Effects of Irrigation Activation Systems on Postoperative Pain and Lesion Healing in Single-Visit Retreatment

In this superiority randomized clinical trial with a parallel design, 75 asymptomatic maxillary anterior teeth with 2-5 mm periapical lesions and a history of primary root canal treatment (PRCT) at least four years earlier were included. Patients were randomly assigned, using a randomization sequence generated on www.random.org, and divided into three groups. In all patients, existing canal fillings were removed using Remover rotary file (Coltene, MicroMega) and hand files. Working lengths were determined with an apex locator and canals reshaped using the step-back technique. For the final irrigation, side-vented needles were positioned 2 mm short of the working length. Activation was performed with Ultra X (Eighteeth) in the ultrasonic group, EDDY (VDW) in the sonic group, and an Er:YAG laser (LightWalker, Fotona) in SWEEPS mode (2940 nm, 5 μs, 20 mJ, 15 Hz) in the laser group. In all groups, each irrigant (EDTA followed by NaOCl) was activated in three cycles of 20 seconds. All canals were obturated with gutta-percha and a bioceramic sealer, and restored with composite. Pain levels were recorded using the Visual Analog Scale (VAS) 0, 6, 12, 24, 48, and 72 hours, and on day 7. The completed forms were collected by another independent investigator blinded to the group assignments. At the end of the treatment, periapical radiographs were obtained and recorded from all patients. Patients whose treatment was completed will be recalled at the 6th, 12th, and 24th months for follow-up periapical radiographs, and the comparison of healing among the groups will be evaluated as a secondary outcome based on changes in the PAI index.