Effect of light-, chemical-, and dual-cured universal adhesives on the internal adaptation of resin composites to pulpal and gingival internal walls.

PURPOSE: To compare the internal adaptation of restorative systems bonded to mid-coronal and gingival dentin using light-cured, chemical-cured, and dual-cured adhesives, both immediately and after aging. METHODS: 60 molars were selected and received occluso-mesial preparations with dentin gingival margins. Restorations were performed using different restorative systems with light-cured, chemical-cured, and dual-cured adhesives. Internal adaptation was assessed by examining the percentage of continuous margin (%CM) at the pulpal and gingival dentin under a scanning electron microscope at x200 magnification. Half of the teeth were stored in sterile water for 24 hours, while the other half underwent 10,000 thermal cycles. Micro-morphological analysis was conducted on representative samples at x1,000 magnification. RESULTS: The restorative system with light-cured adhesive exhibited significantly lower %CM values at the gingival dentin, particularly after aging. Aging had a negative impact on the %CM values of the pulpal and gingival dentin in restorative systems with light-cured and dual-cured adhesives. Regional dentin variations influenced the %CM values, especially after aging, regardless of the restorative system used. The tested restorative system with chemical-cured adhesive is preferable for achieving improved internal adaptation when bonding to both mid-coronal and gingival dentin, compared to the other tested systems. CLINICAL SIGNIFICANCE: The study highlights the variations in adhesive performance between different regional dentin areas using the tested restorative systems.

Macrophage M2 polarization promotes pulpal inflammation resolution during orthodontic tooth movement.

Mechanical force induces hypoxia in the pulpal area by compressing the apical blood vessels of the pulp, triggering pulpal inflammation during orthodontic tooth movement. However, this inflammation tends to be restorable. Macrophages are recognized as pivotal immunoreactive cells in the dental pulp. Whether they are involved in the resolution of pulpal inflammation in orthodontic teeth remains unclear. In this study, we investigated macrophage polarization and its effects during orthodontic tooth movement. It was demonstrated that macrophages within the dental pulp polarized to M2 type and actively participated in the process of pulpal inflammation resolution. Inflammatory reactions were generated and vascularization occurred in the pulp during orthodontic tooth movement. Macrophages in orthodontic pulp show a tendency to polarize towards M2 type as a result of pulpal hypoxia. Furthermore, by blocking M2 polarization, we found that macrophage M2 polarization inhibits dental pulp-secreting inflammatory factors and enhances VEGF production. In conclusion, our findings suggest that macrophages promote pulpal inflammation resolution by enhancing M2 polarization and maintaining dental health during orthodontic tooth movement.

Inhibition of lipopolysaccharide-induced NF-κB maintains osteogenesis of dental pulp and periodontal ligament stem cells.

Dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) can differentiate into osteoblasts, indicating that both are potential candidates for bone tissue engineering. Osteogenesis is influenced by many environmental factors, one of which is lipopolysaccharide (LPS). LPS-induced NF-κB activity affects the osteogenic potencies of different types of MSCs differently. This study evaluated the effect of LPS-induced NF-κB activity and its inhibition in DPSCs and PDLSCs. DPSCs and PDLSCs were cultured in an osteogenic medium, pretreated with/without NF-κB inhibitor Bay 11-7082, and treated with/without LPS. Alizarin red staining was performed to assess bone nodule formation, which was observed under an inverted light microscope. NF-κB and alkaline phosphatase (ALP) activities were measured to examine the effect of Bay 11-7082 pretreatment and LPS supplementation on osteogenic differentiation of DPSCs and PDLSCs. LPS significantly induced NF-κB activity (p = 0.000) and reduced ALP activity (p = 0.000), which inhibited bone nodule formation in DPSCs and PDLSCs. Bay 11-7082 inhibited LPS-induced NF-κB activity, and partially maintained ALP activity and osteogenic potency of LPS-supplemented DPSCs and PDLSCs. Thus, inhibition of LPS-induced NF-κB activity can maintain the osteogenic potency of DPSCs and PDLSCs.

Machine learning assisted 5-part tooth segmentation method for CBCT-based dental age estimation in adults.

