Silver nanoparticles possess unique physicochemical and biological properties in addition to their antibacterial capabilities. Similarly, zinc oxide nanoparticles have demonstrated antibacterial effects against a wide range of bacteria, including heat and pressure resistant spores. Given these characteristics, it would be valuable to evaluate and compare a new irrigation solution containing nanosilver and nanozinc-oxide particles with sodium hypochlorite. Furthermore, Chitosan Nanoparticles are expected to exhibit enhanced antibacterial activity compared to regular-sized Chitosan due to their ability to penetrate and disrupt microbial cell membranes. Consequently, the current study aims to assess and compare the antibacterial activity of Silver Nanoparticles and Chitosan Nanoparticles, as well as their impact on post-operative pain.

Inclusion Criteria:

• Medically stable healthy patients (category: American society of anesthesiologists class I).
• The patient ranges in age from 20 to 40.
• No sexual orientation
• Necrotic pulp evaluated by thermal or electrical pulp testing.
• Enough crown structure to provide adequate isolation.
• One root and one canal.
• Patients' desire to engage in this research.
• Patients' comprehension of the visual analogue scale (VAS).
• Patients' ability to sign informed consent.

Exclusion Criteria:

• Endodontic treatment for the tooth previously.
• Teeth with poor conditions for using rubber dams.
• Vital pulp tissue was observed throughout the treatment.
• Patients who have a medical condition.
• Teeth with open apices that are immature
• Women who are pregnant or breastfeeding.
• Psychologically disturbed patients.
• Patients having a history of allergy to any of the research drugs were barred from participation.
• A periodontally affected tooth with grade 2 or 3 mobility.