This study aimed to investigate the extent of apical transportation following instrumentation with EdgeEvolve rotary instruments applying single-length and crown-down techniques.In this experimental in-vitro study, 60 mandibular molars with mesiobuccal curvatures of 20°-40° were selected, and digital radiographic images were taken. Teeth were randomly assigned into two groups of single-length and crown-down preparation techniques. In both mentioned groups, EdgeEvolve rotary system was used. After preparation, the same as the previous ones, digital radiographic images were taken from the canals. The data were analyzed using Student' t-test and ShapiroWilk normality test (P = 0.05).The mean standard deviation (SD) for apical transportation in the single-length and the crown-down group was 4.42 (2.9) and 7.48 (3.9) degrees, respectively (Using EdgeEvolve rotary instruments canal preparation with both single-length and crown-down techniques led to some degrees of apical transportation.
