The impact of this clinical research on the treatment of necrotic immature permanent teeth is significant because it will create a clinical evidence base for delivering regenerative endodontic procedures to children. The payback from this research will be to increase root growth, accomplish healing, and maintain teeth to improve the quality of life of children. Studies have shown that 25% of school-aged children will experience some kind of dental trauma and 51% will require treatment for dental decay. However, there have been no clinical trials to compare the regenerative effectiveness of nonsurgical root canal MTA apexification and Gutta percha obturation as a control, versus MTA pulpotomy apexogenesis, versus revascularization in immature permanent teeth with pulpal necrosis. Accordingly, it has not been possible for the AAE to create regenerative guidelines. The goal of this study is to stratify clinical outcomes of regenerative endodontic treatments according to tooth and patient variables. The central hypothesis is that endodontic regeneration procedures are more beneficial to children than traditional obturation or apexification procedures. The objective will be tested by pursuing three specific aims: 1) Test the hypothesis that regenerative endodontic procedures can increase root growth and accomplish healing and function of children's necrotic immature permanent teeth. 2) Test the hypothesis that the outcomes of regenerative endodontic procedures are influenced by the stage of tooth maturation, patient age, patient health status, severity of necrosis and presence of periapical lesions. 3) Test the hypothesis that regenerative endodontic procedures can improve the quality of life of children who have necrotic immature permanent teeth. This clinical research study is innovative because it will recruit up to 130 children and their parents/guardians to evaluate and compare the effectiveness of regenerative endodontic treatments to increase root growth, accomplish healing, and maintain teeth to improve the quality of life of children.