• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.30-38
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• 2008

Dental pulp cells are assumed to possess the capacity to elaborate both bone and dentin matrix under the pathological conditions following tooth injury. The purpose of this study is to examine the effects of mineral trioxide aggregate (MTA) on various gene expression regarding dentinogenesis and cell viability assay in cultured primary human dental pulp cells. The author also examined the effects of this material on cellular alkaline phosphatase activity as a potential indicator of dentinogenesis. For gene expression on MTA, reverse transcriptase polymerase chain reaction was performed using primer sets of glyceraldehyde-3-phosphate dehydrogenase, type I collagen, alkaline phosphatase(ALP), osteonectin, and dentin sialoprotein after 2 and 4 days. Cell viability assay showed that the proportion of MTA-treated pulp cells which had been exposed for 5 days to MTA was higher than that of the control cells. Among the genes investigated in this study, ALP and osteonectin(SPARC) were increased in MTA treated group than in control. These findings suggest that this dental pulp culture system may be useful in the future as a model for studying the mechanisms underlying dentin regeneration after the treatment with MTA. Exposure to MTA material would not induce cytotoxic response in the dental pulp cells. In addition, MTA could influence the behavior of human pulp cells by increasing the ALP activity and SPARC synthesis.

• Proceedings of the KACD Conference
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• 2007.11a
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• pp.643-643
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• 2007

• Journal of Korean Dental Science
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• v.9 no.1
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• pp.9-18
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• 2016

Purpose: Wnt signaling plays an essential role in the dental epithelium and mesenchyme during tooth morphogenesis. Deletion of the Wntless (Wls) gene in odontoblasts appears to reduce canonical Wnt activity, leading to inhibition of odontoblast maturation. However, it remains unclear if autonomous Wnt ligands are necessary for differentiation of dental pulp cells into odontoblast-like cells to induce reparative dentinogenesis, one of well-known feature of pulp repair to form tertiary dentin. Materials and Methods: To analyze the autonomous role of Wls for differentiation of dental pulp cells into odontoblast-like cells, we used primary dental pulp cells from unerupted molars of Wls-floxed allele mouse after infection with adenovirus for Cre recombinase expression to knockout the floxed Wls gene or control GFP expression. The differentiation of dental pulp cells into odontoblast-like cells was analyzed by quantitative real-time polymerase chain reaction. Result: Proliferation rate was significantly decreased in dental pulp cells with Cre expression for Wls knockout. The expression levels of Osterix (Osx), runt-related transcription factor 2 (Runx2), and nuclear factor I-C (Nfic) were all significantly decreased by 0.3-fold, 0.2-fold, and 0.3-fold respectively in dental pulp cells with Wls knockout. In addition, the expression levels of Bsp, Col1a1, Opn, and Alpl were significantly decreased by 0.7-fold, 0.3-fold, 0.8-fold, and 0.6-fold respectively in dental pulp cells with Wls knockout. Conclusion: Wnt ligands produced autonomously are necessary for proper proliferation and odontoblastic differentiation of mouse dental pulp cells toward further tertiary dentinogenesis.

• International Journal of Oral Biology
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• v.45 no.4
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• pp.190-196
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• 2020

Several factors, including genetic and environmental insults, impede protein folding and secretion in the endoplasmic reticulum (ER). Accumulation of unfolded or mis-folded protein in the ER manifests as ER stress. To cope with this morbid condition of the ER, recent data has suggested that the intracellular event of an unfolded protein response plays a critical role in managing the secretory load and maintaining proteostasis in the ER. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and hydrophilic bile acid that is known to inhibit apoptosis by attenuating ER stress. Numerous studies have revealed that TUDCA affects hepatic diseases, obesity, and inflammatory illnesses. Recently, molecular regulation of ER stress in tooth development, especially during the secretory stage, has been studied. Therefore, in this study, we examined the developmental role of ER stress regulation in tooth morphogenesis using in vitro organ cultivation methods with a chemical chaperone treatment, TUDCA. Altered cellular events including proliferation, apoptosis, and dentinogenesis were examined using immunostaining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, altered localization patterns of the formation of hard tissue matrices related to molecules, including amelogenin and nestin, were examined to assess their morphological changes. Based on our findings, modulating the role of the chemical chaperone TUDCA in tooth morphogenesis, especially through the modulation of cellular proliferation and apoptosis, could be applied as a supporting data for tooth regeneration for future studies.

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.599-604
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• 1994

Very few reports are available on the occurrence of abnormality of both enamel and dentin. This case has some characteristiced of both amelogenesis imperfecta and dentinogenesis imperfecta. Clinically, the enamel of primary dentition was completely absent and when the permanent teeth came to the pediatric dept. of Dankook University Dental Hopital for treatment. Fixed-removable type resin plate was delivered to increase vertical dimension and to solve esthetic and functional defects. Hypoplastic teeth were restored either stainless steel crown or composite resin restoration or both. The periodic recall check and oral hygiene education are recommended.

