Personalized Cell Therapy for Pulpitis Using Autologous Dental Pulp Stem Cells and Leukocyte Platelet-rich Fibrin: A Case Report

Regenerative Endodontic Procedures With Minced Pulp Tissue Graft in Mature Permanent Teeth: A Clinical Study

INTRODUCTION

Regenerative endodontic procedures (REPs) using cell-based approaches have emerged as novel treatment modalities. This clinical study aimed to present the outcomes and explore factors influencing REPs with minced pulp tissue (MP) grafts in a mature tooth.

METHODS

Healthy patients requiring non-surgical root canal treatment were enrolled. MP obtained from the third molar was grafted into the instrumented, disinfected, and blood-filled root canal. After treatment, patients were evaluated clinically and radiographically.

RESULTS

Follow-ups for 6 cases (male patients aged 20-27) ranged from 19 to 42 months. Radiographically, all the teeth showed favorable outcomes. Among the 6 teeth, 2 showed neither intracanal calcification nor recovery in sensibility tests, and one had no intracanal calcification with an inapplicable sensibility test evaluation. In 2 teeth, intracanal calcification was observed in the apical third; however, there was no recovery in the sensibility tests. One tooth exhibited intracanal calcification in the apical third and showed recovery in the sensibility tests. Considering these outcomes and clinical variables, the size of the apical foramen and the composition of the transplanted pulp tissue were identified as tentative influencing factors.

CONCLUSIONS

This exploratory clinical study on simplified cell-based REPs using autologous MP grafts for pulp/dentin regeneration in adult teeth not only enhances our understanding of REPs but also suggests its potential as an alternative treatment option to conventional endodontic treatment.

NRP1 promotes osteo/odontogenic differentiation via shroom3 in dental pulp stem cells

Neuropilin-1 (NRP1) is a single transmembrane glycoprotein involved in a variety of physiological events. However, the exact mechanisms by which NRP1 regulates dental pulp stem cells (DPSCs) to differentiate toward an osteo/odontogenic phenotype are poorly understood. Here, we determined the significantly increased expression of full-length NRP1 and glycosaminoglycan (GAG)-modified NRP1 during osteo/odontogenesis in DPSCs. NRP1 was confirmed to promote alkaline phosphatase (ALP) activity, mineralized nodule deposition, protein and mRNA expression of Runx2, DSPP and DMP1 in DPSCs via the loss-of-function and gain-of-function approaches. Further, a non-GAG-modified NRP1 mutant (NRP1 S612A) was generated and the suppression of osteo/odontogenic differentiation was observed in the NRP1 S612A overexpression cells. Knockdown of the adaptor protein shroom3 resulted in the inhibition of osteo/odontogenesis. The protein-protein interaction network, the protein-protein docking and confocal analyses indicated the interactions between NRP1 and shroom3. Furthermore, immunoprecipitation followed by western analysis confirmed the binding of NRP1 to shroom3, but overexpression of NRP1 S612A greatly influenced the recruitment of shroom3 by NRP1. These results provide strong evidence that NRP1 is a critical regulator for osteo/odontogenesis through interacting with shroom3. Moreover, our results indicate that NRP1 S612A attenuates osteo/odontogenesis, suggesting that GAG modification is essential for NRP1 in DPSCs.

Dens invaginatus Type II in an Immature Lateral Incisor With Apical Periodontitis Treated With Regenerative and Strategic Antimicrobial Procedures: A Case Report

Dens invaginatus is a developmental dental anomaly that can predispose the tooth to pulp and periradicular disease. Management of this condition can be challenging because of anatomic and microbiologic issues. This case report describes the regenerative endodontic treatment using a strategic antimicrobial protocol for management of an immature maxillary lateral incisor with type-II dens invaginatus associated with apical periodontitis in a 13-year-old patient. The tooth presented with a complex anatomy and was associated with an active sinus tract. Because the true root canal was not negotiable in its coronal part due to the presence of the dens invaginatus, the closed end of the invagination (pseudocanal) was perforated to permit access to the apical segment of the true root canal for cleaning and disinfection. Both the invagination and the true canal were treated using an antimicrobial regimen based on chemomechanical preparation with sodium hypochlorite irrigation, supplementary disinfection with passive ultrasonic irrigation and interappointment calcium hydroxide medication. After 2 exchanges of calcium hydroxide medication, the sinus tract did not disappear, then the antimicrobial protocol was changed to include an antibiotic solution for irrigation and antibiotic paste for intracanal medication. After signs and symptoms disappeared, regenerative endodontic treatment was performed by inducing blood clot formation within the root canal. The coronal canal segment including the invagination was filled with Biodentine. Follow-up including cone-beam computed tomography examination showed complete healing of the apical periodontitis lesion and mineralized tissue formation at the apical portion of the true root canal.

Dental pulp stem cells - A basic research and future application in regenerative medicine

Dental pulp is a valuable and accessible source of stem cells (DPSCs) with characteristics similar to mesenchymal stem cells. DPSCs can regenerate a range of tissues and their potential for clinical application in regenerative medicine is promising. DPSCs have been found to express low levels of Class II HLA-DR (MHC) molecules, making them potential candidates for allogeneic transplantation without matching the donor's tissue. Research on the correlation between non-coding RNAs (ncRNAs) and human dental pulp stem cells (DPSCs) provides promising insights into the use of these cells in clinical settings for a wide range of medical conditions. It is possible to use a number of ncRNAs in order to restore the functional role of downregulated ncRNAs that are correlated with osteoblastogenesis, or to suppress the functional role of overexpressed ncRNAs associated with osteoclast differentiation in some cases.

Recent adavances of functional modules for tooth regeneration

Dental diseases, such as dental caries and periodontal disorders, constitute a major global health challenge, affecting millions worldwide and often resulting in tooth loss. Traditional dental treatments, though beneficial, typically cannot fully restore the natural functions and structures of teeth. This limitation has prompted growing interest in innovative strategies for tooth regeneration methods. Among these, the use of dental stem cells to generate functional tooth modules represents an emerging and promising approach in dental tissue engineering. These modules aim to closely replicate the intricate morphology and essential physiological functions of dental tissues. Recent advancements in regenerative research have not only enhanced the assembly techniques for these modules but also highlighted their therapeutic potential in addressing various dental diseases. In this review, we discuss the latest progress in the construction of functional tooth modules, especially on regenerating dental pulp, periodontal tissue, and tooth roots.

Dental pulp regeneration strategies: A review of status quo and recent advances

Microorganisms, physical factors such as temperature or mechanical injury, and chemical factors such as free monomers from composite resin are the main causes of dental pulp diseases. Current clinical treatment methods for pulp diseases include the root canal therapy, vital pulp therapy and regenerative endodontic therapy. Regenerative endodontic therapy serves the purpose of inducing the regeneration of new functional pulp tissues through autologous revascularization or pulp tissue engineering. This article first discusses the current clinical methods and reviews strategies as well as the research outcomes regarding the pulp regeneration. Then the in vivo models, the prospects and challenges for regenerative endodontic therapy were further discussed.

Regenerative endodontic therapy: From laboratory bench to clinical practice

BACKGROUND

Maintaining the vitality and functionality of dental pulp is paramount for tooth integrity, longevity, and homeostasis. Aiming to treat irreversible pulpitis and necrosis, there has been a paradigm shift from conventional root canal treatment towards regenerative endodontic therapy.

AIM OF REVIEW

This extensive and multipart review presents crucial laboratory and practical issues related to pulp-dentin complex regeneration aimed towards advancing clinical translation of regenerative endodontic therapy and enhancing human life quality.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this multipart review paper, we first present a panorama of emerging potential tissue engineering strategies for pulp-dentin complex regeneration from cell transplantation and cell homing perspectives, emphasizing the critical regenerative components of stem cells, biomaterials, and conducive microenvironments. Then, this review provides details about current clinically practiced pulp regenerative/reparative approaches, including direct pulp capping and root revascularization, with a specific focus on the remaining hurdles and bright prospects in developing such therapies. Next, special attention was devoted to discussing the innovative biomimetic perspectives opened in establishing functional tissues by employing exosomes and cell aggregates, which will benefit the clinical translation of dental pulp engineering protocols. Finally, we summarize careful consideration that should be given to basic research and clinical applications of regenerative endodontics. In particular, this review article highlights significant challenges associated with residual infection and inflammation and identifies future insightful directions in creating antibacterial and immunomodulatory microenvironments so that clinicians and researchers can comprehensively understand crucial clinical aspects of regenerative endodontic procedures.