BACKGROUND: The utilization of segmentation method using volumetric data in adults dental age estimation (DAE) from cone-beam computed tomography (CBCT) was further expanded by using current 5-Part Tooth Segmentation (SG) method. Additionally, supervised machine learning modelling -namely support vector regression (SVR) with linear and polynomial kernel, and regression tree - was tested and compared with the multiple linear regression model. MATERIAL AND METHODS: CBCT scans from 99 patients aged between 20 to 59.99 was collected. Eighty eligible teeth including maxillary canine, lateral incisor, and central incisor were used in this study. Enamel to dentine volume ratio, pulp to dentine volume ratio, lower tooth volume ratio, and sex was utilized as independent variable to predict chronological age. RESULTS: No multicollinearity was detected in the models. The best performing model comes from maxillary lateral incisor using SVR with polynomial kernel ( = 0.73). The lowest error rate achieved by the model was given also by maxillary lateral incisor, with 4.86 years of mean average error and 6.05 years of root means squared error. However, demands a complex approach to segment the enamel volume in the crown section and a lengthier labour time of 45 minutes per tooth.

Evaluation of dental pulp stem cells response to flowable nano-hybrid dental composites: A comparative analysis.

BACKGROUND: Flowable resin composites (FRC) are tooth-colored restorative materials that contain a lower filler particle content, and lower viscosity than their bulk counterparts, making them useful for specific clinical applications. Yet, their chemical makeup may impact the cellular population of the tooth pulp. This in-vitro study assessed the cytocompatibility and odontogenic differentiation capacity of dental pulp stem cells (DPSCs) in response to two recent FRC material extracts. METHODS: Extracts of the FRC Aura easyflow (AEF) and Polofil NHT Flow (PNF) were applied to DPSCs isolated from extracted human teeth. Cell viability of DPSCs was assessed using MTT assay on days 1, 3 and 7. Cell migration was assessed using the wound healing assay. DPSCs' capacity for osteo/odontogenic differentiation was assessed by measuring the degree of mineralization by Alizarin Red S staining, alkaline phosphatase enzyme (ALP) activity, and monitoring the expression of osteoprotegerin (OPG), RUNX Family Transcription Factor 2 (RUNX2), and the odontogenic marker dentin sialophosphoprotein (DSPP) by RT-PCR. Monomer release from the FRC was also assessed by High-performance liquid chromatography analysis (HPLC). RESULTS: DPSCs exposed to PNF extracts showed significantly higher cell viability, faster wound closure, and superior odontogenic differentiation. This was apparent through Alizarin Red staining of calcified nodules, elevated alkaline phosphatase activity, and increased expression of osteo/odontogenic markers. Moreover, HPLC analysis revealed a higher release of TEDGMA, UDMA, and BISGMA from AEF. CONCLUSIONS: PNF showed better cytocompatibility and enhancement of odontogenic differentiation than AEF.

Human dental pulp stem cells mitigate the neuropathology and cognitive decline via AKT-GSK3ß-Nrf2 pathways in Alzheimer's disease.

Oxidative stress is increasingly recognized as a major contributor to the pathophysiology of Alzheimer's disease (AD), particularly in the early stages of the disease. The multiplicity advantages of stem cell transplantation make it fascinating therapeutic strategy for many neurodegenerative diseases. We herein demonstrated that human dental pulp stem cells (hDPSCs) mediated oxidative stress improvement and neuroreparative effects in in vitro AD models, playing critical roles in regulating the polarization of hyperreactive microglia cells and the recovery of damaged neurons. Importantly, these therapeutic effects were reflected in 10-month-old 3xTg-AD mice after a single transplantation of hDPSCs, with the treated mice showing significant improvement in cognitive function and neuropathological features. Mechanistically, antioxidant and neuroprotective effects, as well as cognitive enhancements elicited by hDPSCs, were at least partially mediated by Nrf2 nuclear accumulation and downstream antioxidant enzymes expression through the activation of the AKT-GSK3ß-Nrf2 signaling pathway. In conclusion, our findings corroborated the neuroprotective capacity of hDPSCs to reshape the neuropathological microenvironment in both in vitro and in vivo AD models, which may be a tremendous potential therapeutic candidate for Alzheimer's disease.

GelMA-based hydrogel biomaterial scaffold: A versatile platform for regenerative endodontics.

