• 펄프종이기술
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• 제39권4호
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• pp.61-67
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• 2007

Paper sludges collected from three different paper mills were physico-chemically analyzed in order to use them as raw materials for making bed soils and seedling pots. The sludge from a fine paper mill contained lots of inorganic pigment particles used for coating, as those from a newsprint mill and a tissue mill had not. It was clearly through XRD analysis confirmed that all sludges included calcium carbonate. The paper sludge from the tissue mill contained the greatest amount of particles, which would contribute to water absorption and nutrient storage. The sludge from the fine paper mill had the highest density due to many inorganic elements. While the ash content and the total nitrogen content were the highest in the sludge from the fine paper mill, the C/N ratio was the lowest in the fine paper mill sludge. All sludges seemed to have insufficient contents of potassium. The sludges from the newsprint mill and the tissue mill showed more silicon contents than that from the fine paper mill. It was concluded that the sludge from the fine paper mill would be able to be the most efficient raw materials for making bed soils and seedling pots and the other two sludges would be more efficient for intensive culture for crops such as rice and grain with additional supplement of nitrogen and other nutrients.

• 펄프종이기술
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• 제47권5호
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• pp.80-84
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• 2015

Softness is considered one of the most important attributes of hygiene paper such as tissue and towel. Being subjective in nature, however, softness attribute has been generally believed to be impossible to evaluate using objective methods. Hallmark in his pioneering work proposed that tissue subjective softness should be mainly consisted of the bulk softness component and surface softness component. The bulk softness component can be determined by tensile stiffness; the surface softness component by surface tester. The surface friction turns out far more important than the surface roughness in determining the surface softness component. It cannot be too much emphasized that both results of the tensile stiffness and the surface friction should depend on measuring conditions such as an instrument used, sample sizes (e.g., basis weight, length, and width) and operating conditions of the instrument (e.g., gauge length, cross-head speed, size of stylus, and its scanning speed). This indicates that a direct comparison of the test results would be impossible or misleading unless they have been tested under the identical conditions. This may explain why the standard objective test method for tissue softness has not been available at present.

• Journal of Biosystems Engineering
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• 제38권2호
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• pp.113-120
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• 2013

Purpose: Stem cells provide new opportunities in the regenerative medicine for human or animal tissue regeneration. In this study, we report an efficient method for the modulating behaviors of electro-active stem cells by micro-electric current stimulation (mES) without using chemical agents, such as serum or induction chemicals. Methods: Dental pulp stem cells (DPSCs) were cultured on the tissue culture dish in the mES system. To find a suitable mES condition to promote the DPSC functions, the response surface analysis was used. Results: We found that a working micro-current of 38 ${\mu}A$ showed higher DPSC proliferation compared with other working conditions. The mES altered the expressions of intracellular and extracellular proteins compared to those in unstimulated cells. The mES with 38 ${\mu}A$ significantly increased osteogenesis of DPSCs compared with ones without mES. Conclusions: Our findings indicate that mES may induce DPSC proliferation and differentiation, resulting in applying to DPSCs-based human or animal tissue regeneration.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.20-42
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• 1998

The present study was designed to understand the basic principles of the laser system and to assess the optimal coditions of the Nd:YAG laser irradiation system in order to expand the use of the laser system in the dental field. The laser system used in this study was a pulsed-wave output type and the power level is 9 watts. The incisors of developing rats were irradiated with the laser system explained above for 0.5, 1, and 2 seconds giving energy density 71, 167, and 215 J/$cm^2$ respectively. The rats were sacrificed just after irradiation or 10 minutes and 10 days after irradiation. The specimens were examined with the stereoscope, light microscope and transmission electron microscope. The results are as follows: 1. The tissue removal efficiency (depth of the cavity formed) is increased with the energy density after Nd:YAG laser irradiation. 2. The carbonized area is increased with the energy density. Cracks and melted appearance are seen in all kinds of the energy densities. 3. The lacunae in the damaged alveolar bone by the laser irradiation were empty, while those in the newly formed bone were occupied with the osteocytes. The damaged alveolar bone was repaired by the osteoblasts and macrophages on the periphery of the bone matrix. 4. The damaged enamel was replaced by the loose connective tissues showing many kinds of cells. The ameloblasts were differntiated on the replaced loose connective tissue. 5. The damaged dentin was repaired by the irregular dentin formed by the odontoblasts differentiated from the mesenchymal cells migrated from the pulp core.

• 대한소아치과학회지
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• 제24권1호
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• pp.19-26
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• 1997

Odontodysplasia is a rare developmental anomaly of tooth formation in which hard tissue are affected. Odontodyplasia affects the primary and permanent dentitions in the maxilla, mandible, or both jaws. The maxilla is involved twice as often as the mandible. The condition is more common in female than in male patients and in the anterior than in the posterior regions. The clinical manifestation of odontodysplasia are hypoplasia and hypocalcification of the enamel and dentin of affected teeth. Teeth tend to be small and discolored, with short roots and widely open pulp canal. Delayed eruption of affected teeth with abscess formation is common. Radiographically teeth assume a faint radiolucent image ("ghost teeth"). enamel and dentin appear thin and are similar in radiodensity. The pulp chambers are often larger than normal, calcifications(pulp stone and denticle) are found within them. The etiology of regional odontodysplasia is unknown. However, several causes have been discussed, including somatic mutation, local circulatory disorders, local trauma, failure of migration and differentiation of neural crest cells, local infection.

