Assessment of Postoperative Pain After Using Reciproc Versus One Shape NiTi Systems

* The aim of this study is to assess the postoperative pain and the intake of analgesic medication after using Reciproc single-file reciprocating system or One Shape single-file continuous rotary system in patients with symptomatic irreversible pulpitis. * Patients will be diagnosed to determine whether they are eligible for the inclusion criteria of this study or not. Patients who are eligible will then start their root canal treatment on the same visit and to be completed in one visit only. Patients will be phone called in order to record the intensity of pain, amount and frequency of analgesic intake at 6, 12, 24, 48 and 72 hours after treatment.