This study investigates the success of modified LSTR (Lesion Sterilization and Tissue Repair) techniques. It focuses on primary second molars, which are baby teeth. The conditions addressed in the study are pulp necrosis and irreversible pulpitis. The interventions involved the use of various antibiotic pastes, specifically 3Mix-MP, 3Mix-NS, 2Mix-MP, and 2Mix-NS. The research aimed to evaluate both the clinical and radiographic outcomes of these techniques. The study was sponsored by Uşak University and has been completed.