Stem cells in regenerative dentistry: Current understanding and future directions

BACKGROUND

Regenerative dentistry aims to enhance the structure and function of oral tissues and organs. Modern tissue engineering harnesses cell and gene-based therapies to advance traditional treatment approaches. Studies have demonstrated the potential of mesenchymal stem cells (MSCs) in regenerative dentistry, with some progressing to clinical trials. This review comprehensively examines animal studies that have utilized MSCs for various therapeutic applications. Additionally, it seeks to bridge the gap between related findings and the practical implementation of MSC therapies, offering insights into the challenges and translational aspects involved in transitioning from preclinical research to clinical applications.

HIGHLIGHTS

To achieve this objective, we have focused on the protocols and achievements related to pulp-dentin, alveolar bone, and periodontal regeneration using dental-derived MSCs in both animal and clinical studies. Various types of MSCs, including dental-derived cells, bone-marrow stem cells, and umbilical cord stem cells, have been employed in root canals, periodontal defects, socket preservation, and sinus lift procedures. Results of such include significant hard tissue reconstruction, functional pulp regeneration, root elongation, periodontal ligament formation, and cementum deposition. However, cell-based treatments for tooth and periodontium regeneration are still in early stages. The increasing demand for stem cell therapies in personalized medicine underscores the need for scientists and responsible organizations to develop standardized treatment protocols that adhere to good manufacturing practices, ensuring high reproducibility, safety, and cost-efficiency.

CONCLUSION

Cell therapy in regenerative dentistry represents a growing industry with substantial benefits and unique challenges as it strives to establish sustainable, long-term, and effective oral tissue regeneration solutions.

An innovative cell-based transplantation therapy for an immature permanent tooth in an adult: a case report

BACKGROUND

Immature teeth with necrotic pulps present multiple challenges to clinicians. In such cases, regenerative endodontic procedures (REPs) may be a favorable strategy. Cells, biomaterial scaffolds, and signaling molecules are three key elements of REPs. Autologous human dental pulp cells (hDPCs) play an important role in pulp regeneration. In addition, autologous platelet concentrates (APCs) have recently been demonstrated as effective biomaterial scaffolds in regenerative dentistry, whereas the latest generation of APCs-concentrated growth factor (CGF), especially liquid phase CGF (LPCGF)-has rarely been reported in REPs.

CASE PRESENTATION

A 31-year-old woman presented to our clinic with the chief complaint of occlusion discomfort in the left mandibular posterior region for the past 5 years. Tooth #35 showed no pulp vitality and had a periodontal lesion, and radiographic examination revealed that the tooth exhibited extensive periapical radiolucency with an immature apex and thin dentin walls. REP was implemented via transplantation of autologous hDPCs with the aid of LPCGF. The periodontal lesion was managed with simultaneous periodontal surgery. After the treatment, the tooth was free of any clinical symptoms and showed positive results in thermal and electric pulp tests at 6- and 12-month follow-ups. At 12-month follow-up, radiographic evidence and three-dimensional models, which were reconstructed using Mimics software based on cone-beam computed tomography, synergistically confirmed bone augmentation and continued root development, indicating complete disappearance of the periapical radiolucency, slight lengthening of the root, evident thickening of the canal walls, and closure of the apex.

CONCLUSION

hDPCs combined with LPCGF represents an innovative and effective strategy for cell-based regenerative endodontics.

Characterization of cells in blood evoked from periapical tissues in immature teeth with pulp necrosis and their potential for autologous cell therapy in Regenerative Endodontics

OBJECTIVE

The objectives of this study were to isolate, characterize progenitor cells from blood in the root canals of necrotic immature permanent teeth evoked from periapical tissues and evaluate the applicable potential of these isolated cells in Regenerative Endodontics.

DESIGN

Ten necrotic immature permanent teeth from seven patients were included. Evoked bleeding from periapical tissues was induced after chemical instrumentation of the root canals. Cells were isolated from the canal blood and evaluated for cell surface marker expression, multilineage differentiation potential, proliferation ability, and target protein expression. Cell sheets formed from these cells were transferred into human root segments, and then transplanted into nude mice. Histological examination was performed after eight weeks. Data analysis was conducted using one-way ANOVA followed by Tukey's post-hoc comparison, considering p < 0.05 as statistically significant.

RESULTS

The isolated cells exhibited characteristics typical of fibroblastic cells with colony-forming efficiency, and displayed Ki67 positivity and robust proliferation. Flow cytometry data demonstrated that at passage 3, these cells were positive for CD73, CD90, CD105, CD146, and negative for CD34 and CD45. Vimentin expression indicated a mesenchymal origin. Under differentiation media specific differentiation media, the cells demonstrated osteogenic, adipogenic, and chondrogenic differentiation potential. Subcutaneous root canals with cell sheets of isolated cells in nude mice showed the formation of pulp-like tissues.

CONCLUSIONS

This study confirmed the presence of progenitor cells in root canals following evoked bleeding from periapical tissues of necrotic immature teeth. Isolated cells exhibited similar immunophenotype and regenerative potential with dental mesenchymal stromal cells in regenerative endodontic therapy.

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.

Allogeneic Bone Marrow Mesenchymal Stromal Cell Transplantation Induces Dentin Pulp Complex-like Formation in Immature Teeth with Pulp Necrosis and Apical Periodontitis

INTRODUCTION

Dental pulp regeneration is challenging in endodontics. Cellular therapy is an alternative approach to induce dental pulp regeneration. Mesenchymal stromal cells (MSCs) have the capacity to induce dental pulp-like tissue formation. In this study, we evaluated the capacity of allogeneic bone marrow MSCs (BM-MSCs) to regenerate pulp following necrosis and apical periodontitis in children's permanent immature apex teeth.

METHODS

Patients aged 8 to 12 years with pulp necrosis and apical periodontitis were evaluated. The study included 15 teeth (13 incisors and 2 molars) from 14 patients (8 boys and 6 girls). Radiographic evaluation showed periapical radiolucency and immature apex teeth. There was no response to cold or electric pulp testing. The root canal of each tooth was cleaned, shaped, and Ca(OH)2 used as an interappointment medication. Cryopreserved allogeneic BM-MSCs were thawed, expanded, incorporated into preclotted platelet-rich plasma, and implanted into the tooth's pulp cavity. They were sealed with bioceramic cement and composite. Sensibility, apical foramen, calcium deposits within the root canal, and resolution of periapical lesions were evaluated in each tooth over the following 12 months.

RESULTS

Based on 9 variables established for dental pulp-like tissue regeneration, all MSC-treated teeth showed evidence of successful regeneration. Clinical and radiographic evaluation of the treated teeth showed periapical lesion healing, sensitivity to cold and electricity, decreased width of the apical foramen, and mineralization within the canal space.

CONCLUSIONS

Transplantation of allogeneic MSCs induces the formation of dental pulp-like tissue in permanent immature apex teeth with pulp necrosis and apical periodontitis. Implant of MSCs constitutes a potential therapy in regenerative endodontics in pediatric dentistry. Future studies incorporating a larger sample size may confirm these results.

Cell-Based Regenerative Endodontics for the Treatment of Irreversible Pulpitis: AnIn VivoInvestigation

INTRODUCTION

This study aims to investigate the ability of umbilical cord mesenchymal stem cells (UC-MSC) to enhance the regeneration of pulp-dentin complex in immature permanent teeth with irreversible pulpitis.

METHODS

A total of 32 mandibular premolar teeth with immature apices in 5 dogs were used in this in-vivo randomized controlled trial (RCT). Eight healthy teeth without pre-existing pathosis served as the positive control samples and received no treatment, while in another 8 teeth, the pulp was completely extirpated (negative control). Class V cavities were prepared to induce inflammation in the remaining 16 teeth (groups 3 and 4) and the pulp was extirpated 2-4 mm short of the radiographic apex. Of the 16, the 8 teeth in group 4 received 1 mL of cord blood stem cells with a hydrogel scaffold. Blood clots were covered with mineral trioxide aggregates at the cementoenamel junction in the experimental groups, and teeth were filled with RMGI and composite. Three months later, block sections were removed for histologic evaluations for the evaluation of postoperative apical closure, degree of inflammation, and presence of normal pulp tissue. The data were statistically analyzed with the chi-square test (P < .05).

