Smear layer removal by different chemical solutions used with or without ultrasonic activation after post preparation

Objectives This study evaluated smear layer removal by different chemical solutions used with or without ultrasonic activation after post preparation. Materials and Methods Forty-five extracted uniradicular human mandibular premolars with single canals were treated endodontically. The cervical and middle thirds of the fillings were then removed, and the specimens were divided into 9 groups: G1, saline solution (NaCl); G2, 2.5% sodium hypochlorite (NaOCl); G3, 2% chlorhexidine (CHX); G4, 11.5% polyacrylic acid (PAA); G5, 17% ethylenediaminetetraacetic acid (EDTA). For the groups 6, 7, 8, and 9, the same solutions used in the groups 2, 3, 4, and 5 were used, respectively, but activated with ultrasonic activation. Afterwards, the roots were analyzed by a score considering the images obtained from a scanning electron microscope. Results EDTA achieved the best performance compared with the other solutions evaluated regardless of the irrigation method (p < 0.05). Conclusions Ultrasonic activation did not significantly influence smear layer removal.