Incomplete root growth and thin dentinal walls complicate the treatment of pulp necrosis in primary teeth. The mineral trioxide aggregate (MTA) apical plug approach has shown efficacy in generating apexification and facilitating root development. The purpose of this clinical experiment is to analyze the safety and effectiveness of using a spinal tap needle to create an apical plug out of MTA in undeveloped permanent teeth. Materials and Methods: Forty individuals with pulp necrosis in their baby teeth participated in this research investigation. MTA was injected and compressed into the root tip using the spinal tap needle procedure. Preoperative, immediate postoperative, and follow-up clinical and radiological tests were undertaken to evaluate therapy efficacy. Recovery of the periapical period, root development, and apical closure were the key indicators of success. Both the success rate and the frequency of problems were tracked as secondary outcomes.