comparison of postoperative pain after root canal preparation with two reciprocating and rotary single-file systems: a randomized clinical trial

introduction: root canal preparation techniques may cause postoperative pain. the aim of the present study was to compare the intensity of postoperative pain after endodontic treatment using hand files, single file rotary (oneshape), and single file reciprocating (reciproc) systems. methods and materials: in this single-blind, parallel-grouped randomized clinical trial a total of 150 healthy patients aged between 20 to 50 years old were diagnosed with symptomatic irreversible pulpitis of one maxillary or mandibular molars. the teeth were randomly assigned to three groups according to the root canal instrumentation technique: hand files (control), oneshape and reciproc. treatment was performed in a single visit by an endodontist. the severity of the postoperative pain was assessed by the visual analogue scale (vas) after 6, 12, 24, 48 and 72 h. data were analyzed using the kruskal-wallis and mann-whitney u tests. results: the patients in control group reported significantly higher mean postoperative pain intensity at 12, 24, 48, and 72 h compared to the patients in the two other groups ( p <0.05). there was no significant difference in mean intensity of postoperative pain between reciproc and oneshape at 5 time points ( p >0.05). conclusion: the instrumentation kinematics (single-file reciprocating or single-file rotary) had no impact on intensity of postoperative pain.