• 대한소아치과학회지
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• 제41권2호
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• pp.174-179
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• 2014

치내치란 치아 조직의 석회화가 일어나기 이전에 법랑기가 치유두 내로 함입되어 나타나는 발육성 이상을 말한다. 치내치는 임상적, 방사선학적으로 다양한 변이를 나타내며, 치내치의 여러 분류법 중 Oehlers(1957)가 제안한 분류법이 가장 널리 이용되고 있다. 치수는 건강한 채로 남아 있으나 함입부가 치주염과 연관된 Type III 병소를 치료하는데 다양한 술식들이 설명되어져왔다. 가장 우선시 되어야 하는 목표는 가능하다면 치수를 건전하게 보존하는 것이며, 치수질환의 명백한 증거가 없다면, 함입부를 치근과 별개로 치료하는 보존적인 접근법이 필요하다. 그러나, Type III 치내치의 근관치료는 근관과 함입의 충분한 잔사제거, 재현가능한 근관장의 조절, 일관된 충전등을 충분히 달성하기 어렵다는 문제점이 있다. 본 증례는 치근단 병소를 보이는 Type III 치내치의 치료에 함입부에만 제한된 보존적 근관치료 및 Mineral Trioxide Aggregate(MTA)를 이용한 폐쇄를 통해 양호한 결과를 얻었기에 보고하는 바이다.

• Restorative Dentistry and Endodontics
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• 제43권3호
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• pp.24.1-24.12
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• 2018

Objectives: The aim of this in vitro study was to evaluate the biocompatibility of newly proposed root-end filling materials, Biodentine, Micro-Mega mineral trioxide aggregate (MM-MTA), polymethylmethacrylate (PMMA) bone cement, and Smart Dentin Replacement (SDR), in comparison with contemporary root-end filling materials, intermediate restorative material (IRM), Dyract compomer, ProRoot MTA (PMTA), and Vitrebond, using human periodontal ligament (hPDL) fibroblasts. Materials and Methods: Ten discs from each material were fabricated in sterile Teflon molds and 24-hour eluates were obtained from each root-end filling material in cell culture media after 1- or 3-day setting. hPDL fibroblasts were plated at a density of $5{\times}10^3/well$, and were incubated for 24 hours with 1:1, 1:2, 1:4, and 1:8 dilutions of eluates. Cell viability was evaluated by XTT assay. Data was statistically analysed. Apoptotic/necrotic activity of PDL cells exposed to material eluates was established by flow cytometry. Results: The Vitrebond and IRM were significantly more cytotoxic than the other root-end filling materials (p < 0.05). Those cells exposed to the Biodentine and Dyract compomer eluates showed the highest survival rates (p < 0.05), while the PMTA, MM-MTA, SDR, and PMMA groups exhibited similar cell viabilities. Three-day samples were more cytotoxic than 1-day samples (p < 0.05). Eluates from the cements at 1:1 dilution were significantly more cytotoxic (p < 0.05). Vitrebond induced cell necrosis as indicated by flow cytometry. Conclusions: This in vitro study demonstrated that Biodentine and Compomer were more biocompatible than the other root-end filling materials. Vitrebond eluate caused necrotic cell death.

• Restorative Dentistry and Endodontics
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• 제46권1호
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• pp.2.1-2.8
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• 2021

Objectives: New premixed bioceramic root repair materials require moisture for setting. Using micro-computed tomography (micro-CT), this study evaluated the filling ability and volumetric changes of calcium silicate-based repair materials (mineral trioxide aggregate repair high-plasticity [MTA HP] and Bio-C Repair, Angelus), in comparison with a zinc oxide and eugenol-based material (intermediate restorative material [IRM]; Dentsply DeTrey). Materials and Methods: Gypsum models with cavities 3 mm deep and 1 mm in diameter were manufactured and scanned using micro-CT (SkyScan 1272. Bruker). The cavities were filled with the cements and scanned again to evaluate their filling capacity. Another scan was performed after immersing the samples in distilled water for 7 days to assess the volumetric changes of the cements. The statistical significance of differences in the data was evaluated using analysis of variance and the Tukey test with a 5% significance level. Results: Bio-C Repair had a greater filling ability than MTA HP (p < 0.05). IRM was similar to Bio-C and MTA HP (p > 0.05). MTA HP presented the largest volumetric change (p < 0.05), showing more volume loss than Bio-C and IRM, which were similar (p > 0.05). Conclusions: Bio-C Repair is a new endodontic material with excellent filling capacity and low volumetric change. The gypsum model proposed for evaluating filling ability and volumetric changes by micro-CT had appropriate and reproducible results. This model may enhance the physicochemical evaluation of premixed bioceramic materials, which need moisture for setting.

