• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.149-151
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• 2010

Since its introduction in 1993, Mineral Trioxide Aggregate (MTA) has been shown to be superior to others in sealing, biocompatibility, and many other aspects of clinical endodontics. MTA is primarily Portland cement with bismuth oxide as a radiopacitifier. Although some studies suggested that the reasonable-priced Portland cement could be used instead of MTA, but MTAs are different from Portland cement in its composition, especially in heavy metal contents. Therefore, clinicians should be meticulous adapting the Portland cement as a MTA substitute.

• The Journal of the Korean dental association
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• v.48 no.11
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• pp.803-812
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• 2010

Regenerative endodontic procedure (REP) is a treatment option to replace damaged pulp tissue with the viable tissue which restores the normal function of the pulp-dentin complex. Possible reason for doing REP is not clearly known, however, clinicians perform REP in order to recover the histological structure as well as function of the traumatized and diseased tooth so that this tooth can restore its original root shape and thickness. This REP can be explained by the concept of revascularization or revitalization after induction of blood clot formation in the canal space. For this purpose, several treatment strategies have been suggested. In this regard, the rationale for the application of triantibiotics, calcium hydroxide or mineral trioxide aggregate is discussed in this paper. As a result, we will try to find the best method for REP by reviewing each available technique and their advantages and disadvantages.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.223-228
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• 2003

Recently, owing to the deterioration of reconstruction and the construction, much of the construction waste is discharged in our construction field, and the amount of construction waste is rapidly increased. These waste are raised to financial and environmental problems, so the method of reusing waste concretes has been studied and carried out many direction. Especially being want of resources, if waste concrete could be recycled as aggregates for concrete, it will contribute to solve the exhaustion of natural aggregate, in terms of saving resources and protecting environment. This study is that the mechanical properties of concrete with recycled coarse aggregate were investigated for types of mineral admixture and the substitution of recycled coarse aggregate. The result of this study, in case of using mineral admixture, the property of fresh concrete was rised. And the property of harden concrete for the substitution ratio of recycled coarse aggregate was decreased. But the property of concrete with mineral admixture was better than that of concrete used only cement.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.109-116
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• 2021

In order to replace mineral aggregate used as road pavement materials with steel slag aggregate, this present study evaluated mechanical properties of SMA Concrete mixtures using steel slag aggregate as oxidized slag from electric furnace in iron works. The variables of this experiment are the aggregate type of mineral and steel slag and the sieve sized of 10mm and 13mm. The physical properties inclu ding the specific gravity and absorption rate etc. of the slag aggregate mixtu res satisfied the KS standard as asphalt mixtu re. As a resu lt of evalu ating the mechanical properties of the asphalt mixtures, the optimum asphalt content of the slag aggregate mixtures were lower than that of the mineral aggregate mixtures, but other quality standards were all satisfied. In the deformation strength evaluation, the slag aggregate mixtures were measu red slightly higher than that of the mineral aggregate mixtu res, and the dynamic stability test satisfied the 2,000pass/mm standard value in all specimens. And, the moduli of resilient of the slag aggregate mixtures showed an improved value compared with the mineral aggregate mixtures. Therefore, as the resilient rate of the slag aggregate mixtures improved, it is speculated that there will be an effect of improving public performance according to the repeated traffic load of the vehicle.

• Restorative Dentistry and Endodontics
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• v.37 no.4
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• pp.188-193
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• 2012

Mineral trioxide aggregate (MTA) was developed in early 1990s and has been successfully used for root perforation repair, root end filling, and one-visit apexification. MTA is composed mainly of tricalcium silicate and dicalcium silicate. When MTA is hydrated, calcium silicate hydrate (CSH) and calcium hydroxide is formed. Formed calcium hydroxide interacts with the phosphate ion in body fluid and form amorphous calcium phosphate (ACP) which finally transforms into calcium deficient hydroxyapatite (CDHA). These mineral precipitate were reported to form the MTA-dentin interfacial layer which enhances the sealing ability of MTA. Clinically, the use of zinc oxide euginol (ZOE) based materials may retard the setting of MTA. Also, the use of acids or contact with excessive blood should be avoided before complete set of MTA, because these conditions could adversely affect the hydration reaction of MTA. Further studies on the chemical nature of MTA hydration reaction are needed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.195-196
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• 2023

