This study aims to compare two commonly used root canal instrumentation systems, WaveOne (reciprocating system) and ProTaper (rotary system), in patients diagnosed with symptomatic irreversible pulpitis. Root canal treatment is performed to remove inflamed pulp tissue, disinfect the canal, and relieve pain. However, some patients experience pain after the procedure, particularly within the first few days.

In this randomized controlled trial, 146 patients will be assigned to receive root canal treatment using either WaveOne or ProTaper instruments. All procedures will be performed under standardized clinical conditions by a single operator. Patients will be asked to record their pain levels using a Numerical Rating Scale (NRS) at specific time intervals after treatment, including 6, 12, 24, 48, and 72 hours, and at one week.

The purpose of this study is to determine whether one instrumentation system results in less postoperative pain compared to the other. The findings may help improve patient comfort and guide dentists in selecting the most appropriate root canal instrumentation technique.

Root canal treatment is a commonly performed dental procedure aimed at eliminating inflamed or infected pulp tissue and preventing further periapical complications. Despite advancements in endodontic techniques, postoperative pain remains a frequent concern, particularly in patients with symptomatic irreversible pulpitis.

Mechanical preparation of the root canal system plays a critical role in treatment success. Nickel-titanium (NiTi) instruments are widely used for this purpose and are available in different kinematic systems, including reciprocating single-file systems (such as WaveOne) and continuous rotary multi-file systems (such as ProTaper). These systems differ in their motion, number of files used, and potential for apical extrusion of debris, which may influence postoperative pain.

Previous studies comparing reciprocating and rotary systems have reported inconsistent results regarding postoperative pain outcomes. Some evidence suggests that rotary systems may be associated with reduced early postoperative pain, possibly due to more controlled instrumentation and reduced debris extrusion. However, other studies have found no significant difference between the two systems.

This randomized controlled trial is designed to compare postoperative pain following root canal treatment using WaveOne and ProTaper systems in patients with symptomatic irreversible pulpitis. A total of 146 patients will be randomly allocated into two groups. All treatments will be performed in two visits under standardized clinical conditions by a single operator to minimize variability.

Local anesthesia will be administered, and working length will be determined using an ultrasonic apex locator and radiographic verification. Instrumentation will be performed according to manufacturer guidelines for each system. Irrigation protocols and temporary restoration procedures will be standardized across both groups.

Postoperative pain will be assessed using the Numerical Rating Scale (NRS). Patients will record their pain intensity at multiple time intervals after the procedure. Analgesic intake will also be documented. At the second visit, obturation will be completed using standard techniques.

The primary outcome of this study is the intensity of postoperative pain at different time intervals. Secondary outcomes include the duration of pain and the need for analgesic medication. Statistical analysis will be performed to compare outcomes between the two groups.

The results of this study are expected to provide clinically relevant evidence regarding the effect of instrumentation technique on postoperative pain and may assist clinicians in making evidence-based decisions to improve patient outcomes.

Inclusion Criteria:

Patients aged 18-60 years Patients diagnosed with symptomatic irreversible pulpitis Patients requiring root canal treatment in permanent teeth Teeth with canal curvature ≤25° (assessed using Schneider's method) Patients willing to provide informed consent

Exclusion Criteria:

Patients with systemic illness Pregnant patients Patients with hypersensitivity to nonsteroidal anti-inflammatory drugs Teeth with apical pathology or periapical lesions Teeth with root resorption or internal ankylosis History of dental trauma in the affected tooth Teeth with malposition or severe malocclusion Patients with periodontal disease (periodontal index <3) Patients with trismus or sinus tract Patients with severe anxiety affecting dental procedures

Outcome assessment was performed by blinded evaluators who were not aware of the group allocation. Participants and the operator were not blinded due to the nature of the interventions.