Comprehensive Characterization of 2 Immature Teeth Treated with Regenerative Endodontic Procedures

Introduction: Regeneration of the pulp-dentin complex is the penultimate goal of regenerative endodontic procedures (REPs). Histological outcomes have demonstrated reparative tissue formation in human teeth extracted post-REPs. However, lack of accurate characterization has precluded identification of the true nature of tissues formed post-REP. Methods: Here, we present 2 case reports of tooth #29 and #9 treated with REPs and demonstrate their clinical, radiographic, and histological outcomes. Results: Clinical outcomes revealed healing of apical periodontitis in both teeth and re-establishment of vitality responses in tooth #29. Moreover, radiographic assessments using 2D and 3D-volumetric analyses demonstrate considerable increase in root development for both teeth. Further, histological outcomes evaluated using Hematoxylin and Eosin and immunohistochemical staining demonstrates presence of vascular and lymphatic structures as well as immune cell markers indicative of regeneration of an immunocompetent pulp. Lastly, examination of hard tissue deposition shows dentin-like tissue in parts of tooth #29 demonstrating for the first time, regeneration of a pulp-dentin complex post-REP. Conclusions: Collectively, this is the first study demonstrating recapitulation of several tissues commonly found as part of a pulp-dentin complex in teeth treated with REPs.