• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.590.1-590
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• 2001

This study evaluated the effect of time before addition and surface treatment on the shear bond strength between new and old(direct and indirect) composites. One hundred specimens of Charisma(Heraeus Kulzer, Germany) and thirty-five of Artglass(Heraeus Kulzer, Germany) were prepared in cavities($10mm{\times}5mm$) in acrylic resin molds. Charisma specimens were stored for 5min., 1hr., 24hrs., and 1 week in $37^{\circ}C$ distilled water and Artglass specimens were stored for 1 week in $37^{\circ}C$ distilled water.(omitted)

• Restorative Dentistry and Endodontics
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• 제17권1호
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• pp.191-205
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• 1992

The purpose of this study was to evaluate the microleakage of class II composite resin inlays and compare them with the conventional light-cured resin filling restorations. Class II cavities were prepared in 60 extracted human molars with which cervical margins were located below 1.0mm at the cemento-enamel junction using No. 701 tapered fissure carbide bur. All of the prepared cavities were restored as follows and divided into 6 groups. Group I and 2 were restored using direct filling technique and group 3,4,5 and 6 were restored using direct inlay technique that was cemented with dual-cured resin cements. group I: Cavities were restored with light-curing composite resin, Brilliant Lux. group 2. Cavities were restored with light-curing composite resin, Clearfil PhotoPosterior. group 3: Cavities were restored with Clearfil CR Inlay and heat treated at $125^{\circ}C$ for 7 minutes. group 4: Cavities were restored with same material as group 3 and heat treated at $100^{\circ}C$ for 15 minutes. group 5: Cavities were restored with Brilliant (Indirect esthetic system) and heat treated at $125^{\circ}C$ for 7 minutes. group 6: Cavities were restored with same material as group 5 and heat treated at $100^{\circ}C$ for 15 minutes. All specimens were polished with same method and thermocycled between $6^{\circ}C$ and $60^{\circ}C$, then immersed in a bath of 2.0% aqueous solution of basic fuchsin dye for 24 hours. Dyed specimens were sectioned longitudinally and dye penetration degree was read on a scale of 0 to 4 by Tani and Buonocore's method 45). The results were as follows: 1. Microleakage was observed rather at the cervical margins than at the occlusal margins in all groups. 2. Composite resin inlay groups showed significantly less leakage than direct filling groups at the cervical margins (p < 0.001). 3. In composite resin inlay groups, there was no significant difference in microleakage between specimens by heat treating temperature and time (p > 0.05). 4. There was no significant difference in leakage between each groups at the occlusal margins (p > 0.05).

• Journal of Microbiology and Biotechnology
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• 제32권3호
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• pp.387-395
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• 2022

Deciphering the metabolites of human diseases is an important objective of biomedical research. Here, we aimed to capture the core metabolites of Fanconi anemia (FA) using the bioinformatics method of a multi-omics composite network. Based on the assumption that metabolite levels can directly mirror the physiological state of the human body, we used a multi-omics composite network that integrates six types of interactions in humans (gene-gene, disease phenotype-phenotype, disease-related metabolite-metabolite, gene-phenotype, gene-metabolite, and metabolite-phenotype) to procure the core metabolites of FA. This method is applicable in predicting and prioritizing disease candidate metabolites and is effective in a network without known disease metabolites. In this report, we first singled out the differentially expressed genes upon different groups that were related with FA and then constructed the multi-omics composite network of FA by integrating the aforementioned six networks. Ultimately, we utilized random walk with restart (RWR) to screen the prioritized candidate metabolites of FA, and meanwhile the co-expression gene network of FA was also obtained. As a result, the top 5 metabolites of FA were tenormin (TN), guanosine 5'-triphosphate, guanosine 5'-diphosphate, triphosadenine (DCF) and adenosine 5'-diphosphate, all of which were reported to have a direct or indirect relationship with FA. Furthermore, the top 5 co-expressed genes were CASP3, BCL2, HSPD1, RAF1 and MMP9. By prioritizing the metabolites, the multi-omics composite network may provide us with additional indicators closely linked to FA.

• 무역학회지
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• 제45권4호
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• pp.45-63
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• 2020

This study aims to identify the dimensions of trade show performance in Iranian trade shows and apply the revised importance-performance analysis. The IPA method integrates two types of indirect importance and a composite I-P mapping using traditional four-quadrants, as well as a diagonal line on a two-dimensional grid. Based on the analysis results, this study presents several suggestions to contribute to the development of the trade show industry. First, it is noted that the dimensionality of trade show performance in a developing country context can be different from that of prior literature. Taking different industry development stages of a show hosting countries, examining the dimensions of each trade show performance with every effort to derive proper exhibitors' implications is necessary. Second, the use of statically-derived importance is recommended while considering respondents' convenience to reduce their time and fatigue when collecting data at the busy booths. Further, applying composite I-P mapping is suggested as an effective diagnostic tool to provide optimal trade show strategies for the exhibitors under the dynamic and ever-changing global business environment.

