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Conventional methods and electronic apical locator in determining working length in different primary teeth: systematic review and meta-analysis of clinical studies

Evidence-Based Dentistry volume 26, page 116 (2025)Cite this article

Subjects

Abstract

Aim

The aim of the current systematic review was to investigate differences in the measurement of working length in primary teeth between electronic apex locators (EAL) and radiographic methods (conventional radiography [CR] and digital radiography [DR]).

Methods

A systematic search was conducted in six electronic databases (Medline via PubMed, Web of Science, Science Direct, Virtual Health Library, Scopus and Cochrane Database of Systematic Reviews). Gray literature and reference lists of included studies were also examined. The guiding question of the study was formulated using the PECO strategy (Population, Exposure, Comparator, Outcome): P: primary teeth submitted to pulpectomy; E: measurement of working length using the radiographic methods; C: measurement of working length using electronic apex locator; O: difference in working length. The methodological quality (QUADAS-2) and certainty of the evidence (GRADE) were assessed. Meta-analyses were performed, e foram considerados os tipos de radiografia, grupo de dentes, geração de localizadores apicais. I² statistics were calculated.

Results

Twenty-five studies were included in the review. Of these, eighteen studies were eligible for meta-analysis. Most studies demonstrated fair methodological quality. The working length measured using CR was, on average, 0.52 mm greater when compared to EAL (95% CI: 0.15–0.89, I2 = 75%). When comparing EAL and DR, no statistically significant difference was found (MD = 0.06 mm, 95% CI: –0.12 to 0.24; I2 = 0%). The majority of articles (n = 20) were considered to have fair quality and five had high quality.

Conclusions

The findings of the present review demonstrate a difference in the measurement of working length using CR in comparison with EAL. No difference was found between the EAL and DR methods. The certainty of the evidence was considered low for all outcomes.

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Data availability

The data supporting this article can be made available by the corresponding author upon request.

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Funding

This study was partially supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for supporting academic and professional development. This study was financed in part by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (Capes)—Finance Code 001, The Research Foundation of the State of Minas Gerais (FAPEMIG) APQ: 03370-15 and the National Council for Scientific and Technological Development (CNPQ), Brazil.

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Authors and Affiliations

  1. Department of Dentistry, Faculty of Biological and Health Sciences, Federal University of Vales do Jequitinhonha and Mucuri, Diamantina, Brazil

    Priscila Seixas Mourão, Luana Viviam Moreira, Gabrielly Fernandes Machado, Saulo Gabriel Moreira Falci, Glaciele Maria de Souza & Maria Letícia Ramos-Jorge

  2. Department of Oral Health for Children and Adolescents, Faculty of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil

    Izabella Barbosa Fernandes

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  1. Priscila Seixas Mourão
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Contributions

PSM, IBF, LVM and GFM worked at methodology, investigation and writing of the article. SGMF worked at conceptualization, methodology, investigation, writing—review and editing supervision. GMS worked at conceptualization; methodology; statistical analysis and writing—review. MLRJ and IBF worked at conceptualization; methodology; writing—review and editing supervision.

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Correspondence to Luana Viviam Moreira.

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Mourão, P.S., Fernandes, I.B., Moreira, L.V. et al. Conventional methods and electronic apical locator in determining working length in different primary teeth: systematic review and meta-analysis of clinical studies. Evid Based Dent 26, 116 (2025). https://doi.org/10.1038/s41432-024-01105-4

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