The effect of antimicrobial peptide plantaricin-149 in comparison with chlorhexidine as final root canal irrigant on the reduction of microbial load and postoperative pain in root canals with necrotic pulp - a randomised controlled trial

OBJECTIVES

To compare and evaluate the effect of antimicrobial peptide Plantaricin-149 in comparison with chlorhexidine as final root canal irrigant solution on the reduction of microbial load and postoperative pain

NULL HYPOTHESIS

There will be no difference in bacterial count reduction between two groups of final irrigating solutions and no influence of the final irrigating solutions on postoperative  pain

STUDY PROTOCOL

Local anaesthesia 2% lidocaine with 1:100000 epinephrine will be given. Rubber dam isolation will be done and access cavity preparation will be performed to obtain straight-line canal access. Canal exploration will be done with a size 10 K-file, and working length will be determined using an electronic apex locator and confirmed radiographically. Sample 1 (S1) will be collected using three sterile size-20 paper points inserted sequentially to full working length for 60 seconds each. Root canal instrumentation will then be performed with rotary instruments. After each instrumentation, irrigation will be done with 2 mL of 3% NaOCl using a 30-G side-vented needle, followed by a 3 mL sterile saline rinse. Smear layer will be removed with 5 mL of 17% EDTA and passive ultrasonic activation for 60 seconds, followed by a saline rinse. Patency will be confirmed with a size 20 K-file.

Sample 2 (S2) will be obtained similarly. Final irrigation (5 mL, 90 sec) will be performed using the assigned solution—Group 1: 0.013% Plantaricin 149 peptide, Group 2: 2% Chlorhexidine—followed by passive ultrasonic activation for 60 seconds. Sample 3 (S3) will then be collected as per previous sampling procedures. All paper points from S1, S2, and S3 will be immediately transferred to Cryotubes containing buffer, stored at –20°C, and transported for qPCR analysis. The access cavity will be sealed with a 2 mm temporary restoration.

After 7 days, obturation followed by composite restoration will be done. Postoperative pain will be recorded at 24 h, 48 h, and 7 days using a modified VAS scale (1–none, 2–slight, 3–moderate, 4–severe). Pain reporting will be obtained via scheduled telephone follow-up. Analgesic requirements will be documented, and Ibuprofen 400 mg will be provided in case of emergency.