Endodontic therapy, while generally successful, is primarily limited to mature teeth, hence the pressing need to explore regenerative approaches. Gelatin methacryloyl (GelMA) hydrogels have emerged as pivotal biomaterials, promising a bright future for dental pulp regeneration. Despite advancements in tissue engineering and biomaterials, achieving true pulp tissue regeneration remains a formidable task. GelMA stands out for its injectability, rapid gelation, and excellent biocompatibility, serving as the cornerstone of scaffold materials. In the pursuit of dental pulp regeneration, GelMA holds significant potential, facilitating the delivery of stem cells, growth factors, and other vital substances crucial for tissue repair. Presently, in the field of dental pulp regeneration, researchers have been diligently utilizing GelMA hydrogels as engineering scaffolds to transport various effective substances to promote pulp regeneration. However, existing research is relatively scattered and lacks comprehensive reviews and summaries. Therefore, the primary objective of this article is to elucidate the application of GelMA hydrogels as regenerative scaffolds in this field, thereby providing clear direction for future researchers. Additionally, this article provides a comprehensive discussion on the synthesis, characterization, and application of GelMA hydrogels in root canal therapy regeneration. Furthermore, it offers new application strategies and profound insights into future challenges, such as optimizing GelMA formulations to mimic the complex microenvironment of pulp tissue and enhancing its integration with host tissues.

The Effect of Glycyrrhizin on the Viability and Proliferation of Dental Pulp Stem Cells Compared to Intracanal Medicaments.

AIM: To study the effect of glycyrrhizin (GA) on the viability and proliferation of dental pulp stem cells (DPSCs) compared with intracanal medicaments. MATERIALS AND METHODS: Third molars of an adult donor were used to obtain the DPSCs. Flow cytometry was utilized to conduct phenotypic analysis for DPSCs. The methyl-thiazol tetrazolium (MTT) test was used to detect the cell viability. Cell proliferation assay was conducted at distinct time intervals: 3, 5, and 7 days. RESULTS: The flow cytometry analysis verified the positive expression of mesenchymal cell surface antigen molecules (CD73, CD90, and CD105) and the absence of hematological markers (CD14, CD34, and CD45) in the DPSCs. The cells that treated with concentrations more than 0.5 mg/mL of Ca(OH2) and triple antibiotic paste (TAP) gave significant decrease in viability in comparison to the untreated cells (p < 0.05). Also, the cells treated with concentrations 50 and 25 µM of GA showed no significant difference compared with the untreated cells (p > 0.05), while concentrations 12.5 and 6.25 µM expressed a significant increase in viability compared with the untreated cells (p < 0.05). At 7 days, cells treated with the three different concentrations of GA (12.5, 25, and 50 µM) demonstrated a significant increase in cell density compared with Ca(OH)2 and TAP-treated cells (p < 0.05). CONCLUSION: Based upon the potential of GA on DPSCs proliferation compared with Ca(OH)2 and TAP, It is conceivable to acknowledge that GA could be used as an intracanal medicaments for revascularization process of necrotic immature teeth. CLINICAL SIGNIFICANCE: This study emphasizes the significance of assessing alternative root canal medicaments and their impact on the proliferation and viability of DPSCs. The results regarding GA, specifically its impact on the viability and growth of DPSCs, provide essential understanding for its potential application as an intracanal medicine. This study adds to the continuous endeavors in identifying safer and more efficient intracanal therapies, which are essential for improving patient outcomes in endodontic operations. How to cite this article: Alrashidi MA, Badawi MF, Elbeltagy MG, et al. The Effect of Glycyrrhizin on the Viability and Proliferation of Dental Pulp Stem Cells Compared to Intracanal Medicaments. J Contemp Dent Pract 2024;25(3):267-275.

[Pulp revascularization procedure for external inflammatory dental root resorption treatment]. / Primenenie metodiki regeneratsii pul'popodobnoi tkani dlya ostanovki naruzhnoi vospalitel'noi rezorbtsii kornya zuba.

THE AIM OF THE STUDY: To assess the effectiveness of pulp revascularization procedure in children with external inflammatory root resorption (EIRR) after constant teeth injury. MATERIALS AND METHOS: The study comprised 17 children aged 6-10 years diagnosed with EIRR as a long-term complication of dental trauma in 19 teeth. EIRR was diagnosed with periapical radiographs and CBCT was performed to further assess the pathology extension. Pulp revascularization was carried out in all 19 teeth. RESULTS: There was no resorption progression in all cases. EIRR areas were substituted by bone. In 10 from 19 teeth with early stages of root development bone or cement-like tissue ingrowth into the root canal was observed radiologically. In cases of severe EIRR this ingrowth may partially compensate for lost tissues which is confirmed by a high percentage (94.7%) of functional teeth during mean follow up time of 38±10 months. CONCLUSION: Pulp revascularization is an effective method for retaining teeth with EIRR for a relatively long period of time and allows maintaining alveolar bone volume both due to functional tooth preservation and healing of bone lesions in periapical and resorption areas.

