To evaluate postoperative pain after endodontic treatment of necrotic teeth using large intentional foraminal enlargement (LIFE).

The sample included 60 asymptomatic necrotic teeth (with or without chronic apical periodontitis), and a periodontal probing depth of 3 mm, previously accessed and referred to perform endodontic treatment. After previous procedures, the position and approximate size of the apical foramen (AF) were determined by using an apex locator and K flexo-files, respectively. The chemomechanical preparation was performed with Profile 04 files 2 mm beyond the AF to achieve the LIFE, using 2.5 mL of 2.5% NaOCl at each file change. The filling was performed by Tagger's hybrid technique and EndoFill sealer. Phone calls were made to all the patients at 24, 48 and 72 hours after treatment, to classify postoperative pain. Statistical analysis was performed by different tests with a significance level of 5%.

Age, gender, periradicular status and tooth type did not influence postoperative pain (p > 0.05). Only 1 patient (1.66%) reported severe pain after 72 hours. Moderate pain was reported by 7, 4 and 3 patients after 24, 48 and 72 hours, respectively (p = 0.0001). However, paired analyses showed a statistically significant difference only between 24 and 72 hours (p = 0.04). Sealer extrusion did not influence the postoperative pain (p > 0.05).

Acute or moderate postoperative pain was uncommon after endodontic treatment of necrotic teeth with LIFE.

The Brazilian Clinical Trials Registry Identifier: RBR-3r967t

The aim of this study was to compare smear layer removal by conventional application (CA), passive ultrasonic irrigation (PUI), EasyClean (EC), and XP-Endo Finisher (XPF), using 17% ethylenediaminetetraacetic acid (EDTA) after chemomechanical preparation, as evaluated with scanning electron microscopy (SEM).

Forty-five single-rooted human mandibular premolars were selected for this study. After chemomechanical preparation, the teeth were randomly divided into 5 groups according to the protocol for smear layer removal, as follows: G1 (control): CA of distilled water; G2 (CA): CA of 17% EDTA; G3 (PUI): 17% EDTA activated by PUI; G4 (EC): 17% EDTA activated by EC; and G5 (XPF): 17% EDTA activated by XPF. SEM images (×1,000) were obtained from each root third and scored by 3 examiners. Data were evaluated using the Kruskal-Wallis and Dunn tests (p < 0.05).

In the apical third, there were no statistically significant differences among the groups (p > 0.05). In the cervical and middle thirds, the experimental groups performed better than the control group (p < 0.05); however, G2 presented better results than G3, G4, and G5 (p < 0.05), which showed no differences among one another (p > 0.05).

No irrigation method was able to completely remove the smear layer, especially in the apical third. Using CA for the chelating solution performed better than any form of activation.