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.
Department of Restorative Dentistry, Faculty of Odontology, Complutense University, Madrid, Spain.
M
M
Azabal
D
D
Garcia-Otero
J C
JC
de la Macorra
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*