Group 3- CanalBrush: The root canals were irrigated with 5 mL 2.5% NaOCl and then brushed with a medium size CanalBrush (Coltene/Whaledent GmbHCo. KG, Langenau, Germany) at 600 rpm for 1 min. A final flush was done with 5 mL 2.5% NaOCl. CanalBrushes were inserted 1 mm short of the WL and moved with small vertical movements.