FINITE ELEMENT ANALYSIS OF MAXILLARY CENTRAL INCISORS RESTORED WITH VARIOUS POST-AND-CORE APPLICATIONS

서민석,손원준,이우철,유현미,조병훈,백승호 大韓齒科保存學會 2009 Restorative Dentistry & Endodontics Vol.34 No.4

근관 치료된 치아의 수복에 있어서 파절은 가장 중요하게 고려되는 점이다. 포스트를 사용해서 수복한다는 것은 치수와 다른 단단한 물질을 근관 내에 삽입한다는 것으로 자연스럽지 못한 구조를 만들어서 고유의 응력분산을 변화시킨다. 오랫동안 수많이 in vitro 연구들이 post-and-core로 수복된 치아의 파절 저항에 대해서 이루어졌지만 어떤 것이 최상의 선택인지에 대해서는 많은 상충되는 관점들이 존재한다. 본 연구의 목적은 유한요소분석법을 사용하여 post-and-core system의 물리적인 성질이 치질의 응력분산에 미치는 영향을 분석하고 어떤 조합이 파절 저항에 도움이 되는지를 알아보는 것이다. 근관 치료된 상악 중절치를 삼차원 유한 요소법으로 Modeling하였다. 1.5 mm의 ferrule 높이를 부여하고 외관은 zirconia ceramic crown으로 지정하였다. 세가지 평행한 형태의 포스트 (zirconia ceramic, glass fiber, and stain-less steel)와 두 가치 코어 (Paracore and Tetric ceram) 물질을 6개의 모델로 조합하였다. 각각의 모델은 해면골, 피질골, 치주인대 , 그리고 4 mm 근관 충전을 가지도록 설계하였다. 50 N의 정적인 교합력이 치아 장축에서 60도 각도로 치관의 설면에 적용시켰다. 모델들의 응력전달 특징의 차이를 분석하였고, 결과를 나타내는 데는 Maximum von Mises stress 값을 사용하였고 최대 변위량과 정수압도 계산하였다. Glass fiber post로 수복된 경우 높은 탄성계수를 가진 레진 코어 모델 (29.14 MPa)에서 낮은 탄성계수의 코어 모델(29.21 MPa)보다 더 낮은 응력이 발생하였다. Glass fiber post로 수복된 모델 (0.03497-0.03499 mm)은 다른 포스트로 수복된 모델들 (0.03245-0.03452 mm)보다 더 많은 최대 변위량을 보였다. 이는 glass fiber post로 수복된 치아의 경우가 상대적으로 치아에 가해지는 힘에 의해 더 많이 움직였다는 것을 보여준다. Zirconia ceramic 이나 stainless steel과 같이 탄성계수가 큰 포스트는 응력을 증가시키지만 포스트가 스트레스를 대부분 흡수하여 치질에는 스트레스가 낮게 나타났다. Glass fiber post로 수복된 모델에서는 코어와 크라운이 만나는 순면 치경부에서 가장 높은 응력이 발생하였다. The purpose of this study was to investigate the effect of rigidity of post core systems on stress disthbution by the theoretical technique, finite element stress-analysis method. Three-dimensional finite element models simulating an endodontically treated maxillary central incisor restored with a zirconia ceramic crown were prepared and 1.5 mm ferrule height was provided. Each model contained cortical bone, trabecular bone, periodontal ligament, 4 mm apical root canal filling, and post-and-core. Six combinations of three parallel type post (zirconia ceramic, glass fiber, and stainless steel) and two core (Paracore and Tetric ceram) materials were evaluated, respectively. A 50 N static occlusal load was applied to the palatal Surface of the crown with a 60° angle to the long axis of the tooth. The differences in stress transfer characteristics of the models were analyzed. von Mises stresses were chosen for presentation of results and maximum displacement and hydrostatic pressure were also calculated. An increase of the elastic modulus of the post material increased the stress, but shifted the maximum stress location from the dentin surface to the post material. Buccal side of cervical region (junction of core and crown) of the glass fiber post restored tooth was subjected to the highest stress concentration. Maximum von Mises stress in the remaining radicular tooth structure for low elastic modulus resin core (29.21 MPa) was slightly higher than that for high elastic modulus resin core (29.14 MPa) in case of glass fiber post. Maximum displacement of glass fiber post restored tooth was higher than that of zirconia ceramic or stainless steel post restored tooth.

