 After isolation and access cavity preparation, the initial working length was then determined with an electronic root canal measurement device Root ZX mini; J. Morita, Tokyo, Japan. It was confirmed using periapical radiographs. During the instrumentation, a total of 10 ml of 5 NaOCl were used for irrigation. The irrigation needle NaviTip 31ga needle; Ultradent, South Jordan, UT, USA was placed as deep as possible into the canal without resistance until it was 1 mm short of the predetermined WL.The final irrigation was performed with 5 NaOCl, 17 EDTA, and 2 chlorhexidine. 