ABSTRACT
The purpose of this study was to test in an in-vitro model the accuracy of a new multi frequency third generation apex locator Apex NRG blue both in dry and various wet environments. 60 extracted teeth were taken. The teeth were divided into 6 groups of 10 each. The actual length of the root canal of each tooth was determined and then the teeth were embedded in an alginate model. The radiographic working length was determined and later the electronic working length was taken using different irrigating solutions, (3%H2O2, 3%Naocl, 0.2% chlorhexidine, normal saline and 17%EDTA). The results were compared and sent for statistical analysis. This study showed that the new multi frequency electronic apex locator NRG blue is quiet reliable in determining the root canal length both in dry as well as in wet environment.