Evaluation of EDTA, apple vinegar and SmearClear with and without ultrasonic activation on smear layer removal in different root canal levels - Rodrigues, Clarissa Teles; Bernardineli, Norberti; Duarte, Marco Antonio Hungaro; Bramante, Clovis Monteiro; Andrade, Flaviana Bombarda de (Dental Press Endodontics, 2013)