After infiltration anesthesia, the access cavity was prepared and the root canals were localised. The rubber dam was applied and the tooth and the working area were disinfected. Vital pulp was found in all roots. Four canals were localised at the beginning. However, after initial cleaning of the pulp chamber a fifth canal was found, the third in the MB root. The working length (WL) was obtained by the help of an apex locator and working length radiograph. WL for MB1, MB2 and DB canals was 20 mm and for P canal 22 mm. The canals were first instrumented with hand files to size 20 under constant one per cent NaOCl irrigation. After the initail preparation, the canals were prepared mechanically by rotating instrument to size 40, the palatinal cabnal was further enlarged to size 55 by hand NiTiflex files followed by 17 % EDTA.

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