Regenerative Endodontics: A Systematic Analysis of the Failed Cases

Introduction: The aim of this systematic review was to analyze failed cases of regenerative endodontic treatment (RET) reported in the literature in terms of etiology, diagnosis, treatment protocols, signs of failure, and additional endodontic interventions. Methods: Electronic searches were performed in PubMed, Web of Science, and ProQuest Dissertations & Theses databases. All in vivo publications in humans that reported at least 1 failed case of RET were included in this systematic review. Failed RET cases were defined in the current study as any case that required an additional endodontic intervention or extraction after the completion of the initial RET. Results: A total of 28 studies that reported 67 failed cases of RET were included in this review. A total of 37 failed RET cases reported the etiology that resulted in the initiation of RET; 59% of these cases were caused by dental trauma, and 30% were caused by dens evaginatus. A total of 26 (39%) failed RET cases were detected at least 2 years after the initiation of RET. A total of 53 (79%) failed RET cases were presented with signs and/or symptoms of persistent infection. Conclusions: Persistent infection was the main presentation in 79% of failed RET cases. Furthermore, 39% of failed RET cases were identified after more than 2 years of follow-up. Future studies should include a detailed description of the etiology, preoperative variables, intra-operative protocols, and postoperative follow-up to provide a better understanding of failed cases after RET.