Antibacterial effect of silver diamine fluoride and potassium iodide against E. faecalis , A. naeslundii and P. micra

Background The aim of this study was to determine in vitro the bactericidal potential of 38% silver diamine fluoride (SDF) alone, potassium iodide (PI) alone, and the two in combination (SDF + PI) against three bacterial species commonly found in root canal samples ( Enterococcus faecalis , Actinomyces naeslundii and Parvimonas micra ). Methods The potential bactericidal rates for SDF, PI and SDF + PI against E. faecalis , A. naeslundii and P. micra were calculated as reduction of bacteria colony forming units. Results The bactericidal potential of SDF was at 99.97–100% against E. faecalis and 100% against A. naeslundii and P. micra . SDF + PI showed a 100% bactericidal effect against P. micra , 99.89–99.98% against E. faecalis and 99.98–100% against A. naeslundii . The bactericidal effect of PI was 99.51–99.98% against E. faecalis , 99.27–99.95% against A. naeslundii and 99.93–100% against P. micra . The differences between controls and bacteria exposed to the antibacterial agents were statistically significant ( p < 0.05). Conclusions SDF had an effective bactericidal effect against the examined bacteria. However, the limitations of this in vitro study do not allow a recommendation of the employment of these solutions as root canal irrigants. Additional investigations are necessary to assess their endodontic clinical applicability.