Endodontic treatment was performed in posterior teeth with necrotic pulp and periapical periodontitis using a reciprocating single-file system (Reciproc). Local anesthesia was provided (2% Novocaine with 1:80,000 epinephrine), isolation with rubber dam and standard access cavity preparation was done.Using 2.5 % sodium hypochlorite, canal negotiation was done & apical patency was achieved with #10 K-files in patency group after determining working length. Coronal flaring with # 2 and #3 Gates-Glidden drills was done. The canals were obturated with gutta-percha and epoxy resin sealer. The treatments were carried out in one-visit.

In the control group, apical patency did not maintained.

After determining the working length, a small and flexible size 10 K-file was inserted 1 mm beyond the WL.

Pain severity was evaluated as no pain (0-4 mm), mild pain (5-44 mm), moderate pain (45-74 mm) and severe pain (75-100 mm).

The patients were asked to take an analgesic in the 7 days of time frame.