Clinical trials

This randomized controlled clinical trial aims to evaluate the effect of the number of rotary files on working length negotiation and postoperative pain in the second mesiobuccal (MB2) canals of maxillary first molars. Patients are assigned to one of four groups according to the number of rotary files used: single-, two-, three-, or four-file systems. Postoperative pain is assessed on each of the seven consecutive postoperative days (Days 1-7) using a visual analog scale (VAS), and working length negotiation success is recorded during canal instrumentation.