The rubber dam was placed on the tooth and the area was disinfected with chlorhexidine/ethanol (0.5 % / 70 %). Size 30 reamer (distal canal) and 15 reamer (mb canal) and H-file (ml canal) were inserted into the canals to the length previously measured from the preoperative radiograph and a working length radiograph was taken. The canals were prepared with reamers and Hedstroem files to size 50 / 19 mm. The canals were constantly irrigated with 0.5 % sodium hypochorite. At the end of the preparation the canal was irrigated with 17 % neutral EDTA and dried with paper points.

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