PurposeThis study aimed to evaluate the direct and transdentinal antibacterial activity of some synthetic and biomimetic agents against different cariogenic strains.Materials and methods The antibacterial activity of synthetic and biomimetic agents, including chlorhexidine digluconate (CHX) (positive control), sodium hypochlorite (NaOCl), sodium fluoride (NaF), nisin, Biorepair, UltraDex, and distilled water (negative control) against different cariogenic species, including four Streptococcus strains (S); S. mutans, S. sobrinus, S. mitis, and S. sanguinis, and three Lactobacillus strains (L); L. acidophilus, L. gasseri, and L. casei were evaluated using direct and transdentinal diffusion tests. For the transdentinal test, 0.2mm human dentin discs were used, and their permeability was standardized using a modified fluid transport apparatus. Six replicates were made to determine the inhibition zone for each tested agent against each tested bacterial strain. Data were statistically analyzed using a multivariate analysis of variance using a general linear model.ResultsCHX exhibited the highest antibacterial activity against all strains. Nisin showed moderate efficacy, particularly against S. mutans. NaOCl and Biorepair showed similar effects (p=1.000), as did NaF and UltraDex, which were least effective against Streptococcus. Biorepair showed notable transdentinal activity against S. sanguinis and L. acidophilus.ConclusionChlorhexidine remains the reference standard for cavity disinfection. Nisin demonstrated promising efficacy against the tested strains. Biorepair could be successfully recommended in caries management. S. mutans’ marked resistance defines it as a primary target for antimicrobial intervention. Dentin, as a biological barrier, hinders the effectiveness of the tested antibacterial agents and should be considered in treatment planning.
El‐Deeb et al. (2026) studied this question.