This prospective randomized clinical study will investigate the association between MMP-2 and MMP-3 gene polymorphisms and radiographic healing outcomes following nonsurgical root canal treatment in patients with chronic apical periodontitis. A total of 50 patients will undergo standardized endodontic treatment and will be followed for 12 months. Genotyping will be performed using baseline DNA samples, and periapical healing will be assessed using the Periapical Index (PAI). The relationship between genetic variations and treatment outcomes will be analyzed to determine whether host-related genetic factors influence healing patterns after root canal therapy.