comparison of antimicrobial effects of triple antibiotic paste and calcium hydroxide mixed with 2% chlorhexidine as intracanal medicaments against enterococcus faecalis biofilm

Objectives: the purpose of this in-vitro study was to determine and compare the shortest period needed for a triple antibiotic paste (tap) and calcium hydroxide (ca(oh)2) plus 2% chlorhexidine (chx) to eradicate the biofilm of enterococcus faecalis (ef) from the root canal system. materials and methods: sixty-five extracted single-rooted human teeth with straight root canals were selected. the crowns were cut from the cementoenamel junction (cej), and canal preparations were done by step-back technique. the smear layer was removed by 17% ethylenediaminetetraacetic acid (edta) and 5.25% sodium hypochlorite (naocl). afterwards, the samples were sterilized with gamma ray and were placed inside microtubes for one week. during this week, the teeth were infected with ef. then, a tap and ca(oh)2 mixed with 2% chx were inserted into the canals. the roots were cut longitudinally, and dentin chips were collected from the apical part of the roots by a round bur to the depth of 400 μm. the vital bacterial load was assessed by counting the numbers of colony-forming units (cfus). results: the paste of ca(oh)2 mixed with 2% chx was able to eradicate the ef biofilm in three days. the tap was able to eradicate the biofilm of ef in seven days. conclusions: it seems that ca(oh)2 mixed with 2% chx is more potent than the tap against ef biofilm.