Comparative evaluation of antimicrobial activity of three different probiotic oral rinses: An in-vitro study

Objectives: This study aimed to comparatively evaluate the antimicrobial efficacy of three commercially available probiotic formulations against key oral pathogens associated with dental caries and periodontal disease. Methods: An in-vitro study was conducted to assess the antimicrobial activity of Darolac (2.0 mg), Bifilac (0.5 mg), and Econorm (250 mg) against Streptococcus mutans (ATCC 25175) and Porphyromonas gingivalis (ATCC 33277). Probiotic suspensions were prepared in MRS broth, enzyme-treated, and filtered. Antimicrobial activity was evaluated using the agar well diffusion method. Minimum inhibitory concentration (MIC) was determined using broth microdilution, with optical density measured at 630 nm. Streptomycin and ampicillin were used as positive controls. Statistical analysis was performed to compare intergroup differences. Results: All probiotic formulations demonstrated antimicrobial activity against both test organisms. Econorm exhibited the largest zones of inhibition and the lowest MIC values against S. mutans and P. gingivalis (p < 0.05). Darolac showed comparatively greater efficacy against P. gingivalis , whereas Econorm was more effective against S. mutans . Bifilac demonstrated relatively lower antimicrobial activity compared to the other formulations. Conclusions: Among the tested probiotic formulations, Econorm showed the highest antimicrobial efficacy, followed by Darolac and Bifilac. The superior performance of Econorm may be attributed to the presence of Saccharomyces boulardii , which exhibits strong adaptability and inhibitory effects against oral pathogens. Probiotic-based oral rinses may serve as promising adjuncts in periodontal therapy; however, further in vivo studies are required to validate these findings.