RESULTS

All teeth with complete pulp extirpation demonstrated pulpal necrosis with no postoperative closure of their apices, while apical closure was seen in all the teeth in the remaining groups. There was a statistically significant (P < .001) difference in the presence of inflammation and normal pulp tissue between the experimental groups. The teeth in group 3 showed normal pulp tissue extending to the level of MTA, but there was inflammation within the canal space. In contrast, the teeth in the UC-MSC group demonstrated organized, normal pulp tissue with no inflammation.

CONCLUSION

Based on these results, the regeneration of the pulp-dentin complex is possible with no inflammation when UC-MSCs are used and 2-4 mm of the apical pulp remains intact in immature teeth with irreversible pulpitis.

Mesenchymal Stromal Cells Derived from Dental Tissues: Immunomodulatory Properties and Clinical Potential

Mesenchymal stem/stromal cells (MSCs) are multipotent cells located in different areas of the human body. The oral cavity is considered a potential source of MSCs because they have been identified in several dental tissues (D-MSCs). Clinical trials in which cells from these sources were used have shown that they are effective and safe as treatments for tissue regeneration. Importantly, immunoregulatory capacity has been observed in all of these populations; however, this function may vary among the different types of MSCs. Since this property is of clinical interest for cell therapy protocols, it is relevant to analyze the differences in immunoregulatory capacity, as well as the mechanisms used by each type of MSC. Interestingly, D-MSCs are the most suitable source for regenerating mineralized tissues in the oral region. Furthermore, the clinical potential of D-MSCs is supported due to their adequate capacity for proliferation, migration, and differentiation. There is also evidence for their potential application in protocols against autoimmune diseases and other inflammatory conditions due to their immunosuppressive capacity. Therefore, in this review, the immunoregulatory mechanisms identified at the preclinical level in combination with the different types of MSCs found in dental tissues are described, in addition to a description of the clinical trials in which MSCs from these sources have been applied.

Pulp Regenerative Therapy Using Autologous Dental Pulp Stem Cells in a Mature Tooth with Apical Periodontitis: A Case Report

The utility and feasibility of pulp regenerative therapy with autologous dental pulp stem cells (DPSCs) in mature teeth with irreversible pulpitis were clinically demonstrated. On the other hand, there is no evidence of the utility of DPSCs in mature teeth with apical periodontitis. The aim of this case report was to describe the potential utility of regenerative cell therapy in mature teeth with apical periodontitis. A 44-year-old man was referred for pulp regeneration due to a periapical lesion in his maxillary first premolar. Root canal disinfection was performed by irrigation and intracanal medication by nanobubbles with levofloxacin and amphotericin B in addition to conventional irrigation. Autologous DPSCs isolated from an extracted third molar were transplanted into the root canal after residual bacteria and fungi were below the detection level by polymerase chain reaction assay using universal genes to amplify specific regions within bacterial 16S ribosomal DNA and fungal ribosomal DNA (ITS1), respectively. There were no adverse events or systemic toxicity assessed for clinical evaluations during the 79-week-follow-up period and laboratory evaluations after 4 weeks. The affected tooth was responsive to the electric pulp test. Cone-beam computed tomographic imaging revealed a reduced lesion size, remission of the periapical tissue, and mineralized tissue formation in the apical part of the canal after 79 weeks. The signal intensity on magnetic resonance imaging of the regenerated tissue in the affected tooth was comparable to that of the normal pulp in the adjacent teeth after 24 weeks. This case report demonstrated the potential use of DPSCs for pulp regenerative therapy in mature teeth with apical periodontitis.

Periapical bacterial disinfection is critical for dental pulp regenerative cell therapy in apical periodontitis in dogs

BACKGROUND

Application of pulp regenerative cell therapy for mature teeth with periapical lesions is a critical clinical challenge. The bacterial infection in inaccessible location within the root canal system and in the periapical lesions could cause resistance and impediment, leading to limitations in successful therapy. Thus, the aim of this study was to examine the effect of residual bacteria on the outcome of pulp regeneration in mature teeth with apical periodontitis in dogs.

METHODS

Periapical lesions were induced in 32 root canals of 4 dogs in two different models in severities, model A and model B. Model A (moderate infection): the canal exposed to the oral cavity for 2 weeks and then closed for 2 weeks. Model B (severe infection): the canal exposed to the oral cavity for 2 months and then closed for 5 months. All root canals were irrigated with 6% sodium hypochlorite, and 3% EDTA and further with 0.015% levofloxacin-containing nanobubbles, which was also used as an intracanal medicament. The aseptic conditions were examined by bacterial anaerobic culture and/or PCR analyses. The root canal treatment was repeated several times, and allogeneic dental pulp stem cells were transplanted into the root canals. The radiographic evaluation of periapical lesions was performed by cone-beam computed tomography before the first treatment, just after cell transplantation, and after 2 months and 6 months in both model A, model B, respectively. The animals were then sacrificed and the jaw blocks were harvested for histological and histobacteriological evaluations of pulp regeneration and periapical tissue healing. Furthermore, the DiI-labelled DPSCs were transplanted into the root canals after complete disinfection (n = 4) or without root canal treatment (n = 4) in the apical periodontitis model (model A) in one dog, and cell localization was compared 72 h after transplantation.

RESULTS

In 8 out of 12 canals from model A, and 10 out of 15 canals from model B, pulp regeneration with good vascularization, innervation, and a significant reduction in the radiolucent area of the periapical lesions were observed. However, in the other 4 canals and 5 canals from model A and model B, respectively, no pulp tissue was regenerated, and inflammation in the periapical tissue, and external resorption or healed external resorption were detected. The presence of residual bacteria in the periapical tissues and severe inflammation were significantly associated with inhibition of regenerated pulp tissue in these 9 unsuccessful canals (P < 0.05, each) (OR = 0.075, each) analyzed by multiple logistic regression analysis. For cellular kinetics, transplanted cells remained in the disinfected root canals, while they were not detected in the infected root canals, suggesting their migration through the apical foramen under the influence of inflammation.

CONCLUSIONS

A true pulp-dentin complex was regenerated in the root canal by the pulp regenerative therapy in mature teeth with apical lesions. The successful pulp regeneration was negatively associated both with residual bacteria and inflammation in the periapical tissue.

Clinical application of calcium silicate-based bioceramics in endodontics

Pulp treatment is extremely common in endodontics, with the main purpose of eliminating clinical symptoms and preserving tooth physiological function. However, the effect of dental pulp treatment is closely related to the methods and materials used in the process of treatment. Plenty of studies about calcium silicate-based bioceramics which are widely applied in various endodontic operations have been reported because of their significant biocompatibility and bioactivity. Although most of these materials have superior physical and chemical properties, the differences between them can also have an impact on the success rate of different clinical practices. Therefore, this review is focused on the applications of several common calcium silicate-based bioceramics, including Mineral trioxide aggregate (MTA), Biodentine, Bioaggregate, iRoot BP Plus in usual endodontic treatment, such as dental pulp capping, root perforation repair, regenerative endodontic procedures (REPs), apexification, root-end filling and root canal treatment (RCT). Besides, the efficacy of these bioceramics mentioned above in human trials is also compared, which aims to provide clinical guidance for their clinical application in endodontics.

Quantification of the Culture Stability of Stem Cell Fractions from Oral-Derived, Human Mesenchymal Stem Cell Preparations: A Significant Step toward the Clinical Translation of Cell Therapies

A continuing limitation and major challenge in the development and utilization of predictable stem cell therapies (SCTs) is the determination of the optimal dosages of stem cells. Herein, we report the quantification of stem cell fractions (SCF) of human mesenchymal stem cell (MSC) preparations derived from oral tissues. A novel computational methodology, kinetic stem cell (KSC) counting, was used to quantify the SCF and specific cell culture kinetics of stem cells in oral alveolar bone-derived MSC (aBMSCs) from eight patients. These analyses established, for the first time, that the SCF within these heterogeneous, mixed-cell populations differs significantly among donors, ranging from 7% to 77% (ANOVA p < 0.0001). Both the initial SCF of aBMSC preparations and changes in the level of the SCF with serial culture over time showed a high degree of inter-donor variation. Hence, it was revealed that the stability of the SCF of human aBMSC preparations during serial cell culture shows inter-donor variation, with some patient preparations exhibiting sufficient stability to support the long-term net expansion of stem cells. These findings provide important insights for the clinical-scale expansion and biomanufacturing of MSCs, which can facilitate establishing more effective and predictable outcomes in clinical trials and treatments employing SCT.

