Two endodontic irrigation protocols show similar effect on bacterial contamination during root canal treatment


Elimination of bacteria from the root canal is a key aim of root canal treatment (RoCT). The aim of this study was to compare the results of a non-activated single-irrigation protocol (NAI) that used only 1% Sodium hypochlorite (NaOCl) with a passive ultrasonic multi-irrigation protocol (PUI) that used 1% NaOCl, 17% ethylenediaminetetraacetic acid (EDTA), and 2% chlorhexidine (CHX).

Patients requiring primary RoCT of a posterior tooth with apical periodontitis, which was verified with a radiograph and negative cold test, were eligible for inclusion.  Standard nonsurgical endodontic therapy was performed on both groups in a 2-visit approach by using calcium hydroxide intracanal medicament with patients randomised to either the PUI or NAI protocols. The primary outcome was bacterial cultures taken at 4 time periods, before instrumentation, after irrigation protocol, after CaOH2 medication, and before obturation.

  • 50 teeth in 49 patients were included, 4 patients did not return for 2nd visit obturation.
  • There was no statistical difference between the two groups
    • 21 of 25 teeth (84%) in the PUI group and 20 of 25 teeth (80%) in the NAI group had a negative bacterial culture after the initial irrigation protocols were completed.
    • After intracanal medication with calcium hydroxide 40 of 46 remaining teeth (87%) had a negative bacterial culture. This number increased to 91% after the second instrumentation and irrigation was completed.

The authors concluded

There was no statistical difference between irrigation methods. Each protocol resulted in a high frequency of negative cultures. This high frequency of negative cultures obtained in 1 visit is most likely related to an increased volume and depth of irrigation compared with previously reported protocols.


This trail compares an irrigation protocol involving 3 key agents (NaOCL, EDTA and CHX) ) with a single agent NaOCL  and finds no statistical difference in negative bacterial cultures.  The study provides a great deal of detail regarding the clinical procedures employed, although no power calculation was presented to assess whether the sample size was large enough to detect a difference.

In a recent blog  (Dental Elf 13th Sept 2012) we highlighted the Cochrane review by Fedorowicz et al that compared different endodontic irrigation protocols. In a article by Basrani from the JCDA Express looks at 3 articles that examines three reviews of passive ultrasonic irrigation in endodontics.


Beus C, Safavi K, Stratton J, Kaufman B. Comparison of the effect of two endodontic irrigation protocols on the elimination of bacteria from root canal system: a prospective, randomized clinical trial. J Endod. 2012 Nov;38(11):1479-83. doi: 10.1016/j.joen.2012.07.005. Epub 2012 Sep 5. PubMed PMID: 23063221.

Dental Elf 13th Sept 2012

Basrani B – Is ultrasonic irrigation needed in Endodontics?


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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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