• Restorative Dentistry and Endodontics
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• v.48 no.1
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• pp.2.1-2.12
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• 2023

Objectives: In this study, natural substances were introduced as primary dental pulp caps for use in pulp therapy, and the antimicrobial and cytotoxic properties of these substances were investigated. Materials and Methods: In this in vitro study, the antimicrobial properties of calcium-enriched mixture (CEM) cement, propolis, and propolis individually combined with the extracts of several medicinal plants were investigated against Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Then, the cytotoxicity of each substance or mixture against pulp stem cells extracted from 30 primary healthy teeth was evaluated at 4 concentrations. Data were gathered via observation, and optical density values were obtained using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) test and recorded. SPSS software version 23 was used to analyze the data. Data were evaluated using 2-way analysis of variance and the Tukey test. Results: Regarding antimicrobial properties, thyme alone and thyme + propolis had the lowest minimum inhibitory concentrations (MICs) against the growth of S. aureus, E. coli, and P. aeruginosa bacteria. For E. faecalis, thyme + propolis had the lowest MIC, followed by thyme alone. At 24 and 72 hours, thyme + propolis, CEM cement, and propolis had the greatest bioviability in the primary dental pulp stem cells, and lavender + propolis had the lowest bioviability. Conclusions: Of the studied materials, thyme + propolis showed the best results in the measures of practical performance as a dental pulp cap.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.273-284
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• 2010

The objective of this study was to observe the histology of dental pulp healing after tooth replantation in rats. The maxillary right first molars of 4-week-old rat were extracted, and then the teeth were repositioned in the original socket. At 3 days after replantation, there was localized inflammatory reaction. But, pulp revasculization and healing had already begun in the root area. At 5 days after replantation, odontoblast-like cells were observed. Tertiary dentin deposition was observed beneath the pulp-dentin border from 1 week after replantation. And tertiary dentin was increased at 2 weeks after replantation. The presence of odontoblast-like cells and the formation of tertiary dentin were continued to 4 weeks after replantation. At 4 weeks after replantation, the deposition of bone-like tissues and cementum-like tissues was observed. This results show that there is a possibility of pulp healing after tooth replantation in rats and the mineralization of tooth can progress. The mineralization of tooth after replantation was initially occurred by the deposition of tertiary dentin, but as time passed, the deposition of bone-like tissues and cementum-like tissues was begun and increased.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.4
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• pp.291-301
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• 2015

This study compared the in vitro cell viability and differentiation potentials of human deciduous dental pulp cells (DPCs) on mineral trioxide aggregate (MTA)-like products (ProRoot MTA, RetroMTA and Endocem Zr). The experimental materials were prepared as circular discs, which were used to test the effects of the materials on the viability of human DPCs when placed in direct and indirect contact. Furthermore, the pH of the extracted materials was recorded, and their effect on cell differentiation potential was evaluated by evaluating the alkaline phosphatase (ALP) activity and Alizarin Red S staining of DPCs incubated with the test materials. In direct contact, the cell viability of human DPCs was higher with ProRoot MTA and RetroMTA than with Endocem Zr. However, when in indirect contact, the cell viability of human DPCs was generally higher in Endocem Zr than in ProRoot MTA and Retro MTA. With respect to pH, the alkalinity was lower for Endocem Zr than for the other test materials. The ALP activities of the cells were not enhanced by any of the experimental materials. Alizarin Red S staining of the tested human DPCs revealed that their differentiation potential was lower than for cells incubated with osteogenic induction medium. While there were differences in the responses of the human DPCs to the test materials, all displayed degrees of cytotoxicity and were unable to enhance either the viability or differentiation of human DPCs. However, Endocem Zr exhibited better cell viability and was less alkaline than the other test materials.

• International Journal of Oral Biology
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• v.37 no.2
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• pp.77-83
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• 2012

We investigated the pulpal response to direct pulp capping in rat molar teeth using mineral trioxide aggregate (MTA) and calcium hydroxide (CH). A palatal cavity was prepared in rat maxillary molar teeth. Either MTA or CH was placed on the exposed pulp and all cavities were restored with composite. Rats were sacrificed for histological evaluation after 12 hours and at 2, 7, 14 and 21 days. In both the MTA and CH groups, reparative dentin formation was clearly observed on histology after 14 days. The MTA-capped pulps were found to be mostly free from inflammation, and hard tissue of a tubular consistent barrier was observed. In contrast, in CH-capped teeth, excessive formation of reparative dentin toward residual pulp was evident. The pulpal cell response beneath the reparative dentin layer was examined by immunofluorescence using antibodies against DSP. After 2 days, a few DSP immunopositive cells, most of which showed a cuboidal shape, appeared beneath the predentin layer. At 7 days, DSP-immunopositive cells with columnar odontoblast-like cells were seen beneath the newly formed hard tissues. At 14 and 21 days, DSP was more abundant in the vicinity of the odontoblastic process along the dentinal tubules than in the mineralized reparative dentin. The CH group showed strong expression patterns in terms of DSP immunoreactivity. Our results thus indicate that MTA may be a more effective pulp capping material as it induces the differentiation of odontoblast-like cells and the formation of reparative dentin without the loss of residual pulp functions.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.311-316
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• 2006