Reconstructing Critical-Sized Mandibular Defects in a Rabbit Model: Enhancing Angiogenesis and Facilitating Bone Regeneration via a Cell-Loaded 3D-Printed Hydrogel-Ceramic Scaffold Application.

In this study, we propose a spatially patterned 3D-printed nanohydroxyapatite (nHA)/beta-tricalcium phosphate (ß-TCP)/collagen composite scaffold incorporating human dental pulp-derived mesenchymal stem cells (hDP-MSCs) for bone regeneration in critical-sized defects. We investigated angiogenesis and osteogenesis in a rabbit critical-sized mandibular defect model treated with this engineered construct. The critical and synergistic role of collagen coating and incorporation of stem cells in the regeneration process was confirmed by including a cell-free uncoated 3D-printed nHA/ß-TCP scaffold, a stem cell-loaded 3D-printed nHA/ß-TCP scaffold, and a cell-free collagen-coated 3D-printed nHA/ß-TCP scaffold in the experimental design, in addition to an empty defect. Posteuthanasia evaluations through X-ray analysis, histological assessments, immunohistochemistry staining, histomorphometry, and reverse transcription-polymerase chain reaction (RT-PCR) suggest the formation of substantial woven and lamellar bone in the cell-loaded collagen-coated 3D-printed nHA/ß-TCP scaffolds. Histomorphometric analysis demonstrated a significant increase in osteoblasts, osteocytes, osteoclasts, bone area, and vascularization compared to that observed in the control group. Conversely, a significant decrease in fibroblasts/fibrocytes and connective tissue was observed in this group compared to that in the control group. RT-PCR indicated a significant upregulation in the expression of osteogenesis-related genes, including BMP2, ALPL, SOX9, Runx2, and SPP1. The findings suggest that the hDP-MSC-loaded 3D-printed nHA/ß-TCP/collagen composite scaffold is promising for bone regeneration in critical-sized defects.

Dental Stem Cells and Lipopolysaccharides: A Concise Review.

Dental tissue stem cells (DTSCs) are well known for their multipotent capacity and regenerative potential. They also play an important role in the immune response of inflammatory processes derived from caries lesions, periodontitis, and gingivitis. These oral diseases are triggered by toxins known as lipopolysaccharides (LPS) produced by gram-negative bacteria. LPS present molecular patterns associated with pathogens and are recognized by Toll-like receptors (TLRs) in dental stem cells. In this review, we describe the effect of LPS on the biological behavior of DTSCs. We also focus on the molecular sensors, signaling pathways, and emerging players participating in the interaction of DTSCs with lipopolysaccharides. Although the scientific advances generated provide an understanding of the immunomodulatory potential of DTSCs, there are still new reflections to explore with regard to their clinical application in the treatment of oral inflammatory diseases.

Construction of dental pulp decellularized matrix by cyclic lavation combined with mechanical stirring and its proteomic analysis.

The decellularized matrix has a great potential for tissue remodeling and regeneration; however, decellularization could induce host immune rejection due to incomplete cell removal or detergent residues, thereby posing significant challenges for its clinical application. Therefore, the selection of an appropriate detergent concentration, further optimization of tissue decellularization technique, increased of biosafety in decellularized tissues, and reduction of tissue damage during the decellularization procedures are pivotal issues that need to be investigated. In this study, we tested several conditions and determined that 0.1% Sodium dodecyl sulfate and three decellularization cycles were the optimal conditions for decellularization of pulp tissue. Decellularization efficiency was calculated and the preparation protocol for dental pulp decellularization matrix (DPDM) was further optimized. To characterize the optimized DPDM, the microstructure, odontogenesis-related protein and fiber content were evaluated. Our results showed that the properties of optimized DPDM were superior to those of the non-optimized matrix. We also performed the 4D-Label-free quantitative proteomic analysis of DPDM and demonstrated the preservation of proteins from the natural pulp. This study provides a optimized protocol for the potential application of DPDM in pulp regeneration.

