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

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, I = 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.