Root canal treatment outcomes and pulpal status


Root canal treatment is a commonly undertaken in teeth with compromised pulpal tissue in order to maintain the tooth as a functional unit. Worldwide it is estimated that around 55% of people have undergone root canal treatment (Dental Elf – 21st Sep 2022). While there are challenges in making accurate pulpal diagnosis (Dental Elf – 15th Jun 2022) the health of the pulp is considered to influence the outcome of treatment.

The aim of this review was to compare the effectiveness of root canal treatment outcomes in teeth with a vital pulp versus a necrotic pulp.


A protocol was registered on the PROSPERO database. Searches were conducted in the Embase, PubMed, Scopus, Google Scholar (first 100 returns), Networked Digital Library of Theses and Dissertations, Open Access Theses and Dissertations, DART-Europe E-theses Portal—DEEP,  and Opening access to UK theses— EThOS  databases supplements by hand searches of the journals, International Endodontic Journal and Journal of Endodontics. Randomized control trials (RCTs), comparative clinical trials— nonrandomized and longitudinal observational studies (retrospective and prospective comparative cohort and case–control studies with a minimum of 20 patients published in English were considered.  Two reviewers independently conducted the searches and data abstraction. Risk of bias was assessed using a customised version of the Newcastle–Ottawa Quality Assessment Scale for case-control studies. Effects of pulpal status were estimated and expressed as risk ratio (RR) using fixed- and random-effect meta-analyses. The quality of evidence was assessed through the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool.


  • 28 studies were included.
  • 9 studies were considered to be at low risk of bias, 2 at high risk with 17 having some concerns.
  • None of the studies reported a significant association between pulpal status and tooth survival outcome, regardless of the duration of follow-up.
  • 5 studies compared tooth survival at 2 – 10 years post-op in teeth with vital versus necrotic pulp with 4 studies reporting that pulpal status was not a predictor consistent with meta-analysis, risk ratio (RR) = 1.00 (95%CI; 1.00 to 1.00) [3 studies].
  • 7 studies compared post-op pain at 7 days to 3 months.
  • 19 studies reported on evidence of apical radiolucency at 1–30 years post treatment.
    • Meta-analysis [17 studies] indicated a statistically significant effect in favour of root canal treatment in teeth with vital pulps, RR= 1.09 (95%C; 1.05 to 1.13)
  • No studies reported on tooth function, need for further intervention, adverse effects, or oral health related quality of life (OHRQoL).


The authors concluded: –

There was no significant difference in the “tooth survival,” “postoperative pain” and “evidence of apical radiolucency” outcomes of root canal treatment in teeth with vital or necrotic pulps.


This review was undertaken as in order to inform the development of new guidelines for the European Society of Endodontology (ESE). A protocol was lodged with the PROSPERO database and searches undertaken in a broad range of databases. A range of studies designs were included but restriction of inclusions to publications in English may have excluded some relevant studies. Only 9 of the 28 included studies were considered to be at low risk of bias which should be taken into consideration when interpreting the findings. None of the 28 included studies reported a significant association between pulpal status and tooth survival with a meta-analysis of 4 studies supporting this finding. Although a meta-analysis of 19 studies did demonstrate significantly lower periapical radiolucencies in teeth with vital pulps. No studies reported on more patient focussed outcomes such as adverse effect, tooth function or OHRQoL. Future studies should be prospective, well conducted and reported and use common outcomes to facilitate future review. Studies should also involve the primary care setting as a majority of the studies included in this review were in hospital or institutional settings.


Primary Paper

Rossi-Fedele G, Ng YL. Effectiveness of root canal treatment for vital pulps compared with necrotic pulps in the presence or absence of signs of periradicular pathosis: A systematic review and meta-analysis. Int Endod J. 2022 Sep 15. doi: 10.1111/iej.13833. Epub ahead of print. PMID: 36107038.

Review protocol in PROSPERO

Other references

Dental Elf – 21st Sep 2022

How common is root canal treatment?

Dental Elf – 13th Jun 2022

Primary root canal treatment success rates

Dental Elf – 15th  Jun 2022

Pulpitis – How effective are diagnostic tests?




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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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