The effect of continuous long-term illumination with visible light in different spectral ranges on mammalian cells.

One of the biggest challenges in tissue engineering and regenerative medicine is to ensure oxygen supply of cells in the (temporary) absence of vasculature. With the vision to exploit photosynthetic oxygen production by microalgae, co-cultivated in close vicinity to oxygen-consuming mammalian cells, we are searching for culture conditions that are compatible for both sides. Herein, we investigated the impact of long-term illumination on mammalian cells which is essential to enable photosynthesis by microalgae: four different cell types-primary human fibroblasts, dental pulp stem cells, and osteoblasts as well as the murine beta-cell line INS-1-were continuously exposed to warm white light, red or blue light over seven days. We observed that illumination with red light has no adverse effects on viability, metabolic activity and growth of the cells whereas exposure to white light has deleterious effects that can be attributed to its blue light portion. Quantification of intracellular glutathione did not reveal a clear correlation of this effect with an enhanced production of reactive oxygen species. Finally, our data indicate that the cytotoxic effect of short-wavelength light is predominantly a direct effect of cell illumination; photo-induced changes in the cell culture media play only a minor role.

Dental Pulp Stem Cell-Derived Exosomes Promote Sciatic Nerve Regeneration via Optimizing Schwann Cell Function.

Repair strategies for injured peripheral nerve have achieved great progresses in recent years. However, the clinical outcomes remain unsatisfactory. Recent studies have found that exosomes secreted by dental pulp stem cells (DPSC-exos) have great potential for applications in nerve repair. In this study, we evaluated the effects of human DPSC-exos on improving peripheral nerve regeneration. Initially, we established a coculture system between DPSCs and Schwann cells (SCs) in vitro to assess the effect of DPSC-exos on the activity of embryonic dorsal root ganglion neurons (DRGs) growth in SCs. We extracted and labeled human DPSC-exos, which were subsequently utilized in uptake experiments in DRGs and SCs. Subsequently, we established a rat sciatic nerve injury model to evaluate the therapeutic potential of DPSC-exos in repairing sciatic nerve damage. Our findings revealed that DPSC-exos significantly promoted neurite elongation by enhancing the proliferation, migration, and secretion of neurotrophic factors by SCs. In vivo, DPSC-exos administration significantly improved the walking behavior, axon regeneration, and myelination in rats with sciatic nerve injuries. Our study underscores the vast potential of DPSC-exos as a therapeutic tool for tissue-engineered nerve construction.

KAT2A-mediated succinylation modification of notch1 promotes the proliferation and differentiation of dental pulp stem cells by activating notch pathway.

BACKGROUND: Dental pulp stem cells (DPSCs) are a kind of undifferentiated dental mesenchymal stem cells with strong self-renewal ability and multi-differentiation potential. This study aimed to investigate the regulatory functions of succinylation modification in DPSCs. METHODS: DPSCs were isolated from the dental pulp collected from healthy subjects, and then stem cell surface markers were identified using flow cytometry. The osteogenic differentiation ability of DPSCs was verified by alkaline phosphatase (ALP) and alizarin red staining methods, while adipogenic differentiation was detected by oil red O staining. Meanwhile, the mRNA of two desuccinylases (SIRT5 and SIRT7) and three succinylases (KAT2A, KAT3B, and CPT1A) in DPSCs before and after mineralization induction were detected using quantitative real-time PCR. The cell cycle was measured by flow cytometry, and the expression of bone-specific genes, including COL1a1 and Runx2 were evaluated by western blotting and were combined for the proliferation and differentiation of DPSCs. Co-immunoprecipitation (co-IP) and immunofluorescence were combined to verify the binding relationship between proteins. RESULTS: The specific markers of mesenchymal stem cells were highly expressed in DPSCs, while the osteogenic differentiation ability of isolated DPSCs was confirmed via ALP and alizarin red staining. Similarly, the oil red O staining also verified the adipogenic differentiation ability of DPSCs. The levels of KAT2A were found to be significantly upregulated in mineralization induction, which significantly decreased the ratio of G0/G1 phase and increased S phase cells; converse results regarding cell cycle distribution were obtained when KAT2A was inhibited. Moreover, overexpression of KAT2A promoted the differentiation of DPSCs, while its inhibition exerted the opposite effect. The elevated KAT2A was found to activate the Notch1 signaling pathway, which succinylated Notch1 at the K2177 site to increase their corresponding protein levels in DPSCs. The co-IP results showed that KAT2A and Notch1 were endogenously bound to each other, while inhibition of Notch1 reversed the effects of KAT2A overexpression on the DPSCs proliferation and differentiation. CONCLUSION: KAT2A interacted directly with Notch1, succinylating the Notch1 at the K2177 site to increase their corresponding protein levels in DPSCs. Similarly, KAT2A-mediated succinylation modification of Notch1 promotes the DPSCs proliferation and differentiation, suggesting that targeting KAT2A and Notch1 may contribute to tooth regeneration.

