Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis.
OBJECTIVE
This clinical study was undertaken to compare the effectiveness of 2.5% sodium hypochlorite (NaOCl) and 0.12% chlorhexidine digluconate as irrigants in reducing the cultivable bacterial populations in infected root canals of teeth with apical periodontitis.


METHODS
According to stringent inclusion/exclusion criteria, 32 teeth with primary intraradicular infections and chronic apical periodontitis were selected and followed in the study. Bacterial samples were taken at the baseline (S1) and after chemomechanical preparation using either NaOCl (n = 16) or chlorhexidine (n = 16) as irrigants (S2). Cultivable bacteria recovered from infected root canals at the 2 stages were counted. Isolates from S2 samples were identified by means of 16S rRNA gene sequencing analysis.


RESULTS
At S1, all canals were positive for bacteria, and the median number of bacteria per canal was 7.32 x 10(5) for the NaOCl group and 8.5 x 10(5) for the chlorhexidine group. At S2, the median number of bacteria in canals irrigated with NaOCl and chlorhexidine was 2.35 x 10(3) and 2 x 10(2), respectively. Six of 16 (37.5%) canals from the NaOCl group and 8 of 16 (50%) canals from the chlorhexidine group yielded negative cultures. Chemomechanical preparation using either solution substantially reduced the number of cultivable bacteria in the canals. No significant difference was observed between the NaOCl and chlorhexidine groups with regard to the number of cases yielding negative cultures (P = .72) or quantitative bacterial reduction (P = .609). The groups irrigated with NaOCl or chlorhexidine showed a mean number of 1.3 and 1.9 cultivable species per canal, respectively. The great majority of isolates in S2 were from gram-positive bacteria, with streptococci as the most prevalent taxa.


CONCLUSIONS
The present findings revealed no significant difference when comparing the antibacterial effects of 2.5% NaOCl and 0.12% chlorhexidine used as irrigants during the treatment of infected canals.
Siqueira
José F
JF
Estácio de Sá University, Rio de Janeiro, RJ, Brazil. jf_siqueira@yahoo.com <jf_siqueira@yahoo.com>
Rôças
Isabela N
IN
Paiva
Simone S M
SS
Guimarães-Pinto
Tatiana
T
Magalhães
Karen M
KM
Lima
Kenio C
KC
D002710:Chlorhexidine / Q000627:therapeutic use*; D015169:Colony Count, Microbial / Q000379:methods; D003786:Dental Pulp Cavity / Q000382:microbiology*; D006801:Humans; D010485:Periapical Periodontitis / Q000382:microbiology / Q000628:therapy*; D016133:Polymerase Chain Reaction / Q000379:methods; D012336:RNA, Ribosomal, 16S; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D012390:Root Canal Therapy / Q000379:methods; D012973:Sodium Hypochlorite / Q000627:therapeutic use*; D018709:Statistics, Nonparametric; D013234:Stem Cells; D013291:Streptococcus / Q000302:isolation & purification
D012336:RNA, Ribosomal, 16S; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; D002710:Chlorhexidine