The effect of the final irrigant on the antimicrobial activity of root canal sealers

Root canal irrigation is an essential step in root canal therapy as it enables the elimination of microorganisms. The final irrigant may affect the properties of the root canal sealer used during obturation particularly with tricalcium silicate-based sealers, which interact with dentine. The aim of this study was to assess the antimicrobial activity of tricalcium silicate-containing sealers in contact with different irrigants. Furthermore the sealer surface in contact with the irrigant was characterized.

The antimicrobial activity of BioRoot RCS, MTA Fillapex and AH Plus in contact with water, ethylenediaminetetracetic acid (EDTA) and phosphate buffered saline (PBS) was assessed by agar diffusion test and by the intratubular infection test against Enterococcus faecalis. The sealer surface in contact with the three solutions was characterized after 1min contact and also after simulation of in vivo sealer contact with irrigating solution inside a tooth model by grazing angle X-ray diffraction analysis.

Irrigation with EDTA showed the highest antimicrobial properties of the three root canal sealers followed by water without significant differences. The antimicrobial activity of BioRoot RCS was significantly higher than the other sealers after exposition to the three root canal irrigants followed by MTA Fillapex. AH Plus lost its antimicrobial properties after irrigation with water and PBS.

BioRoot RCS showed the greatest antimicrobial activity. The root canal sealers exerted a higher antimicrobial activity when EDTA was used as final irrigant. PBS may be contraindicated as a final irrigant as it reduces the antimicrobial activity of sealers.