The effect of dilution and organic matter on the antibacterial property of 5.25% sodium hypochlorite

By Harrison JW, Hand RE

Date: 01/1981
Journal: JOE


  • Purpose: evaluate the effect of dilution on the antibacterial proper- ty of NaOCl, and the effect of organic matter on the antibacterial property of 5.25% NaOCl.
  • N=27 experimental groups for dilution test, 24 for organic matter effect.
  • Materials/Methods:

  • 27 paper points were infected with Strep faecalis . 27sterile beakers, each containing 10 ml of a test solution.
  • Paper points were placed in each solution for 5, 10, 30, 45, 60, 90 sec and 2, 5, 15 minutes.
  • Each paper point was placed in trypticase soy broth, inspected for turbidity after 72 h, then all tubes were subculture on plate for 96 h, gram stained
  • the effect of organic matter was assessed by preparing 3 organic matter at a ratio of 10mg/1 ml of NaOCl. Each solution was tested .subculturing done.
  • antibacterial activity. 5.25, 2.5, 1, 0.5% NaOCl, 3% H2O2, 3% H2O2 /5.25% NaOCl (equal volumes), normal saline.
  • Most highlighted Results:
  • Dilution has significant effect on antibacterial properties of NaOCl.(table1)
  • Albumen did not affect antibacterial activity, while blood enhanced it, and yeast inhibited the action.(table2)


Clinical significance:

With lower concentration of NaOCl more time is needed to disinfect the canal.