Root canal retreatment: review suggests microsurgery better than retreatment

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While primary root canal therapy is an established treatment with good levels of clinical and radiographic success outcomes are not always favourable. If this is the case the options are, non-surgical retreatment, surgical endodontic treatment of extraction and/or replacement with a dental implant.

The aim of this study is to evaluate and compare the clinical and radiographic outcomes of nonsurgical root canal retreatment and endodontic microsurgery.


Searches were conducted in the PubMed/Medline, Embase and The Cochrane Library databases. Human clinical studies with a minimum sample size of 20 teeth and 6 months follow up that had clinical and radiographic assessment of success/failure were considered. Only English language papers were selected. Three reviewers screened the studies and quality assessed using a 10-point checklist. Weighted pooled success rates and 95 % confidence interval (CI) estimates of the outcome were calculated.


  • 18 studies involving 2373 patients were included.
  • There were 11 studies on microsurgery (1175 patients) and 7 on retreatment (1198 patients)
  • 6 of the retreatment studies were prospective, one retrospective.
  • 4 microsurgery studies were RCTs, 3 prospective and 4 retrospective.
  •  The outcomes for each group were pooled separately.
  •  There was a statistically significant difference was between the weighted pooled success rates for the microsurgery group and retreatment group. This was apparent in all follow up periods except those greater than 4 years.
Weighted pooled success rate Microsurgery groupMean (95%CI) Retreatment groupMean (95%CI)
Overall 91.9% (88.1% – 95.7%) 79.7% (73.7% – 85.7%)
< 2 years 95.0% (91.3% – 98.8%) 84.5% (80.4% – 88.6%)
2-4 years 90.4% (86.4% – 94.5%) 71.0% (64.8% – 77.2%)
> 4 years 82.5% (71.3% – 93.7%) 81.7% (76.7% – 86.7%)
  • Weighted pooled success rate for the studies considered higher quality (7 microsurgery studies and2 retreatment studies) were: – 90.4% (95% CI; 86.0% – 94.7%) and 74.3% ( 95%CI; 62.7% – 85.8%) respectively.


The authors concluded

Based on this study, endodontic microsurgery was confirmed as a reliable treatment option with favorable initial healing and a predictable outcome. Further long-term clinical studies investigating endodontic microsurgery and retreatment are needed in the future.


As the authors highlight at the beginning of their discussion this review does not provide a direct comparison between these two approaches of managing a failed root canal treatment. Each of the approached have been combined separately to provide a success rate for each method. Ideally there would be high quality randomised controlled trials (RCTs) comparing the two approaches but these are not available. While about a third of the studies available for the microsurgery group were RCTs there were no RCTs for retreatment.

Recently we looked at a review that compared microsurgery with implant placement after failed root canal treatment (Dental Elf – 15th Oct 2014) that review also did not have any direct comparisons. Torabinejad the lead author of that review had published a review in 2009 that also looked at surgical and nonsurgical approaches to endodontic treatment. That also suggested more favourable outcomes with endodontic surgery. A commentary on the 2009 review is available in the Evidence-based Dentistry Journal (EBD-2010).


Kang M, In Jung H, Song M, Kim SY, Kim HC, Kim E. Outcome of nonsurgical retreatment and endodontic microsurgery: a meta-analysis. Clin Oral Investig. 2015 Jan 18. [Epub ahead of print] PubMed PMID: 25595864.

Dental Elf – 15th Oct 2014 – Endodontic microsurgery or single tooth implants after failed root canal treatment

Dental Elf – 21st Feb 2013 – Review finds predictable outcomes with modern endodontic surgery techniques.

Torabinejad M, Corr R, Handysides R, Shabahang S. Outcomes of nonsurgical retreatment and endodontic surgery: a systematic review. J Endod. 2009 Jul;35(7):930-7. doi: 10.1016/j.joen.2009.04.023. Review. PubMed PMID: 19567310.

EBD -2010 – Surgical or nonsurgical treatment for teeth with existing root filings?

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