Accuracy of the Justy II Apex locator in determining working length in simulated horizontal and vertical fractures.
OBJECTIVE
To study the effectiveness of an electronic apex locator (EAL; Justy II; Yoshida Dentcraft, Tokyo, Japan) in locating simulated horizontal and vertical fractures in single roots.


METHODS
An EAL was used to measure the distance within the canal of horizontal (n = 31) and vertical (n = 31) fractures, created with a disk in single-rooted teeth. Accuracy of the EAL was evaluated by comparing the measurements with those made using a size 10 file. Data were analysed with the non-parametric Passing and Bablok method.


RESULTS
For simulated horizontal fractures, the EAL measured exactly the same length as a size 10 file, without constant or proportional errors. In vertical simulated fractures, the EAL measured (on average) with a constant error of 7.5 mm shorter than the size 10 file; the difference had a wide confidence interval (-72.3 to 2.6 mm).


CONCLUSIONS
In this laboratory study, the Justy II EAL was able to determine accurately the position of simulated horizontal fractures, but was unreliable when measuring simulated vertical fractures.
Azabal
M
M
Department of Restorative Dentistry, Faculty of Odontology, Complutense University, Madrid, Spain.
Garcia-Otero
D
D
de la Macorra
J C
JC
D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004582:Electronics, Medical; D006801:Humans; D009811:Odontometry / Q000295:instrumentation; D012044:Regression Analysis; D015203:Reproducibility of Results; D018915:Root Canal Preparation / Q000295:instrumentation*; D019227:Tooth Apex / Q000033:anatomy & histology*; D014082:Tooth Fractures / Q000175:diagnosis*; D014092:Tooth Root / Q000293:injuries*