Objective To evaluate accuracy of Propex, Raypex R5, Root ZX electronic apex locator in positions of the perforation with different irrigations in the root canal. Methods Perforation lengths were measured with Propex, RaypexR5, Root ZX electronic apex locators in 19 extracted human teeth embedded in model after simulate perforation preparation by ultrasonic ET40 and compared with the actual canal length measurements taken before embedding the teeth in model. Measurements were taken with the different canal contents. Results Propex, RaypexR5, and Root ZX could locate the positions of the perforation with different irrigations in the root canal. The differences between actual root canal perforation length and measured root canal perforation length of same electronic apex locators in different irrigations were no statistically significant（P>0.05）. Meanwhile, the differences between actual root canal perforation length and measured root canal perforation length of three kinds of electronic apex locators in same irrigations were not statistically significant（P>0.05）. Conclusion Propex, RaypexR5, and Root ZX electronic apex locators can detect perforation accurately.
