IADR Abstract Archives
Antibacterial Properties Of AgNCls/PMAA For Arresting Dental Caries
Objectives: To assess the antibacterial properties of 20% AgNCls/PMAA against two bacterial strains associated with dental caries.
Methods: Streptococcus mutans and Lactobacillus acidophilus obtained from frozen stock were seeded onto blood agar plates. A single bacterial colony was used to inoculate 10 mL of BHI broth, incubated at 37 °C for 24 hours. The bacterial cells were harvested by centrifugation at 5,000 rpm, washed twice with phosphate buffered saline and their optical density was measured at 660 nm using a microplate reader. The cells were then diluted in phosphate buffered saline in 10-fold steps to a final dilution of 10-6. To evaluate Minimum Inhibitory Concentration (MIC), AgNCls/PMAA, was diluted two-fold from 20% to 0.03%; 100 μL of each two-fold dilution, 100 μL of bacterial culture and 100 μL of BHI were added to each well of a 96-well plate. Positive and negative controls were included. Growth was determined by measuring the optical density (OD) of each sample at 660 nm using a spectrophotometer. Agar diffusion tests (ADTs) were used to calculate the minimum bactericidal concentration (MBC) of the solution; 10 μL was removed from the 96-well plate, observed after 24 h of incubation at 37°C and placed onto the BHI agar plates separately, with MBC being the lowest concentration of the substance at which no colonies formed. The bacterial colonies were counted, and the measurements were repeated three times. Colony forming unit (CFU/mL) count was performed using the agar plate count method after incubation at 37 °C for 24 hours under anaerobic conditions.
Results: For MIC, a plateau of the bacterial growth inhibition phase was observed from the 1.25 % dilution upwards, confirming the strong antibacterial capacity of AgNCls/PMAA. MBC results showed 2.5% was the lowest concentration for killing most bacteria for both strains. Log CFU counts for both S. mutans and L. acidophilus in 1.25% AgNCls/PMAA groups were significantly lower than in the control groups (p<0.01).
Conclusions: AgNCls/PMAA presented a powerful antibacterial effect for S. Mutans and Lactobacillus even at low concentrations.
Methods: Streptococcus mutans and Lactobacillus acidophilus obtained from frozen stock were seeded onto blood agar plates. A single bacterial colony was used to inoculate 10 mL of BHI broth, incubated at 37 °C for 24 hours. The bacterial cells were harvested by centrifugation at 5,000 rpm, washed twice with phosphate buffered saline and their optical density was measured at 660 nm using a microplate reader. The cells were then diluted in phosphate buffered saline in 10-fold steps to a final dilution of 10-6. To evaluate Minimum Inhibitory Concentration (MIC), AgNCls/PMAA, was diluted two-fold from 20% to 0.03%; 100 μL of each two-fold dilution, 100 μL of bacterial culture and 100 μL of BHI were added to each well of a 96-well plate. Positive and negative controls were included. Growth was determined by measuring the optical density (OD) of each sample at 660 nm using a spectrophotometer. Agar diffusion tests (ADTs) were used to calculate the minimum bactericidal concentration (MBC) of the solution; 10 μL was removed from the 96-well plate, observed after 24 h of incubation at 37°C and placed onto the BHI agar plates separately, with MBC being the lowest concentration of the substance at which no colonies formed. The bacterial colonies were counted, and the measurements were repeated three times. Colony forming unit (CFU/mL) count was performed using the agar plate count method after incubation at 37 °C for 24 hours under anaerobic conditions.
Results: For MIC, a plateau of the bacterial growth inhibition phase was observed from the 1.25 % dilution upwards, confirming the strong antibacterial capacity of AgNCls/PMAA. MBC results showed 2.5% was the lowest concentration for killing most bacteria for both strains. Log CFU counts for both S. mutans and L. acidophilus in 1.25% AgNCls/PMAA groups were significantly lower than in the control groups (p<0.01).
Conclusions: AgNCls/PMAA presented a powerful antibacterial effect for S. Mutans and Lactobacillus even at low concentrations.