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.