Creating a Microenvironment to Give Wings to Dental Pulp Regeneration-Bioactive Scaffolds

Engineered MXene Biomaterials for Regenerative Medicine

MXene-based materials have attracted significant interest due to their distinct physical and chemical properties, which are relevant to fields such as energy storage, environmental science, and biomedicine. MXene has shown potential in the area of tissue regenerative medicine. However, research on its applications in tissue regeneration is still in its early stages, with a notable absence of comprehensive reviews. This review begins with a detailed description of the intrinsic properties of MXene, followed by a discussion of the various nanostructures that MXene can form, spanning from 0 to 3 dimensions. The focus then shifts to the applications of MXene-based biomaterials in tissue engineering, particularly in immunomodulation, wound healing, bone regeneration, and nerve regeneration. MXene's physicochemical properties, including conductivity, photothermal characteristics, and antibacterial properties, facilitate interactions with different cell types, influencing biological processes. These interactions highlight its potential in modulating cellular functions essential for tissue regeneration. Although the research on MXene in tissue regeneration is still developing, its versatile structural and physicochemical attributes suggest its potential role in advancing regenerative medicine.

Angiogenic and neurogenic potential of dental-derived stem cells for functional pulp regeneration: A narrative review

BACKGROUND

Dental pulp tissue engineering is expected to become an ideal treatment for irreversible pulpitis and apical periodontitis. However, angiogenesis and neurogenesis for functional pulp regeneration have not yet met the standard for large-scale clinical application, and need further research.

OBJECTIVE

This review focused on the potential mechanisms of angiogenesis and neurogenesis in pulp regeneration, including stem cell types, upstream and downstream regulatory molecules and cascade signalling pathways, thereby providing a theoretical basis and inspiring new ideas to improve the effectiveness of dental pulp tissue engineering.

METHODS

An electronic literature search was carried out using the keywords of 'pulp regeneration', 'stem cell transplantation', 'dental pulp stem cells', 'angiogenesis' and 'neurogenesis'. The resulting literature was screened and reviewed.

RESULTS

Stem cells used in dental pulp tissue engineering can be classified as dental-derived and non-dental-derived stem cells, amongst which dental pulp stem cells (DPSC) have achieved promising results in animal experiments and clinical trials. Multiple molecules and signalling pathways are involved in the process of DPSC-mediated angiogenic and neurogenetic regeneration. In order to promote angiogenesis and neurogenesis in pulp regeneration, feasible measures include the addition of growth factors, the modulation of transcription factors and signalling pathways, the use of extracellular vesicles and the modification of bioscaffold materials.

CONCLUSION

Dental pulp tissue engineering has had breakthroughs in preclinical and clinical studies in vivo. Overcoming difficulties in pulpal angiogenesis and neurogenesis, and achieving functional pulp regeneration will lead to a significant impact in endodontics.

Scaffold-Free Strategies in Dental Pulp/Dentine Tissue Engineering: Current Status and Implications for Regenerative Biological Processes

Conventionally, root canal treatment is performed when the dental pulp is severely damaged or lost due to dental trauma or bacterial endodontic infections. This treatment involves removing the compromised or infected pulp tissue, disinfecting the root canal system, and sealing it with inert, non-degradable materials. However, contemporary endodontic treatment has shifted from merely obturating the root canal system with inert materials to guiding endodontic tissue regeneration through biological approaches. The ultimate goal of regenerative endodontics is to restore dental pulp tissue with structural organization and functional characteristics akin to the native pulp, leveraging advancements in tissue engineering and biomaterial sciences. Dental pulp tissue engineering commonly employs scaffold-based strategies, utilizing biomaterials as initial platforms for cell and growth factor delivery, which subsequently act as scaffolds for cell proliferation, differentiation and maturation. However, cells possess an intrinsic capacity for self-organization into spheroids and can generate their own extracellular matrix, eliminating the need for external scaffolds. This self-assembling property presents a promising alternative for scaffold-free dental pulp engineering, addressing limitations associated with biomaterial-based approaches. This review provides a comprehensive overview of cell-based, self-assembling and scaffold-free approaches in dental pulp tissue engineering, highlighting their potential advantages and challenges in advancing regenerative endodontics.

Adrenomedullin-loaded Gelatin Methacryloyl Hydrogel Promotes Endogenous Dental Pulp Regeneration: An In Vitro and In Vivo Study

INTRODUCTION

To prepare a gelatin methacryloyl (GelMA) hydrogel scaffold embedded with adrenomedullin (ADM) and investigate its impact and underlying mechanisms in endogenous pulp regeneration.

METHODS

ADM was evenly distributed within the GelMA hydrogel through a simple and conventional physical mixing technique. The scaffold underwent characterization via scanning electron microscopy, alongside assessments of swelling, degradation, and release properties. Biocompatibility was evaluated using cytoskeletal and live-dead staining techniques. The hydrogel's influence on dental pulp stem cells' proliferation, migration, and differentiation was assessed with CCK-8 assays, Transwell assays, and alizarin red and alkaline phosphatase staining. Transcriptomics provided insights into potential mechanisms. The angiogenic effects on umbilical vein endothelial cells were examined using scratch and tube formation assays. In vivo, the composite hydrogel's regenerative capacity was tested in a rat model of pulp regeneration. Statistical analysis involved Student's t-test and one-way analysis of variance, with significance set at P < .05.

