Comparison of Post-operative Pain and Levels of MMP -9 Following Root Canal Irrigation With Sodium Hypochlorite Versus Cold Atmospheric Plasma in Patient With Necrotic Single Rooted Teeth: Randomized Clinical Trial

The goal of this clinical trial is to compare the effect of cold atmospheric plasma versus sodium hypochlorite as irrigating solutions in necrotic single rooted teeth. The main questions it aims to answer are: * Does the use of sodium hypochlorite solution or cold atmospheric plasma as root canal irrigant will have the same effect on the level of postoperative pain in necrotic single rooted teeth? * Does the use of sodium hypochlorite solution or cold atmospheric plasma as root canal irrigant will have the same effect on the level of MMP -9 in necrotic single rooted teeth? Researchers will compare cold atmospheric plasma to sodium hypochlorite solution as root canal irrigant to see if cold atmospheric plasma works to have the same effect on the level of postoperative pain and levels of MMP -9 in necrotic single rooted teeth. Participants will: * be asked to rate their pain level according to the given instructions and will be asked to return for follow up after 2 days to hand the pain scale chart. * be instructed to call the operator and will be permitted to take Ibuprofen 400 mg not more than 6 hours apart and to record their tablet intake within 48 hours postoperatively, in case of severe or persistent pain. * be referred to the fixed prosthodontics department for final restoration.

Inclusion Criteria: 1. Patients in good physical health; American Society of Anesthesiologists (ASA) class I or II, with no known allergic manifestations to the drugs used in the study and no involvement with other medication during the study (Appendix) 2. Patient's age between 18-55 years. 3. Male and female patients. 4. Patients who can understand the numerical rating scale (Appendix 4). 5. Patients who accept to participate in the trial and can sign the informed consent (Appendix 1). 6. Mature mandibular premolar teeth with: * Negative response to electric pulp tester. * No intra-canal calcifications or internal resorptive lesions. Exclusion Criteria: 1. Medically compromised patients having substantive functional limitations (ASA III or IV) (Appendix 2). 2. Patients having two or more adjacent teeth requiring endodontic treatment. 3. Patients who received antibiotic therapy within the last three months before treatment (Rôças et al., 2016). 4. Patients administered analgesics in the last 24 hours before treatment. 5. Teeth with: * Vital pulps. * Immature apices. * Acute periapical abscess, swellings and facial cellulitis. * Periodontally affected (mobility grade II or III). * Previous root canal treatment. * Non-restorable coronal portion. 6. TMJ problems, bruxism or traumatic occlusion. 7. Inability to perceive the given instructions.