This study investigated the effect of MTA (Mineral Trioxide Aggregate) on healing and biomarkers in endodontic-periodontal lesions. Specifically, it focused on conditions such as apical periodontitis and periapical disease. The research involved several interventions to compare different treatment approaches. One group received root canal treatment with an MTA apical plug. Another group underwent root canal treatment using a resin-based sealer called AH Plus. All participants also received periodontal therapy, which included scaling and root planing. To assess the healing process and biomarkers, gingival crevicular fluid samples were collected. The study was sponsored by Istanbul Medipol University Hospital and has been completed.