• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.219-225
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• 2019

The purpose of this study was to investigate the odontoblast gene expression related to the subculture speed of supernumerary dental pulp stem cells (sDPSCs). The stem cell is undifferentiated cells which has the ability to differentiate into various cells. Specific stimulation or environment induces cell differentiation, and these differentiation leads to bone or muscle formation. 20 sDPSCs were obtained from 20 children under aseptic condition. During the culture through the 10th passage, the third passage cells which showed short subculture period and 10th passage cells which showed long subculture period were earned. Each cell was divided into differentiated group and non-differentiated group. Quantitative real-time polychain reaction (q-RT-PCR) was performed for each group. The genes related to odontoblast differentiation, Alkaline Phosphatase (ALP), Osteocalcin (OCN), Osteonectin (ONT), Dentin sialophosphoprotein (DSPP) and Dentin matrix acidic phosphoprotein 1 (DMP-1), were measured. Differentiated cells showed more gene expression levels. Undifferentiated cells showed higher gene expression level in 10th passages but differentiated cells showed higher gene expression level in 3rd passages. Cells that showed faster subculture period showed relatively lower gene expression level except for OCN and DSPP.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.1
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• pp.88-98
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• 2024

Patients with pediatric cancer often undergo multiple therapies, such as chemotherapy, radiation therapy, and stem cell transplantation. These treatments, while essential, can result in dental developmental issues, including hypodontia, microdontia, short roots, and delayed dental development. This report presents two cases of pediatric patients diagnosed with neuroblastoma who exhibited severe tooth mobility due to short roots as a complication of cancer treatment. Moreover, we investigated the conservative management of the patients' conditions using resin wire splints and orthodontic miniscrews for skeletal anchorage along with long-term follow-ups to evaluate their prognosis.

• Restorative Dentistry and Endodontics
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• v.41 no.2
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• pp.98-105
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• 2016

Objectives: The biocompatibility of two experimental scaffolds for potential use in revascularization or pulp regeneration was evaluated. Materials and Methods: One resilient lyophilized collagen scaffold (COLL), releasing metronidazole and clindamycin, was compared to an experimental injectable poly(lactic-co-glycolic) acid scaffold (PLGA), releasing clindamycin. Human dental pulp stem cells (hDPSCs) were seeded at densities of $1.0{\times}10^4$, $2.5{\times}10^4$, and $5.0{\times}10^4$. The cells were investigated by light microscopy (cell morphology), MTT assay (cell proliferation) and a cytokine (IL-8) ELISA test (biocompatibility). Results: Under microscope, the morphology of cells coincubated for 7 days with the scaffolds appeared healthy with COLL. Cells in contact with PLGA showed signs of degeneration and apoptosis. MTT assay showed that at $5.0{\times}10^4$ hDPSCs, COLL demonstrated significantly higher cell proliferation rates than cells in media only (control, p < 0.01) or cells co-incubated with PLGA (p < 0.01). In ELISA test, no significant differences were observed between cells with media only and COLL at 1, 3, and 6 days. Cells incubated with PLGA expressed significantly higher IL-8 than the control at all time points (p < 0.01) and compared to COLL after 1 and 3 days (p < 0.01). Conclusions: The COLL showed superior biocompatibility and thus may be suitable for endodontic regeneration purposes.

• Journal of Biosystems Engineering
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• v.38 no.1
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• pp.55-63
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• 2013

Purpose: The present study aimed at image processing methods for automatic cell pattern recognition and morphological analysis for tissue engineering applications. The primary aim was to ascertain the novel algorithm of adaptive brightness correction from microscopic images for use as a potential image analysis. Methods: General microscopic image of cells has a minor problem which the central area is brighter than edge-area because of the light source. This may affect serious problems to threshold process for cell-number counting or cell pattern recognition. In order to compensate the problem, we processed to find the central point of brightness and give less weight-value as the distance to centroid. Results: The results presented that microscopic images through the brightness correction were performed clearer than those without brightness compensation. And the classification of mixed cells was performed as well, which is expected to be completed with pattern recognition later. Beside each detection ratio of hBMSCs and HeLa cells was 95% and 92%, respectively. Conclusions: Using this novel algorithm of adaptive brightness correction could control the easier approach to cell pattern recognition and counting cell numbers.

• IMMUNE NETWORK
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• v.23 no.6
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• pp.44.1-44.16
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• 2023

Mesenchymal stem cells (MSCs) are effective in treating autoimmune diseases and managing various conditions, such as engraftment of allogeneic islets. Additionally, autologous and HLA-matched allogeneic MSCs can aid in the engraftment of human allogeneic kidneys with or without low doses of tacrolimus, respectively. However, HLA alloantigens are problematic because cell therapy uses more HLA-mismatched allogeneic cells than autologous for convenience and standardization. In particular, HLA-mismatched MSCs showed increased Ag-specific T/B cells and reduced viability faster than HLA-matched MSCs. In CRISPR/Cas9-based cell therapy, Cas9 induce T cell activation in the recipient's immune system. Interestingly, despite their immunogenicity being limited to the cells with foreign Ags, the accumulation of HLA alloantigen-sensitized T/B cells may lead to allograft rejection, suggesting that alloantigens may have a greater scope of adverse effects than foreign Ags. To avoid alloantigen recognition, the β2-microglobulin knockout (B2MKO) system, eliminating class-I MHC, was able to avoid rejection by alloreactive CD8 T cells compared to controls. Moreover, universal donor cells in which both B2M and Class II MHC transactivator (CIITA) were knocked out was more effective in avoiding immune rejection than single KO. However, B2MKO and CIITA KO system remain to be controlled and validated for adverse effects such as the development of tumorigenicity due to deficient Ag recognition by CD8 T and CD4 T cells, respectively. Overall, better HLA-matching or depletion of HLA alloantigens prior to cell therapy can reduce repetitive transplantation through the long-term survival of allogeneic cell therapy, which may be especially important for patients seeking allogeneic transplantation.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.4
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• pp.421-433
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• 2023

