Not all electronic foramen locators are accurate in teeth with enlarged apical foramina: an in vitro comparison of 5 brands

Abstract

Introduction: Electronic working length measurement during root canal treatment in teeth with enlarged apical foramina is a challenge. The aims of this in vitro study were (1) to assess the influence of foramen widening on the accuracy of 5 different electronic foramen locators (EFLs) and (2) to compare the accuracy of EFLs in different foramen sizes.

Methods: The following EFLs were used: MiniApex, Root ZXII, iPex, Propex II, and Elements Apex Locator. Each EFL was used in 3 groups (n = 20) of extracted teeth, with foramen diameters of 0.27 mm (G27), 0.47 mm (G47), and 0.72 mm (G72). Working length was measured according to manufacturer's instructions and compared with visual measurements (control method). Results were classified as accurate (equal or differences ≤ 0.05 mm) or inaccurate (differences > 0.5 mm).

Results: In G27, all EFLs yielded accurate findings (intragroup reliability; Fisher exact test, P < .05), compared with only MiniApex, Root ZXII, and Elements Apex Locator in G47 and G72. MiniApex, Root ZXII, and Elements Apex Locator were similarly accurate regardless of foramen size. iPex and Propex II were the least accurate among the devices tested, and foramen diameter influenced their accuracy, with greater diameters yielding poorer EFL performance.

Conclusions: Foramen diameter did not influence the accuracy of MiniApex, Root ZXII, and Elements Apex Locator EFLs. iPex and Propex II showed decreased accuracy as foramen size increased.

Keywords: Apical foramen; apical widening; electronic apex locator; file size; root canal instrumentation; root length determination.