Effect of N-acetylcysteine Versus Calcium Hydroxide Used as an Intracanal Medicament on the Intensity of Postoperative Pain, Bacterial Load Reduction and Levels of MMP -9 in Periapical Fluids in Patients With Necrotic Pulp

To compare the effect of N-acetylcysteine versus calcium hydroxide as intra canal medication on:Intensity of postoperative pain.Bacterial load reduction.levels of MMP -9 in Periapical Fluids.

Inclusion Criteria:Patients who are free from any physical or mental handicapping condition.Males & Females withMandibular single rooted permanent premolar teeth.Absence of spontaneous pain.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 (Appendix I)Exclusion Criteria:Medically compromised patients.Pregnant womenPatients undergoing previous endodontic treatment or analgesics and/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 or teeth that could not be adequately isolated with a rubber damTeeth with vital pulp.Immature teeth.Radiographic evidence of external or internal root resorption vertical root fracture, perforation, calcification.