RESULTS

The ADM-loaded GelMA (GelMA@ADM) hydrogel displayed a porous architecture under electron microscopy conducive to cell adhesion and demonstrated excellent biocompatibility. In vitro experiments showed that GelMA@ADM significantly boosted dental pulp stem cells' migration, proliferation, and differentiation, and enhanced the angiogenic activity of umbilical vein endothelial cells after one week of treatment. Corresponding in vivo experiments revealed that GelMA@ADM facilitated the formation of new vascularized pulp tissue after 2 weeks of treatment.

CONCLUSIONS

The GelMA@ADM hydrogel effectively promotes dental pulp stem cells' proliferation and differentiation, augments vascularization by umbilical vein endothelial cells, and fosters the creation of new vascularized pulp tissue. These findings underscore the potential of GelMA@ADM hydrogel for endogenous pulp regeneration.

Histological Evaluation of Photobiomodulation and Calcium Aluminosilicate on Direct Pulp Capping of Dogs' Permanent Teeth

Introduction: Photobiomodulation (PBM) is beneficial to biological tissues; depending on the optical dose that is absorbed by tissues, it can function as a biostimulative, analgesic, and anti-inflammatory mediator. Thus, the current research aimed to assess the impacts of PBM and Calcium aluminosilicate-based material on direct pulp capping (DPC) of dogs' permanent teeth through histological analysis. Methods: To study DPC of dogs' teeth, we separated 24 canines and premolars obtained from mature, healthy mongrel dogs into four equal groups: group 1, which served as the control (exposed pulp was covered with a sterile polytetrafluoroethylene, Teflon tape); group 2, which received PBM treatment using a 980 nm diode laser with a 100 mw output power for one minute; group 3: Calcium aluminosilicate-based material; group 4: Calcium aluminosilicate+PBM. In accordance with the assessment period, each group was divided into three equal subcategories: (A) 1 week; (B) 2 months; (C) 3 months. The teeth were evaluated histologically for inflammatory response and dentine bridge formation. Results: Statistical analysis detected that there was a significant difference between PBM, Calcium aluminosilicate cement, and the combination group of PBM and Calcium aluminosilicate related to the control group in variant evaluation periods regarding the inflammatory response and dentine bridge thickness through the histological analysis. In relation to the inflammatory response after one week, the combined group (Calcium silicate cement+PBM) exhibited a significantly decreased intensity of inflammation compared to other groups at an identical time. As for dentin bridge creation, the PBM+calcium aluminosilicate group detected thicker dentine bridge creation at three months than other studied groups. Conclusion: Combined with calcium aluminosilicate-based material, PBM using a 980 nm diode laser with output power of 100 mw for one minute decreased the initial inflammatory response and enhanced a complete thick dentine bridge formation.

Recent Advances in Whiskers: Properties and Clinical Applications in Dentistry

Whiskers are nanoscale, high-strength fibrous crystals with a wide range of potential applications in dentistry owing to their unique mechanical, thermal, electrical, and biological properties. They possess high strength, a high modulus of elasticity and good biocompatibility. Hence, adding these crystals to dental composites as reinforcement can considerably improve the mechanical properties and durability of restorations. Additionally, whiskers are involved in inducing the value-added differentiation of osteoblasts, odontogenic osteocytes, and pulp stem cells, and promoting the regeneration of alveolar bone, periodontal tissue, and pulp tissue. They can also enhance the mucosal barrier function, inhibit the proliferation of tumor cells, control inflammation, and aid in cancer prevention. This review comprehensively summarizes the classification, properties, growth mechanisms and preparation methods of whiskers and focuses on their application in dentistry. Due to their unique physicochemical properties, excellent biological properties, and nanoscale characteristics, whiskers show great potential for application in bone, periodontal, and pulp tissue regeneration. Additionally, they can be used to prevent and treat oral cancer and improve medical devices, thus making them a promising new material in dentistry.

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.

Injectable Xenogeneic Dental Pulp Decellularized Extracellular Matrix Hydrogel Promotes Functional Dental Pulp Regeneration

The present challenge in dental pulp tissue engineering scaffold materials lies in the development of tissue-specific scaffolds that are conducive to an optimal regenerative microenvironment and capable of accommodating intricate root canal systems. This study utilized porcine dental pulp to derive the decellularized extracellular matrix (dECM) via appropriate decellularization protocols. The resultant dECM was dissolved in an acid pepsin solution to form dECM hydrogels. The analysis encompassed evaluating the microstructure and rheological properties of dECM hydrogels and evaluated their biological properties, including in vitro cell viability, proliferation, migration, tube formation, odontogenic, and neurogenic differentiation. Gelatin methacrylate (GelMA) hydrogel served as the control. Subsequently, hydrogels were injected into treated dentin matrix tubes and transplanted subcutaneously into nude mice to regenerate dental pulp tissue in vivo. The results showed that dECM hydrogels exhibited exceptional injectability and responsiveness to physiological temperature. It supported the survival, odontogenic, and neurogenic differentiation of dental pulp stem cells in a 3D culture setting. Moreover, it exhibited a superior ability to promote cell migration and angiogenesis compared to GelMA hydrogel in vitro. Additionally, the dECM hydrogel demonstrated the capability to regenerate pulp-like tissue with abundant blood vessels and a fully formed odontoblast-like cell layer in vivo. These findings highlight the potential of porcine dental pulp dECM hydrogel as a specialized scaffold material for dental pulp regeneration.