• 대한심미치과학회지
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• 제24권2호
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• pp.122-133
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• 2015

성공적싱 완전도재관 치료를 위한 요구조건은 통상적 치료와 크게 다르지 않다. 적절한 치아삭제, 임시치아, 및 정확한 최종인상이 중요하다. 그럼에도 불구하고 차별점은 본딩에 있다. 수복물 내면과 지대치 외면에 레진시멘트를 도포하는 것 이외에도 본딩 술식은 비생활치의 포스트 코어 치료에도 적용할 수 있다. 생활치 지대치는 비생활치보다 심미와 기능 면에서 성공을 거두기가 더 쉽다. 포스트 코어 본딩 술식은 비생활치 지대치의 장기 성공에 중요한 역할을 한다. 본 논문에서 완전 도재관의 성공 전략 중에서 포스트 코어 축성 및 완전 도재관 본딩에 관하여 임상적 경험을 나누고자 한다.

• The Journal of Advanced Prosthodontics
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• 제16권2호
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• pp.77-90
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• 2024

PURPOSE. The study aims to investigate the influence of the ferrule effect and types of posts on the stress distribution in three morphological types of the maxillary central incisor. MATERIALS AND METHODS. Nine models were created for 3 maxillary central incisor morphology types: "Fat" type - crown 12.5 mm, root 13 mm, and buccolingual cervical diameter 7.5 mm, "Medium" type - crown 11 mm, root 14 mm, and buccolingual cervical diameter 6.5 mm, and "Slim" type - crown 9.5 mm, root 15 mm, and buccolingual cervical diameter 5.5 mm. Each model received an anatomical castable post-and-core or glass-fiber post with resin composite core and three ferrule heights (nonexistent, 1 mm, and 2 mm). Then, a load of 14 N was applied at the cingulum with a 45° slope to the long axis of the tooth. The Maximum Principal Stress and the Minimum Principal Stress were calculated in the root dentin, crown, and core. RESULTS. Higher tensile and compression stress values were observed in root dentin using the metallic post compared to the fiber post, being higher in the slim type maxillary central incisor than in the medium and fat types. Concerning the three anatomical types of maxillary central incisors, the slim type without ferrule height in mm presented the highest tensile stress in the dentin, for both types of metal and fiber posts. CONCLUSION. Post system and tooth morphology were able to modify the biomechanical response of restored endodontically-treated incisors, showing the importance of personalized dental treatment for each case.

• Earthquakes and Structures
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• 제16권5호
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• pp.589-599
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• 2019

Conventional buckling restrained braces used in concentrically braced frames are expected to yield in both tension and compression without major degradation of capacity under severe seismic ground motions. One of the weakness points of a standard buckling restrained braced frame is the low post-yield stiffness and thus large residual deformation under moderate to severe ground motions. This phenomenon can be attributed to low post-yield stiffness of core member in a BRB. This paper introduces a multi-core buckling restrained brace. The multi-core term arises from the use of more than one core component with different steel materials, including high-performance steel (HPS-70W) and stainless steel (304L) with high strain hardening properties. Nonlinear dynamic time history analyses were conducted on variety of diagonally braced frames with different heights, in order to compare the seismic performance of regular and multi-core buckling restrained braced frames. The results exhibited that the proposed multi-core buckling restrained braces reduce inter-story and especially residual drift demands in BRBFs. In addition, the results of seismic fragility analysis designated that the probability of exceedance of residual drifts in multi-core buckling restrained braced frames is significantly lower in comparison to standard BRBFs.

• Nuclear Engineering and Technology
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• 제43권6호
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• pp.489-498
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• 2011

UK National Nuclear Laboratory's (NNL's) version of the ENIGMA fuel performance code is described, including details of the development history, the system modelled, the key assumptions, the thermo-mechanical solution scheme, and the various incorporated models. The recent development of ENIGMA in the areas of whole core analysis and dry storage applications is then discussed. With respect to the former, the NEXUS code has been developed by NNL to automate whole core fuel performance modelling for an LWR core, using ENIGMA as the underlying fuel performance engine. NEXUS runs on NNL's GEMSTONE high performance computing cluster and utilises 3-D core power distribution data obtained from the output of Studsvik Scandpower's SIMULATE code. With respect to the latter, ENIGMA has been developed such that it can model the thermo-mechanical behaviour of a given LWR fuel rod during irradiation, pond cooling, drying, and dry storage - this involved: (a) incorporating an out-of-pile clad creep model for irradiated Zircaloy-4; (b) including the ability to simulate annealing out of the clad irradiation damage; (c) writing of additional post-irradiation output; (d) several other minor modifications to allow modelling of post-irradiation conditions.

