“…Others considered AE1 mm as ''acceptable'' because of the enormous anatomic variability of the apical region, even though this range might overestimate the precision of the EALs (12,20); >AE1 mm was considered ''mistaken'' measurements because it may result in over-or underinstrumentation of the root canal system (3,7,20,24). In the study herein, the percentage of ''mistaken'' measurements obtained was higher than those previously reported (11,14,15,(19)(20)(21). This may stem from the difference in the methods used to determine the position of the AC.…”