Comparing the effect of Simvastatin versus calcium hydroxide used as an intracanal medicament on Post-operative Pain and Total amount of IL-6 and IL-8 in Periapical Fluids of lower premolars in patients with Symptomatic Apical Periodontitis:

Lower premolars with symptomatic apical periodontitis will be selected according to the eligibility and exclusion criteria and patients are then randomized to receive treatment either using simvastatin or calcium hydroxide intracanal medication for 1 week. The endodontic treatment will be completed in two visits. Postoperative pain will be assessed using the Numerical Rating scale at 6, 12, 24, 48 hours post-instrumentation and at 6, 12, 24, 48 hours post-obturation. Periapical fluid sample will be collected immediately post-instrumentation and 1 week later pre-obturation. The periapical samples will be analyzed for total amounts of IL-6 and IL-8.

Inclusion Criteria:

• Patients who are free from any physical or mental handicapping condition with no underlying systemic disease.

• Lower single rooted premolars:

  • Presence of pain with percussion.
  • Widening in the periodontal membrane space or with small sized periapical radiolucency.
  • Diagnosed clinically with symptomatic apical periodontitis.

• Patients' acceptance to participate in the trial.

• Patients who can understand pain scale and can sign the informed consent

Exclusion Criteria:

• Medically compromised patients
• Pregnant women
• Patients who are allergic to non-steroidal anti-inflammatory drugs.
• Patients with two or more adjacent teeth requiring root canal therapy
• If analgesics or antibiotics have been administrated by the patient during the past two weeks preoperatively.
• Patients reporting bruxism or clenching.
• Teeth associated with acute periapical abscess, swelling or a fistulous tract.
• Greater than grade I mobility or pocket depth greater than 5mm.
• Non restorable teeth.
• Immature teeth.
• Teeth with previous endodontic treatment.
• Radiographic evidence of external or internal root resorption vertical root fracture, perforation, calcification.

After the participant is confirmed eligible for the study, the participant will drag an envelope and will be given a number. Based on this number the patient will be allocated to either intervention or control group after contacting the co- supervisor to reveal the assigned group of the current patient according to the generated random sequence.