• 대한소아치과학회지
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• 제10권1호
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• pp.67-76
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• 1983

The state of pulp and dental hard tissue during the process of resorption and shedding of 104 non-carious primary teeth was assessed by histomorphologic study. The teeth were extracted from the Korean school children aged 5 to 15 and classified into preshedding, shedding, delayed shedding groups according to the age of the child at the time of extraction, The results were as follows: 1. The inflammatory cell infiltration in primary pulp tissues occurred in 61.5% of observed teeth and were increased in the order of preshedding, shedding and delayed shedding stages. 2. The odontoclasts were appeared in 43.3% of observed teeth and were increased in the order of preshedding, shedding and delayed shedding stages. 3. The polymorphonuclear leukocytes and odontoclasts couldn't be observed in the exfoliated primary pulp tissues before the process of resorption has involved the root surface about 1.8mm subjacent to the cemento-enamel junction. 4. The intact root surface was the longest and largest in the preshedding stage. 5. The resorption process of primary teeth roots occurred mainly in the stage of preshedding and shedding stages. 6. There was a tendency of repair of resorbing root surfaces in the delayed shedding stage.

• Restorative Dentistry and Endodontics
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• 제8권1호
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• pp.133-137
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• 1982

Radiography is one of the important tool adopted in daily dental practice and medical diagnosis. To visualize soft tissuechange various contrast media has Been introduced. Any cavity or space can be easily determined by increasing the X-ray absorption of the cavity using the radiopaque contrast media which widely employed in medical radiography to show much of the digestive, cardiovascular, pulmonary, and renal system. The essential part of any radiopaque medium is a heavy element that can absoarb most of the X-ray beam. The element must be noninjurious and easily eliminated. Both aqueous and oil suspensions of iodine containing compounds' are available to the dental profession, for example Lipiodol and Dionosil. The study was designed to determine toxic effect of Lipiodol to the vital pulp and to confirm visualization ioprovement in pulp canal. 1. Thin mixture of Calcium hydroxide and Lipiodol was applied to 19 deep vital cavities for 24 hours. Only one case complained slight pain for short time. 2. Cotton pellet over-saturated in Lipiodol was inserted in coronal chamber of which 6 were non vital and 5 were vital. The transference of Lipiodol was not noticed in every case after 24 hours. 5 cases with vital pulp tissue in the canals showed no clinical symptome. 3. Extracted 20 teeth were routinely prepared for endodontic treatment and applied Lipiodol in conjunction with cotton fiber as deep as midportion of the roots. After 24, hours the medicament reached to nearly the end of apex, but there were no evidence of penetration in dentine layer and migrate into ramified canal.

• BMB Reports
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• 제55권7호
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• pp.336-341
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• 2022

Narrowing of arteries supplying blood to the limbs provokes critical hindlimb ischemia (CLI). Although CLI results in irreversible sequelae, such as amputation, few therapeutic options induce the formation of new functional blood vessels. Based on the proangiogenic potentials of stem cells, in this study, it was examined whether a combination of dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs) could result in enhanced therapeutic effects of stem cells for CLI compared with those of DPSCs or HUVECs alone. The DPSCs+ HUVECs combination therapy resulted in significantly higher blood flow and lower ischemia damage than DPSCs or HUVECs alone. The improved therapeutic effects in the DPSCs+ HUVECs group were accompanied by a significantly higher number of microvessels in the ischemic tissue than in the other groups. In vitro proliferation and tube formation assay showed that VEGF in the conditioned media of DPSCs induced proliferation and vessel-like tube formation of HUVECs. Altogether, our results demonstrated that the combination of DPSCs and HUVECs had significantly better therapeutic effects on CLI via VEGF-mediated crosstalk. This combinational strategy could be used to develop novel clinical protocols for CLI proangiogenic regenerative treatments.

• 대한치과의사협회지
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• 제56권10호
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• pp.572-580
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• 2018

Adequate access cavity is the key to achieving endodontic success. The aims of the access cavity can be considered as follows: 1) Creation of a smooth unimpeded pathway for instruments to canal orifices 2) Removal of the entire roof of the pulp chamber in order to inspect the pulp floor, 3) Preservation of natural tooth substance consistent with the above. Recently, contracted endodontic cavities based on minimally invasive endodontics has introduced. This has the benefit of preserving the pericervical dentin more than traditional access cavity with achieving long-term success. However, some studies reported controversial results regarding root canal detection, instrumentation efficacy (noninstrumented canal area, hard tissue debris accumulation, canal transportation, and centering ratio) as well as fracture resistance. Therefore, further studies are required for accepting contracted access cavity, and modified form of traditional and contracted access cavity could be considered.

• 펄프종이기술
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• 제42권2호
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• pp.27-34
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• 2010

To obtain the basic information for the use of bamboo, the anatomical characteristics of moso bamboo shoots, and 20-day-old, 60-day-old, one-year-old, and two-year-old moso bamboo were observed by using polarizing microscope. The cross section showed that the bamboo shoots consists of the early stage of cell formation, atactostele, parenchyma, and bundle sheath was formed in 20-day-old moso bamboo, and all cells completely formed in 60-day-old moso bamboo. The tissues in one-year-old moso bamboo appeared to be completely matured. On the tangential surface, no atactostele was observed in the bamboo shoot, but metaxylem, parenchyma, and bundle sheath were found. atactostele and parenchyma appeared to be formed between 20 and 60 days. All tissues and cells were totally formed and the cell wall of parenchyma were completely matured after one year. The metaxylem in bamboo shoots was observed to have pits, which means that it could be the tissues first formed of all bamboo cells.