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

Achieving effective root canal disinfection while minimizing postoperative pain is a critical goal in endodontic therapy. Advanced irrigation protocols, such as ultrasonic activation, laser activation, negative pressure irrigation (PulpSucker device), and mechanical activation (Easy Clean device), have shown promise in enhancing bacterial reduction within the root canal system. However, their impact on postoperative pain has not been fully explored. This randomized controlled clinical trial aims to compare bacterial reduction and postoperative pain levels in infected root canals using four different irrigation protocols. The study will use metagenomic analysis to evaluate changes in bacterial community composition and the Visual Analogue Scale (VAS) to assess patient-reported pain levels at multiple time points postoperatively.

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.

Inclusion Criteria: * Adult patients aged 18-60 years * Requiring root canal treatment for teeth with necrotic pulp * Presence of periapical radiolucency confirmed radiographically * Good general health with no systemic diseases affecting healing outcomes * Willing to provide informed written consent * Available for follow-up appointments Exclusion Criteria: * Patients with open apices * Severe periodontal disease * Currently taking antibiotics * Allergy to study materials (lidocaine, sodium hypochlorite, methylene blue, latex) * Pregnant or breastfeeding women * Compromised immunity or systemic conditions (e.g., uncontrolled diabetes, HIV, immunosuppressive therapy) * Previous root canal treatment on the study tooth * Tooth not restorable * Presence of vertical root fracture