The Influence of Lysosomal Stress on Dental Pulp Stem Cell-Derived Schwann Cells.

BACKGROUND: Dysregulation of the endo-lysosomal-autophagy pathway has been identified as a critical factor in the pathology of various demyelinating neurodegenerative diseases, including peripheral neuropathies. This pathway plays a crucial role in transporting newly synthesized myelin proteins to the plasma membrane in myelinating Schwann cells, making these cells susceptible to lysosome-related dysfunctions. Nevertheless, the specific impact of lysosomal dysfunction in Schwann cells and its contribution to neurodegeneration remain poorly understood. METHODS: We aim to mimic lysosomal dysfunction in Schwann cells using chloroquine, a lysosomal dysfunction inducer, and to monitor lysosomal leakiness, Schwann cell viability, and apoptosis over time. Additionally, due to the ethical and experimental issues associated with cell isolation and the culturing of human Schwann cells, we use human dental pulp stem cell-derived Schwann cells (DPSC-SCs) as a model in our study. RESULTS: Chloroquine incubation boosts lysosomal presence as demonstrated by an increased Lysotracker signal. Further in-depth lysosomal analysis demonstrated an increased lysosomal size and permeability as illustrated by a TEM analysis and GAL3-LAMP1 staining. Moreover, an Alamar blue assay and Caspase-3 staining demonstrates a reduced viability and increased apoptosis, respectively. CONCLUSIONS: Our data indicate that prolonged lysosomal dysfunction leads to lysosomal permeability, reduced viability, and eventually apoptosis in human DPSC-SCs.

Performance evaluation of carbon quantum dots impregnated glass ionomer cement to avoid peri-implant disease.

Dental cement residues exacerbate peri-implant tissue irritation and peri-implantitis. The present study aims to evaluate the cytotoxicity, physiochemical, optical, and rheological properties of carbon quantum dots (CQDs) impregnated glass ionomer cement (GIC). Surface passivated fluorescent CQDs were synthesized using citric acid via thermal decomposition and blended with GIC. Characterization studies and rheological measurements were made to evaluate their performance. 3D-printed dental implant models cemented with GIC and GIC-CQD were compared to analyze excess cement residues. MTT assay was performed with human dental pulp stem cells (hDPSCs) and statistically analyzed using ANOVA and Tukey's test. CQDs with a particle dimension of ∼2 nm were synthesized. The amorphous property of GIC-CQD was confirmed through XRD. The fluorescence properties of GIC-CQD showed three times higher emission intensity than conventional GIC. GIC-CQD attained maturation with a setting time extended by 64 s than GIC. Cement residue of size 2 mm was detected with a UV light excitation at a distance between 5 to 10 cm. Biocompatibility at 0.125 mg ml-1dilution concentrations of GIC-CQD showed viability greater than 80% to hDPSCs. For the first time, we report that CQDs-impregnated GIC is a unique and cost-effective strategy for in-situ detection of excess cement rapidly using a hand-held device. A novel in-situ rapid detection method enables the dentist to identify residual cement of size less than 2 mm during the implantation. Therefore, GIC-CQD would replace conventional GIC and help in the prevention of peri-implant diseases.

Chemically modified microRNA delivery via DNA tetrahedral frameworks for dental pulp regeneration.

