Evaluation of the Antibacterial Effects of Single and Combined use of Different Irrigation Solutions Against Intracanal Enterococcus Faecalis

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.