Conventional needle irrigation(CNI) Group: A total of 6 mL of 2.5% NaOCl was delivered in three cycles using a 31-gauge irrigation needle positioned 2 mm short of the working length. Each cycle lasted 20 seconds, followed by a 20-second waiting period. Subsequently, 2 mL of 17% Ethylenediaminetetraacetic acid(EDTA) (Imicryl Dental, Konya, Türkiye) was applied for 1 minute, followed by another 1-minute waiting period, and finally 2 mL of distilled water was used as the final rinse.

Passive ultrasonic irrigation(PUI) Group: Passive ultrasonic activation was performed with an ultrasonic device (Ultra X, Eighteeth, Changzhou, China) using a 20/.02 tip during the waiting periods used in the CNI group. The ultrasonic tip was positioned 2 mm short of the working length and activated vertically with 2-3 mm strokes without contacting the canal walls.

Sonic irrigation(SI) Group: Sonic activation was performed using a polymer tip (Dentsply Tulsa Dental Specialties) loosely fitted into the canal and placed 2 mm short of the working length during the waiting periods used in the CNI group. The tip was activated by vertical in-and-out motion to induce sonic agitation.

Potassium titanyl phosphate(KTP) Laser Group: In this group, after shaping was completed, the final irrigation procedure was carried out as in the CNI group. Following irrigation, the root canals were dried with sterile paper points at the working length. Then, KTP laser irradiation (SMARLITE D, DEKA laser system, Calenzano FI, Italy) was applied in a pulsed mode at 1.5 W power (Ton: 20 ms, Toff: 50 ms). A 200 µm fiber tip attached to the handpiece was inserted 1 mm short of the working length and moved coronally in a spiral motion for 5 seconds. After each 5-second irradiation, a 20-second interval was allowed, and the process was repeated five times. Laser safety protocols were strictly followed, and protective goggles were used by the operator, assistant, and patient.

Root canals will be irrigated using a conventional syringe and needle technique with standard irrigant solutions. This method relies solely on manual delivery without activation devices.

Postoperative pain intensity assessed using the Visual Analog Scale (VAS), ranging from 0 to 100, where 0 indicates no pain and 100 indicates the worst pain imaginable; higher scores indicate greater pain severity