Efficacy of a combined nanoparticulate/calcium hydroxide root canal medication on elimination of Enterococcus faecalis.

The purpose of this study was to evaluate the efficacy of Ca(OH)2 with or without a silver nanoparticle suspension to eliminate Enterococcus faecalis from root canals. A total of 66 extracted human single-rooted teeth contaminated with E. faecalis were treated with 10% Ca(OH)2 alone, Ca(OH)2 with nanosilver or sterile water (as a negative control). Samples were obtained with paper points and Gates-Glidden burs at 1 and 7 days after root canal preparation and the number of colony-forming units (CFU) was determined. The number of CFUs observed after dressing with Ca(OH)2  + nanosilver was significantly less than the number observed with Ca(OH)2 alone after 1 or 7 days (P < 0.001, P < 0.001). No differences in antimicrobial properties were observed between the two time points in the Ca(OH)2  + nanosilver group (P > 0.05). Higher antimicrobial efficacy was observed in the Ca(OH)2 group after 7 days than 1 day (P < 0.001). This study highlighted the potential advantage of using a mixture of Ca(OH)2 and nanosilver for intracanal medicament.