Accuracy of five electronic foramen locators with different operating systems: An ex vivo study

Objective: the aim of this study was to evaluate,ex vivo,the precision of five electronic root canal length measurement devices (erclmds) with different operating systems: the root zx,mini apex locator,propex ii,ipex,and romiapex a-15,and the possible influence of the positioning of the instrument tips short of the apical foramen. material and methods: forty-two mandibular bicuspids had their real canal lengths (rl) previously determined. electronic measurements were performed 1.0 mm short of the apical foramen (-1.0),followed by measurements at the apical foramen (0.0). the data resulting from the comparison of the erclmd measurements and the rl were evaluated by the wilcoxon and friedman tests at a significance level of 5%. results: considering the measurements performed at 0.0 and -1.0,the precision rates for the erclmds were: 73.5% and 47.1% (root zx),73.5% and 55.9% (mini apex locator),67.6% and 41.1% (propex ii),61.7% and 44.1% (ipex),and 79.4% and 44.1% (romiapex a-15),respectively,considering ±0.5 mm of tolerance. regarding the mean discrepancies,no differences were observed at 0.0; however,in the measurements at -1.0,the ipex,a multi-frequency erclmd,had significantly more discrepant readings short of the apical foramen than the other devices,except for the propex ii,which had intermediate results. when the erclmds measurements at -1.0 were compared with those at 0.0,the propex ii,ipex and romiapex a-15 presented significantly higher discrepancies in their readings. conclusions: under the conditions of the present study,all the erclmds provided acceptable measurements at the 0.0 position. however,at the -1.0 position,the erclmds had a lower precision,with statistically significant differences for the propex ii,ipex,and romiapex a-15.