Effect of Diclofenac Sodium Versus Calcium Hydroxide as Intracanal Medication on the Intensity of Postoperative Pain, Bacterial Load Reduction and MMP-9 Levels in Patients With Necrotic Pulp.

Inclusion Criteria: \- Inclusion criteria: * Patients who are free from any physical or mental handicapping condition with no underlying systemic disease. * Age between 18-50 years. * Males \& Females. * Mandibular single rooted permanent premolar teeth: * Diagnosed clinically with pulp necrosis. * Absence of spontaneous pain. * Positive pain on percussion denoting apical periodontitis. * Slight widening in the periodontal membrane space or with periapical radiolucency not exceeding 2\*2 mm radiographically. * Patients' acceptance to participate in the trial. * Patients who can understand pain scale and can sign the informed consent Exclusion Criteria: * Medically compromised patients * Pregnant women. * If analgesics or antibiotics have been administrated by the patient during the past 24 hours preoperatively. * Patients reporting bruxism or clenching. * Teeth that show association with acute periapical abscess and swelling. * Greater than grade I mobility or pocket depth greater than 5mm. * Non-restorable teeth * Teeth with vital pulp. * Immature teeth. * Radiographic evidence of external or internal root resorption vertical root fracture, perforation, calcification.