• International Journal of Oral Biology
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• v.47 no.4
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• pp.55-62
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• 2022

Bioactive flavonoids have been shown to improve the biological activity of stem cells derived from different sources in tissue regeneration. The goal of this study was to see how naringin, a natural flavonoid discovered in citrus fruits, affected the biological properties of human dental pulp stem cells (HDPSCs). In this study, we found that naringin increases the migratory ability of HDPSCs. Naringin increased matrix metalloproteinase-2 (MMP-2) and C-X-C chemokine receptor type 4 (CXCR4) mRNA and protein expression in HDPSCs. ARP100, a selective MMP-2 inhibitor, and AMD3100, a CXCR4 antagonist, both inhibited the naringin-induced migration of HDPSCs. Furthermore, naringin increased osteogenic differentiation of HDPSCs and the expression of the osteogenic-related marker, alkaline phosphatase in HDPSCs. Taken together, our findings suggest that naringin may be beneficial on dental tissue or bone regeneration by increasing the biological activities of HDPSCs.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.311-319
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• 2005

In order to examine the effects of advanced periodontitis on the dental pulps, 38 extracted human teeth were examined histologically. The 38 teeth had a positive or negative state in the electric pulp test(EPT). In addition, almost of the 38 teeth had a deep pocket and severe mobility, and floating state. A medical and dental history was elicited. The extracted teeth fixed in 10% neutral formalin solution. The general tissue processing method was followed. The tissue block including the teeth was prepared for optical microscopy using hematoxillin-eosin staining. Among the 38 periodontally involved teeth, the dental pulps were respectively intact in 12(31%), and a pulp stone(or linear calcifications) was found in 18 teeeth(47%). In addition, 17 teeth(44%) had pulps exhibiting inflammatory reactions with varying intensities, such as hyperemia, pulp abscess, pulp necrosis. Among the 38 periodontally involved teeth, 37 teeth tested a positive to the EPT, and 7 teeth tested negative. The EPT positive 37 teeth had various histological features such as 7 normal pulp(18%), 17 pulp stone(44%), 1 hyperemia (2%), 9 pulpitis(23%), 5 root resorption(13%), 3 pulp abscess(7%), and 3 pulp necrosis(7%), In conclusion, it is suggested that in the EPT positive teeth, advanced periodontally involved teeth can cause inflammation of the dental pulp.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.2
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• pp.166-175
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• 2016

There is no genetic activity information with the functions of dental pulp and periodontal ligament in human. The purpose of this study was to identify the gene-expression profiles of, and the molecular biological differences between periodontal ligament and dental pulp obtained from human permanent teeth. cDNA microarray analysis identified 347 genes with a fourfold or greater difference in expression level between the two tissue types 83 and 264, of which were more plentiful in periodontal ligament and dental pulp, respectively. Periodontal ligament exhibited strong expression of genes related to collagen synthesis (FAP), collagen degradation (MMP3, MMP9, and MMP13), and bone development and remodeling (SSP1, BMP3, ACP5, CTSK, and PTHLH). Pulp exhibited strong expression of genes associated with calcium ions (CALB1, SCIN, and CDH12) and the mineralization and formation of enamel and dentin (SPARC/SPOCK3, PHEX, AMBN, and DSPP). Among these genes, SPP1, SPARC/SPOCK3, AMBN, and DSPP were well known in dental research. However, the other genes are the newly found and it may help to find a good source of regenerative therapy if further study is performed.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.3
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• pp.185-193
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• 2013

