The goal of this randomized clinical trial is to evaluate whether different root canal preparation systems and sealer types affect postoperative pain after root canal treatment in adult patients (18-60 years) with asymptomatic irreversible pulpitis in mandibular premolars.

The main questions it aims to answer are:

Do different instrumentation systems (TruNatomy vs ProTaper Gold) influence postoperative pain levels? Do different sealer types (AH Plus vs TotalFill BC) affect postoperative pain and analgesic consumption? Researchers will compare TruNatomy and ProTaper Gold systems combined with AH Plus or TotalFill BC sealers to determine their effect on postoperative pain.

Participants will:

Undergo single-visit root canal treatment using one of the assigned file system and sealer combinations Record their pain levels using a Numerical Rating Scale (NRS) at specific time intervals (6, 12, 24, 48, 72 hours, and 7 days) Take ibuprofen only if needed and record analgesic intake Attend a follow-up visit on the 7th day

Postoperative pain remains a significant concern in endodontic treatment, even in cases of asymptomatic irreversible pulpitis. Although root canal therapy is highly effective, patients may experience discomfort due to mechanical, chemical, or microbial irritation of periapical tissues during treatment. Among these factors, the type of instrumentation system and root canal sealer may influence the degree of postoperative pain through their effects on debris extrusion, canal shaping characteristics, and biological tissue response.

Minimally invasive instrumentation systems have been introduced to preserve dentin structure and maintain the original canal anatomy. TruNatomy (Dentsply Maillefer) is designed with a slim Ni-Ti wire and regressive taper, aiming to reduce canal transportation and minimize apical extrusion of debris. In contrast, ProTaper Gold (Dentsply Maillefer) features a progressive taper and enhanced cutting efficiency, which may improve shaping ability but could potentially increase the extrusion of debris beyond the apex.

In addition to instrumentation, the chemical composition and biological properties of root canal sealers may influence postoperative outcomes. AH Plus, an epoxy resin-based sealer, demonstrates strong adhesion and dimensional stability. TotalFill BC Sealer, a calcium silicate-based bioceramic material, is characterized by high biocompatibility and bioactivity, including calcium ion release, which may promote favorable tissue response.

This study is designed as a prospective, randomized clinical trial with a factorial structure to evaluate both the independent and combined effects of instrumentation systems and sealer types on postoperative pain. The interaction between these variables will also be assessed to determine whether specific combinations are associated with increased or reduced pain levels.

All treatments will be performed under standardized clinical conditions using a single-visit protocol, with consistent irrigation regimens and obturation techniques to minimize confounding variables. Pain intensity will be recorded at multiple postoperative time points using a validated numerical scale, allowing evaluation of both the intensity and temporal pattern of pain.

The findings of this study are expected to provide clinically relevant evidence regarding the selection of instrumentation systems and root canal sealers to optimize patient comfort following endodontic treatment.

Inclusion Criteria

• Asymptomatic teeth with delayed positive response to thermal and electric pulp testing
• Vital teeth with signs of irreversible pulpitis
• Mature mandibular first or second premolars
• Periodontally healthy teeth Exclusion Criteria
• Patients with systemic conditions (e.g., diabetes, immunocompromised status, pregnancy)
• Antibiotic use within the past month
• Use of analgesics within 7 days prior to treatment
• Known allergy to materials used
• Teeth with periapical lesions
• Non-vital or symptomatic teeth
• Teeth requiring post-core restorations
• Calcified canals, root resorption, or immature teeth