Stem Cells from Human Exfoliated Deciduous Teeth: Biology and Therapeutic Potential

Stem cells isolated from human exfoliated deciduous teeth (SHEDs) are a type of mesenchymal stem cells (MSCs), widely investigated for regenerative treatment. They are isolated from dental pulp tissues remaining in physiologically shedding human deciduous teeth. Thus, SHEDs are easy to access and not required invasive procedure to obtain cells. SHEDs are multipotent mesenchymal stem cells; however, they possess distinct properties when compared to other MSCs. In this regard, SHEDs exhibit higher proliferative rate than bone marrow‐derived MSCs and greater osteogenic differentiation potency than human dental pulp stem cells. This chapter reviews the isolation technique and basic characteristics of SHEDs. Moreover, the intracellular signalling involved in the stemness regulation and differentiation ability of SHEDs is discussed, particularly on fibroblast growth factor, Notch, and Wnt signalling. Finally, the potential regenerative therapeutic application of SHEDs is also described

Polycaprolactone-Based Biomaterials for Guided Tissue Regeneration Membrane

Guided tissue regeneration (GTR) is a clinical procedure promoting regeneration of periodontal tissues. In general, this technique provides spaces for periodontal cells to repopulate and regenerate in the periodontal defect by physically preventing an invasion of gingival tissues in the affected area. Although various reports certify clinical success of GTR, high variation of favourable outcome among studies leads to the investigation to improve clinical GTR efficiency for periodontal tissue regeneration. Recent development of GTR membrane aims to augment bioactivity for facilitating and enhancing tissue healing and regeneration. Various approaches are examined, for example, the release of growth factor, the incorporation of bioactive ceramics and the delivery of antimicrobial agents. Polycaprolactone (PCL) is widely used in biomedical application due to its acceptable biocompatibility and degradability. Physical characteristics are easy to manipulate. Various forms and shapes are simple to fabricate. PCL can be employed as GTR membrane and scaffold filling in the periodontal-defect area. Bioactive PCL could be fabricated by various techniques to enhance periodontal tissue regeneration. The present chapter reviews the bioactive approaches for GTR membrane, and the potential utilization of PCL for GTR application is described

Microporous nanofibrous fibrin -based scaffolds for craniofacial bone tissue engineering

The fibrotic response of the body to synthetic polymers limits their success in tissue engineering and other applications. Though porous polymers have demonstrated improved healing, difficulty in controlling their pore sizes and pore interconnections has clouded the understanding of this phenomenon. In this study, a novel method to fabricate natural polymer/calcium phosphate composite scaffolds and immobilized alkaline phosphatase fibrin scaffolds with tightly controllable pore size, pore interconnection has been investigated. Microporous, nanofibrous fibrin scaffolds (FS) were fabricated using sphere-templating method. Calcium phosphate/fibrin composite scaffolds were created by solution deposition of calcium phosphate on fibrin surfaces or by direct incorporation of nanocrystalline hydroxyapatite (nHA). The SEM results showed that fibrin scaffolds exhibited a highly porous and interconnected structure. Osteoblast-like cells, obtained from murine calvaria, attached, spread and showed a polygonal morphology on the surface of the biomaterial. Multiple cell layers and fibrillar matrix deposition were observed. Moreover, cells seeded on mineralized fibrin scaffolds (MFS) exhibited significantly higher alkaline phosphatase activity as well as osteoblast marker gene expression compared to FS and nHA incorporated fibrin scaffolds (nHA/FS). These fibrin-based scaffolds were degraded both in vitro and in vivo. Furthermore, these scaffolds promoted bone formation in a mouse calvarial defect model and the bone formation was enhanced by addition of rhBMP-2. The second approach was to immobilize alkaline phosphatase (ALP) on fibrin scaffolds. ALP enzyme was covalently immobilized on the microporous nanofibrous fibrin scaffolds using 1-ethyl-3-(dimethylaminopropyl)carbodiimide hydrochloride (EDC). The SEM results demonstrated mineral deposition on immobilized ALP fibrin scaffolds (ALP/FS) when incubated in medium supplemented with β-glycerophosphate, suggesting that the immobilized ALP enzyme was active. Mineral deposition was also observed in cells seeded on immobilized ALP/FS. Furthermore, cells seeded on immobilized ALP/FS exhibited higher osteoblast marker gene expression compared to those on control FS. Upon implantation in mouse calvarial defect, the immobilized ALP/FS treated group had slightly higher bone volume in the defect compared to empty defect control and FS alone. In conclusion, the enhanced biological responses both in vitro and in vivo demonstrated the potential application of these novel microporous nanofibrous fibrin-based scaffolds for bone tissue engineering