In this study, the mechanical properties, alkali-silica reaction(ASR) expansion and residual mechanical properties after ASR of waste glass fine aggregate(GS) mortar according to mineral mixture were evaluated. As a result, it was found that the mineral mixture reduces the ASR expansion. However, mechanical properties and residual mechanical properties have decreased.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.65-72
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• 2001

Portland cement concrete is made with coarse aggregate, fine aggregate, portland cement, water and, in some cases, selected chemical admixture such as air-entraining agents, water reducer, superplasticizer, and so on, and mineral admixture such as fly ash, silica fume, slags, etc. Typically, in the concrete, the coarse aggregate and fine aggregate will occupy approximately 80 percent of the total volume of the finished mixture. Therefore, the coarse and fine aggregates affect to the properties of the portland cement concrete. As the deposits of natural sands have slowly been depleted, it has become necessary and economical to produce crushed sand(manufactured fine aggregate). It is reported that crushed sand differs from natural sands in gradation, particle shape and texture, and that the content of micro fines in the crushed sand affect to the quality of the portland cement concrete. Therefore, the purpose of this paper is to investigate the characteristics of fresh and hardened concrete with higher micro fines. This study provides a firm data to apply crushed sand with higher micro fines.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.535-547
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• 2021

Aggregate is an essential construction material, and the demand is increasing every year. Aggregate has different properties in each region, and it is difficult to supply it over long distances due to its quantity and weight. For the stabilization of aggregate supply and demand, regional aggregate resource surveys have been conducted since 1993 in Korea. In this study, an aggregate resource survey was conducted in Goyang City to understand the characteristics of aggregate distribution as part of the annual regional aggregate resource survey in 2020. Goyang City has a high mountainous area to the east, and the southwestern part shows a topography where a wide flatland develops. It has 18 small streams originated from the eastern mountainuos area and 1 large stream Han River. The drilling data shows that thickness of the Quaternary deposits tend to deepen toward the south. The aggregate reserves are relatively abundant, the depth of the aggregates are relatively deep. Changes in the depth of the Quaternary deposits and the amount of aggregate in Goyang are seems to be closely related to the activities of the Han River rather than the sedimentation characteristics from the upstream to the downstream of the small streams. This characteristics show a similar tendency to the distribution of aggregates in adjacent regions to the west coast in Korea. Therefore, the regions that close to west coast have a high probability of aggregate reserves around relatively large-scale streams flowing into the west coast.

• Journal of Periodontal and Implant Science
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• v.39 no.3
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• pp.359-365
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• 2009

Purpose: The purpose of this study was to investigate the ability of Mineral trioxide aggregate(MTA) to support osteoclastic differentiation from fetal rat calvarial cell. Methods: In this study, response of IL-6, RANKL, and OPG in fetal rat calvarial cells stimulated with IL-$1{\beta}$ on MTA was evaluated by ELISA and RT-PCR. Results: The results were as follows; there was no significant difference between glass and MTA at 5days. In ELISA analysis, Glass group and MTA group showed similar IL-6 expression, Glass+IL-$1{\beta}$ group and MTA+IL-$1{\beta}$ group showed similar IL-6 expression. In RT-PCR analysis, Glass group and MTA group showed similar IL-6, RANKL, OPG mRNA expression, MTA+IL-$1{\beta}$ group and Glass+IL-$1{\beta}$ group showed 3 fold increase of IL-6 and RNAKL mRNA expression when compared with MTA group. All groups showed similar OPG mRNA expression. Conclusions: MTA does not suppress cell proliferation and increase the proinflammatory cytokine that induce osteoclastogenesis. Thus, MTA is biocompatible material that could be used in various clinical conditions.

• Korean Business Review
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• v.11
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• pp.173-194
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• 1998

This study suggests the theoretical framework and strategy of new product development in the advanced mineral aggregate composite industry. The advanced mineral aggregate composite area needs to prepare the plan and guidelines on the new product development owing to the characteristic of the related technology. Alternative scenarios on the hierachy of new product idea is effective to the success of new product development strategy. Especially, the existing market, product, and the technological advantages affects the possibility of the success of new product development of the small firms. Also considering the interrelationship between the technological trends is important to the new product development of advanced mineral aggregate composite industry.