• Journal of Yeungnam Medical Science
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• v.4 no.1
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• pp.157-163
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• 1987

Osteogenesis imperfecta has been categorized as a heritable disorder of connective tissue affecting both bone and soft tissues and is characterized by fragility of bone, blue sclerae, and deafness, less frequently by dentinogenesis imperfecta and laxity of ligament. The goals of orthopedic management with osteogenesis imperfecta are the treatment of acute fractures and long-term rehabilitation in an effort to maintain ambulation. We report a case of osteogenesis imperfecta with anterior bowing of tibia which was successfully corrected by multiple osteotomies and intramedullary fixation by Sofield method and reviewed literatures.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.430-441
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• 2009

The purpose of this study was to characterize functional distinction between human dental pulp cells(PC) and periodontal ligament cells(PDLC) using cDNA micro array assay and to confirm the results of the microarray assay using RT-PCR. 3 genes out of 51 genes which were found to be more expressed(>2 fold) in PC were selected, and 3 genes out of 19 genes which were found to be more expressed(>2 fold) in PDLC were selected for RT-PCR as well. According to this study, the results were as follows: 1. From the micro array assay, 51 genes were more expressed (2 fold) from PC than PDLC. 2. RT-PCR confirmed that ITGA4 and TGF ${\beta}2$ were more expressed in PC than in PDLC 3. From the micro array assay, 19 genes were more expressed (2 fold) from PDLC than PC. 4. RT-PCR confirmed that LUM, WISP1. and MMP1 were more expressed in PDLC than in PC. From the present study, different expression of the genes between the PC and PDLC were characterized to show the genes which play an important role in dentinogenesis were more expressed from PC than PDLC, while the genes which were related with collagen synthesis were more expressed from PDLC than PC.

• BMB Reports
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• v.42 no.2
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• pp.86-90
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• 2009

Deletion of smpd3 induces osteogenesis and dentinogenesis imperfecta in mice. smpd3 is highly elevated in the parietal bones of developing mouse calvaria, but not in sutural mesenchymes. Here, we examine the mechanism of smpd3 regulation, which involves BMP2 stimulation of Runx2. smpd3 mRNA expression increased in response to BMP2 treatment and Runx2 transfection in C2C12 cells. The Runx2-responsive element (RRE) encoded within the -562 to -557 region is important for activation of the smpd3 promoter by Runx2. Electrophoretic mobility shift assays revealed that Runx2 binds strongly to the -355 to -350 RRE and less strongly to the -562 to -557 site. Thus, the smpd3 promoter is activated by BMP2 and is directly regulated by the Runx2 transcription factor. This novel description of smpd3 regulation will aid further studies of bone development and osteogenesis.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.6 no.1
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• pp.33-38
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• 1976

The author observed the effects of the cobalt-60 irradiation on the amelogenesis and dentinogenesis of the albino rat fetuses by means of histological and histochemical methods. Females in oestrus were mated overnight and examined the next morning for evidence of copulation. The lower left abdomen of mothers were exposed to cobalt-60 irradiation on the 10th day of gestation, l00R 200R and 300R respectively. The fetuses were removed from the mothers on the 18th day of gestation. The employed histochemical methods were PAS reaction, colloidal iron reaction, aldehyde fuchsin stain, α-amino acid reaction, -SH radical reaction and methyl- green pyronin stain. The results were as follows; 1. The group irradiated by l00R made no histological differences in comparison with the control group. 2. Increasing the irradiation to 200R, abnormal dentin formation occured, and resulted in enamel hypoplasia and in atrophy and necrosis of odontoblasts. In dentinal papilla, the dilation and the degeneration of the blood vessels, excessive reticular atrophy and osteodentin were revealed. 3. With the more irradiation (200R-300R), the positive material of PAS, α-amino acid and aldehyde fuchsin tended to decrease in the ameloblast and the odontoblast. No significant changes appeared in DNA, the stainability of methylgreen pyronin.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.4
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• pp.775-787
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• 1996

The purpose of this study was to investigate the postnatal development of pulpal innervation with the tooth development and eruption process in developing rat mandibular molars (postnatal 1, 5, 10, 15, 20, 25, 35day-old and adult rats). Immunohistochemical method was carried out for the detection of nerve fibers, using the antibody against calcitonin gene-related peptide(CGRP). The results were as follows: The feature of CGRP-IR nerve fibers were shown in a bead-like appearance. The time of nerve entering into the dental papilla of tooth follicle began at the occured advanced dentinogenesis. The development of Raschkow plexus began at the formative stage of the roots and was accelerated at the stage of the crown emerged into the oral cavity. The number of nerve fibers entering the odontoblastic layer increased with the tooth eruption and mastication. The development of innervation was shown to be related with the stage of the development of individual teeth rather than the chronological age of the rat.