This study was to examine the developmental dental abnormalities in childhood cancer survivors. Risk factors were assessed for 125 children with radiographic data through a retrospective analysis of medical records and panoramic images. 68.0% of childhood cancer survivors exhibited at least one dental abnormality. The types of abnormalities varied depending on the age at cancer diagnosis and treatment intensity, ranging from microdontia (43.2%), to abnormal root development (39.2%) and tooth agenesis (33.6%). Logistic regression analysis demonstrated that a young age at diagnosis (under 3 years), the use of heavy metal agents, a history of hematopoietic stem cell transplantation (HSCT), and combination treatment of chemotherapy, radiation therapy, and HSCT were associated with a significantly higher risk for overall dental abnormalities. The increased risk ratios were 6.00, 3.06, 3.22, and 7.87, respectively (p < 0.05). The results of this study will predict dental abnormality in permanent dentition according to the diagnosis age and treatment method of childhood cancer.

• Journal of Korean Dental Science
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• v.15 no.2
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• pp.121-131
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• 2022

Ameloblastoma is the most representative epithelial odontogenic tumor in the craniofacial region. Through several studies on Ameloblastoma that have been conducted so far, we have been able to get closer to the reality of Ameloblastoma. However, groundbreaking insight into the pathophysiology of Ameloblastoma has not yet been provided. This review assessed three aspects of five recently published papers on Ameloblastoma: cancer stem cells, calcium signaling, and tumor microenvironment, and compared them with previous studies on tumor physiology, including cancer. In addition, the characteristics of Ameloblastoma revealed by the experimental methods presented in the currently published five papers provide the possibility of Ameloblastoma as a study model in general tumor or cancer studies. Furthermore, the mechanisms of action of the chemicals identified in the studies support their potential as candidates for the second-line treatment of Ameloblastoma.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.6
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• pp.454-464
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• 2021

Objectives: This study aimed to investigate the in vitro osteoinductivity of the combination of bone morphogenetic protein-2 (BMP-2) and nanohydroxyapatite (nHAp) and the in vivo effects of implants coated with nHAp/BMP-2. Materials and Methods: To evaluate the in vitro efficacy of nHAp/BMP-2 on bone formation, bone marrow-derived mesenchymal stem cells (BM-MSCs) were seeded onto titanium disks coated with collagen (Col), Col/nHAp, or Col/nHAp/BMP-2. Protein levels were determined by a biochemical assay and reverse transcriptase-polymerase chain reaction. Stem cell differentiation was analyzed by flow cytometry. For in vivo studies with mice, Col, Col/nHAp, and Col/nHAp/BMP-2 were injected in subcutaneous pockets. Titanium implants or implants coated with Col/nHAp/BMP-2 were placed bilaterally on rabbit tibias and evaluated for 4 weeks. Results: In the in vitro study, BM-MSCs on Col/nHAp/BMP-2 showed reduced levels of CD73, CD90, and CD105 and increased levels of glycosaminoglycan, osteopontin, and alkaline phosphatase activity. After 4 weeks, the Col/nHAp/BMP-2 implant showed greater bone formation than the control (P=0.07), while no differences were observed in bone implant contact and removal torque. Conclusion: These results suggest that a combination of BMP-2 and an nHAp carrier would activate osseointegration on dental implant surfaces.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.2
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• pp.165-175
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• 2024

This study aimed to investigate the effects of blood contamination on the Vickers hardness and the surface morphology of premixed MTA and compare them with the effects on conventional MTA. The Vickers microhardness of Endocem MTA Premixed Regular (EP) and ProRoot MTA (PM) was assessed after immersion in fetal bovine serum (FBS) and saline. Stem cells from human exfoliated deciduous teeth (SHED) were seeded on MTA after immersion in FBS, saline, and deionized water (DW). Cell adhesion patterns and surface morphology were visualized via scanning electron microscopy (SEM). The surface microhardness of EP and PM in FBS was lower than in saline. However, short-term exposure of PM to FBS did not reduce the microhardness compared to saline. Angular crystals formed in water, while rounded crystals with more air voids appeared in FBS. Favorable SHED attachment occurred in all groups. Overall, the surface hardness of EP and PM decreased after FBS exposure, although PM was less influenced. We suggest minimizing the amount of bleeding when using MTA clinically; nevertheless, PM remains an option with more expected blood contamination than EP. In summary, exposure to FBS decreased mechanical performance but allowed cell adhesion for both MTAs, with PM being more resistant to these changes.

• Development and Reproduction
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• v.13 no.2
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• pp.89-95
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• 2009

p63 has been demonstrated to localize in stem cells and precursor cells of various epithelial tissues previously, but the localization of p63 throughout tooth formation, particularly during the enamel and root formation stages, remains to be adequately characterized. Therefore, in this study, we have demonstrated, via immunohistochemical methods, that p63 is ubiquitously expressed in the dental epithelium during tooth development. p63 was detected in the basal and suprabasal layers of the epithelia, including the skin, hair follicles, oral mucosa, and submandibular ducts. However, in the tooth region, all cells of the dental lamina, enamel organ, Hertwig's epithelial root sheath (HERS), and epithelial cell rests of Malassez (ERM) evidenced immunoreactivity for p63. These results indicate that p63 may perform different roles, other than stem cell maintenance, in tooth development.