• 한국산학기술학회논문지
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• 제19권9호
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• pp.362-373
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• 2018

본 연구의 목적은 졸업반 간호학생에게 한 학기 동안 적용한 핵심기본간호술 교육프로그램이 핵심기본간호술 수행능력, 임상수행능력 및 문제해결과정에 미치는 효과를 규명하고자 하는 것이었으며 단일군 사전사후 설계의 원시실험연구였다. 핵심기본간호술 교육프로그램은 3단계로 구성하였으며, 총 12회기로 운영하였다. 연구대상자는 일개 간호대학의 졸업학년 총 192명이었으며 2017년 3월 20일부터 6월 23일까지 실시하였다. 자료는 AMOS 20.0과 S AS 9.3 프로그램을 이용해 기술통계와 paired t-test, t-검정, ANOVA로 분석되었다. 연구결과로, 핵심기본간호술 교육프로그램에 대한 사전사후 인식으로 수기능력 증진 도움 여부는 사전 $(3.42{\pm}.42)$점, 사후 $3.88({\pm}.61)$점, 임상적응력증진 도움 여부는 사전 $3.74({\pm}.47)$점, 사후 $(3.98{\pm}.67)$점으로 나타났다. 핵심기본간호술 수행능력(p=.017)과 임상수행능력(p=.041)은 핵심기본간호술 교육프로그램 후에 통계적으로 유의하게 증가하였다. 대상자의 사후 핵심기본간호술 수행능력은 남성 군(p=.003), 간호학전공 만족도가 매우 만족한 군(p=<.000), 핵심경진대회 참여 목적은 자신감 향상 군(p=.044)에서, 사후 임상수행능력은 남성 군(p=.013), 간호학전공 만족도가 매우 만족한 군(p=.009), 핵심경진대회 참여 목적은 자신감 향상 군(p=.047), 사후 문제해결과정은 남성 군(p=.005), 간호학전공 만족도가 매우 만족한 군(p=<.000), 핵심경진대회 참여 목적은 자신감 향상 군(p=.004)에서 유의한 차이가 있었다. 결론적으로 이 연구는 졸업반 간호학생의 핵심기본간호술 교육프로그램이 핵심기본간호술 수행능력 및 임상수행능력에 긍정적인 영향을 미친 것으로 나타났다.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.339-352
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• 1996

Many dentists have been taken an interest in restoration of severly damaged teeth after endodontic treatment and it is a true that there are lots of studies about it. In these days, although we have used Para-Post, pins, threaded steel post, cast gold post and core, and so on, as a method of restoration frequently, it has been in controversy with the effects of them on the teeth and surrounding periodontal tissue. In this study, we assume that the crown of the upper 1st premolar was severly damaged, and after the root canal therapy, two most common types of restoration were carried out ; 1) coronal-radicular amalgam restoration, 2) after setting up the Para-Post, restore with amalgam core and gold crown. After restoration, in order to present the concentration of stress at internal portion of the tooth and the surrounding periodontal tissue, we doveloped a 2-dimensional finite element model of labiopalatal section, then loaded forces from 2 long perpendicular to the lingual incline of buccal ridge an the middle point, parallel to the long direction axis of tooth at the fossa-were applied. The analyzed results were as follows : 1. Stress of the normal first premolar was concentrated on the most weakest anatomical structure, that is, cervical area, and no stress on the bifurcated area of the canal. 2. Crown restoration after root canal therapy causes large stress concentration on the bifurcated area of the canal. This stress concentration has larger value in case of lateral movement of mandible, and there are decrease in the stress concentration compared with natural tooth. 3. Coronal-radicular amalgam restoration method transports more stress to the tooth structure than restoration using Para-Post. 4. There are more stress concentration around Para-Post in the case of lateral movement, and we have more favo rable result when restored with Para-Post. 5. Generally, stress in the lateral movement is larger than stress in the perpendicular load.