편도체 기저외측핵의 AP5 투여가 상승된 경악반응의 습득에 미치는 영향

서미숙,조소현,김기석,이만영 한국심리학회 한국심리학회지 생물 및 생리 Vol.5 No.1

본 연구는 고전적 공포조건화에 관여하는 장소로 알려진 편도체의 기저 외측핵에 장기상승작용(Long-Term Potentiation: LTP)의 생성을 차단하는 약물인 MNDA (N-methyl-D-aspartate)길항제 AP5를 미세주입함으로써 시각적 조건자극(CS)을 사용한 경우에, 상승된 경악 반응의 습득이 차단되는지를 보고자 하였다. 동물은 AP5-AP5, AP5-식염수, 식염수-AP5, 식염수-식염수 집단으로 나누어서 CS-US 배쌍직전에 AP5나 식염수를 주입한 후 훈련시켰다고 다시 검사직전에 AP5 혹은 식염수를 주입하였다. AP5-AP5집단과 AP5-식염수집단은 상승된 경악반응을 보이지 않았고, 식염수-AP5, 식염수-식염수 집단은 상승된 경악반응을 보였다. CS-US배쌍 직전에 주입한 AP5는 상승된 경악반응을 차단하였고, 검사직전에 주입한 AP5는 상승된 경악반응을 차단하지 않은 결과는 AP5가 습득을 차단했으되 그 표현에는 영향을 미치지 않았다고 해석된다. 그리고 AP5-AP5, AP5-식염수 집단이 상승률에서 유의미한 차이를 보이지 않았으므로, 상승된 경악반응의 차단이 상태의존적 인출 실패에 기인한 것이 아니고, AP5 자체의 약효때문임을 알 수 있다. It has been known that the amygadala is the neural substrate for conditioned fear as well as unconditioned fear. Among the substructures of amygdala, the basolateral nucleus where CS and US inputs converge and LTP occurs, contains high densities of NMDA receptors and so seems to have a critical role in synaptiplasticity. NMDA antagonist, AP5 prevent induction of Long-term potentiation, but not expression of LTP. LTP is an activity dependent enhancement of synaptic efficacy and is regarded the psysiological mechanisms that might underlie learning and memory. So this experiment was done to investigate what effect AP5 injection to the basolateral amygdala on the acquisition and expression of the fear conditioning, using the fear potentiated Startle paradigm. Animals were allocated to AP5-AP5, AP5-saline, saline-AP5, saline-saline groups. AP5 or saline was injected just before conditioning and testing. The re sult is that AP5-AP5, AP5-saline group didn't show the potentiated startle, comparative to the saline-AP5, saline-saline group, and AP5-AP5 group is not significantly different from AP5-saline. So we conclude that AP5 blocked the acquisition but not expression of conditio-ned fear-potentiated startle and convince that the blocking is not due to state-dependent retrieval failure.