Fluoride Concentration in Tap Water from Different Regions in Thailand: Konsentrasi Fluoride dalam Air Keran dari Berbagai Daerah di Thailand

Fluoride supplementation in drinking tap water is one of the well-known effective methods for dental caries prevention. However, overexposure to fluoride following excessive fluoride intake from drinking water leads to dental fluorosis. Therefore, the assessment of daily fluoride consumption is required to calculate the optimal fluoride intake. The present study investigated the fluoride concentration in tap water collected from different areas in Thailand. A total of 27 locations were selected. Three samples of tap water (500 mL each) were independently collected from one location. Each sample in the same location was collected from the same faucet of tap water and stored in different containers. The samples were collected by dental students or dentists who worked in the selected areas from March 2020 to June 2020. Briefly, the faucet was cleaned with the tap water and the water was run from the faucet for 1-2 mins. Then, water was collected in 500 mL bottles and immediately capped. Samples were then stored at room temperature in tightly sealed bottles until analysis. Findings showed that most samples contained fluoride at a concentration lower than 0.7 mg/mL. Further, the water pH was in the range of 6.81-8.37. These levels were lower than the cut-offs established by the World Health Organization (WHO) for maximum levels of fluoride and pH in drinking water. In conclusion, the present study demonstrated that fluoride levels in tap water from different regions in Thailand are lower than those recommended by WHO for fluoride levels in drinking water.

Regulation of osteoprotegerin expression by Notch signaling in human oral squamous cell carcinoma cell line

Objective: To investigate the influence of Notch signaling on osteoprotegerin (OPG) expression in a human oral squamous cell carcinoma cell line. Methods: Activation of Notch signaling was performed by seeding cells on Jagged1 immobilized surfaces. In other experiments, a γ-secretase inhibitor was added to the culture medium to inhibit intracellular Notch signaling. OPG mRNA and protein were determined by real-time PCR and ELISA, respectively. Finally, publicly available microarray database analysis was performed using connection up- or down-regulation expression analysis of microarrays software. Results: Jagged1-treatment of HSC-4 cells enhanced HES1 and HEY1 mRNA expression, confirming the intracellular activation of Notch signaling. OPG mRNA and protein levels were significantly suppressed upon Jagged1 treatment. Correspondingly, HSC-4 cells treated with a γ-secretase inhibitor resulted in a significant reduction of HES1 and HEY1 mRNA levels, and a marked increase in OPG protein expression was observed. These results implied that Notch signaling regulated OPG expression in HSC-4 cells. However, Jagged1 did not alter OPG expression in another human oral squamous cell carcinoma cell line (HSC-5) or a human head and neck squamous cell carcinoma cell line (HN22). Conclusions: Notch signaling regulated OPG expression in an HSC-4 cell line and this mechanism could be cell line specific

Effect of Jagged-1 and Delta-Like-1 on the Proliferation of Primary Deciduous Pulp Cells