Endodontic Tissue Regeneration: A Review for Tissue Engineers and Dentists

The paradigm shift in the endodontic field from replacement toward regenerative therapies has witnessed the ever-growing research in tissue engineering and regenerative medicine targeting pulp-dentin complex in the past few years. Abundant literature on the subject that has been produced, however, is scattered over diverse areas of knowledge. Moreover, the terminology and concepts are not always consensual, reflecting the range of research fields addressing this subject, from endodontics to biology, genetics, and engineering, among others. This fact triggered some misinterpretations, mainly when the denominations of different approaches were used as synonyms. The evaluation of results is not precise, leading to biased conjectures. Therefore, this literature review aims to conceptualize the commonly used terminology, summarize the main research areas on pulp regeneration, identify future trends, and ultimately clarify whether we are really on the edge of a paradigm shift in contemporary endodontics toward pulp regeneration.

Adult Mesenchymal Stem Cells from Oral Cavity and Surrounding Areas: Types and Biomedical Applications

Adult mesenchymal stem cells are those obtained from the conformation of dental structures (DMSC), such as deciduous and permanent teeth and other surrounding tissues. Background: The self-renewal and differentiation capacities of these adult stem cells allow for great clinical potential. Because DMSC are cells of ectomesenchymal origin, they reveal a high capacity for complete regeneration of dental pulp, periodontal tissue, and other biomedical applications; their differentiation into other types of cells promotes repair in muscle tissue, cardiac, pancreatic, nervous, bone, cartilage, skin, and corneal tissues, among others, with a high predictability of success. Therefore, stem and progenitor cells, with their exosomes of dental origin and surrounding areas in the oral cavity due to their plasticity, are considered a fundamental pillar in medicine and regenerative dentistry. Tissue engineering (MSCs, scaffolds, and bioactive molecules) sustains and induces its multipotent and immunomodulatory effects. It is of vital importance to guarantee the safety and efficacy of the procedures designed for patients, and for this purpose, more clinical trials are needed to increase the efficacy of several pathologies. Conclusion: From a bioethical and transcendental anthropological point of view, the human person as a unique being facilitates better clinical and personalized therapy, given the higher prevalence of dental and chronic systemic diseases.

Clinical trials using dental stem cells: 2022 update

For nearly 20 years, dental stem cells (DSCs) have been successfully isolated from mature/immature teeth and surrounding tissue, including dental pulp of permanent teeth and exfoliated deciduous teeth, periodontal ligaments, dental follicles, and gingival and apical papilla. They have several properties (such as self-renewal, multidirectional differentiation, and immunomodulation) and exhibit enormous potential for clinical applications. To date, many clinical articles and clinical trials using DSCs have reported the treatment of pulpitis, periapical lesions, periodontitis, cleft lip and palate, acute ischemic stroke, and so on, and DSC-based therapies obtained satisfactory effects in most clinical trials. In these studies, no adverse events were reported, which suggested the safety of DSC-based therapy. In this review, we outline the characteristics of DSCs and summarize clinical trials and their safety as DSC-based therapies. Meanwhile, we also present the current limitations and perspectives of DSC-based therapy (such as harvesting DSCs from inflamed tissue, applying DSC-conditioned medium/DSC-derived extracellular vesicles, and expanding-free strategies) to provide a theoretical basis for their clinical applications.

Neural Regeneration in Regenerative Endodontic Treatment: An Overview and Current Trends

Pulpal and periapical diseases are the most common dental diseases. The traditional treatment is root canal therapy, which achieves satisfactory therapeutic outcomes-especially for mature permanent teeth. Apexification, pulpotomy, and pulp revascularization are common techniques used for immature permanent teeth to accelerate the development of the root. However, there are obstacles to achieving functional pulp regeneration. Recently, two methods have been proposed based on tissue engineering: stem cell transplantation, and cell homing. One of the goals of functional pulp regeneration is to achieve innervation. Nerves play a vital role in dentin formation, nutrition, sensation, and defense in the pulp. Successful neural regeneration faces tough challenges in both animal studies and clinical trials. Investigation of the regeneration and repair of the nerves in the pulp has become a serious undertaking. In this review, we summarize the current understanding of the key stem cells, signaling molecules, and biomaterials that could promote neural regeneration as part of pulp regeneration. We also discuss the challenges in preclinical or clinical neural regeneration applications to guide deep research in the future.

BACH1 regulates the proliferation and odontoblastic differentiation of human dental pulp stem cells

Background

The preservation of biological and physiological vitality as well as the formation of dentin are among the main tasks of human dental pulp for a life time. Odontoblastic differentiation of human dental pulp stem cells (hDPSCs) exhibits the capacity of dental pulp regeneration and dentin complex rebuilding. Exploration of the mechanisms regulating differentiation and proliferation of hDPSCs may help to investigate potential clinical applications. BTB and CNC homology 1 (BACH1) is a transcription repressor engaged in the regulation of multiple cellular functions. This study aimed to investigate the effects of BACH1 on the proliferation and odontoblastic differentiation of hDPSCs in vitro.

Methods

hDPSCs and pulpal tissues were obtained from extracted human premolars or third molars. The distribution of BACH1 was detected by immunohistochemistry. The mRNA and protein expression of BACH1 were examined by qRT-PCR and Western blot analysis. BACH1 expression was regulated by stable lentivirus-mediated transfection. Cell proliferation and cell cycle were assessed by cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine assay and flow cytometry. The expression of mineralization markers, alkaline phosphatase (ALP) activity and alizarin red S staining were conducted to assess the odontoblastic differentiation ability.

Results

BACH1 expression was stronger in the odontoblast layer than in the cell rich zone. The total and nuclear protein level of BACH1 during odontoblastic differentiation was downregulated initially and then upregulated gradually. Knockdown of BACH1 greatly inhibited cell proliferation, arrested cell cycle, upregulated the heme oxygenase-1 (HO-1) expression and attenuated ALP activity, decreased calcium deposits and downregulated the expression of mineralization markers. Treatment of Tin-protoporphyrin IX, an HO-1 inhibitor, failed to rescue the impaired odonto/osteogenic differentiation capacity. Overexpression of BACH1 increased cell proliferation, ALP activity and the expression of mineralization markers.

Conclusions

Our findings suggest that BACH1 is an important regulator of the proliferation and odontoblastic differentiation of hDPSCs in vitro. Manipulation of BACH1 expression may provide an opportunity to promote the regenerative capacity of hDPSCs.

The Allogenic Dental Pulp Transplantation from Son/Daughter to Mother/Father: A Follow-Up of Three Clinical Cases

The study investigated allogenic pulp transplantation as an innovative method of regenerative endodontic therapy. Three patients were selected for the endodontic treatment of single-root teeth, who also had a son/daughter with deciduous teeth or third molars scheduled for extraction. Receptor teeth were endodontically instrumented and irrigated using a tri-antibiotic solution. During the transplant procedures, the teeth from the son/daughter were extracted, sectioned, and the pulp was carefully removed. The harvested pulp from the donor was inserted into the root canal of the host tooth (father/mother), followed by direct pulp capping and resin composite restoration. The teeth were followed-up with for 2 years and were surveyed with computed tomography, the electric pulp vitality test, and Doppler ultrasound examination. At the 6-month follow-up, positive pulp vitality and the formation of periapical lesions were verified in cases 1 and 2. Case 3 showed remarkable periapical radiolucency before transplantation, but after 1 year, such lesions disappeared and there was positive vitality. All teeth were revascularized as determined by Doppler imaging after 2 years with no signs of endodontic/periodontal radiolucency. In conclusion, although this was a case series with only three patients and four teeth treated, it is possible to suppose that this allogenic pulp transplantation protocol could represent a potential strategy for pulp revitalization in specific endodontic cases.