• 자원리싸이클링
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• 제16권5호
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• pp.25-30
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• 2007

건설폐기물 발생량이 매년 급격히 증가함에 따라 건설폐기물 처리의 중요성이 점차 심화되고 있으며, 그 중에서도 가장 많은 비중을 차지하고 있는 폐콘크리트의 처리에 가장 많은 노력을 기울이고 있다. 현재 폐콘크리트는 단순 파쇄를 통해 매움재나 채움재 등의 저급한 용도의 순환골재로 재활용되고 있다. 그러나 부족한 구조용 골재 수급문제를 해결하고 자원의 효율적인 활용을 위해서, 천연골재를 대체하여 구조용 골재로 사용될 수 있는 고품질의 순환골재 생산이 절실히 요구되고 있다. 따라서 본 연구에서는 autogenous mill과 가열처리 방법을 이용하여 고품질 순환골재 생산 공정을 개발하였다. 개발된 공정을 이용하여 약 30분간 파분쇄과정을 통해 생산된 순환골재의 품질은 밀도 $2.5\;g/cm^3$이상, 흡수율 3% 이하로 KS F 2573의 1종 굵은 순환골재 품질 기준을 만족하였으며, 이를 바탕으로 고품질의 순환골재 생산을 위한 연속공정을 개발하였다.

• Industrial Engineering and Management Systems
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• 제13권3호
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• pp.319-329
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• 2014

Supply chain management is a subject that has an increasing importance due to the developments in the global markets and technology. In this paper, a fuzzy multi-objective linear programming model is developed for the supply chain of a company dealing with procurement, storage, filling, and distribution of liquefied petroleum gas (LPG) in Turkey. The model intends to determine the quantities of LPG to be procured, stored, filled to cylinders, and transported between the plants and demand centers for six planning periods. In this model, which aims to minimize both total costs (sum of procurement, storage, filling, and transportation costs) and total transportation distances, demand quantities of the main demand centers and decision maker's aspiration levels about objective functions are fuzzy. After comparing the results obtained from the model with those obtained by using different methods, it is concluded that the proposed method can be applied to real world problems practically and it may be used in this type of problems in order to generate an efficient solution.

• 대한치과의사협회지
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• 제48권11호
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• pp.813-818
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• 2010

Since MTA has many beneficial properties such as biocompatibility, great sealing capacity, antibacterial effects, low cytotoxicity, and stimulation of formation of mineralized tissue, it has been widely used as the material of choice in root-end filling, apexification, pulpotomy, perforation repair and so on. However, despite its favorable characteristics, MTA presents working properties which are less than ideal. The resulting cement from the mixing of powder and water is difficult to manipulate, and its setting time has been reported to be 2 h 45 min whereas the working time is <4 minutes. Additional moisture is also required to activate the setting of the cement. Moreover, according to recent studies, the physical properties of MT A may be hampered by acidic environment or blood contamination. Therefore, practitioners may have surprisingly worse results than they expected when they are not fully acquainted with the characteristics and manipulation method of MTA.

• 한국농공학회논문집
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• 제48권4호
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• pp.23-30
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• 2006

This study is performed to evaluate flowability of high flowable concrete using ordinary portland cement, crushed coarse aggregate, crushed sand, sea sand, fly ash, lime powder and superplasticizer. The slump flow and air content are increased with increasing the content of lime powder. But, the O-type funneling time and Box-type passing are decreased with increasing the content of lime powder. The slump flow, air content, O-type funneling time, Box-type passing and L-type filling of target compressive strength 21-27 MPa and 35-42 MPa at curing age 28 days are 47-50 cm and 56-60 cm, 4.2-5.5% and 4.0-5.7%, 8-12s and 5-10s, 4.3-5.0 cm and 3.4-5.0 cm, and excellent, respectively. These concrete can be used for high flowable concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.112-116
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• 1996

This experimental study was performed to produce high flowing nomal strength concrete using viscosity agent. Test variables were selected to the viscosity agent contents with 4 levels, the cement contents with 5 levels and the coarse aggregate contents with 3 levels, etc. As a result, the high flowing and filling properties of concrete were obtatined by proper amount of viscosity agent and superplasticizer in the normal strength concrete. For the concrete mix proportions, it was found that unit weight of cement was more than 364kg/㎥ and volume of coarse aggregate was less than $280\ell/\textrm{m}^3$ in this study.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.1127-1132
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• 2000

The purpose of this study is to investigate the utilization of recycled fine aggregates as a material to apply to concrete curbs. This study also intends to improve the quality of recycling aggregates by adding an excellent polyester resin for the improvement of durability, anti-corrosiveness, and strength. The experimental mixing proportion was planned to acquire optimum workability and filling capability of resin mortar mixed with the recycled fine aggregate. The curbs products made for test have four type cross sections. Their flexible fracture load is 1,918~6,883kgf and their weight is 15.31~31.61kg.

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.17-32
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• 1995

The purpose of this study was to examine the response of periradicular tissues to amalgam, IRM, Ketac-silver and MTA(Mineral trioxide aggregate) used as a root end fillings. The lower third and fourth premolars of 5 mongrel dogs were used. Each root was resected, followed by root end fillings with experimental materials. The animals were sacrificed after 16 weeks and radiographic and histologic results were evaluated. The results were as follows : 1. Severe inflammation around apex and disruption of cortical were noted in relation to the amalgam. 2. With IRM, there was severe infiltration of inflammatory cells around filling material, but healing of cortical bone was noted. 3. With Ketac-silver, mild inflammation and thick band of fibrous connetive tissue around filling material were seen, with a cortical bone healing. 4. In case of MTA, complete regeneration of cortical bone was seen, and free MTA was surrounded with newly formed bone tissue.