The effect of different needle-insertion depths on the accuracy of the Root ZX II and Root ZX mini apex locators in the presence of various irrigants

Background and aim: the aim of the present study was to evaluate the effect of different needle-insertion depths onthe accuracy of the root zx ii and root zx mini apex locators in the presence of various irrigants.methods: ninety extracted single-canal human teeth were used in nine experimental groups. the coronal one-third ofthe canals was preflared, and the length to the major foramen was determined visually under a microscope. the teethwere embedded in an alginate model. naocl concentrations of 5.25%, 2.60%, and 2.00% chlorhexidine with threeendodontic needles (21, 25, and 30 gauges) were delivered into the root canals of teeth in each group. electronic lengthwas determined with both devices using k-files of size 10. the results obtained with electronic apex locators werecompared with the corresponding actual length. a multivariate linear regression model was used to determine thevariables influencing the accuracy of the root zx ii and root zx mini apex locators.results: irrigant solution concentrations had no effect on the accuracy of the measurements with these locators(p = 0.83). the statistical analysis of the results showed eal accuracy to be 100% for both root zx and root zx mini,within a tolerance of ± 0.5 mm. data were analyzed by anova. multivariate linear regression model demonstratedthat needle-insertion depths influenced the electronic measurements (p = 0.05), while the concentrations of irrigants didnot influence the results.conclusion: under the conditions of this ex vivo study, needle-insertion depths influenced the electronic measurements.