Enterococcus faecalis (E. faecalis) has been reported as one of the most important causes of failed endodontic treatments. Various antibacterial agents have been suggested to remove E. faecalis from the root canal. We aimed to investigate and compare the antibacterial efficacy of silver diamine fluoride (SDF), Sodium hypochlorite (NaOCl) and ozone gel on E. faecalis in the root canal.

Materials and Methods:

This study involved 60 extracted roots of molar teeth with a single root canal to generate a 6-week-old biofilm for evaluating antibacterial effects. After teeth decorating and removing the smear layer using sodium hypochlorite (2.5%) and EDTA (17%), roots were sterilized by autoclave. Under sterile conditions, 1 ml of the suspension containing E. faecalis bacteria was transferred to each of the microtubes containing teeth. The samples were divided into four groups: exposed to NaOCl (2.5%) as a positive control, exposed to liquid ozone (25 ppm), exposed to SDF (3.8%), and exposed to normal saline as a negative control group. Then, the colony forming unit (CFU) was counted in the studied groups. Kruskal-Wallis test and Dunn-Bonferroni post-hoc analysis were carried out for comparison of CFU in the studied groups.


The mean of CFU were 17846, 920, 234, and 336 for saline, ozone, NaOCl, and SDF, respectively. There were significant differences in CFU in the comparison of (NaOCl-Ozone), (NaOCl-saline), (SDF-saline), and (ozone-saline) (P< 0.05). However, there was no significant difference for CFU in the comparison of NaOCl-SDF (P= 0.570).


The study findings showed that NaOCl (2.5%) and SDF (3.8%) were more effective against the 6-week-old E. faecalis biofilms than ozone and saline.

Keywords : Antibacterial agents, Enterococcus faecalis, Root Canal Therapy, Deciduous Teeth, Silver Diamine Fluoride, Endodontic Treatment.
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