Effects of Sucrose and Farnesol on Biofilm Formation by and .

() and () are frequently detected in the plaque biofilms of children with early childhood caries. This study investigated the effects of sucrose and farnesol on biofilm formation by the oral pathogens and , including their synergistic interactions. Biofilm formation dynamics were monitored using the Cell Index (CI). The CI for increased in the brain-heart infusion medium, peaking at 10 h; however, the addition of sucrose reduced the CI. For yeast cells, the CI increased at sucrose concentrations > 0.5%, peaking at 2 h. Mixed cultures of and yeast cells showed significantly higher CI values in the presence of sucrose, suggesting a synergistic effect on biofilm formation. Farnesol consistently suppressed biofilm formation by yeast cells, even in the presence of sucrose, and higher farnesol concentrations resulted in greater inhibition. Regarding hyphal cells, sucrose did not enhance biofilm formation, whereas farnesol significantly reduced biofilm formation at all concentrations tested. These findings elucidate the complex roles of sucrose and farnesol in biofilm formation by and and emphasize the potential of farnesol as an effective oral biofilm inhibitor.