복합레진 수복 시 재접착 술식이 미세누출에 미치는 영향

이미애,서덕규,손호현,조병훈 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.3

복합레진 수복시, 일반적으로 연마, 산부식, 수세 및 건조 단계를 거쳐 저점도 레진을 적용하는 재접착 술식을 통해 예상되는 수축간극을 봉쇄한다. 그러나, 이 과정은 재접착제 적용 이전에 물이나 잔사가 간극을 매워버릴 수 있어 그 효과가 의심된다. 본 실험에서는 연마 단계 이전, 즉 복합레진을 중합한 직후에 재접착제를 도포한다면 변연누출을 더 줄일 수 있을 것이라는 가설을 검증하고자 하였다. 실험을 위해 35개의 발거한 대구치에서 협면과 설면에 교합면 변연은 법랑질에, 치은측 변연은 상아질에 위치하는 5급 와동을 형성하였다. 와동은 Z250 (3M ESPE, USA)로 충전하였고, 접착제로는 AdperTM Single Bond 2(3M ESPE)을 사용하였다. 재접착제로는 Biscover LV (Bisco, USA) 레진 전색제와 ScotchBond Multi-purpose system(3M ESPE)의 접착제, 및 점도가 낮은 실험용 접착제를 연마 전 또는 일련의 연마 및 산부식 후 수복물의 변연에 적용하였다. 2% 메틸렌 블루 용액에 네 시간 동안 침적한 뒤 교합측 및 치은측 변연에서의 색소 침투 깊이를 광학 입체 현미경으로 측정하였다. 재접착제의 점도와 변연미세누출의 상관관계도 평가하였다. 재접착 술식, 재접착제, 및 변연의 위치, 그 각각에서는 통계적으로 유의한 차이를 관찰할 수 없었다. 그러나, 재접착 술식을 시행하지 않은 대조군의 경우에는 세 가지 재접착제를 사용한 재접착군에 비해 치은측 변연에서 미세누출이 통계적으로 유의하게 크게 나타났다(p < 0.05). 대조군과 재접착군의 미세누출의 차이는 교합측 변연에서는 관찰되지 않았다. 연마 및 산부식 후 치은변연에 재접착제를 적용한 경우에서 약한 음의 상관관계(r = -0.326, p = 0.041)를 보인 경우를 제외하고는, 재접착제의 점도와 미세누출은 유의한 상관관계를 보이지 않았다. During a composite resin restoration, an anticipating contraction gap is usually tried to seal with low-viscosity resin after successive polishing, etching, rinsing and drying steps, which as a whole is called rebonding procedure. However, the gap might already have been filled with water or debris before applying the sealing resin. We hypothesized that microleakage would decrease if the rebonding agent was applied before the polishing step, i.e., immediately after curing composite resin. On the buccal and lingual surfaces of 35 extracted human molar teeth, class V cavities were prepared withthe occlusal margin in enamel and the gingival margin in dentin. They were restored with a hybrid composite resin Z250 (3M ESPE, USA) using an adhesive AdperTM Single Bond 2 (3M ESPE). As rebonding agents, BisCover LV (Bisco, USA), ScotchBond Multi-Purpose adhesive (3M ESPE) and an experimental adhesive were applied on the restoration margins before polishing step or after successive polishing and etching steps. The infiltration depth of 2% methylene blue into the margin was measured using an optical stereomicroscope. The correlation between viscosity of rebonding agents and mciroleakage was also evaluated. There were no statistically significant differences in the microleakage within the rebonding procedures, within the rebonding agents, and within the margins. However, when the restorations were not rebonded, the microleakage at gingival margin was significantly higher than those groups rebonded with 3 agents (p < 0.05). The difference was not observed at the occlusal margin. No significant correlation was found between viscosity of rebonding agents and microleakage, except very weak correlation in case of rebonding after polishing and etching at gingival margin (r = -0.326, p = 0.041).

Polyaaccharide 類의 固形分斯體에 의한 藥物 傳達體系의 開發

서성훈,김길수,김동현,이승진,장미경 경희대학교 약학대학 1994 慶熙藥大論文集 Vol.22 No.

노인의 스트레스원과 스트레스 인지정도에 관한 연구

서현미,하양숙 서울대학교 간호대학 간호과학연구소 1997 간호학 논문집 Vol.11 No.1

The purpose of this study was to identify stressors and perceived stress level experienced by elderly. And the intent of this investigation is to suggest nursing intervention for care of the elderly. A convenient saplling of 331 elderly who lives in Seoul, Kwang-Ju, Yang-Ju Gun-Kyung-Ki Do, Ui-Jong Bu, and Young-Am Kun, Jeun-Ra Nam Do was done. The period of collection was from January in 1996 to May in 1996. The constructing process of Seo's Elderly Stress Scale(SESS) were as follows; 1) Make preliminary items which related to stress and stressor of the elderly that was based upon review of literature and unstructured interview with 45 elderly. 2) Modification of items and pilot study were performed to determing the stressors. Consequently, 64 stressors were identified. The SESS was composed of 3-areas(1. If you experienced the following stressors in the past one years, Please mark "0" on the "yes" column 2. How many frequently occurred the experienced stressors you felt.; "1=seldom", "2=sometimes", "3=often", "4=always", 3. How much stressful the experienced stressors you felt. The degree of stressfulness is 0-10 and it was a ladder scale. ). The total score of perceived stress level was calculated from frequency score by stressfulness score. The range of total score is 0-2,560. Internal consistency of SESS was Cronbach's α=0.9060. SPSS/PC?? program was used for statistical analysis and the data was analyzed in terms of frequency (percentile score), mean (SD), t-test, F-test and the reliability coefficient. The results of this study were as follows: 1. Most frequently experienced stressors by elderly were ranked 'decreased eyesight'(86.1%), 'decreased strength'(83.1%), 'change of dental condition'(82.5%), 'decreased memory'(81.0%), 'sleep change'(76.7%), 'thinking about own death'(72.2%), 'loneliness'(69.5%) and 'decreased hearing'(69.2%). 2. Always experienced stressors by elderly were ranked 'change of dental condition'(40.2%), 'decreased eyesight'(40.2%), 'south and north Korean unification'(31.4%). 3. Most stressfulness stressors experienced by elderly were ranked 'death of your children'(9.83), 'death of your spouse'(9.62), 'divorce of your children'(8.67) and 'infertility of your children'(8.55) 4. Total mean (SD) score of perceived stress level is 431(218), maximum score is 992 and minimum score is 4 by subjects, 5. Compared the perceived stress level of subjects with sex, live together children, disease, and perceived health status were significantly differences. In conclusion, most frequently experienced stressors by elderly which was changed of physical function according to aging process. And most stressfulness stressors which was death of family members.

