The Four Pillars for Successful Regenerative Therapy in Endodontics: Stem Cells, Biomaterials, Growth Factors, and Their Synergistic Interactions

Guidance for evaluating biomaterials' properties and biological potential for dental pulp tissue engineering and regeneration research

BACKGROUND

Dental pulp regeneration is a complex and advancing field that requires biomaterials capable of supporting the pulp's diverse functions, including immune defense, sensory perception, vascularization, and reparative dentinogenesis. Regeneration involves orchestrating the formation of soft connective tissues, neurons, blood vessels, and mineralized structures, necessitating materials with tailored biological and mechanical properties. Numerous biomaterials have entered clinical practice, while others are being developed for tissue engineering applications. The composition and a broad range of material properties, such as surface characteristics, degradation rate, and mechanical strength, significantly influence cellular behavior and tissue outcomes. This underscores the importance of employing robust evaluation methods and ensuring precise and comprehensive reporting of findings to advance research and clinical translation.

AIMS

This article aims to present the biological foundations of dental pulp tissue engineering alongside potential testing methodologies and their advantages and limitations. It provides guidance for developing research protocols to evaluate the properties of biomaterials and their influences on cell and tissue behavior, supporting progress toward effective dental pulp regeneration strategies.

Recent Advances in Regenerative Endodontics: A Review of Current Techniques and Future Directions

Regenerative endodontics is a rapidly evolving discipline focused on biologically restoring the pulp-dentin complex to revive vitality in non-vital teeth. Unlike traditional endodontic therapies that rely on inert materials to preserve structure, regenerative techniques aim to re-establish natural structure and function by harnessing advancements in tissue engineering. This narrative review examines recent progress in stem cell applications, scaffold development, signaling molecules, and clinical protocols that contribute to successful regenerative outcomes. Advances in stem cell sources, biomimetic scaffolds, and growth factor delivery systems have shown promising results, though challenges such as variability in outcomes and the need for standardized clinical protocols remain. This review also highlights future directions, including gene therapy and three-dimensional bioprinting, which hold the potential to overcome current limitations and pave the way for effective and reliable biologically restorative dental treatments.

Revolutionizing Endodontics: Innovative Approaches for Treating Mature Teeth With Closed Apices and Apical Lesions: A Report of Two Cases

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.

Growth Factors Released from Advanced Platelet-Rich Fibrin in the Presence of Calcium-Based Silicate Materials and Their Impact on the Viability and Migration of Stem Cells of Apical Papilla

Advanced platelet-rich fibrin (A-PRF) provides the scaffold and growth factors necessary for stem cells to proliferate and differentiate in successful regenerative endodontic procedures. This study investigates the release of transforming growth factor-β1 (TGF-β1), platelet-derived growth factor (PDGF), and vascular endothelial growth factor (VEGF) from A-PRF in cell culture media in the presence and absence of mineral trioxide aggregate (MTA) or Biodentine. Additionally, this research assesses the viability and migration of stem cells of the apical papilla (SCAP) in previously conditioned media. A-PRF obtained from 14 participants were incubated for 7 days in cell culture media alone or via layering with MTA or Biodentine discs and the release of selected growth factors in the media was evaluated using ELISA. The viability of SCAP grown in conditioned media was measured using the CCK8 assay, while SCAP migration was assessed via a transwell assay by counting migrated cells. The release of TGF-β1, PDGF, and VEGF was significantly higher in media with A-PRF alone than in the presence of either calcium-based silicate material (p < 0.05), which showed no difference from the no-A-PRF control (p < 0.05). None of the tested growth factors released in the A-PRF-conditioned media correlated with clot weight. A-PRF-conditioned media, both with and without calcium-based silicate materials, did not impact SCAP viability and migration (p > 0.05). This study shows that SCAP behavior is not impacted by the decrease in growth factor released in the presence of calcium-based silicate materials and that their role in REPs warrants further investigation.

Promotive Effect of FBXO32 on the Odontoblastic Differentiation of Human Dental Pulp Stem Cells

Odontoblastic differentiation of human dental pulp stem cells (hDPSCs) is crucial for the intricate formation and repair processes in dental pulp. Until now, the literature is not able to demonstrate the role of ubiquitination in the odontoblastic differentiation of hDPSCs. This study investigated the role of F-box-only protein 32 (FBXO32), an E3 ligase, in the odontoblastic differentiation of hDPSCs. The mRNA expression profile was obtained from ribonucleic acid sequencing (RNA-Seq) data and analyzed. Immunofluorescence and immunohistochemical staining identify the FBXO32 expression in human dental pulp and hDPSCs. Small-hairpin RNA lentivirus was used for FBXO32 knockdown and overexpression. Odontoblastic differentiation of hDPSCs was determined via alkaline phosphatase activity, Alizarin Red S staining, and mRNA and protein expression levels were detected using real-time quantitative polymerase chain reaction and Western blotting. Furthermore, subcutaneous transplantation in nude mice was performed to evaluate the role of FBXO32 in mineralization in vivo using histological analysis. FBXO32 expression was upregulated in the odontoblast differentiated hDPSCs as evidenced by RNA-Seq data analysis. FBXO32 was detected in hDPSCs and the odontoblast layer of the dental pulp. Increased FBXO32 expression in hDPSCs during odontoblastic differentiation was confirmed. Through lentivirus infection method, FBXO32 downregulation in hDPSCs attenuated odontoblastic differentiation in vitro and in vivo, whereas FBXO32 upregulation promoted the hDPSCs odontoblastic differentiation, without affecting proliferation and migration. This study demonstrated, for the first time, the promotive role of FBXO32 in regulating the odontoblastic differentiation of hDPSCs, thereby providing novel insights into the regulatory mechanisms during odontoblastic differentiation in hDPSCs.