Antimicrobial efficacy of 4.2% sodium hypochlorite adjusted to pH 12, 7.5, and 6.5 in infected human root canals.
OBJECTIVE
The purpose of this study was to determine the antimicrobial efficacy of sodium hypochlorite adjusted to pH 12, 7.5, and 6.5 in human root canals infected by Enterococcus faecalis.


METHODS
One hundred sixty-five human single-rooted teeth were prepared and inoculated with E. faecalis for 48 h. Teeth were divided into 3 experimental groups according to the irrigation pattern used: group 1, 4.2% NaOCl pH 12; group 2, 4.2% NaOCl pH 7.5; and group 3, 4.2% NaOCl pH 6.5. Samples from the root canals were collected, and bacterial growth was analyzed by turbidity of the culture medium.


RESULTS
None of the irrigating solutions used in this study demonstrated 100% effectiveness against E. faecalis. The antibacterial effectiveness of 4.2% NaOCl at pH 6.5 was significantly increased (P = .03) compared with 4.2% NaOCl at pH 12 (chi-squared test: P < .05).


CONCLUSIONS
Bactericidal activity of NaOCl solution is enhanced by weak acidification of 4.2% NaOCl solution at pH 6.5.
Mercade
Montse
M
Department of Endodontics, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Barcelona, Spain. monmer9@hotmail.com
Duran-Sindreu
Fernando
F
Kuttler
Sergio
S
Roig
Miguel
M
Durany
Nuria
N
D000891:Anti-Infective Agents, Local / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D003786:Dental Pulp Cavity / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000187:drug effects*; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009391:Nephelometry and Turbidimetry; D012388:Root Canal Irrigants / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D012973:Sodium Hypochlorite / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use
D000891:Anti-Infective Agents, Local; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite