Which retrograde root filling material?


Traditional (orthograde) root filling is a very successful procedure although failure rates ranging from 4-15% have been reported.  While orthograde retreatment is the usual choice for failures this may not be indicated so periapical surgery and retrograde root filling can be undertaken. For many years amalgam was the retrograde root filling material of choice although increasingly alternatives such as super ethoxybenzoic acid and mineral trioxide are being used.

The aim of this Cochrane review update was to determine the effects of different materials used for retrograde root filling in children and adults for whom retrograde filling is necessary in order to save the tooth.


Searches were conducted in the Cochrane Oral Health’s Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) Medline; Embase; LILACS; OpenSIGLE; Chinese BioMedical Literature Database; VIP (in Chinese);China National Knowledge Infrastructure; ClinicalTrials.gov (clinicaltrials.gov); World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch; ) and  Sciencepaper Online (in Chinese)databases. This was supplemented by handsearching of the journals; Chinese Journal of Stomatology; Stomatology; West China Journal of Stomatology; Journal of Practical Stomatology; Journal of Clinical Stomatology; Journal of Comprehensive Stomatology; Journal of Modern Stomatology; Chinese Journal of Conservative Dentistry; Journal of Maxillofacial Surgery;  Shanghai Journal of Stomatology; Chinese Journal of Dental Material and Devices; Beijing Journal of Stomatology; Chinese Journal of Dental Prevention and Treatment; Chinese Journal of Orthodontics;  Chinese Journal of Implantology; Journal of International Stomatology; Chinese Journal of Prosthodontics; China Journal of Oral and Maxillofacial Surgery; Chinese Journal of Geriatric Dentistry.  Randomised controlled trials (RCTs) were considered. Standard Cochrane selection and data collection and analysis processes were followed. Outcome measures of success rates and adverse events were classified as dichotomous data and reported as risk ratios (RRs) with 95% confidence intervals (CIs). The GRADE system was used to assess the certainty of the evidence.


  • 8 RCTs involving a total of 1399 patients (1471 teeth) were included.
  • Studies were published between 1995 and 2019.
  • Six retrograde filling material were tested.
  • All 8 RCTs were at high risk of bias.
  • Mineral trioxide aggregate (MTA) versus intermediate restorative material (IRM) [2 studies] shows little to no difference in success rates at 1 year for MTA compared with IRM. RR = 1.09 (95%CI; 0.97 to 1.22) [very low certainty evidence].
  • MTA versus super ethoxybenzoic acid (Super-EBA) [1 study] found little to no difference in success rates at 1 year for MTA compared with Super-EBA. RR = = 1.03 (95%CI; 0.96 to 1.10) [very low certainty evidence].
  • Super-EBA versus MTA [1 study] show Super-EBA may reduce or have no effect on success rate RR = 0.90 (95%CI; 0.80 to 1.01) [very low certainty evidence].
  • Compared to glass ionomer cement (GIC) dentine-bonded resin composite may increase the success rate of the treatment at 1 year. RR = 2.39 (95%CI ;1.60 to 3.59) [ 1 study, very low-certainty evidence].
  • One study (105 teeth) comparing GIC and amalgam indicated GIC may reduce or have no effect on success rate at 1 year. RR = 0.98 (95%CI; 0.86 to 1.12) [very low certainty evidence].
  • 2 studies compared root repair material (RRM) and MTA showing little to no effect of MTA compared to RRM on success rate at 1 year. RR = 1.00 (95%CI; 0.94 to 1.07) [very low certainty evidence].
  • No studies assessed adverse events.


The authors concluded: –

Based on the present limited evidence, there is insufficient evidence to draw any conclusion as to the benefits of any one material over another for retrograde filling in root canal therapy. We conclude that more high-quality RCTs are required.


This Cochrane review updates a previous review (Dental Elf – 9th Jan 2017) and even though there has been an extensive literature search only two additional RCTs have been included.  All the included studies are at high risk of bias and of small size with most of the comparisons included involving single studies. Consequently, there is little good evidence on which to base a choice of retrograde root filling materials and more RCTs are needed. New trials should be larger with longer follow-up times to better assess efficacy and safety. They should be conducted and reported in line with the SPIRIT and CONSORT guidelines.


Primary Paper

Li H, Guo Z, Li C, Ma X, Wang Y, Zhou X, Johnson TM, Huang D. Materials for retrograde filling in root canal therapy. Cochrane Database Syst Rev. 2021 Oct 14;10:CD005517. doi: 10.1002/14651858.CD005517.pub3. PMID: 34647617.10.1002/14651858.CD005517.pub3.

Other references

Cochrane Oral Health Blog – What are the benefits and risks of different materials used for retrograde filling in people who need this treatment in order to save a tooth?

Dental Elf – 9th Jan 2017

Retrograde root filling: insufficient evidence for best material




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