05-01-202605-01-2026<p>Introduction: Modern tissue engineering strategies have elucidated the potential of regenerative endodontic treatment (RET) as an alternative for treating mature teeth. Methods: Here, we report two cases in which cell-based RET (CB-RET) using encapsulated allogeneic umbilical cord mesenchymal stem cells (UC-MSCs) in a platelet-poor plasma (PPP)-based scaffold was used in two mature teeth with pulp necrosis and apical periodontitis. Results: After 5 years of follow-up, the healing response was satisfactory in both cases, with evidence of pulp revitalization. Conclusions: This is the first study to report the success of an extended, 5-year follow-up for allogeneic CB-RET. This report presents an innovative and sustainable solution to challenging endodontic scenarios.</p>info:eu-repo/semantics/restrictedAccessApical periodontitismature teethmesenchymal stem cell transplantationplatelet-poor plasmaregenerative medicineArticle