• 대한치과보철학회:학술대회논문집
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• 대한치과보철학회 2001년도 춘계학술대회
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• pp.35-35
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• 2001

• 대한치과보철학회지
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• 제34권4호
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• pp.780-790
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• 1996

The endodontically treated tooth is generally restored with post and core, owing to the brittleness and the loss of large amount of tooth structure. Although there have been lots of studies about the endodontically treated teeth, the three-dimensional quantitative studies about the stress distribution of them are in rare cases. In this study, it was assumed that the coronal portion of the upper incisor had extensively damaged. After the root canal therapy it was post cored, and restored with PFG crown. The three-dimensional model, in which the root was supported with a normal alveolar bone, was constructed. Force was applied to the centric stop point with the angle of 135 degrees to the long axis of the tooth. Force was assumed to be 250N as functional maximum bite force of upper central incisors. The results analyzed with three-dimensional finite element method were as follows : 1. Stress was concentrated on the middle portion of the labial side dentin and the apical portion of the dentin. 2. Stress in the post was more concentrated on the post apex. 3. The displacement of the post at the post-cement interface was almost symmetrical la-bio-lingually. 4. It assumed that restoring extensively damaged tooth with a post-core and PFG crown is an adequate method of restoration.

• 대한치과보철학회지
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• 제35권4호
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• pp.674-696
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• 1997

There're many cases that should be reconstructed with post and core when clinical crown is destructed. But this post and core restoration may cause damaging stress on the teeth. Previous finite element study was restricted to normal bone model relatively close to cemen-toenamel junction. Moreover, the test of a model with diminished bone support was rare. The purpose of this study is to test the effects of alveolar bone loss on the magnitude, stress distribution and displacement of post reconstructed teeth. In this study, it was assumed that the coronal portion of upper incisor was severely destructed. After conventional endodontic treatment, it was restored with post and core. The PFM restoration was made on it. This crown was cemented with ZPC. Alveolar bone was classified by 4 types of bone, such as normal, 2 mm, 4 mm, 6 mm bone, according to the bone loss. Meanwhile, the material of post are divided into 2 types of materials, such as gold, co-cr. Force was applied to two directions. One was fuctional maximum bite force (300 N) applied to the spot just lingual to the incisal edge with the angle of 45 degree to the long axis of the tooth, and the other one was horizontal force (300 N) applied to the labial surface. The results analyzed with three dimensional finite element method were as follows : 1. Stress was concentrated on the adjacent dentin of the post apex, one third portion of the post apex and the labial & lingual mid-portion of the root in all case. The stress of middle third of the root was apparently concentrated on the labial aspect. 2. The stress on adjacent dentin of the post apex and one third of the post apex increased as alveolar bone height moved apically. This increase was dramatic beyond 4 mm bone loss model. 3. The stress of the post apex was spreaded to the middle third of the post and greater than gold post in the case of metal post. 4. The displacement of the neck of post was the greatest in one of the post-cement interface and this increased as alveolar bone height moved apically. Besides the displacement of the metal post is slightly lower than one of the gold post.

• Steel and Composite Structures
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• 제34권2호
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• pp.279-288
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• 2020

The computational post-buckling strength of the tilted sandwich composite shell structure is evaluated in this article. The computational responses are obtained using a mathematical model derived using the higher-order type of polynomial kinematic in association with the through-thickness stretching effect. Also, the sandwich deformation behaviour of the flexible soft-core sandwich structural model is expressed mathematically with the help of a generic nonlinear strain theory i.e. Green-Lagrange type strain-displacement relations. Subsequently, the model includes all of the nonlinear strain terms to account the actual deformation and discretized via displacement type of finite element. Further, the computer code is prepared (MATLAB environment) using the derived higher-order formulation in association with the direct iterative technique for the computation of temperature carrying capacity of the soft-core sandwich within the post-buckled regime. Further, the nonlinear finite element model has been tested to show its accuracy by solving a few numerical experimentations as same as the published example including the consistency behaviour. Lastly, the derived model is utilized to find the temperature load-carrying capacity under the influences of variable factors affecting the soft-core type sandwich structural design in the small (finite) strain and large deformation regime including the effect of tilt angle.