Evaluation of Postoperative Pain and Bacterial Load Reduction With ProTaper Ultimate Versus ProTaper Gold Rotary Systems

Inclusion Criteria: * Patient's age ranges between 22 to 45 years with no sex predilection. * Medically free patients. * Maxillary permanent premolar teeth: * Diagnosed clinically with pulp necrosis. * Absence of pain. * Radiographic evidence of two roots or single root with double canals. * Slight widening in the periodontal membrane space or with peri-apical radiolucency * No response to cold pulp tester and ethyl chloride spray. * Patients who can understand Modified Visual Analogue Scale (VAS). * Patients' acceptance to participate in the trial. 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 with: i. Vital teeth. ii. Single canal maxillary premolar teeth iii. Association with swelling or fistulous tract. iv. Acute peri-apical abscess and swelling. v. Mobility Grade II or III. vi. Pocket depth more than 5mm. vii. Previous root canal therapy. viii. Non-restorable teeth: Hopeless tooth * Immature teeth. * Radiographic evidence of external or internal root resorption vertical root fracture, perforation, calcification, root caries.