Dental pulp regeneration is a promising strategy for addressing tooth disorders. Incorporating this strategy involves the fundamental challenge of establishing functional vascular networks using dental pulp stem cells (DPSCs) to support tissue regeneration. Current therapeutic approaches lack efficient and stable methods for activating DPSCs. In the study, we used a chemically modified microRNA (miRNA)-loaded tetrahedral-framework nucleic acid nanostructure to promote DPSC-mediated angiogenesis and dental pulp regeneration. Incorporating chemically modified miR-126-3p into tetrahedral DNA nanostructures (miR@TDNs) represents a notable advancement in the stability and efficacy of miRNA delivery into DPSCs. These nanostructures enhanced DPSC proliferation, migration, and upregulated angiogenesis-related genes, enhancing their paracrine signaling effects on endothelial cells. This enhanced effect was substantiated by improvements in endothelial cell tube formation, migration, and gene expression. Moreover, in vivo investigations employing matrigel plug assays and ectopic dental pulp transplantation confirmed the potential of miR@TDNs in promoting angiogenesis and facilitating dental pulp regeneration. Our findings demonstrated the potential of chemically modified miRNA-loaded nucleic acid nanostructures in enhancing DPSC-mediated angiogenesis and supporting dental pulp regeneration. These results highlighted the promising role of chemically modified nucleic acid-based delivery systems as therapeutic agents in regenerative dentistry and tissue engineering.

Effect of graphene oxide/ poly-L-lactic acid composite scaffold on the biological properties of human dental pulp stem cells.

BACKGROUND: Tissue engineering has attracted recent attention as a promising bone repair and reconstruction approach. Dental pulp stem cells (DPSCs) are pluripotent and can differentiate into bone cells with the correct environment and substrate. Therefore, suitable scaffold materials are essential for fabricating functional three-dimensional (3D) tissue and tissue regeneration. Composite scaffolds consisting of biodegradable polymers are very promising constructs. This study aims to verify the biological function of human DPSCs seeded onto composite scaffolds based on graphene oxide (GO) and poly-L-lactic acid (PLLA). METHODS: The surface morphology was observed under scanning electron microscopy (SEM). Chemical composition was evaluated with Fourier transform infrared (FTIR) spectroscopy. The biocompatibility of GO/PLLA scaffolds was assessed using phalloidin staining of cytoskeletal actin filaments, live/dead staining, and a CCK-8 assay. The effect of GO/PLLA scaffolds on cell osteogenic differentiation was detected through ALP staining, ALP activity assays, and alizarin red S staining, complemented by quantitative real-time PCR (qRT-PCR) analysis. RESULTS: Our data showed that GO and PLLA are successfully integrated and the GO/PLLA scaffolds exhibit favorable bioactivity and biocompatibility towards DPSCs. Additionally, it was observed that the 0.15% GO/PLLA scaffold group promoted DPSC proliferation and osteogenic differentiation by forming more calcium nodules, showing a higher intensity of ALP staining and ALP activity, and enhancing the expression levels of differentiation marker genes RUNX2 and COL1. CONCLUSIONS: These results demonstrate that the GO/PLLA scaffold is a feasible composite material suitable for cell culture and holds promising applications for oral bone tissue engineering.

Assessment of dental pulp response to carries via MR T2mapping and histological analysis.

OBJECTIVES: The aim of our study was to assess the correlation between T2 relaxation times and their variability with the histopathological results of the same teeth in relation to caries progression. MATERIALS AND METHODS: 52 extracted permanent premolars were included in the study. Prior to extractions, patients underwent magnetic resonance imaging (MRI) scanning and teeth were evaluated using ICDAS classification. Pulps of extracted teeth were histologically analysed. RESULTS: MRI T2 relaxation times (ms) were 111,9 ± 11.2 for ICDAS 0, 132.3 ± 18.5* for ICDAS 1, 124.6 ± 14.8 for ICDAS 2 and 112. 6 ± 18.2 for ICDAS 3 group (p = 0,013). A positive correlation was observed between MRI T2 relaxation times and macrophage and T lymphocyte density in healthy teeth. There was a positive correlation between vascular density and T2 relaxation times of dental pulp in teeth with ICDAS score 1. A negative correlation was found between T2 relaxation times and macrophage density. There was a positive correlation between T2 relaxation time variability and macrophage and T lymphocyte density in teeth with ICDAS score 2. In teeth with ICDAS score 3, a positive correlation between T2 relaxation times and T2 relaxation time variability and lymphocyte B density was found. CONCLUSION: The results of our study confirm the applicability of MRI in evaluation of the true condition of the pulp tissue. CLINICAL RELEVANCE: With the high correlation to histological validation, MRI method serves as a promising imaging implement in the field of general dentistry and endodontics.