The clinical observation of the accuracy in molar root canal working length measurement with Propex apex locator.

Objective:To evaluate the accuracy of the Propex apex locator in molar canal working length measurement. Method:102 molars from 50 periodontitis patients were divided into two groups. The root canals of the experiment group and the control group were measured by Propex apex locator and the X-ray respectively. All canals were prepared and filled. The accuracy was evaluated by radiological observation. Result:The successful ratio of root canal therapy of the experimental group was significantly higher than that of the control group(p 0.05). Conclusion:The Propex apex locator is more accurate in the posterior tooth root canal length measuring.