(PR51) Influence of Acidic Environment on Antimicrobial Activity of Different Calcium Silicate-based Endodontic Sealers

Abstract:

Objective: To investigate the antibacterial activity of calcium silicate-based-sealers (CSBSs) against E. faecalis biofilm in a neutral or acidic condition.

Methods: Dentin cylinders (4 mm length) were prepared and infected with 3 week-old E.faecalis. The samples were filled with BioRoot RCS (BioRoot), Endosequence BC (ES), and NeoMTA Plus (NMTA) and incubated in either neutral or acidic conditions for 7 days (n=10/group). Sterile or infected samples alone were used as positive and negative control (n=5/group). The root canal sealers were removed after 7 days, and the remaining bacteria on dentinal walls were determined by colony-forming units (CFUs/ml) and three samples from each group were visualized under a confocal laser scanning microscope (CLSM). The pH was also measured (n=3/group) after 4 h and 7 days of incubation at 37°C in both conditions.

Results: In the neutral condition, all sealers resulted in a significant decrease in the log-CFU values (p < 0.05). The antibacterial activity of CSBSs was similar in neutral conditions (p>0.05) while CSBSs, especially ES and NMTA reduced its antibacterial effect in the acidic condition (p>0.05). CSBSs in the presence of dentin had a pH of 8.2-8.8 after 7 days in neutral condition and decreased the pH values in acidic condition except BR.

Conclusions: All CSBSs showed similar antibacterial activity in neutral conditions while acidic pH had a reducing antibacterial effect on CSBSs.