Influencing factors of pulp-dentin complex regeneration and related biological strategies

Regenerative endodontic therapy (RET) utilizing tissue engineering approach can promote the regeneration of pulp-dentin complex to restore pulp vascularization, neuralization, immune function and tubular dentin, therefore the regenerated pulp-dentin complex will have normal function. Multiple factors may significantly affect the efficacy of RET, including stem cells, biosignaling molecules and biomaterial scaffolds. Stem cells derived from dental tissues (such as dental pulp stem cells) exhibit certain advantages in RET. Combined application of multiple signaling molecules and activation of signal transduction pathways such as Wnt/β-catenin and BMP/Smad play pivotal roles in enhancing the potential of stem cell migration, proliferation, odontoblastic differentiation, and nerve and blood vessel regeneration. Biomaterials suitable for RET include naturally-derived materials and artificially synthetic materials. Artificially synthetic materials should imitate natural tissues for biomimetic modification in order to realize the temporal and spatial regulation of pulp-dentin complex regeneration. The realization of pulp-dentin complex regeneration depends on two strategies: stem cell transplantation and stem cell homing. Stem cell homing strategy does not require the isolation and culture of stem cells in vitro, so is better for clinical application. However, in order to achieve the true regeneration of pulp-dentin complex, problems related to improving the success rate of stem cell homing and promoting their proliferation and differentiation need to be solved. This article reviews the influencing factors of pulp-dentin complex regeneration and related biological strategies, and discusses the future research direction of RET, to provide reference for clinical translation and application of RET.

Biomaterial scaffolds for clinical procedures in endodontic regeneration

Regenerative endodontic procedures have been rapidly evolving over the past two decades and are employed extensively in clinical endodontics. These procedures have been perceived as valuable adjuvants to conventional strategies in the treatment of necrotic immature permanent teeth that were deemed to have poor prognosis. As a component biological triad of tissue engineering (i.e., stem cells, growth factors and scaffolds), biomaterial scaffolds have demonstrated clinical potential as an armamentarium in regenerative endodontic procedures and achieved remarkable advancements. The aim of the present review is to provide a broad overview of biomaterials employed for scaffolding in regenerative endodontics. The favorable properties and limitations of biomaterials organized in naturally derived, host-derived and synthetic material categories were discussed. Preclinical and clinical studies published over the past five years on the performance of biomaterial scaffolds, as well as current challenges and future perspectives for the application of biomaterials for scaffolding and clinical evaluation of biomaterial scaffolds in regenerative endodontic procedures were addressed in depth.

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Overview of biomaterials for scaffolding in regenerative endodontics are presented.

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Findings of preclinical and clinical studies on the performance of biomaterial scaffolds are summarized.

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Challenges and future prospects in biomaterial scaffolds are discussed.

Investigating the Effects of Conditioned Media from Stem Cells of Human Exfoliated Deciduous Teeth on Dental Pulp Stem Cells

Pulp regeneration has recently attracted interest in modern dentistry. However, the success ratio of pulp regeneration is low due to the compromising potential of stem cells, such as their survival, migration, and odontoblastic differentiation. Stem cells from human exfoliated deciduous teeth (SHED) have been considered a promising tool for regenerative therapy due to their ability to secrete multiple factors that are essential for tissue regeneration, which is achieved by minimally invasive procedures with fewer ethical or legal concerns than those of other procedures. The aim of this study is to investigate the potency of SHED-derived conditioned media (SHED CM) on dental pulp stem cells (DPSCs), a major type of mesenchymal stem cells for dental pulp regeneration. Our results show the promotive efficiency of SHED CM on the proliferation, survival rate, and migration of DPSCs in a dose-dependent manner. Upregulation of odontoblast/osteogenic-related marker genes, such as ALP, DSPP, DMP1, OCN, and RUNX2, and enhanced mineral deposition of impaired DPSCs are also observed in the presence of SHED CM. The analysis of SHED CM found that a variety of cytokines and growth factors have positive effects on cell proliferation, migration, anti-apoptosis, and odontoblast/osteogenic differentiation. These findings suggest that SHED CM could provide some benefits to DPSCs in pulp regeneration.

Specific microRNAs regulate dental pulp stem cell behavior

INTRODUCTION

MicroRNAs (miRNAs), small non-coding RNA, control the translation of messenger RNAs into proteins. miRNAs have a crucial role in regulating the diverse biological processes of many physiological and pathological activities. The aim of this systematic review is to explore various functions of miRNAs in the regulation of dental pulp stem cells (DPSCs) behavior.

METHODS

The articles were searched in PubMed, SCOPUS and ISI Web of Science database using designated keywords. Full-length manuscripts published in English in peer-reviewed journals relevant to the role of miRNAs in DPSC functions were included and reviewed by 2 independent researchers.

RESULTS

The original search of the database generated 299 studies. One hundred and two duplicate studies were removed. After their exclusion, 48 studies were selected for review. miRNAs have shown to modulate the stemness and differentiation of various mesenchymal stem cells. The miRNAs expression profiles in DPSCs were differed compared with other cell types and have been demonstrated to regulate the levels of proteins crucial for promoting or inhibiting DPSC proliferation as well as differentiation. Further, miRNAs also modulate inflammatory processes in dental pulp.

CONCLUSION

miRNAs have various function upon the regulation of DPSCs and understanding these roles of miRNAs is crucial for the development of new therapeutics in regenerative dental medicine. With the advancing technologies, the utilization of miRNA technology could revolutionarily change the future of regenerative endodontics.

Biomolecule-Mediated Therapeutics of the Dentin–Pulp Complex: A Systematic Review

The aim of this systematic review was to evaluate the application of potential therapeutic signaling molecules on complete dentin-pulp complex and pulp tissue regeneration in orthotopic and ectopic animal studies. A search strategy was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement in the MEDLINE/PubMed database. Animal studies evaluating the application of signaling molecules to pulpectomized teeth for pulp tissue or dentin-pulp complex regeneration were included. From 2530 identified records, 18 fulfilled the eligibility criteria and were subjected to detailed qualitative analysis. Among the applied molecules, basic fibroblast growth factor, vascular endothelial growth factor, bone morphogenetic factor-7, nerve growth factor, and platelet-derived growth factor were the most frequently studied. The clinical, radiographical and histological outcome measures included healing of periapical lesions, root development, and apical closure, cellular recolonization of the pulp space, ingrowth of pulp-like connective tissue (vascularization and innervation), mineralized dentin-like tissue formation along the internal dentin walls, and odontoblast-like cells in contact with the internal dentin walls. The results indicate that signaling molecules play an important role in dentin/pulp regeneration. However, further studies are needed to determine a more specific subset combination of molecules to achieve greater efficiency towards the desired tissue engineering applications.

Mesenchymal Stem Cells Based Treatment in Dental Medicine: A Narrative Review

Application of mesenchymal stem cells (MSC) in regenerative therapeutic procedures is becoming an increasingly important topic in medicine. Since the first isolation of dental tissue-derived MSC, there has been an intense investigation on the characteristics and potentials of these cells in regenerative dentistry. Their multidifferentiation potential, self-renewal capacity, and easy accessibility give them a key role in stem cell-based therapy. So far, several different dental stem cell types have been discovered and their potential usage is found in most of the major dental medicine branches. These cells are also researched in multiple fields of medicine for the treatment of degenerative and inflammatory diseases. In this review, we summarized dental MSC sources and analyzed their treatment modalities with particular emphasis on temporomandibular joint osteoarthritis (TMJ OA).

Alginate bone scaffolds coated with a bioactive lactose modified chitosan for human dental pulp stem cells proliferation and differentiation

Bioactive and biodegradable porous scaffolds can hasten the healing of bone defects; moreover, patient stem cells seeded onto scaffolds can enhance the osteoinductive and osteoconductive properties of these biomaterials. In this work, porous alginate/hydroxyapatite scaffolds were functionalized with a bioactive coating of a lactose-modified chitosan (CTL). The highly interconnected porous structure of the scaffold was homogeneously coated with CTL. The scaffolds showed remarkable stability up to 60 days of aging. Human Dental Pulp Stem Cells (hDPSCs) cultured in the presence of CTL diluted in culture medium, showed a slight and negligible increase in terms of proliferation rate; on the contrary, an effect on osteogenic differentiation of the cells was observed as a significant increase in alkaline phosphatase activity. hDPSCs showed higher cell adhesion on CTL-coated scaffolds than on uncoated ones. CTL coating did not affect cell proliferation, but stimulated cell differentiation as shown by alkaline phosphatase activity analysis.

