The Effect of Exosomes Derived from Human Umbilical Cord Mesenchymal Stromal/Stem Cells on the Regeneration of Human Pulpectomized Tooth: A Case Report

Abstract

The dental pulp is essential for tooth health and sensory function. However, conventional treatments for infected or necrotic pulp, such as root canal therapy, frequently result in tooth loss and increased fracture risk. Regenerative endodontic procedures (REPs) aim to regenerate pulp tissue while preserving tooth vitality. Exosomes from human umbilical cord mesenchymal stromal/stem cells (hUCMSCs) demonstrated potential for tissue regeneration. In this case report, the potential of hUCMSC-derived exosomes for regenerating the dental pulp of a pulpectomized tooth was investigated. The patient, a 40-year-old man, was presented with irreversible pulpitis in the mandibular second premolar. The patient underwent a pulpectomy, followed by the application of a chitosan and hUCMSC-derived exosome mixture into the root canal. This project was conceived and executed as a joint project in Bushehr (Iran), Shiraz (Iran), and Aktobe (Kazakhstan) from 2022 to 2024. Exosomes were isolated and characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Clinical evaluations, including visual inspection, palpation, pulp vitality tests, radiography, and cone beam computed tomography (CBCT) imaging, were conducted over 24 weeks post-treatment. The SEM and TEM images confirmed the effective isolation and characterization of exosomes. Clinical follow-ups showed no signs of infection, swelling, or tenderness around the treated tooth. Radiographic assessments indicated periapical radiolucency and periodontal ligament widening, suggesting active healing. Despite these radiographic changes, the absence of clinical symptoms indicated successful tissue regeneration and integration. This case report demonstrated the potential of hUCMSC-derived exosomes for dental pulp regeneration, with promising results in maintaining tooth vitality and promoting healing.

Keywords: Dental pulp; Exosomes; Mesenchymal stem cells; Regeneration; Regenerative endodontics.

Figure 1

Isolated exosomes from human umbilical cord mesenchymal stromal/stem cells (hUCMSCs) were confirmed using different imaging techniques. Panel A presents scanning electron microscopy (SEM) images, demonstrating the size and morphology of the exosomes. Panel B displays transmission electron microscopy (TEM) images, further verifying their lipid bilayer structure. Panel C provides an analysis of exosome diameter frequencies, illustrating the size distribution of the exosomes, with a mean diameter of 101.06 nm, and sizes ranging from 20 to 180 nm. These findings confirmed the successful isolation and characterization of hUCMSC-derived exosomes.

Figure 2

To clarify the process, the treatment procedure is illustrated schematically. It illustrates the step-by-step process of root canal preparation, the injection of human umbilical cord mesenchymal stromal/stem cells (hUCMSCs)-derived exosomes mixed with chitosan into the root canal, and the final sealing of the cavity with glass ionomer cement. The diagram outlines the use of dental tools, exosome injection, and restoration procedures, providing a clear visual overview of the entire regenerative endodontic therapy process.

Figure 3

Mandibular second premolar was imaged with cone beam computed tomography (CBCT) and periapical radiographs. The CBCT imaging shows the target tooth at the 24th week after transplantation of chitosan and human umbilical cord mesenchymal stromal/stem cells (hUCMSCs)-derived exosomes in pulpectomized teeth (A). The periapical imaging analysis shows the changes and evolution of periapical tissues at the first visit (B), pre-operation just before chitosan and hUCMSCs-derived exosomes transplantation (C), post-operation just after chitosan and hUCMSCs-derived exosomes transplantation and completing tooth restoration (D), and 2 weeks (E), 4 weeks (F), 12 weeks (G), and 24 weeks (H) following the transplantation of chitosan and hUCMSCs-derived exosomes in pulpectomized teeth.