Effectiveness of three instrumentation systems to remove Enterococcus faecalis from root canals.
OBJECTIVE
To assess the effectiveness of three systems of mechanical preparation to reduce Enterococcus faecalis within root canals.


METHODS
Twenty-four human single-rooted canine teeth were standardized to a length of 17 mm and the canal contents removed using a size 20 K-file, as the last apical file. After irrigation and sterilization, the canals were contaminated with E. faecalis and incubated for 21 days at 37 °C with 5% CO(2). Then, the teeth were divided into three groups for mechanical preparation with: ProTaper rotary system, ProTaper manual system and manual K-files. Samples of the root canal contents, before and after the debridement, were collected with sterile paper points for 1 min. Then, the samples were diluted and plated in Brain Heart Infusion (BHI) agar. The colony-forming units were counted and the percentage reduction calculated. The reduction and log CFU mL(-1) were compared between groups using Wilcoxon nonparametric test and two-way analysis of variance, respectively.


RESULTS
There was a significant reduction in the number of CFU/mL (P = 0.000) before and after debridement for all the systems used. However, there was no significant difference between the systems.


CONCLUSIONS
All the three instrumentation systems reduced E. faecalis counts to a similar degree.
Basic Science Institute, University of Taubaté, Taubaté, São Paulo, Brazil.
M
M
Matos Neto
S S F
SS
Santos
M V P
MV
Leão
S M
SM
Habitante
J R D D
JR
Rodrigues
A O C
AO
Jorge
D058491:Bacterial Load; D001431:Bacteriological Techniques; D003481:Cuspid / Q000382:microbiology; D003786:Dental Pulp Cavity / Q000382:microbiology*; D004492:Edetic Acid / Q000627:therapeutic use; D013293:Enterococcus faecalis / Q000302:isolation & purification*; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D011670:Pulpectomy / Q000295:instrumentation; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013696:Temperature; D013997:Time Factors
D012388:Root Canal Irrigants; D004492:Edetic Acid; D012973:Sodium Hypochlorite