Evaluation of Injectable Hyaluronic Acid-Based Hydrogels for Endodontic Tissue Regeneration

Dental pulp tissue engineering (TE) endeavors to regenerate dentin/pulp complex by combining a suitable supporting matrix, stem cells, and biochemical stimuli. Such procedures foresee a matrix that can be easily introduced into the root canal system (RCS) and tightly adhere to dentin walls to assure the dentin surface’s proper colonization with progenitor cells capable of restoring the dentin/pulp complex. Herein was investigated an injectable self-setting hyaluronic acid-based (HA) hydrogel system, formed by aldehyde-modified (a-HA) with hydrazide-modified (ADH), enriched with platelet lysate (PL), for endodontic regeneration. The hydrogels’ working (wT) and setting (sT) times, the adhesion to the dentine walls, the hydrogel’s microstructure, and the delivery of human dental pulp cells (DPCs) were studied in vitro. Hydrogels incorporating PL showed a suitable wT and sT and a porous microstructure. The tensile tests showed that the breaking point occurs after 4.3106 ± 1.8677 mm deformation, while in the indentation test after 1.4056 ± 0.3065 mm deformation. Both breaking points occur in the hydrogel extension. The HA/PL hydrogels exhibited supportive properties and promoted cell migration toward dentin surfaces in vitro. Overall, these results support using PL-laden HA injectable hydrogels (HA/PL) as a biomaterial for DPCs encapsulation, thereby displaying great clinical potential towards endodontic regenerative therapies.

Vital Pulp Therapy in Aesthetic Zone-Identifying the Biomaterial That Reduces the Risk of Tooth Discolouration

Calcium silicate-based cements are biocompatible materials for vital pulp therapy. However, they discolour the tooth tissue, which is important for the aesthetics of the anterior teeth. The aim of this study was to investigate the effect of calcium silicate-based cements on tooth discolouration. The study included 70 extracted bovine incisors. The crown of the tooth was cut off from the root, 2 mm below the cement-enamel junction. The pulp tissue was removed via a cervical cut with a barbed broach. The teeth were randomly divided into five experimental, one positive, and one negative control groups. The evaluated materials included Biodentine, Ortho MTA, Retro MTA, MTA Plus, MTA Repair HP, and in the positive group, ProRoot MTA. A VITA Easyshade Compact 5.0 spectrophotometer was used before the application, after 1 week, 1 month, 3 months, and 6 months. The significance levels were set at p < 0.05. All materials significantly changed the teeth colour (p < 0.05). However, Ortho MTA, ProRoot MTA, MTA Plus, and Biodentine (ΔE > 6) caused maximum colour change after 6 months. While the ProRoot MTA, Ortho MTA, and MTA Plus caused grey discolouration, Biodentine darkened the shade of the base colour. Thus, Retro MTA and MTA Repair HP can be safely used in the aesthetic dentition zone. According to these clinical results, the possibility of using Biodentine, due to its lack of gray discoloration, can be considered.

Assessment of Microstructure and Release of Fluoride Ions from Selected Fissure Sealants: An In Vitro Study

The aim of this study was to compare fluoride release from four selected fissure sealants: fissure sealant manufactured by Arkona, Helioseal F, Helioseal F Plus, and Conseal. Tested parameters included emission of fluoride ions into saline (0.9% NaCl) and deionized water over a period of 2 weeks. Values were recorded after 1, 3, 24, 48, 72, and 96 h, and then after 1 and 2 weeks. All sealants were characterized by a constant fluoride release level. The highest fluoride release level was noted for Conseal (0.0169 ppm/mg), while the lowest was noted for fissure sealant manufactured by Arkona (0.063 ppm/mg). Fissure sealants, which contain fluoride, release it not only during polymerization, but also for several days after application. The use of fissure sealants whose composition includes fluoride is an effective method of preventing tooth decay.

Functional Dental Pulp Regeneration: Basic Research and Clinical Translation

Pulpal and periapical diseases account for a large proportion of dental visits, the current treatments for which are root canal therapy (RCT) and pulp revascularisation. Despite the clinical signs of full recovery and histological reconstruction, true regeneration of pulp tissues is still far from being achieved. The goal of regenerative endodontics is to promote normal pulp function recovery in inflamed or necrotic teeth that would result in true regeneration of the pulpodentinal complex. Recently, rapid progress has been made related to tissue engineering-mediated pulp regeneration, which combines stem cells, biomaterials, and growth factors. Since the successful isolation and characterisation of dental pulp stem cells (DPSCs) and other applicable dental mesenchymal stem cells, basic research and preclinical exploration of stem cell-mediated functional pulp regeneration via cell transplantation and cell homing have received considerably more attention. Some of this effort has translated into clinical therapeutic applications, bringing a ground-breaking revolution and a new perspective to the endodontic field. In this article, we retrospectively examined the current treatment status and clinical goals of pulpal and periapical diseases and scrutinized biological studies of functional pulp regeneration with a focus on DPSCs, biomaterials, and growth factors. Then, we reviewed preclinical experiments based on various animal models and research strategies. Finally, we summarised the current challenges encountered in preclinical or clinical regenerative applications and suggested promising solutions to address these challenges to guide tissue engineering-mediated clinical translation in the future.

Dental Pulp Autotransplantation: A New Modality of Endodontic Regenerative Therapy-Follow-Up of 3 Clinical Cases

The aim of this study was to develop a novel method of endodontic therapy, which we refer to as dental pulp autotransplantation. Three patients (2 males and 1 female) were selected for endodontic treatment of a uniradicular premolar and extraction of a third molar (without odontosection). Electric assessment of pulp vitality and computed tomographic imaging were undertaken followed by endodontic access and instrumentation using triantibiotic solution for irrigation in the host tooth. A few minutes before the transplant procedure, the third molar was extracted, the tooth was sectioned with a diamond blade in a low-speed handpiece, and the pulp was carefully removed. After premolar instrumentation, the harvested and preserved pulp tissue was reinserted into the root canal followed by direct pulp capping performed using Biodentine (Septodont, Saint-Maur-des-Fossés, France), a liner of resin-modified glass ionomer cement and composite resin restoration. The teeth were followed up for at least 12 months after the procedures and were analyzed using computed tomographic imaging, electric pulp vitality testing, and Doppler ultrasound examination. At the 3- and 6-month follow-ups, positive pulp vitality and regression of periapical lesions were verified. After 9-12 months, all teeth were revascularized as determined by Doppler imaging, and the tooth vitality was reestablished with no signs of endodontic/periodontal radiolucency or complications. Within the limitations of the study, considering that it was a case series with only 3 patients, we described a highly innovative procedure of pulp autotransplantation, which appears to be feasible, highlighting the potential for clinical application of pulp regeneration using this new modality of endodontic therapy.

Roles of Dental Mesenchymal Stem Cells in the Management of Immature Necrotic Permanent Teeth

Dental caries and trauma always lead to pulp necrosis and subsequent root development arrest of young permanent teeth. The traditional treatment, apexification, with the absence of further root formation, results in abnormal root morphology and compromises long-term prognosis. Regeneration endodontics procedures (REPs) have been developed and considered as an alternative strategy for management of immature permanent teeth with pulpal necrosis, including cell-free and cell-based REPs. Cell-free REPs, including revascularization and cell homing with molecules recruiting endogenous mesenchymal stem cells (MSCs), have been widely applied in clinical treatment, showing optimistic periapical lesion healing and continued root development. However, the regenerated pulp-dentin complex is still absent in these cases. Dental MSCs, as one of the essentials of tissue engineering, are vital seed cells in regenerative medicine. Dental MSC-based REPs have presented promising potential with pulp-dentin regeneration in large animal studies and clinical trials via cell transplantation. In the present review, we summarize current understanding of the biological basis of clinical treatments for immature necrotic permanent teeth and the roles of dental MSCs during this process and update the progress of MSC-based REPs in the administration of immature necrotic permanent teeth.

Knowledge, Attitude, and Perception Among Endodontists Toward Regenerative Endodontics: A Cross-sectional Survey of Four Indian Universities

Background:

Regenerative endodontics is a rapidly developing field in dentistry. However, the regenerative endodontic procedures are not familiar to many clinicians in India.

Aim:

This survey aimed at assessing the level of knowledge, attitude, and perception (KAP) among endodontists toward regenerative endodontics.