Mineral trioxide aggregate (MTA) has recently been used as a pulpotomy medicament for primary molars. The aim of this study was to evaluate and compare the proliferation and differentiation potential of dental pulp stromal cells of permanent teeth and deciduous teeth cultured on MTA-coated surface. Human dental pulp stromal cells were obtained from human permanent premolars and deciduous teeth and cultured on MTA-coated culture plates. The cells were subjected to proliferation assay and cell cycle analysis. Their differentiation potential was evaluated by analysing changes in the mRNA expressions of runt-related transcriptional factor 2 (Runx2) and alkaline phosphatase (ALP). Morphological changes of cells in direct contact with MTA were observed using scanning electron microscopy (SEM). The proliferation rates, distribution of cell cycles and mRNA expression patterns of Runx2 and ALP were similar in both types of pulpal cells. SEM observations revealed that both types changed into more dendrite-like cells. On the surface of MTA, human dental pulp stromal cells from deciduous and permanent teeth were able to both proliferate and differentiate into cells that induce mineralization. MTA is suitable as a biocompatible pulpotomy medicament for primary teeth.

• International Journal of Oral Biology
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• v.38 no.4
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• pp.161-167
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• 2013

Human dental pulp stem cells (DPSCs) are multi-potent mesenchymal stem cells that have several differentiation potentials. An understanding of thetissues that differentiate from these cells can provide insights for future regenerative therapeutics and tissue engineering strategies. The mesiodens is the most frequent form of supernumerary tooth from which DPSCs can differentiate into several lineages similar to cells from normal deciduous teeth. Recently, it has been shown that nanoscale structures can affect stem cell differentiation. In our presentstudy, we investigated the effects of a 250-nm nanoscale ridge/groove pattern array on the osteogenic and adipogenic differentiation of dental pulp cells from mesiodenscontaining human DPSCs. To this end, the expression of lineage specific markers after differentiation induction was analyzed by lineage specific staining and RT-PCR. The nanoscale pattern arrayed surface showed apositive effect on the adipogenic differentiation of DPSCs. There was no difference between nanoscale pattern arrayed surface and conventional surface groups onosteogenic differentiation. In conclusion, the nanoscale ridge/groove pattern arrayed surface can be used to enhance the adipogenic differentiation of DPSCs derived from mesiodens. This finding provides an improved understanding of the effects of topography on cell differentiation as well as the potential use of supernumerary tooth in regenerative dental medicine.

• International Journal of Oral Biology
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• v.42 no.3
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• pp.91-97
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• 2017

Although anti-aging activities of melatonin, a hormone secreted by the pineal gland, have been reported in senescence-accelerated mouse models and several types of cells, its impact and mechanism on the senescence of human dental pulp cells (HDPCs) remains unknown. In this study, we examined the impact of melatonin on cellular premature senescence of HDPCs. Here, we found that melatonin markedly inhibited senescent characteristics of HDPCs after exposure to hydrogen peroxide ($H_2O_2$), including the increase in senescence-associated ${\beta}$-galactosidase (SA-${\beta}$-gal)-positive HDPCs and the upregulation of p21 protein, an indicator for senescence. In addition, as melatonin attenuated $H_2O_2$-stimulated phosphorylation of c-Jun N-terminal kinase (JNK), while selective inhibition of JNK activity with SP600125 significantly attenuated $H_2O_2$-induced increase in SA-beta-gal activity. Results reveal that melatonin antagonizes premature senescence of HDPCs via JNK pathway. Thus, melatonin may have therapeutic potential to prevent stress-induced premature senescence, possibly correlated with development of dental pulp diseases, and to maintain oral health across the life span.

• Restorative Dentistry and Endodontics
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• v.40 no.3
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• pp.223-228
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• 2015

