Although the available scientific evidence base is short and at considerable risk of bias , it is still possible to conclude that the apical locator reduces the patient radiation exposure and also that the electronic method may perform better on the working length determination .
INTRODUCTION Apical constriction has been proposed as the most appropriate apical limit for the endodontic working length .
Despite being the most used , some limitations are attributed to the radiographic method of working length determination .
It lacks precision because it is based on the average position of the apical constriction .
The electronic apex locators have been presented as an alternative to the odontometry performed by radiography .
These devices detect the transition of the pulp to the periodontal tissue , which is anatomically very close to the apical constriction and may perform with improved accuracy .
Effect of using electronic apex locators on selected endodontic treatment parameters.
The purpose of this study was to determine the effect of using electronic apex locators on the number of radiographs taken and the adequacy in length of the final obturation .  Patients in an undergraduate student endodontics clinic participated in the study . The working length ( WL ) was estimated by the authors for all cases ( 36 teeth ; 58 canals ) , using both a preoperative st and ardized radiograph and an electronic measurement . The students were then asked to place WL files to one of the estimates ( electronic or radiographic ; chosen by r and om assignment ) and take a WL radiograph . Neither the students nor their instructors knew which method was chosen for the estimates . Once treatment was completed , the total number of working radiographs was counted . The number of cases with acceptable ( 0 to 2 mm short of the apex ) or unacceptable obturation was also blindly registered . An electronic estimate of the WL improved length quality of the final obturation , compared with a radiographic estimate . The number of working radiographs taken was less in the electronic apex locator group in anterior and premolar teeth , but not in molars
Although the available scientific evidence base is short and at considerable risk of bias , it is still possible to conclude that the apical locator reduces the patient radiation exposure and also that the electronic method may perform better on the working length determination .
INTRODUCTION Apical constriction has been proposed as the most appropriate apical limit for the endodontic working length .
Despite being the most used , some limitations are attributed to the radiographic method of working length determination .
It lacks precision because it is based on the average position of the apical constriction .
The electronic apex locators have been presented as an alternative to the odontometry performed by radiography .
These devices detect the transition of the pulp to the periodontal tissue , which is anatomically very close to the apical constriction and may perform with improved accuracy .