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Objective@#To study the effect of stem cell factor (SCF) on the angiogenic ability of cocultured dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs).@*Methods @#This study has been reviewed and approved by the Ethics Committee. The experiment was split into the HUVECs, SCF+HUVECs, DPSCs+HUVECs, and SCF+DPSCs+HUVECs groups. A mixture of SCF and culture medium was used to prepare a mixed culture medium with an SCF concentration of 100 ng/mL. In vitro coculture of DPSCs and HUVECs was performed at a 1∶5 ratio. CCK-8 proliferation assay was used to observe the proliferative capacity of cells in each group on days 1, 3, 5, and 7. Wound healing and Transwell migration assays were used to detect the effect of SCF on cell migration under either direct or indirect coculture conditions, respectively. In vitro angiogenesis experiments were performed to detect the angiogenic capacity of the cells in each group. The vascular endothelial growth factor A (VEGFA) concentration in the cell culture supernatant was detected using ELISAs, and the protein expression levels of CD31, CD34, and VEGFA were detected using Western blot analysis. @*Results @# Wound healing and Transwell migration experiments showed that SCF significantly promoted the migration of cocultured DPSCs and HUVECs (P<0.05). The in vitro angiogenesis experiment showed that the number of branches and the total length of branches of tubular structures in the SCF+DPSCs+HUVECs group were significantly greater than those of the other groups (P<0.05), and the expression levels of the vascular-related proteins CD31, CD34, and VEGFA in this group were greater (P<0.01). @*Conclusion @# SCF can enhance the migration and in vitro angiogenesis of cocultured DPSCs and HUVECs.
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@#With the development of molecular biology, biomaterials and tissue engineering, regenerative treatment of pulpal and periradicular diseases is facing new opportunities. At present, a large number of studies on dental pulp regeneration reveal that cytokines are essential for promoting migration, proliferation and osteogenic differentiation of dental pulp stem cells. In this paper, we review several kinds of cytokines related to dental pulp regeneration, and analyze their roles and regulatory mechanisms in dental pulp regeneration.
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Objective @#To investigate the effects of N-cadherin silencing on the proliferation and migration of human dental pulp stem cells (DPSCs) and to provide experimental evidence for DPSCs-based dental pulp regeneration.@* Methods@# DPSCs were transfected with N-cadherin shRNA lentivirus, and the knockdown efficiency of N-cadherin at both the mRNA and protein levels was confirmed by qRT-PCR and Western blot. The experiment included a negative control group (shRNA -NC) and an N-cadherin shRNA silencing group. Cell proliferation was detected by the CCK-8 method. Cell cycle and apoptosis were assessed by flow cytometry, and cell migration was detected using the Transwell method.@*Results@#N-cadherin shRNA significantly reduced the expression levels of N-cadherin mRNA and protein in DPSCs (P<0.001). The proliferation activity of the N-cadherin shRNA group was significantly greater than that of the shRNA-NC group on the 3rd and 4th days after cell inoculation and lower than that of the shRNA-NC group from the 6th to 8th days (P<0.05). On the 3rd day after cell inoculation, the proportion of cells in S phase and G2 phase in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.05). On the 6th day after cell inoculation, the proportion of cells in S phase and G2 phase in the N-cadherin shRNA group was lower than that in the shRNA-NC group (P<0.05), and the proportion of apoptotic cells in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.01). Low densities cells and high densities cells were inoculated into Transwell upper chamber for 20 h, the number of cells passing through the membrane pores of upper chamber in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.001).@*Conclusion@#Silencing N-cadherin expression can promote the early proliferation and migration of DPSCs.
