Neutralization effect of some agents on the antimicrobial activity of ammoniacal silver nitrate.

The effect of some agents on the antimicrobial activity of ammoniacal silver nitrate, an endodontic medicament, was tested with Streptococcus faecalis by the serial tube dilution method. Its results indicated that sodium hypochlorite, hydrogen peroxide, and blood had a marked inhibitory effect. However, the presence of dentin, necrotic tissue, saliva, and hydrogen sulfide gas liberated from protein decomposition showed no or little effect on the antibacterial properties of the chemical. Since antiseptics or antibiotics generally may be decomposed by necrotic tissues, these findings suggested that the use of ammoniacal silver nitrate not only may resolve the problem of recalcitrant cases in endodontic treatment but also may simplify the disinfecting procedure for root canals.