The aim of this in vitro study was to evaluate the cleaning efficacy of various irrigation methods in the mandibular mesial roots. The forty five mesial root canals were shaped by Profile .06 instruments to apical size #30 and irrigated with 5 ml of 3.5% NaOCl. The teeth were divided into 3 groups and irrigated finally for 1 minute; Group 1: syringe irrigation, Group 2: ultrasonic irrigation, Group 3: RinsEndo irrigation.

After histological processing, the cross sections of apical 1, 3, and 5 mm level were examined with an optical microscope. The cleanliness values of canals and isthmuses were calculated and analyzed by Mann-Whitney U test.

There were no significant differences in both canal and isthmus cleanliness between syringe irrigation and ultrasonic irrigation except 5 mm level of isthmus.

The aim of this study was to evaluate the retrievability of Resilon as a root canal filling material. Twenty-seven human single-rooted extracted teeth were instrumented utilizing a crown down technique with Gates-Glidden burs and ProFile system. In group1 (n = 12) canals were obturated with gutta percha and AH-26 plus sealer using a continuous wave technique and backfilled. In group 2 (n = 15) Resilon was used as a filling material. Then teeth were sealed and kept in 37℃ and 100% humidity for 7 days. For retreatment, the samples were re-accessed and filling material was removed using Gates-Glidden burs and ProFiles. Teeth were sectioned longitudinally to compare the general cleanliness and amount of debris (× 75) using SEM. Chi-square test was used (α = 0.05) to analyze the data. The total time required for removal of filling materials was expressed as mean ± SD (min) and analyzed by the Student t-test (α = 0.05). Required time for retreatment was 3.25 ± 0.32 minutes for gutta percha/AH 26 plus sealer and 3.05 ± 0.34 minutes for Resilon. There was no statistically significant difference between the two experimental groups. There was no significant difference between the groups in the cleanliness of the root canal wall. This study showed that Resilon was effectively removed by Gates-Glidden burs and ProFiles.