as for mouthwashes containing these agents, all showing high CEMIC values. Hydrogen peroxide (H2O2) and fluoride-containing formulations also demonstrated notable activity. In contrast, ethacridine lactate and boric acid showed variable effects, while sodium hypochlorite and potassium permanganate exhibited weak antibacterial activity and no antibiofilm effect.

CONCLUSIONS

OCT, CHX, and PHMB were the most effective against both planktonic and biofilm forms of S. mutans. H2O2 and fluoride-containing formulations also showed promising activity. These findings support the role of selected antiseptics in reducing dental plaque formation, a key factor in the development of oral diseases.