Gingival Crevicular Fluid Biomarkers and Healing After Root Canal Treatment in Asymptomatic Apical Periodontitis

Inclusion Criteria: Adults 18 -40 years . Presence of one permanent tooth diagnosed with asymptomatic apical periodontitis. Diagnosis confirmed by pulp necrosis or non-vital pulp and presence of a periapical radiolucency on digital periapical radiograph. Tooth indicated for primary nonsurgical root canal treatment. Tooth must be restorable and periodontally healthy. Periapical lesion detectable radiographically and suitable for follow-up evaluation. Participant able and willing to provide written informed consent. Participant willing to attend follow-up visits during the study period. Exclusion Criteria Participants will be excluded if any of the following conditions are present: Teeth previously treated with root canal treatment (retreatment cases). Teeth with acute apical abscess, swelling, or sinus tract. Teeth with combined endodontic-periodontal lesions. Periodontal pockets \>3 mm or evidence of active periodontal disease around the study tooth. Teeth with vertical root fracture, root perforation, or severe root resorption. Teeth with hopeless restorative or periodontal prognosis. Patients with systemic diseases that may affect healing (e.g., uncontrolled diabetes, immunosuppression). Pregnant or breastfeeding women. Patients currently taking systemic antibiotics, corticosteroids, or anti-inflammatory medications within the last 2 weeks. Current smokers or tobacco users. Inability to attend scheduled follow-up visits.