An in Vivo Evaluation of Root ZX Electronic Apex Locator.

Objective: To evaluate the accuracy of determining root canal length by Root ZX electronic apex locator in vivo. Methods: 49 teeth (70 canals) were obtained from patients waiting to have teeth extracted for orthodontic reason. The teeth were anesthetized, isolated and accessed. Root canal lengths were determined by Root ZX apex locator. After extracted the teeth, accurate canal length of teeth was accessed. The accuracy was compared. Results: By Root ZX apex locator, 84.29%(59/70)were short of apical foramen, 8.57%(6/70)were at the apical foramen, 7.14%(5/70)protruded beyond foramen. With a tolerance level of 0.5mm, an accuracy rate of 64.29% was recorded. With a 1.0mm tolerance level, an accuracy rate of 81.43% was found. With a 1.5mm tolerance level, accuracy was increased to 90%. Conclusion: Root ZX electronic apex locator is an useful and accurate device for the determination of canal length. But it also should be conbined with the exposure of radiograph.