Abstract Objectives: The objective of this study was to compare the effect of Notch ligands, Jagged-1 and Delta-like-1 (Dll-1), on the proliferation of primary deciduous pulp cells. Methods: Jagged-1 and Dll-1 ligands were immobilized to the tissue culture surface using an indirect affinity immobilization technique. At day 1, 3 and 7, the morphology of primary deciduous pulp cells was observed under an inverted transmitted light microscope. Cell proliferation was determined by an MTT assay and the mRNA expression levels of apoptosis related-genes were determined using reverse transcriptase polymerase chain reaction. Results: Cells exhibited elongated spindle (fibroblast-like) morphology. There was no difference in morphology among different conditions. Cell proliferation was decreased in the Notch ligand treated groups. The Jagged-1 group exhibited the attenuated appearance of cell proliferation greater than Dll-1 and the control group. However, no statistical significant difference was observed. The increase of the CASPASE3 and the BAD mRNA expression was noted in Notch ligand treated groups. Though, the significant difference was observed only for the CASPASE3 mRNA expression in the Jagged-1 group compared to the control group (p<0.05). There was no marked difference in the BCL-2 and the BAX mRNA expression. Conclusion: Notch ligands, Jagged-1, may attenuatethe primary deciduous pulp cell proliferation via the activation of apoptosis pathway. Keywords: Notch Signaling, Deciduous pulp cells, Proliferation, CASPASE

Simvastatin Induces Apoptosis but Attenuates Migration in SCAPs

ABSTRACT: Aim: Simvastatin has emerged as having a promising role in controlling stem cell behaviours. This study aimed to evaluate the effects of simvastatin on the viability, growth, and migration of stem cells isolated from apical papillae (SCAPs) in vitro. Methods: SCAPs were isolated and characterised. The viability and proliferation were assessed using live/dead and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays, respectively. Cell migration was evaluated using scratch assays. Cell cycle progression and apoptosis were examined using flow cytometry analysis. Results: Simvastatin at a concentration of 100 to 1000 nM did not exhibit cytotoxicity. Simvastatin reduced cell numbers at days 3 and 7. In addition, simvastatin markedly decreased colony formation in both colony number and cell density in a dose-dependent manner. An increase in apoptosis was observed at day 7. There was statistically significant increased in sub G0 population. An in vitro cell migration was attenuated in a dose-dependent manner. Conclusion: Simvastatin affects SCAPs’ viability, proliferation, and cell migration. The reduction of cell viability at day 7 could be due to apoptotic induction

Oral Fluid Biomarkers for Peri-Implantitis: A Scoping Review

Peri-implantitis, a prevalent complication in dental implant therapy, poses a significant threat to long-term implant success. The identification of reliable biomarkers for the early detection and monitoring of peri-implantitis is crucial for timely intervention and improved treatment outcomes. Salivary and peri-implant sulcular fluid (PISF) biomarkers have become promising diagnostic tools in the field of implant dentistry. This scoping review aims to explore current studies in the literature on salivary and PISF biomarkers for peri-implantitis. A systematic search was conducted on 2 databases (PubMed and Scopus) to identify relevant studies published up to January 2023. A total of 86 articles were included, which underwent data extraction and analysis. Several biomarkers have been investigated in salivary and PISF samples for association with peri-implantitis. Investigations included a wide range of biomarkers, including inflammatory markers, matrix metalloproteinases and bone loss markers. The findings suggested that certain salivary and PISF biomarkers demonstrated potential in distinguishing healthy peri-implant conditions from peri-implantitis. Elevated levels of proinflammatory cytokines, such as interleukin-1β (IL-1β) and interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), and matrix metalloproteinases, have been consistently associated with peri-implantitis. Additionally, alterations in bone loss markers have shown potential as indicators of disease progression and treatment response. In conclusion, this scoping review provides an overview of current knowledge on salivary and PISF biomarkers for peri-implantitis. The identified biomarkers are promising as noninvasive diagnostic tools for early detection, monitoring, and personalised management of peri-implantitis. Future studies should focus on establishing standardised protocols and conducting well-designed clinical trials to validate the diagnostic accuracy and clinical relevance of these biomarkers