[Accuracy of integrated apex locators in endodontic motors according to the type of file used: comparison between manual and mechanized files].

Objectives: This pilot in vitro analytical observational study evaluated the accuracy of three apex locators-Root ZX mini (Morita), Endo Radar Plus (Woodpecker), and Endo Motor SCM-011 (Fanta)-in determining root canal length, comparing measurements obtained using manual and mechanized files against a reference value obtained through cone-beam computed tomography (CBCT). Materials and Methods: Sixty permanent human teeth were randomly distributed into three groups according to the apex locator used. Root canal length was measured with manual files (without motor) and with mechanized files driven by endodontic motors with integrated apex locator functionality. Absolute errors were calculated in relation to the reference value, and statistical analyses were performed using Student's t-test and ANOVA (p<0.05). Results: Manual files showed a lower mean absolute error (0.253 mm) than mechanized files (0.423 mm), with statistically significant differences (p < 0.0001). Among the apex locators, when using manual files, Endo Radar exhibited higher absolute errors compared to Root ZX mini (p = 0.021) and Endo Motor SCM-011 (p = 0.004), with no significant differences between Root ZX mini and Endo Motor SCM-011 (p = 1.000). With mechanized files, the error rates were similar across the three devices (p = 0.768). Conclusion: Manual files provided more accurate root length measurements than mechanized ones. The Root ZX mini and Endo Motor SCM-011 showed greater accuracy when used with manual files. These preliminary findings highlight the influence of file type and activation mode of the apex locator on the accuracy of root length determination.