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Objective@#To compare the color stability of Biodentine and mineral trioxide aggregate (MTA) within the blood environment in vitro and to further investigate the underlying reasons for such color instability. @*Methods @#We first generated Biodentine and MTA discs with a diameter of 5 mm and a height of 3 mm. 24 discs of each material were randomly divided into two groups: the deionized water group and the defibrinated sheep blood group. Discs of each group were immersed for 1 day or 7 days before assessments. First, all discs were photographed to directly compare the discoloration of Biodentine and MTA. The color degree of the two materials was tested by a spectrophotometer. Then, the high-resolution morphological characteristics were observed by scanning electron microscopy. Finally, the chemical contents of each element in the material were measured by energy-dispersive spectroscopy.@*Results @#Compared to immediately after stripping, a change in the brightness of discs after immersion in defibrinated sheep blood for 1 day was observed only in MTA. On the 7th day after being immersed in blood, the colors of both the Biodentine and MTA discs darkened and turned deep red, but the darkness of the MTA discs increased significantly. The color change of MTA immersed in blood was measured on a spectrophotometer with a greater 7-day ∆E (21.257 ± 0.955) than the Biodentine 7-day ∆E (5.833 ± 0.501) (t=24.781, P < 0.001). MTA exhibits more discoloration as the immersion time goes on. A significant difference was noted between the 1-day ∆E(6.233 ± 0.888) and the 7-day ∆E(t=19.956, P < 0.001) of MTA immersed in blood. However, there was no statistically significant difference between the 1-day ∆E (6.790 ± 0.831) and the 7-day ∆E(t=1.707, P=0.163) of Biodentine immersed in blood. It was observed by scanning electron microscopy that after 7 days of immersion in the defibrinated sheep ablood, the surface porosity of MTA was larger than that of Biodentine, and the crystal edge of MTA became rounded and blunt. The analysis by energy-dispersive X-ray spectroscopy showed that the oxygen content decreased and the bismuth content increased in MTA after immersion in defibrinated sheep blood for 7 days. Zirconium was not detected in Biodentine due to its low radiodensity, but the contents of other elements were stable in Biodentine after immersion in defibrinated sheep blood for 7 days. @* Conclusion@#The color stability of Biodentine within the blood environment is better than that of MTA in vitro, which is mainly related to the low surface porosity and stable composition of the anti-radiation agent of Biodentine.
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@#The development of materials science is of great significance to the treatment of dental pulp diseases. Poly lactic acid glycolic acid (PLGA) copolymer is an organic macromolecule compound that is widely used in the preparation of biomedical materials. In recent years, PLGA, as a drug/molecular loaded system and tissue regeneration scaffold, has shown prospects for application in the treatment of dental pulp diseases. This paper will review the application of PLGA in the treatment of dental pulp diseases and provide a basis for its further development and utilization. The results of the literature review show that PLGA is a drug/molecular delivery system that is mainly used in the improvement of pulp capping materials, root canal disinfectant and apexification materials. PLGA-improved pulp capping agents can prolong the action time of the drug and reduce toxicity. The modified root canal disinfectant can realize the sustained release of drug, make the drug penetrate deeper into the subtle structure, and contact more widely with the pathogenic bacteria. The modified apexification materials can provide more convenient administration methods for apexifixment. As a scaffold for tissue engineering, PLGA is mainly used in the study of pulp regeneration. The optimization of PLGA physical properties and action environment can provide a more suitable microenvironment for seed cells to proliferate and differentiate. How to utilize the advantages of PLGA to develop a more suitable material for endodontic application needs further study.
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Pulp necrosis can cause increased tooth fragility and easy fracture, and hinder the sustainable development of young permanent teeth. Therefore, pulp regeneration therapy has important clinical significance. However, due to the complicated and varied anatomical structure of the pulp tissue, and various components such as nerves and blood vessels, there are many challenges in dental pulp regeneration strategy. In this paper, the recent research progress in the application of dental pulp tissue construction and transplantation by tissue engineering method was reviewed, and the selection of suitable scaffold materials and the construction of dental pulp tissue were discussed. The functional characteristics of scaffold materials were described,such as sodium alginate, chitosan, hyaluronic acid, collagen, gelatin, fibrous protein, silk fibroin, peptides and self-assembled peptides, polylactic acid, polyglycolic acid and their copolymers. In addition, the functions and characteristics of these materials were briefly introduced, as well as the functional modification with growth factors and other biological matrix extract involvement, and functional improvement of the composite scaffolds with complementary effects.Combined with the requirements of clinical operability, the composition design and functional characteristics of the injectable hydrogel scaffolds consisted of hydrophilic composite materials and/or modified with hydrophilic groups were also discussed.This review paper would be useful in providing some reference for the future research and exploration of dental pulp regeneration.