Objectives: The aim of this study was to investigate the expression of 7 different sirtuin genes (SIRT1-SIRT7) in human dental pulp cells (HDPCs), and to determine the role of SIRTs in the odontoblastic differentiation potential of HDPCs. Materials and Methods: HDPCs were isolated from freshly extracted third molar teeth of healthy patients and cultulred in odontoblastic differentiation inducing media. Osteocalcin (OCN) and dentin sialophosphoprotein (DSPP) expression was analyzed to evaluate the odontoblastic differentiation of HDPCs by reverse transcription-polymerase chain reaction (RT-PCR), while alizarin red staining was used for the mineralization assay. To investigate the expression of SIRTs during odontoblastic differentiation of HDPCs, real time PCR was also performed with RT-PCR. Results: During the culture of HDPCs in the differentiation inducing media, OCN, and DSPP mRNA expressions were increased. Mineralized nodule formation was also increased in the 14 days culture. All seven SIRT genes were expressed during the odontogenic induction period. SIRT4 expression was increased in a time-dependent manner. Conclusions: Our study identified the expression of seven different SIRT genes in HDPCs, and revealed that SIRT4 could exert an influence on the odontoblast differentiation process. Further studies are needed to determine the effects of other SIRTs on the odontogenic potential of HDPCs.

• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.39.1-39.23
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• 2023

Objectives: This study aimed to investigate the effectiveness of different topical/systemic agents in reducing the damage caused by bleaching gel to pulp tissue or cells. Materials and Methods: Electronic searches were performed in July 2023. In vivo and in vitro studies evaluating the effects of different topical or systemic agents on pulp inflammation or cytotoxicity after exposure to bleaching agents were included. The risk of bias was assessed. Results: Out of 1,112 articles, 27 were included. Nine animal studies evaluated remineralizing/anti-inflammatories agents in rat molars subjected to bleaching with 35%-38% hydrogen peroxide (HP). Five of these studies demonstrated a significant reduction in inflammation caused by HP when combined with bioglass or MI Paste Plus (GC America), or following KF-desensitizing or Otosporin treatment (n = 3). However, orally administered drugs did not reduce pulp inflammation (n = 4). Cytotoxicity (n = 17) was primarily assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human dental pulp cells and mouse dental papilla Cell-23 cells. Certain substances, including sodium ascorbate, butein, manganese chloride, and peroxidase, were found to reduce cytotoxicity, particularly when applied prior to bleaching. The risk of bias was high in animal studies and low in laboratory studies. Conclusions: Few in vivo studies have evaluated agents to reduce the damage caused by bleaching gel to pulp tissue. Within the limitations of these studies, it was found that topical agents were effective in reducing pulp inflammation in animals and cytotoxicity. Further analyses with human pulp are required to substantiate these findings.

• The Journal of the Korean dental association
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• v.22 no.5 s.180
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• pp.423-427
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• 1984

A total of 114 extracted human mandibular first molars were used to study the configuration of the floor of the chamber. The specimens were ground and the pulp chamber was examined with a magnifier and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and the type of canal orifice. The results were as follows; 1. In so far as observing the shape of the pulp chamber of the teeth, 58.8% of the teeth were square, 34.2% were triangle and 7.0% were ovoid shape. 2. 58.8% of the specimens have 4 root canal orifices, 34.2% have 3 root canal orifices, 7.0% have 2 root canal orifices. 3. 41.2% of the specimens show 'H' shape, 17.6% show 'Square' shape, 31.6% show 'T' shape, 2.0% show 'reverse-T' shape and 7.0% show 'I' shape.

• Restorative Dentistry and Endodontics
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• v.12 no.1
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• pp.165-169
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• 1986

A total of 114 extracted human mandibular 2nd molars were used to study the configuration of the floor of the chamber. The specimens were ground and the pulp chamber was examined with a magnifier and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and the type of canal orifice. The results were as follows, 1. In so far as observing the shape of the pulp chamber of the teeth, 47.4% of the teeth were square, 42.9% were triangle and 9.7% were ovoid shape. 2. 35% of the samples had 2 root canal orifices, 62% had 3 root canal orifices, 3% had 4 root canal orifices. 3. 3% of the specimens showed 'H' shape, 5% showed 'Square' shape, 51% showed 'T' shape, 1% showed 'reverse-T' shape, 35% showed 'I' shape and 5% showed the specific 'C' shape.