A SEM STUDY OF IN-VIVO ACCURACY OF THE ROOT ZX ELECTRONIC APEX LOCATOR

Twenty-nine unprepared, vital teeth were used to evaluate the accuracy of the Root ZX in locating the root canal foramen, After extraction o f the teeth, a scanning electron microscope analyzed the relation of t he file tip to the foramen, The sample was divided into two groups (Gr oup A and Group B) according to the presence of a normal apical forame n (along the root main axis) or of a lateral foramen (deviating from t he root main axis). With a tolerance level of +/- 0.5 mm, a clinical a ccuracy rate of 82.75% was recorded in the total sample. With a +/- 1. 0-mm tolerance level, an accuracy of 100% was found. The error in loca ting the apex was significantly smaller in cases with a normal apical foramen (Group A) than in cases with a lateral foramen (Group B) (p < 0.001), An accuracy of 100% at the +/- 0.5-mm tolerance level was regi stered in Group A.