Comparison of the Efficacy of Calcium Hydroxide With Silver Nanoparticle and Conventional Calcium Hydroxide Intra Canal Medications on Post-Operative Pain in Symptomatic Root Canal Treatment Failure Cases:

Inclusion Criteria: * Medically free patients. * Patient's age between 25-50 years. * Anterior or premolar teeth diagnosed clinically and radio graphically as symptomatic root canal treatment failure. * Positive patient's acceptance for participation in the study. * Sex include both male and female. * Patients who can understand Numerical Rating Scale (NRS) * Patients able to sign informed consent. Exclusion Criteria: * Pregnancy or lactation. * Medically compromised patients. * Patient with multiple teeth that required retreatment to eliminate the possibility of pain referral.