Abstract
In order to find a simple and effective method for endodontic treatment of recalcitrant cases, the efficacy of ammoniacal silver nitrate was re-evaluated. The modified serial tube dilution method was conducted to determine the effective antimicrobial concentration of ammoniacal silver nitrate on selected test microorganisms and clinical isolates. The effective antimicrobial concentration for the most resistant microorganism, Streptococcus faecalis, was 5.0×10-10 g/ml and the effectiveness persisted for several days. The diffusion ability of 4% ammoniacal silver nitrate into the dentinal tubules from root canal wall was also tested with freshly extracted teeth treated as in routine procedure for root canal therapy. The diffusibility was evident and the extent of infiltration was various, with more infiltration at cervical dentin than at apical one.
