Inclusion Criteria:  1- Age between 18-50 years old. 2-Males or females. 3-Healthy patients whom are categorized as I or II according to The American Society of Anesthesiologists. (ASA I or II) 4-Patients' accepting to participate in the trial. 5-Patients who can understand pain scale and can sign the informed consent. 6- Mandibular Single rooted premolars, having single root canal:  Diagnosed clinically with pulp necrosis. Absence of spontaneous pain Slight widening in the periodontal membrane space or with periapical radiolucency not exceeding 2*2 mm radiographically. Normal occlusal contact with opposing teeth.  Exclusion Criteria:  1- Medically compromised patients having significant systemic disorders (ASA III or IV).  2-If analgesics or antibiotics have been administrated by the patient during the past 24 hours preoperatively as it might alter their pain perception.  3-Pregnant women: to avoid radiation exposure, anaesthesia, medication and hormonal Fluctuation that might increase pain prevalence.  4-Patients reporting bruxism, clenching, TMJ problems or traumatic occlusion: to avoid further pressure on inflamed tooth which induce subsequent irritation and inflammation.  5-Patients with two or more adjacent teeth requiring endodontic treatment. 6- Teeth that requires further procedural steps or multidisciplinary approach, which is out of this experiment's scope: i.Association with swelling or fistulous tract. ii. Acute periapical abscess. iii. Mobility Grade II or III. iv. Pocket depth more than 5mm. v. Previous root canal treatment. vi. Non-restorable. vii. Immature root. Vii. Radiographic evidence of external or internal root resorption, vertical root fracture, perforation, calcification.  7-Inability to perceive the given instructions.