Evaluation of Residual Antibacterial Effect of Human Radicular Dentin Treated with Triple and Double Antibiotic Pastes

• Triple antibiotic paste (TAP) concentrations have a residual antibacterial effect for up to 7 to 14 days.
• Double antibiotic paste (DAP) concentrations have a residual antibacterial effect for up to 14 to 30 days.
• DAP produced a longer residual antibacterial effect compared with TAP.
• 1 mg/mL TAP or DAP has a comparable residual antibacterial effect with 1000 mg/mL.

IntroductionThe aim of this study was to investigate the residual antibacterial effect of human radicular dentin treated with various concentrations of triple antibiotic paste and double antibiotic paste (DAP).MethodsSterilized dentin specimens were randomly assigned to 6 treatment groups and a no-treatment control group (n = 45 per group). For treatment groups, specimens were treated with either TAP or DAP at various concentrations (1000, 1, or 0.5 mg/mL) for 2 weeks. Then, each specimen was irrigated with 5 mL saline and incubated in phosphate-buffered solutions for 3, 7, 14, or 30 days. After that, Enterococcus faecalis was cultured on the specimens for 3 days. Each specimen was then transferred to a tube containing 200 μL saline, sonicated, and vortexed to detach the bacterial biofilm. The detached biofilm was spiral plated, and the number of colony-forming units was determined using an automated counting machine.ResultsDentin specimens treated with 1000 mg/mL TAP or DAP had a significant residual antibacterial effect up to 14 days and 30 days, respectively. No significant difference was observed between 1000 and 1 mg/mL TAP and DAP at all time points. Dentin treated with all concentrations of DAP has a significantly longer residual antibacterial effect compared with dentin treated with TAP at the same concentrations.ConclusionsRadicular dentin treated with TAP and DAP showed a significant residual antibacterial effect compared with untreated dentin. All concentrations of DAP showed a significantly longer residual antibacterial effect compared with the same concentrations of TAP.