Metagenomic Analysis and Postoperative Pain in Infected Root Canals Using Different Irrigation Protocols

Background: Effective bacterial reduction in root canals remains a significant challenge in endodontics due to complex bacterial communities, including species like Enterococcus faecalis that resist conventional treatment methods. Advanced irrigation protocols offer innovative solutions by disrupting biofilms and ensuring deeper penetration of irrigants into apical regions of the canal system. Study Design: This is a randomized, parallel-group clinical trial involving 40 adult patients (18-60 years) requiring root canal treatment for teeth with necrotic pulp and periapical radiolucency. Patients will be randomly assigned to one of four irrigation protocol groups (10 patients per group): Group 1: Ultrasonic Activation Group 2: Laser Activation with methylene blue Group 3: Mechanical Activation (Easy Clean device) Group 4: Negative Pressure Irrigation (PulpSucker device) Procedures: All patients will undergo standardized root canal preparation using rotary nickel-titanium files. Pre-irrigation bacterial samples will be collected before instrumentation, and post-irrigation samples will be collected after the irrigation protocol. All samples will undergo next-generation sequencing (NGS) for metagenomic analysis to assess bacterial reduction and community composition changes. Outcomes: Postoperative pain will be evaluated using the Visual Analogue Scale (VAS) at 6 hours, 24 hours, 48 hours, and 7 days post-treatment. Statistical analyses will compare bacterial reduction efficacy and pain levels across all four groups.