• Advances in nano research
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• 제16권2호
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• pp.127-140
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• 2024

Upon direct/indirect exposure to flame or heat, composite structures may burn or thermally buckle. This issue becomes more important in the natural fiber-based composite structures with higher flammability and lower mechanical properties. The main goal of the present study was to obtain an optimal eco-friendly composite system with low flammability and high thermal buckling resistance. The studied composite consisted of polypropylene (PP) and short abaca fiber (AF) with eggshell powder (ESP) and halloysite clay nanotubes (HNTs) additives. An optimal base composite, consisting of 30 wt.% AF and 70 wt.% PP, abbreviated as OAP, was initially introduced based on burning rate (BR) and the Young's modulus determined by horizontal burning test (HBT) and tensile test, respectively. The effects of adding ESP to the base composite were then investigated with the same experimental tests. The results indicated that though the BR significantly decreased with the increase of ESP content up to 6 wt.%, it had a very destructive influence on the stiffness of the composite. To compensate for the damaging effect of ESP, small amount of HNT was used. The performance of OAP composite with 6 wt.% ESP and 3 wt.% HNT (OAPEH) was explored by conducting HBT, cone calorimeter test (CCT) and tensile test. The experimental results indicated a 9~23 % reduction in almost all flammability parameters such as heat release rate (HRR), total heat released (THR), maximum average rate of heat emission (MARHE), total smoke released (TSR), total smoke production (TSP), and mass loss (ML) during combustion. Furthermore, the combination of 6 wt.% ESP and 3 wt.% HNT reduced the stiffness of OAP to an insignificant amount by maximum 3%. Moreover, the char residue analysis revealed the distinct differences in the formation of char between AF/PP and AF/PP/ESP/HNT composites. Afterward, dilatometry test was carried out to examine the coefficient of thermal expansion (CTE) of OAP and OAPEH samples. The obtained results showed that the CTE of OAPEH composite was about 18% less than that of OAP. Finally, a theoretical model was used based on first-order shear deformation theory (FSDT) to predict the critical bucking temperatures of the OAP and OAPEH composite plates. It was shown that in the absence of mechanical load, the critical buckling temperatures of OAPEH composite plates were higher than those of OAP composites, such that the difference between the buckling temperatures increased with the increase of thickness. On the contrary, the positive effect of CTE reduction on the buckling temperature decreased by raising the axial compressive mechanical load on the composite plates which can be assigned to the reduction of stiffness after the incorporation of ESP. The results of present study generally stated that a suitable combination of AF, PP, ESP, and HNT can result in a relatively optimal and environmentally friendly composite with proper flame and thermal buckling resistance with no significant decline in the stiffness.

• Journal of the Korean Data and Information Science Society
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• 제11권1호
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• pp.111-126
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• 2000

지방자치제 실시에 따라 우리나라에서도 전국 또는 도 단위의 통계뿐만 아니라 시 군 구 등의 소지역 통계에 대한 수요가 증대되고 있다. 하지만 정부통계 생산을 위해 실시되는 표본조사의 경우 시(특별시, 광역시) 및 도별 통계생산을 목적으로 하기 때문에 신뢰성 있는 소지역 통계를 산출하는 것이 불가능하고, 따라서 이런 소지역 통계생산을 위해 간접 추정 기법을 적극적으로 활용하는 것이 필요하다. 본 논문에서는 정부통계 생산을 위한 소지역 통계 기법의 도입 및 활용 가능성을 검토해 보기 위해 인천광역시 숙박 및 음식점업의 총매출에 대한 구별 소지역 통계를 산출할 수 있는 여러 가지 간접 추정 방법을 제시하고, 아울러 도소매업 총조사 자료를 이용하여 제시된 간접추정량들의 효율성을 비교 분석해 보고자 한다.

• 치위생과학회지
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• 제15권4호
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• pp.407-412
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• 2015

본 연구에서는 심미성 향상을 위한 3종의 GS 복합 레진의 굽힘 특성 평가를 위해 ISO 4049 규격에 따라 실험을 설계하여 3점 FS 실험을 통하여 FS와 FM, WOF를 측정하고 분석하여 각각의 기계적 특성간의 상호 상관성 및 신뢰도를 평가하고, GS 복합레진의 기계적 거동 평가 및 재료 선택에 유용한 정보를 얻고자 하였다. 그 결과, 3종의 GS 복합레진의 FS와 FM은 TP에서 가장 높았으며, TF의 FS는 ISO 권장 강도인 80 MPa에 미치지 못했다. 파절될 때 흡수한 에너지를 나타내는 WOF는 T에서 가장 높았으며, TP에서 가장 낮았다. GS 복합 레진의 FS, FM은 재료별 유의한 차이를 보였으나(p<0.05), WOF는 유의한 차이가 없었다(p>0.05). GS 복합 레진의 와이블 계수는 TP에서 가장 높았으며(m=14.22) 신뢰도가 높았고, CL에서 가장 낮은 값(m=6.09)으로 낮은 신뢰도를 보였다. 복합 레진은 각각의 굽힘 특성 간 매우 높은 상관성을 보였으며($r^2>0.97$), FS와 WOF, FM과와 WOF는 높은 음의 상관성을 보였다. 따라서 굽힘 특성 간의 기계적 거동 평가에 중요한 요인으로 상호 상관성이 입증되었으며, 향후 재료 선택에 있어서 임상 적용 시 중요한 지표로 사용될 수 있을 것으로 생각된다.

