Objectives
This study assessed the antibacterial activity of both separate and combined uses of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 17% ethylenediaminetetraacetic acid (EDTA), 3% hydrogen peroxide (H
2
O
2
), MTAD, SmearClear (SC) and 13.8% chlorine dioxide (ClO
2
) irrigation solutions against
Enterococcus faecalis.
Materials and Methods
Two hundred eighty single rooted human premolars were randomly grouped into 26 test and 2 control (negative and positive) groups and were incubated for 24 h with
E. faecalis
, except for the negative control group. The tested solutions were as follow: NaOCl; CHX; ClO
2
; MTAD; SC; EDTA; H
2
O
2
; NaOCl + CHX; NaOCl + MTAD; SC + NaOCl; EDTA + NaOCl; H
2
O
2
+ NaOCl; ClO
2
+ CHX; CHX + MTAD; SC + CHX; EDTA + CHX; CHX + H
2
O
2
; ClO
2
+ MTAD; SC + ClO
2
; EDTA + ClO
2
; ClO
2 +
H
2
O
2
; SC+MTAD; EDTA+MTAD; MTAD + H
2
O
2
; SC + H
2
O
2;
and EDTA + H
2
O
2.
Optic density values were recorded at 0, 6, 12, 18, 24, 30, 36, 42 and 48 h and bacterial growth curve created for each solution.
Results
The CHX, MTAD and ClO
2
showed a high potential for the elimination of
E. faecalis,
both alone and in all combinations. The EDTA, H
2
O
2
, H
2
O
2
+ EDTA, H
2
O
2
+ NaOCl and SC + NaOCl groups showed less antibacterial activity than the other groups. The SC + CHX group showed the best antibacterial effect against
E. faecalis
.
Conclusion
The SC + CHX combination can be recommended as the most effective irrigation regimen against
E. faecalis
in persistent endodontic infections.