Materials and Methods:

A cross-sectional survey was conducted in the year 2019 to collect data. A questionnaire to collect data on KAP toward regenerative endodontics was administered to 49 faculty and 69 postgraduate students of endodontics from four universities. The Chi-Square test and logistic regression were applied to study the association between KAP and demographic variables. Spearman's rho was computed to study the correlation between KAP scale scores of the participants. The data were analyzed by using Statistical Package for the Social Sciences software program (SPSS), version 15.0 (South Asia, Bangalore).

Results:

The survey yielded an overall response rate of 81%. Less than 50% of the participants had sound knowledge, 65% had a positive attitude, and only 21% had a positive perception about Regenerative Endodontic Procedures (REPs). Most of the participants (86.5%) were of the opinion that regenerative therapies should be a part of dentistry. Majority of the participants (89.6%) were inclined to receive training in REPs. About 80% of the participants felt that the higher cost of treatment is a significant hurdle for patients to accept REPs. Less than half the participants (41.7%) were using REPs in their clinical practice, such as the use of membranes, scaffolds, and revascularization.

Conclusion:

Endodontists have a positive attitude toward the use of regenerative therapies. However, there is a deficiency of training in REPs in dental colleges.

Clinical cell-based versus cell-free regenerative endodontics: clarification of concept and term

There is no consensus on the true meaning of clinical regenerative endodontics, and there is confusion over the concept and the term. Commonly used terms include revitalization and revascularization. The clinical methods for endodontic revitalization procedures and the tissue engineering concept differ depending on whether there is exogenous delivery of cells - called cell therapy, or not. Here, in this review, the difference is clarified by emphasizing the correct terminology: cell-free versus cell-based regenerative endodontic therapy (CF-RET versus CB-RET). The revitalization procedures practised clinically do not fit into the modern tissue engineering concepts of pulp regeneration but can be categorized as CF-RET. The modern tissue engineering concept in pulp regeneration is a CB-RET, which so far is at the clinical trial stage. However, histological examination of teeth following regenerative endodontic treatments reveals healing with repair derived from stem cells that originate from the periodontal, bone and other tissues. The aim of regenerative endodontics is regeneration of the pulp-dentine complex. This review discusses why CF-RET is unlikely to regenerate a pulp-dentine complex with current protocols. The American Association of Endodontists and the European Society of Endodontology have not yet recommended autologous stem cell transplantation (CB-RERT) which aspires for regeneration. Therefore, an understanding of the concept, term, difficulties and differences in current protocols is important for the clinician. However, rather than being discouraged that ideal regeneration has not been achieved to date, repair can be an acceptable outcome in clinical regenerative endodontics as it has also been accepted in medicine. Repair should also be considered in the context that resolution of the clinical signs/symptoms of pulp necrosis/apical periodontitis is generally reliably obtained in clinical regenerative endodontics.

Treatment outcome of regenerative endodontic procedures in mature permanent teeth compared to nonsurgical endodontic treatment: A systematic review and meta-analysis

Background:

Regenerative endodontic procedures (REP) have the advantage of restoring root canal's native defense ability by re-establishing vital pulp-like tissue. This review aims to determine the overall clinical and/or radiographic success rate (O) of REP (I) in mature permanent teeth (P) and to compare it (C) with nonsurgical endodontic treatment (NSET).

Materials and Methods:

Sources: PubMed, Web of Science, Embase, EBSCO, Cochrane Central Register of Controlled trials, ClinicalTrials.gov, Clinical Trials Registry-India and OpenGrey. Inclusion: Randomized clinical trials and single-arm prospective studies evaluating the treatment outcomes of REP in mature permanent teeth. Exclusion: Incomplete trials/studies, in vitro studies, animal studies, case reports/series, conference proceedings. Cochrane ROB2.0 and ROBINS-I tools were used to assess the risk of bias. Risk difference (R.D.) between NSET and REP was determined by meta-analysis of the randomized clinical trials. The overall success rate of REP was calculated using data from both randomized clinical trials and single-arm prospective studies. Sensitivity analysis and subgroup analysis were performed.

Results:

Ten studies (n = 552) were included. R.D between REP and NSET was 0.032 (95% C.I: 0.023–0.087; P = 0.258). Overall success rate of REP was 96.0% (95% confidence interval: 94%–98%). No significant difference was found in sensitivity analysis (P = 0.551), or any of the subgroup analysis (P > 0.05).

Discussion:

A limited number of randomized clinical trials were available, and only two of them had a low risk of bias. Consistent results were obtained in both types of included studies.

Conclusion:

Based on a limited number of comparative studies, REP has a similar success rate to NSET in mature permanent teeth.

Other:

Funding: Nil. Registration: PROSPERO (CRD42020204882).

Hydrogels and Dentin-Pulp Complex Regeneration: From the Benchtop to Clinical Translation

Dentin-pulp complex is a term which refers to the dental pulp (DP) surrounded by dentin along its peripheries. Dentin and dental pulp are highly specialized tissues, which can be affected by various insults, primarily by dental caries. Regeneration of the dentin-pulp complex is of paramount importance to regain tooth vitality. The regenerative endodontic procedure (REP) is a relatively current approach, which aims to regenerate the dentin-pulp complex through stimulating the differentiation of resident or transplanted stem/progenitor cells. Hydrogel-based scaffolds are a unique category of three dimensional polymeric networks with high water content. They are hydrophilic, biocompatible, with tunable degradation patterns and mechanical properties, in addition to the ability to be loaded with various bioactive molecules. Furthermore, hydrogels have a considerable degree of flexibility and elasticity, mimicking the cell extracellular matrix (ECM), particularly that of the DP. The current review presents how for dentin-pulp complex regeneration, the application of injectable hydrogels combined with stem/progenitor cells could represent a promising approach. According to the source of the polymeric chain forming the hydrogel, they can be classified into natural, synthetic or hybrid hydrogels, combining natural and synthetic ones. Natural polymers are bioactive, highly biocompatible, and biodegradable by naturally occurring enzymes or via hydrolysis. On the other hand, synthetic polymers offer tunable mechanical properties, thermostability and durability as compared to natural hydrogels. Hybrid hydrogels combine the benefits of synthetic and natural polymers. Hydrogels can be biofunctionalized with cell-binding sequences as arginine-glycine-aspartic acid (RGD), can be used for local delivery of bioactive molecules and cellularized with stem cells for dentin-pulp regeneration. Formulating a hydrogel scaffold material fulfilling the required criteria in regenerative endodontics is still an area of active research, which shows promising potential for replacing conventional endodontic treatments in the near future.

Dentin-Pulp Tissue Regeneration Approaches in Dentistry: An Overview and Current Trends

Conventional treatment approaches in irreversible pulpitis and apical periodontitis include the disinfection of the pulp space followed by filling with various materials, which is commonly known as the root canal treatment. Disadvantages including the loss of tooth vitality and defense mechanism against carious lesions, susceptibility to fractures, discoloration and microleakage led to the development of regenerative therapies for the dentin pulp-complex. The goal of dentin-pulp tissue regeneration is to reestablish the physiological pulp function such as pulp sensibility, pulp repair capability by mineralization and pulp immunity. Recent dentin-pulp tissue regeneration approaches can be divided into cell homing and cell transplantation. Cell based approaches include a suitable scaffold for the delivery of potent stem cells with or without bioactive molecules into the root canal system while cell homing is based on the recruitment of host endogenous stem cells from the resident tissue including periapical region or dental pulp. This review discusses the recent treatment modalities in dentin-pulp tissue regeneration through tissue engineering and current challenges and trends in this field of research.

Retrospective evaluation of endodontic case reports published in the International Endodontic Journal and the Journal of Endodontics for their compliance with the PRICE 2020 guidelines

AIM

To evaluate, retrospectively, the quality of previously published case reports in Endodontics according to the PRICE 2020 guidelines.

METHODOLOGY

An electronic literature search was conducted in PubMed database on 12 March 2020, to identify case reports published during the last five years in the International Endodontic Journal and the Journal of Endodontics. For each of the included case reports, information regarding fulfilment of each of the items of the PRICE 2020 guidelines was extracted as '0' (not present in the manuscript), '1' (present in the manuscript) and 'NA' (not applicable) and translated into a score (percentage of items fulfilled). Additionally, the percentage of papers fulfilling each item was calculated.

