The effectiveness of passive ultrasonic irrigation and the easy-clean instrument for removing remnants of filling material.

Objective: This study aimed to evaluate the efficacy of passive ultrasonic irrigation (PUI) and the easy clean instrument by micro-computed tomography (CT) for removing remnant filling materials during endodontic retreatment. Materials and Methods: Forty mesial roots of mandibular molars were divided into four groups (n = 10) according to the agitation system and sealer used: Group 1: PUI/AH Plus; Group 2: PUI/TotalFill; Group 3: Easy Clean/AH Plus; and Group 4: Easy Clean/TotalFill. The groups were compared by micro-CT analysis according to the volumes of the obturation and the remaining material before and after the agitation systems were used. Results: There was no difference between the groups for total filling volume and initial and final remaining filling volume (P > 0.05). Conclusions: Both the PUI and easy-clean instrument are effective for removing remnants of filling material with no difference between the groups.