The role of short fibre pulp - Mixed Harwood, Eucalyptus, Aspen, Birch, etc for the manufacture of different grades of paper is very well recognized. At the same time, lots of efforts are in progress to maximize the advantages while preserving their own special property. Bleached Acacia Kraft Pulp (BAKP) is comparatively new entry but gained quick recognition. BAKP was introduced to the world market by South East Asian suppliers in the late 1990's. This paper discusses in detail the role and opportunities of use of short fibre pulps. A logical technical comparison has been made between BAKP and another short fibre grades. BAKP being a short, thin-walled fibre shows several similarities with Eucalyptus pulp in terms of good bulk and stiffness. Refining energy and strength properties are very similar, but the shorter fibres and thinner cell walls give an outstanding opacity and formation compared to other commercial short fibre pulps. The collapsed and band-shaped nature gives a matchless smoothness, enabling less calendaring and exceptional printing properties. BAKP is shown to give several advantages to fine paper manufactures, compared with a number of established short fibre pulps such as Brazilian and Chilean Eucalyptus, Canadian Aspen and Indonesian Mixed Hardwood. It is important to consider refining and calendaring conditions to achieve optimum performance. For outer layers of multiply board, Acacia gives excellent coverage due to its high opacity and uniform fibre distribution. Its low roughness property gives improved printability. For tissue products, Acacia gives unique property of superior softness both in terms of hand feel and bulk softness. The high fibre population gives an impression of much higher quality due to the higher opacity and good formation.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.1
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• pp.2-9
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• 2019

Because mesenchymal stem cells (MSCs) maintain distinct capacities with respect to self-renewal, differentiation ability and immunomodulatory function, they have been highly considered as the therapeutic agents for cell-based clinical application. Of particular, differentiation condition alters characteristics of MSCs, including cellular morphology, expression of gene/protein and cell surface molecule, immunological property and apoptosis. However, the previous results for differentiation-related apoptosis in MSCs have still remained controversial due to varied outcomes. Therefore, the present study aimed to disclose periodical alterations of pro- and anti-apoptosis in MSCs under differentiation inductions. The human dental pulp-derived MSCs (DP-MSCs) were differentiated into adipocytes and osteoblasts during early (1 week), middle (2 weeks) and late (3 weeks) stages, and were investigated on their apoptosis-related changes by Annexin V assay, qRT-PCR and western blotting. The ratio of apoptotic cell population was significantly (p < 0.05) elevated during the early to middle stages of differentiations but recovered up to the similar level of undifferentiated state at the late stage of differentiation. In the expression of mRNA and protein, whereas expressions of pro-apoptosis-related makers (BAX and BAK) were not altered in any kind and duration of differentiation inductions, anti-apoptosis marker (BCL2) was significantly (p < 0.05) elevated even at the early stage of differentiations. The recovery of apoptotic cell population at the late stage of differentiation is expected to be associated with the response by elevation of anti-apoptotic molecules. The present study may contribute on understanding for cellular mechanism in differentiation of MSCs and provide background data in clinical application of MSCs in the animal biotechnology to develop effective and safe therapeutic strategy.

• Mycobiology
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• v.28 no.1
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• pp.47-50
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• 2000

The capability of higher ascomyceteous fungi to cause typical soft-rot decay for wood under laboratory conditions is reviewed and discussed. Fungi tested were extremely active in the decomposition of timbers. Scanning electron micrographs illustrated typical soft-rot decay pattern of higher wood decay ascomycetes, with the exception of H. trugodes that caused white-rot decay. Most of the fungi tested could be grouped as soft-rot fungi that showed typical soft-rot type II. Hypha confined primarily to the resin canals in softwoods or vessel elements in hardwoods and spread tracheid to tracheid via pits of cell wall to cell wall with mechanical force.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.11-17
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• 2008

The purpose of this study was to investigate early histological changes and calcitonin gene-related peptide (CGRP) expression in the dental pulp of the rat after Er:YAG laser preparation. Occlusal cavities were prepared in the upper first molars using either Er:YAG laser and conventional bur. At 48 hours after cavity preparation, the teeth were processed for hematoxylin-eosin stain and CGRP immunohistochemistry. The results were as follows : 1. The cavity floor by Er:YAG laser preparation was more irregular shape compared with those by bur preparation and there are some cracks in the directions of dentinal tubules. 2. There were more inflammatory cell infiltration and disruption of odontoblast in the dental pulp by Er:YAG laser preparation in comparison with the dental pulp by bur preparation. 3. CGRP expression in the pulp tissue by both Er:YAG laser and bur preparations were increased and higher than in the normal pulp. The expression pattern of CGRP was more strong in the pulp by Er:YAG laser preparation. These results indicate that Er:YAG laser is useful in the operative dentistry such as caries removal and cavity preparation if properly applied.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.324-332
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• 2008

Traumatic crown fracture in mixed dentition or early permanent dentition is relatively common. Crown fracture is classified into simple or complicated crown fracture by the presence of pulp exposure. The condition of pulp must be considered in treatment of crown fractures with pulp exposure. Treatment of immature crown-fractured incisor with pulp exposure is more complex because of its incomplete root formation. Pulp capping, partial pulpotomy, cervical pulpotomy can be used for continuous root development in immature crown-fractured incisor with pulp exposure. The success rate of partial pulpotomy is very high and there are several advantages of partial pulpotomy because the cell-rich coronal pulp tissue is preserved. This paper reports 2 cases of crown-fractured permanent incisors with pulp exposure that had been treated by partial pulpotomy successfully.

• 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.