Inclusion Criteria:  Pulpal necrosis in mature mandibular molar as confirmed by negative response to pulp sensibility test (cold and electric pulp test) Radiographic evidence of apical periodontitis in the form of periapical radiolucency Radiographic alveolar bone breakdown not more than one third of root length.  Exclusion Criteria:  Obese (BMI >30 kg/m2), smoker, pregnant, diabetic, immunocompromised or have any other systemic inflammatory condition. Having a positive history of antibiotic use within the past month or require antibiotic premedication for dental treatment (including infective endocarditis or prosthetic joint prophylaxis). Teeth having previous root fillings, unrestorable teeth, fractured/perforated roots, grade 3 mobility, and history of recent periodontal therapy (within previous 6 months). Teeth with established endodontic-periodontal lesions exhibiting <2 mm radiopaque bone between the root apex.