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@#Endothelial regeneration is a research hotspot in the field of dental pulp. The regeneration of endodontic blood flow is the bottleneck of dental pulp regeneration, and the applied scaffold material is the key to revascularization. Stent materials were reviewed. The literature review Results show that, depending on the source of the stent material used for endodontic revascularization, there are mainly natural, synthetic and composite materials. The natural scaffold materials used for vascular regeneration include chitosan, hyaluronic acid, bacterial cellulose, and proanthocyanidin; artificial scaffold materials include hydrogel, cryogel, and electrospinning. The bionic composite scaffold system with a double-layer tubular structure is low immunogenicity and good biocompatibility. Studies on the scaffold materials of bionic extracellular matrix, such as injectable hydrogels/microspheres, have promoted the development of dental pulp regeneration, that is, uniformly distributed scaffold materials in the root canal promote the generation of pulp-like tissue; Whether dental pulp tissue can establish effective blood circulation through the apical foramen remains a great challenge.
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BACKGROUND: With the application of tissue engineering technology In the field of stomatology, It Is possible to construct a tissue-engineered dental pulp for the regeneration of dentin-pulp complex. Formation of new blood supply system through angiogenesis Is mandatory to dental pulp regeneration. Angiogenesis is defined as the formation of new blood vessels from preexisting capillaries, which has great significance in pulp regeneration and homeostasis. OBJECTIVE: To review the contribution of exosomes and angiogenic factors to angiogenesis in the dental pulp. METHODS: A search of PubMed and CNKI was performed for relevant literature published from 2017 through 2019. The search terms were "tissue engineering, pulp regeneration, regenerative endodontics, angiogenesis, neovascularization, angiogenic, signal molecules, exosomes, factors, role, mechanism" In English and Chinese, respectively. RESULTS AND CONCLUSION: Many studies have indicated an intimate relationship between angiogenesis and dental pulp regeneration. The contribution of exosomes and angiogenic factors to angiogenesis of the dental pulp has been previously discussed. Angiogenesis is an indispensable process during dental pulp regeneration. The survival of transplanted pulp tissue is closely linked to the process of angiogenesis at sites of application. However, further Investigations are warranted on the detailed regulatory mechanisms of exosomes and factors Involved In Initiation and progression of angiogenesis In pulp tissue.
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BACKGROUND: Rapid development in tissue engineering research and technology makes dental pulp regeneration and revascularization possible. The interactions of stem cells, scaffolds and signaling factors in tissue engineering are particularly important. Whether stem cells can proliferate, differentiate and develop dental pulp-like tissue greatly depends on the choice of scaffolds OBJECTIVE: To review the widely studied and effective scaffold materials and two methods of scaffold preparation and analyze their applications in dental pulp reconstruction and their revascularization ability. METHODS: The first author searched PubMed, Wanfang and CNKI databases using a computer for relevant articles published between January 1, 2019 and September 30, 2019 with the search terms “pulp regeneration, pulp revascularization, scaffold” in English, and “pulp regeneration, pulp revascularization, revascularization, scaffold” in Chinese. A total of 421 English articles and 181 Chinese articles were retrieved. Finally, 61 articles were reviewed. RESULTS AND CONCLUSION: Platelet-derived scaffolds, extracellular-matrix-derived scaffolds, and self-assembling peptide take effect in pulp regeneration and revascularization. Composite materials combining natural and synthetic materials prepared by hydrogel and nanomaterial techniques exhibited advantages in cell proliferation, differentiation, migration, adherence, anti-inflammation, and factor delivery. The modified composite materials have a strong ability to promote vascularization. With the development of scaffold design and preparation technology based on hydrogels and nanomaterials, problems regarding insufficient scaffold source and unstable clinical effect will be solved in the future.