Evaluation of the Effects of Different Irrigation Solutions and Activation Methods on Postoperative Pain and Quality of Life in Root Canal Treatment

The primary aim of this prospective randomized controlled clinical trial is to evaluate the effects of two different irrigation solutions (2.5% NaOCl and HEDP) and three different activation methods (conventional syringe, EDDY, diode laser) on postoperative pain and oral health-related quality of life in single-visit root canal treatment of asymptomatic mandibular molars, aiming to overcome the limitations of conventional irrigation. Additionally, the study will compare patients' oral health-related quality of life before treatment and one week after treatment. While no significant difference in postoperative pain is expected, an improvement in quality of life is anticipated.Eligible participants will be adult patients requiring endodontic treatment of asymptomatic mandibular molars. After meeting inclusion criteria and providing informed consent, participants will be randomly assigned to six different groups. Randomization will be performed using a computer-generated random number sequence and the codes will be kept in sealed opaque envelopes to prevent bias between groups.The irrigation protocols and activation methods to be applied in the study are as follows:Irrigation Solutions: 2.5% NaOCl and HEDP (HEDP; Dual Rinse, Medcem GmbH, Weinfelden,Switzerland)Activation Techniques: Conventional syringe, EDDY (Micron, Tokyo, Japonya), diode laser Dentsply Sirona Sirolaser Advance; Sirona Dental Systems, Bensheim, Germany)Anesthesia: Regional mandibular block using Articaine-containing MaxicainAll procedures will be performed under rubber dam isolation. Root canal working length will be determined using a #10 K-type file and apex locator, and canals will be shaped using a nickel-titanium rotary system. Each canal will be irrigated according to the assigned protocol, and root canals will be obturated using gutta-percha and an epoxy resin-based sealer with a single-cone technique. Postoperative radiographs will be taken to confirm obturation, and definitive restorations will be completed with composite resin materials.Postoperative pain will be assessed using the Visual Analog Scale (VAS) at 6, 12, 24, 36, 48, 72 hours, and one week after treatment. Quality of life will be measured using the OHIP-14 questionnaire before treatment and one week postoperatively.The study sample size is 90 participants, with 15 volunteers per group. All treatments will be performed by a single operator, and the materials and devices used in the study are standard products routinely used in clinical practice. The expected benefit of the study is to determine the effects of different irrigation solutions and activation methods on postoperative pain and patient quality of life, providing insights for clinical practice.