Journal of Dentistry of Tehran University of Medical Sciences 2018. 15(1):1-9.

Minimum Intracanal Dressing Time of Triple Antibiotic Paste to Eliminate Enterococcus Faecalis (ATCC 29212) and Determination of Minimum Inhibitory Concentration and Minimum Bactericidal Concentration: An Ex Vivo Study
Sholeh Ghabraei, Mohammad Marvi, Behnam Bolhari, Parisa Bagheri


Objectives: Enterococcus faecalis (E. faecalis) is the most commonly isolated microorganism from teeth with postoperative infection. Triple antibiotic paste (TAP) has the ability to eradicate microorganisms from the root canal system when used as an intracanal medicament. The aim of this study was to determine the minimum duration of application of TAP required for elimination of E. faecalis from the root canal system and its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in an ex-vivo model.

Materials and Methods: Root canals of 34 extracted human single canal teeth were inoculated with E. Faecalis after instrumentation, and then 4 g of TAP (ciprofloxacin, metronidazole and doxycycline) was mixed with 4.5 mL of saline and applied as intracanal medicament. The teeth were sectioned longitudinally and dentin chips were collected and evaluated to determine the count of bacterial colonies. Micro-dilution broth test was used to assess the MIC and MBC of TAP. Data were analyzed using SPSS version 22 via the Wilcoxon signed rank test.

Results: After seven days of application of TAP as intracanal medicament, E. faecalis was eliminated from the dentinal tubules of the apical half of root canal up to 400 µ depth. The MIC and MBC of TAP in its original concentration were both found to be 16 µg/mL.  

Conclusions: The original concentration of TAP was found to be 5×104 times its MIC. Considering the risk of coronal discoloration of teeth following the use of TAP, application of its lower concentrations is recommended.


Calcium Hydroxide; Doxycycline; Enterococcus Faecalis; Metronidazole

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- Kakehashi S, Stanley HR, Fitzgerald RJ. The Effects of Surgical Exposures of Dental Pulps in Germ-Free and Conventional Laboratory Rats. Oral Surg Oral Med Oral Pathol. 1965 Sep;20:340-9.

- Hargreaves K, Berman L. Cohen's pathways of the pulp. 11th ed., St. Louis, Elsevier. 2016:619-22.

- Chavez De Paz LE, Dahlen G, Molander A, Moller A, Bergenholtz G. Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment. Int Endod J. 2003 Jul;36(7):500-8.

- Mohammadi Z, Farhad A, Tabrizizadeh M. One-visit versus multiple-visit endodontic therapy--a review. Int Dent J. 2006 Oct;56(5):289-93.

- Molander A, Reit C, Dahlen G, Kvist T. Microbiological status of root-filled teeth with apical periodontitis. Int Endod J. 1998 Jan;31(1):1-7.

- Hoshino E, Kurihara-Ando N, Sato I, Uematsu H, Sato M, Kota K, et al. In-vitro antibacterial susceptibility of bacteria taken from infected root dentine to a mixture of ciprofloxacin, metronidazole and minocycline. Int Endod J. 1996 Mar;29(2):125-30.

- Sato I, Ando-Kurihara N, Kota K, Iwaku M, Hoshino E. Sterilization of infected root-canal dentine by topical application of a mixture of ciprofloxacin, metronidazole and minocycline in situ. Int Endod J. 1996 Mar;29(2):118-24.

- American Association of Endodontics. Considerations for Regenerative Procedures. Chicago American Association of Endodontics; Revised 6-8-16. Available at:

- Banchs F, Trope M. Revascularization of immature permanent teeth with apical periodontitis: new treatment protocol? J Endod. 2004 Apr;30(4):196-200.

- Torabinejad M, Turman M. Revitalization of tooth with necrotic pulp and open apex by using platelet-rich plasma: a case report. J Endod. 2011 Feb;37(2):265-8.

- Nosrat A, Homayounfar N, Oloomi K. Drawbacks and unfavorable outcomes of regenerative endodontic treatments of necrotic immature teeth: a literature review and report of a case. J Endod. 2012 Oct;38(10):1428-34.

- Nosrat A, Li KL, Vir K, Hicks ML, Fouad AF. Is pulp regeneration necessary for root maturation? J Endod. 2013 Oct;39(10):1291-5.

- Kahler B, Mistry S, Moule A, Ringsmuth AK, Case P, Thomson A, et al. Revascularization outcomes: a prospective analysis of 16 consecutive cases. J Endod. 2014 Mar;40(3):333-8.

- Kim JH, Kim Y, Shin SJ, Park JW, Jung IY. Tooth discoloration of immature permanent incisor associated with triple antibiotic therapy: A case report. J Endod 2010 Jun;36(6):1086-91.

- Sabrah AH, Yassen GH, Gregory RL. Effectiveness of antibiotic medicaments against biofilm formation of Enterococcus faecalis and Porphyromonas gingivalis. J Endod. 2013 Nov;39(11):1385-9.

- Miles AA, Misra SS, Irwin JO. The estimation of the bactericidal power of the blood. J Hyg (Lond). 1938 Nov;38(6):732-49.

- Sundqvist G, Figdor D, Persson S, Sjogren U. Microbiologic analysis of teeth with failed endodontic treatment and the outcome of conservative re-treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1998 Jan;85(1):86-93.

- Sheykhrezaei MS, Aligholi M, Biglar KH. An in-vitro evaluation of the ability of 5.25% NaOCl in the elimination of Enterococcus Faecalis from root canal. J Dent (Tehran). 2004;1(2):45-8.

- Adl A SSN, Motamedifar M. A comparison between the antimicrobial effect of triple antibiotic paste and calcium hydroxide against Enterococcus faecalis. Iran Endod J. 2012;7(3):149-55.

- Adl A, Hamedi S, Sedigh Shams M, Motamedifar M, Sobhnamayan F. The ability of triple antibiotic paste and calcium hydroxide in disinfection of dentinal tubules. Iran Endod J. 2014;9(2):123-6.

-Thomson A, Kahler B. Regenerative endodontics--biologically-based treatment for immature permanent teeth: a case report and review of the literature. Aust Dent J. 2010 Dec;55(4):446-52.

- Ricucci D, Siqueira JF Jr. Biofilms and apical periodontitis: study of prevalence and association with clinical and histopathologic findings. J Endod. 2010 Aug;36(8):1277-88.

- Saber SD, El-Hady SA. Development of an intracanal mature Enterococcus faecalis biofilm and its susceptibility to some antimicrobial intracanal medications; an in vitro study. Eur J Dent. 2012 Jan;6(1):43-50.

- Thibodeau B, Trope M. Pulp revascularization of a necrotic infected immature permanent tooth: case report and review of the literature. Pediatr Dent. 2007 Jan-Feb;29(1):47-50.

- Sato T, Hoshino E, Uematsu H, Noda T. In vitro antimicrobial susceptibility to combinations of drugs on bacteria from carious and endodontic lesions of

human deciduous teeth. Oral Microbiol Immunol. 1993 Jun;8(3):172-6.

- Akcay M, Arslan H, Yasa B, Kavrik F, Yasa E. Spectrophotometric analysis of crown discoloration induced by various antibiotic pastes used in revascularization. J Endod. 2014 Jun;40(6):84


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