Comparison of the in vivo antimicrobial effectiveness of sodium hypochlorite and chlorhexidine used as root canal irrigants: a molecular microbiology study.
BACKGROUND
The purpose of this clinical study was to compare the antimicrobial effects of 2.5% sodium hypochlorite (NaOCl) and 0.12% chlorhexidine digluconate (CHX) when used as irrigants during treatment of teeth with apical periodontitis.


METHODS
Forty-seven single-rooted single-canal teeth with necrotic pulps and asymptomatic apical periodontitis were selected for this study according to stringent inclusion/exclusion criteria. Bacterial samples were taken at the baseline (S1) and after (S2) chemomechanical preparation using 2.5% NaOCl (n = 30) or 0.12% CHX (n = 17) as the irrigant. Bacterial, archaeal, and fungal presence was evaluated by broad-range polymerase chain reaction (PCR), whereas bacterial identifications were performed by a closed-ended reverse-capture checkerboard approach targeting 28 candidate endodontic pathogens.


RESULTS
All S1 samples were PCR positive for bacterial presence but negative for both archaea and fungi. Both NaOCl- and CHX-based protocols were significantly effective in reducing the bacterial levels and number of taxa. No significant differences were observed between them in all tested parameters including the incidence of negative PCR results in S2 (40% for NaOCl vs 47% for CHX, p = 0.8), reduction in the number of taxa per canal (p = 0.3), and reduction in the bacterial levels (p = 0.07). The most prevalent taxa in S2 samples from the NaOCl group were Propionibacterium acnes, Streptococcus species, Porphyromonas endodontalis, and Selenomonas sputigena. In the CHX group, the most prevalent taxa in S2 were Dialister invisus, Actinomyces israelii, Prevotella baroniae, Propionibacterium acidifaciens, and Streptococcus species.


CONCLUSIONS
Treatment protocols using irrigation with either NaOCl or CHX succeeded in significantly reducing the the number of bacterial taxa and their levels in infected root canals, with no significant difference between these substances.
Department of Endodontics and Molecular Microbiology Laboratory, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
Isabela N
IN
Rôças
José F
JF
Siqueira
D001419:Bacteria / Q000145:classification / Q000187:drug effects; D002710:Chlorhexidine / Q000627:therapeutic use*; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000382:microbiology*; D004202:Disinfectants / Q000737:chemistry / Q000627:therapeutic use*; D006801:Humans; D010485:Periapical Periodontitis / Q000382:microbiology / Q000628:therapy*; D012388:Root Canal Irrigants / Q000737:chemistry / Q000627:therapeutic use*; D012973:Sodium Hypochlorite / Q000627:therapeutic use*; D016896:Treatment Outcome
D004202:Disinfectants; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; D002710:Chlorhexidine