RESULTS

Overall, 70 endodontic case reports were identified. The scores of the papers ranged between 56.41% and 79.55%, with a mean score of 70.26 ± 4.36% (SD). The percentage of papers fulfilling each item of the applicable PRICE 2020 items ranged widely, between 0% and 100%. The median of the percentage of all the items (n = 47) was 97.01% and mean 73.33 ± 36.28% (SD). The lowest scores were recorded for specific items in the following domains: 'Case Report Information'-Items 6c, 6g-i, 'Patient Perspective'-Item 8a and 'Quality of Images'-Items 12c-d.

CONCLUSIONS

Several areas with low reporting rates were identified in case reports published over the last 5 years in Endodontics. Authors should be encouraged to follow the PRICE 2020 guidelines in order to increase the quality and improve reproducibility of their case reports.

A Xeno-Free Strategy for Derivation of Human Umbilical Vein Endothelial Cells and Wharton's Jelly Derived Mesenchymal Stromal Cells: A Feasibility Study toward Personal Cell and Vascular Based Therapy

Coimplantation of endothelial cells (ECs) and mesenchymal stromal cells (MSCs) into the transplantation site could be a feasible option to achieve a sufficient level of graft-host vascularization. To find a suitable source of tissue that provides a large number of high-quality ECs and MSCs suited for future clinical application, we developed a simplified xeno-free strategy for isolation of human umbilical vein endothelial cells (HUVECs) and Wharton's jelly-derived mesenchymal stromal cells (WJ-MSCs) from the same umbilical cord. We also assessed whether the coculture of HUVECs and WJ-MSCs derived from the same umbilical cord (autogenic cell source) or from different umbilical cords (allogenic cell sources) had an impact on in vitro angiogenic capacity. We found that HUVECs grown in 5 ng/ml epidermal growth factor (EGF) supplemented xeno-free condition showed higher proliferation potential compared to other conditions. HUVECs and WJ-MSCs obtained from this technic show an endothelial lineage (CD31 and von Willebrand factor) and MSC (CD73, CD90, and CD105) immunophenotype characteristic with high purity, respectively. It was also found that only the coculture of HUVEC/WJ-MSC, but not HUVEC or WJ-MSC mono-culture, provides a positive effect on vessel-like structure (VLS) formation, in vitro. Further investigations are needed to clarify the pros and cons of using autogenic or allogenic source of EC/MSC in tissue engineering applications. To the best of our knowledge, this study offers a simple, but reliable, xeno-free strategy to establish ECs and MSCs from the same umbilical cord, a new opportunity to facilitate the development of personal cell-based therapy.

Dental Tissue-Derived Human Mesenchymal Stem Cells and Their Potential in Therapeutic Application

Human mesenchymal stem cells (hMSCs) are multipotent cells, which exhibit plastic adherence, express specific cell surface marker spectrum, and have multi-lineage differentiation potential. These cells can be obtained from multiple tissues. Dental tissue-derived hMSCs (dental MSCs) possess the ability to give rise to mesodermal lineage (osteocytes, adipocytes, and chondrocytes), ectodermal lineage (neurocytes), and endodermal lineages (hepatocytes). Dental MSCs were first isolated from dental pulp of the extracted third molar and till now they have been purified from various dental tissues, including pulp tissue of permanent teeth and exfoliated deciduous teeth, apical papilla, periodontal ligament, gingiva, dental follicle, tooth germ, and alveolar bone. Dental MSCs are not only easily accessible but are also expandable in vitro with relative genomic stability for a long period of time. Moreover, dental MSCs have exhibited immunomodulatory properties by secreting cytokines. Easy accessibility, multi-lineage differentiation potential, and immunomodulatory effects make dental MSCs distinct from the other hMSCs and an effective tool in stem cell-based therapy. Several preclinical studies and clinical trials have been performed using dental MSCs in the treatment of multiple ailments, ranging from dental diseases to nondental diseases. The present review has summarized dental MSC sources, multi-lineage differentiation capacities, immunomodulatory features, its potential in the treatment of diseases, and its application in both preclinical studies and clinical trials. The regenerative therapeutic strategies in dental medicine have also been discussed.

Allogeneic Cellular Therapy in a Mature Tooth with Apical Periodontitis and Accidental Root Perforation: A Case Report

INTRODUCTION

Cell therapy in regenerative endodontics introduces an alternative option to classic treatment strategies for complex endodontic cases. The aim of this case report was to describe cell-based therapy using allogeneic umbilical cord mesenchymal stem cells (UC-MSCs) encapsulated in a bioscaffold for a complex case of a mature permanent tooth with apical periodontitis and accidental root perforation.

METHODS

A healthy 19-year-old man undergoing orthodontic treatment was referred for endodontic treatment in tooth #7; he was diagnosed with apical periodontitis during a previously initiated treatment associated with accidental perforation of the radicular cervical third. The root perforation was sealed with glass ionomer and composite resin, and the root canal was instrumented, disinfected, and dressed with calcium hydroxide. After 3 weeks, allogeneic UC-MSCs were encapsulated in platelet-poor plasma and then implanted into the root canal, and Biodentine (Septodont, Saint-Maur-des-Fosses, France) was placed below the cementoenamel junction. Finally, the tooth was restored with composite resin.

RESULTS

Follow-up examinations were performed 6 months and 1 year later. The examinations included periapical radiography, cone-beam computed tomographic imaging, and sensitivity and vitality tests. Radiographic and cone-beam computed tomographic images indicated remission of the apical lesion. Clinical evaluations revealed normal responses to percussion and palpation tests; the tooth was responsive to the electric pulp test, and the vitality test indicated low blood perfusion units.

CONCLUSIONS

This case report reveals the potential use of allogeneic cellular therapy using encapsulated UC-MSCS in a platelet-poor plasma scaffold for a complex case of a permanent tooth with apical periodontitis and root perforation.

A Practical Guide to Class IIa Medical Device Development

There are many beneficial medical device ideas based on clinical needs and laboratory research, but medical device development is an expensive, time-consuming and complex challenge. Research and quality management, which are both needed to develop a medical device, are two distinct fields, initiated by a researcher or a clinician having a concept for a medical device, and it is often challenging to find and achieve the proper steps to create a licensed product. Thus, in this paper, we demonstrate the required mindset and main steps of the medical device development procedure through an existing example, a Class IIa medical device, called hypACT Inject Auto. HypACT is a specific syringe, which is capable of blood drawing and serum from platelet-rich fibrin (SPRF) isolation in one step in a closed system. SPRF is intended to be used to improve joint functions in the case of musculoskeletal diseases, specifically osteoarthritis.

Cell-Based Regenerative Endodontics for Treatment of Periapical Lesions: A Randomized, Controlled Phase I/II Clinical Trial

A randomized controlled phase I/II clinical trial was designed to evaluate the safety and efficacy of encapsulated human umbilical cord mesenchymal stem cells in a plasma-derived biomaterial for regenerative endodontic procedures (REPs) in mature permanent teeth with apical lesions. The trial included 36 patients with mature incisors, canines, or mandibular premolars showing pulp necrosis and apical periodontitis. Patients were randomly and equally allocated between experimental (REP) or conventional root canal treatment (ENDO) groups. On the first visit, cavity access and mechanical preparation of the root canal were performed. Calcium hydroxide medication was used, and the cavity was sealed. Three weeks later, patients were treated following their assigned protocol of ENDO or REP. Clinical follow-up examinations were performed at 6 and 12 mo. Categorical variables were evaluated by Fisher's exact test. Quantitative variables were compared using the Mann-Whitney test. The evolution over time of the percentage of perfusion units and the dimensions of lesion and cortical compromise were explored. After the 12-mo follow-up, no adverse events were reported, and the patients showed 100% clinical efficacy in both groups. Interestingly, in the REP group, the perfusion unit percentage measured by laser Doppler flowmetry revealed an increase from 60.6% to 78.1% between baseline and 12-mo follow-up. Sensitivity tests revealed an increase of the positive pulp response in the REP group at 12-mo follow-up (from 6% to 56% on the cold test, from 0% to 28% on the hot test, and from 17% to 50% on the electrical test). We present the first clinical safety and efficacy evidence of the endodontic use of allogenic umbilical cord mesenchymal stem cells encapsulated in a plasma-derived biomaterial. The innovative approach, based on biological principles that promote dentin-pulp regeneration, presents a promising alternative for the treatment of periapical pathology (ClinicalTrials.gov NCT03102879).