Inclusion Criteria:  •1. Patient age between 18-60 years old.  2. Both males and females will be included. 3. All patients are in a good health without systemic condition. 4. The offending tooth is a molar. 5. The offending molar is indicated for root canal treatment. 6. One molar for every patient. 7. All patients will sign an informed consent.  Exclusion Criteria:  1. The offending tooth has previous attempt of pulp therapy or root canal treatment.  2. The patient showing any clinical or radiographic evidence of periapical pathosis. 3. Patients received analgesics or systemic antibiotic prior to treatment. 4. Immunocompromised patients. 5. Any unknown infectious disease (e.g. HBV, HCV, HIV, or T.B.) 6. History of cancer with radio or chemotherapy. 7. Offending molar with mobility score ≥2. 8. Offending molar with pocket depth ≥6mm. 9. Immature molars. 10. Nonodontogenic pain. 11. Patients with more than one tooth requiring endodontic intervention.