Antimicrobial Efficacy of Nano-Based ICM on E.F

Inclusion Criteria: * Single rooted, single canal premolar teeth. * Teeth indicated for non-surgical root canal retreatment. * Teeth have signs and/or symptoms of post-treatment disease manifested by recurrent acute and/or chronic periapical abscess. * Teeth have clinical signs and symptoms of endodontic failure as sensitivity to percussion, pain, swelling or fistula. * Teeth with radiographic features of endodontic failure as persistent periapical lesion or widening of periodontal ligament. * Symptomatic or asymptomatic teeth with short root canal filling indicated for prosthetic restoration Exclusion Criteria: * Patients with any systemic diseases. * Pregnant or lactating patients. * Immunocompromised patients. * Non-restorable tooth. * Calcified root canal. * Teeth with root fracture. * Teeth with periodontal pocket deeper than 4mm. * Teeth have procedural error like ledge, broken instrument, or perforation