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Clinical outcomes and prognostic factors in endodontic treatment: a systematic review from 2002-2022

British Dental Journal (2025)Cite this article

Abstract

Objective This systematic review evaluates prognostic factors influencing the success of endodontic treatments for apical periodontitis over two decades (2002-2022), identifying key clinical variables affecting outcomes in primary and non-surgical retreatments.

Materials and methods A comprehensive literature search following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines was conducted in PubMed, Scopus, ScienceDirect and Embase (January 2002 to December 2022). Studies meeting strict inclusion criteria and focusing on clinical and radiographic outcomes were analysed. Risk assessment was performed using version two of the Cochrane risk-of-bias tool for randomised trials and the Newcastle-Ottawa scale for longitudinal studies. Factors evaluated included pre-operative, intra-operative and post-operative aspects.

Results In total, 13 studies met the inclusion criteria. Apical periodontitis before treatment significantly reduced success rates. Other influential factors included pulp condition, lesion size and the length and quality of previous fillings. The two randomised trials showed concerns about intervention bias and underreporting, while three of eleven longitudinal studies had a moderate risk of bias.

Conclusions This review emphasises the multifactorial nature of endodontic success and highlights the importance of apical periodontitis and other pre-operative factors for treatment prognosis. It suggests that a comprehensive approach considering these factors is crucial for improving treatment outcomes in endodontic practice.

Key points

  • Apical periodontitis is the most critical prognostic factor. The presence of pre-existing apical periodontitis significantly reduces the success rates of both primary endodontic treatments and non-surgical retreatments. Additionally, other pre-operative factors, such as pulp condition, lesion size and pre-treatment complications, also influence treatment outcomes.

  • The quality of root canal filling and coronal restoration significantly affects success. Properly filled root canals (0-2 mm from the apical limit) and high-quality coronal restorations are closely linked to improved treatment outcomes. Inadequate obturation, overextended fillings, or poor restorations heighten the risk of failure.

  • Heterogeneity in study design prevents meta-analysis. The variability in study methodologies, inclusion criteria and follow-up periods limits direct statistical comparisons. This systematic review emphasises the need for future research with standardised protocols to enable more reliable meta-analyses and enhance evidence-based clinical decision-making.

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Data availability

The datasets generated and analysed during the current study are available from the corresponding author upon reasonable request.

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Author information

Authors and Affiliations

  1. Department of Endodontics, Rey Juan Carlos University, Madrid, Spain

    Rocío Piñas-Alonzo, Celia Vinuesa-Maqueda & Alejandro R. Pérez

  2. Department of Endodontics, Universidad de Carabobo, UC, Valencia, Venezuela

    Rebeca Bello & Andrés Hernández

  3. Department of Operative Dentistry, School of Dentistry, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, Brazil

    Mariane F. L. S. Lacerda

  4. Member of Surpreendente for Education Group, Weston, USA

    Omar Pérez-Ron

  5. Department of Endodontics, Universidad Central de Venezuela (UCV), Caracas, Venezuela

    Isis González Graterol

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  1. Rocío Piñas-Alonzo
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  2. Rebeca Bello
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Contributions

All authors contributed to the study's conception and design. RPA: conceptualisation, investigation, data curation, software. RB: investigation, data curation. AH: investigation, data curation. MFLSL: data curation, software. CVM: investigation. OPR: conceptualisation. IGG: reviewing and editing. ARP: writing - reviewing and editing, conceptualisation, supervision.

Corresponding author

Correspondence to Alejandro R. Pérez.

Ethics declarations

The authors deny any conflicts of interest. As no human participants, and no human or animal teeth, tissues, or cells were used, it was not necessary to obtain an ethics committee approval or consent to conduct the current study. PROSPERO protocol number: CRD42024510849.

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Piñas-Alonzo, R., Bello, R., Hernández, A. et al. Clinical outcomes and prognostic factors in endodontic treatment: a systematic review from 2002-2022. Br Dent J (2025). https://doi.org/10.1038/s41415-025-8639-x

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