Effect of 1% Melatonin Gel Versus Calcium Hydroxide as an Intracanal Medicament on the Intensity of Postoperative Pain, Bacterial Load Reduction and Periapical MMP-9 Levels in Patients With Necrotic Pulp.

Inclusion criteria

• Age between 18-50 years old.
• Males and females.
• Healthy patients categorized as I or II according to The American Society of Anesthesiologists. (ASA I or II), with no underlying allergies.
• Single-rooted mandibular premolar teeth, having single root canal: diagnosed clinically with pulp necrosis.
• Patients accepting to participate in the trial.
• Patients who can understand pain scale (Appendix I) and can sign the informed consent (Appendix II).

Exclusion criteria

• Medically compromised patients having significant systemic disorders (ASA III or IV).
• Pregnant females.
• If analgesics or antibiotics have been administrated by the patient during the past 24 hours preoperatively as it might alter their pain perception.
• Teeth with multiple canals.
• Teeth that show association with acute periapical abscess or swelling.
• Teeth with vital pulp.
• Non-restorable teeth or teeth that could not be adequately isolated with a rubber dam.
• Immature teeth.
• Teeth with greater than grade I mobility or pocket depth greater than 4 mm.
• Teeth showing radiographic evidence of external or internal root resorption, vertical root fracture, perforation or calcification.
• Patients with two or more adjacent teeth requiring endodontic treatment.
• Patients reporting bruxism, clenching or TMJ problems.
• Teeth with previous endodontic treatment.
• Inability to perceive the given instructions.