• Restorative Dentistry and Endodontics
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• 제30권6호
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• pp.493-504
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• 2005

본 연구는 상아질 접착제와 레진 시멘트의 적합성 여부를 알아보고자 시행하였다. 발거한 제3대구치의 상아질 표면을 노출시킨 후 Tescera ATL 복합레진 시편을 상아질 접착제 [All Bond 2 (Bisco), Clearfil SE Bond (Kuraray), Adper Prompt L-POP (3M), One-Up Bond F (Tokuyama)]와 레진시멘트 [Choice (Bisco), Panavia F (Kuraray), RelyX ARC (3M), Bistite II DC (Tokuyama)]로 접착하고 미세인장 결합강도 및 주사전자 현미경 관찰을 시행한 결론은 다음과 같다. 1. Clearfil SE Bond와 All-Bond 2가 Prompt L-Pop과 One-Up Bond F 보다 높은 미세인장 결합강도를 보였다(p<0.05). 2. Clearfil SE Bond와 All-Bond 2 사용시 1-step 상아질 접착제보다 혼성층이 두껍고 레진 tag가 길었다.

• Restorative Dentistry and Endodontics
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• 제26권2호
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• pp.134-140
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• 2001

The polymerization shrinkage of composite resins is an important drawback although the composites have many advantages-more esthetic and conservative than metallic restoratives etc. The purposes of this research were to develop a new measurement method and to manufacture an instrument that can measure the initial dynamic volumetric shrinkage of composite resins during polymerization. The instrument was basically an electromagnetic balance that constructed with a force transducer using position sensitive photo detector(PSPD) and a negative feedback servo amplifier of proportional-derivative(PD) controller. The volumetric change of composites during polymerization was detected continuously as buoyancy change in distilled water by means of Archimedes's principle. It was converted to continuous electrical voltage signal in real time. The signal was properly conditioned and filtered and then it was stored in computer by a data acquisition(DAQ) board. By using this electronic instrument. the dynamic patterns of the polymerization shrinkage of eight commercial(Z-100, DenFil, AeliteFil, Z-250, P-60, SureFil, Synergy compact, and Tetric ceram) composite resins were measured and compared. The results were as follows. 1. From this project of developing instrument, the ability has been achieved that can acquire and process data of electrical signal transformed from various physical phenomenon by using temperature, displacement. photo. and force transducer. As a consequence, the instrumentation and measurement system used to analyze the physical characteristics of various dental materials in dental research field can be designed, manufactured and implemented in lab. 2. This instrument has some advantages. It was insensible to temperature change and could measure true dynamic volumetric shrinkage in real time without complicated process. It showed accuracy and high precision results with small standard deviation. 3. The polymerization shrinkage of composites was significantly different between brands and ranged from 2.47％ to 3.89％, The order of polymerization shrinkage was as follows, in order of increasing shrinkage, SureFil, P60, Z250, Z100, Synergy compact. DenFil, Tetric ceram, and AeliteFil. 4. The polymerization shrinkage rate per unit time, dVol％/dt, showed that the instrument can provide an indirect research method for polymerization reaction kinetics.

• Restorative Dentistry and Endodontics
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• 제44권3호
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• pp.27.1-27.12
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• 2019

This case report describes a technique in which endodontic treatment and permanent indirect restoration were completed in the same clinical appointment with the aid of a computer-aided design/computer-aided manufacturing (CAD/CAM) system. Two patients were diagnosed with irreversible pulpitis of the mandibular first molar. After access preparation, root canals were located, irrigation was performed until bleeding ceased, and the coronal tooth structure was prepared for indirect restoration. Then, utilizing an interim 3-mm build-up of the endodontic access cavity, a hemi-arch digital scan was performed with an intraoral scanner. Subsequent to digital scanning, restoration design was performed simultaneously with the endodontic procedure. The root canals were shaped using the Race system under irrigation with 2.5% sodium hypochlorite followed by root canal filling. The pulp chamber was subsequently filled with a 3-mm-thick composite resin restoration mimicking the interim build-up previously utilized to facilitate block milling in the CAD/CAM system. Clinical try-in of the permanent onlay restoration was followed by acid etching, application of a 5th generation adhesive, and cementation of the indirect restoration. Once the restoration was cemented, rubber dam isolation was removed, followed by occlusal adjustment and polishing. After 2 years of follow-up, the restorations were esthetically and functionally satisfactory, without complications.