Residual antibacterial activity of a new modified sodium hypochlorite-based endodontic irrigation solution.

OBJECTIVE In this in vitro study the antibacterial substantivity of a new sodium hypochlorite-based root canal irrigant (Hypoclean) in bovine root dentin was investigated. STUDY DESIGN Ninety dentin tubes prepared from bovine incisor teeth were used. After contamination for 14 days with Enterococcus faecalis, the specimens were divided into five groups as follows: Hypoclean; Tetraclean; 5.25% sodium hypochlorite (NaOCl); infected dentin tubes (positive control); and sterile dentin tubes (negative control). Dentin chips were collected with round burs into tryptic soy broth and after culturing, the number of colony-forming units (CFU) was counted. RESULTS The number of CFU was minimum in the first cultures in all experimental groups, and the results obtained were significantly different from each other at any time period (P < 0.05). At all five experimental periods, the Tetraclean group showed the most effective antibacterial action (P < 0.05). Regular 5.25% NaOCl group showed the worst result at all periods. Hypoclean group demonstrated no bacterial growth after treatment. In each group, the number of CFU increased significantly by time-lapse (P < 0.05). CONCLUSION The residual antibacterial activity of Tetraclean was significantly greater than Hypoclean and 5.25% NaOCl.