하악 우측 측절치에 발생한 선양 치성 종양

박미선,박호원,서현우,이주현 大韓小兒齒科學會 2011 大韓小兒齒科學會誌 Vol.38 No.4

선양 치성 종양(adenomatoid odontogenic tumor)은 악골에 드물게 발생하는 치성 기원의 종양이다. 이전에는 법랑모세 포종(ameloblastoma)의 한 종류로 여겨졌으나 양성이며 재발되는 경우는 극히 드물다. 상악 견치에 호발하며 대개는 무증 상이지만 크기가 천천히 커져 무통성 종창을 일으킬 수 있다. 방사선학적으로 함치성 낭종(dentigerous cyst) 및 단방성 법 랑모세포종(unicystic ameloblastoma)과 매우 유사하다. 일반적으로 보존적인 소파술(curettage) 및 적출술(enucleation) 을 통해 치료한다. 본 증례는 하악 우측 측절치 미맹출을 주소로 내원한 10세 여자 환아에서 방사선 사진 검사를 통해 치아의 매복 및 병소를 확인하고 적출술을 시행하였다. 치아에는 브라켓을 부착하여 교정적 정출을 유도하였다. 조직학적 검사를 통해 선양 치성 종 양으로 확진되었으며 양호한 치료 결과를 보였기에 보고하는 바이다. Adenomatoid odontogenic tumor(AOT) is an infrequent odontogenic tumor which arise in the jaw. It was considered as a variant of ameloblastoma. The adenomatoid odontogenic tumor is clearly benign and, in contrast to the ameloblastoma, present a very low recurrence. It most often appears in the canine region of the maxilla. The adenomatoid odontogenic tumor is frequently asymptomatic, however it may cause painless swelling. The radiological findings of adenomatoid odontogenic tumor frequently share characteristics of dentigerous cyst and unicystic ameloblastoma. Conservative surgical enucleation and curettage are the treatment of choice. In this case a 10-year-old child was presented with mandibular right lateral incisor in unerupted. Radiographically, the tooth was impacted and a radiolucency was seen in the area. The lesion was enuclated without extraction of the tooth. Bracket was attached on the tooth for orthodontic extrusion installed. Histopathologically adenomatoid odontogenic tumor was revealed.

유아 멀티미디어 교육 활성화를 위한 방향

서현아,고은미 경성대학교 2000 論文集 Vol.21 No.2

The Education of Multimedia in the kindergarten become more and more important to young children these days. However most educators didn't integrate multimedia activities to their other parts of the classroom. The purpose of this study is to recognize the importance of multimedia education for young children and promote teacher's positive role. Accordingly, this study examined computer activity, software, use of internet and the factors the influence teacher to integrate computer technology into the teaching and learning process. The results of this study are as follows, 1) Multimedia should be understood by the concept of multimedia computer and interacting environment. 2) The important thing in computer activity is not controversy about computer effects but how we connect computer activity into children's life well. 3) Developmentally appropriate software is essential part of successful computer activities. 4) Developmentally appropriate internet program may serve as an interesting, creative platform in the acquisition of general skills. 5) External factors and intern릴 factors should be considered together for early multimedia education and integrate multimedia activity to children's environment.

백금박막 RTD를 이용한 유속센서의 제조와 그 동작특성

서현미,장경훈,김영진,설철규 경북대학교 센서기술연구소 1997 센서技術學術大會論文集 Vol.8 No.1

A flow sensor for detecting the flow rate of a air, composing a substrate, a heating element, and one or two fluid temperature sensing elements disposed symmetrically around the heating element. Wherein resistence changes by a fluid temperature change and heating element is maintained at fixed level by the control of voltage that is applied to the heating element. The function of the heating element(microheater) is based on the self-heating effect of the resistor when current is applied to it. A airflow sensor is capable of accuritely measuring a air flow irrespective of changes in ambient temperature. Pt thin films were deposited by a DC magnetron sputtering with Ar/O_(2) gas mixtures. Due to the oxygen incorporation into the Pt films, deposition rate and resistivity of as-deposited Pt thin films increased with oxygen fraction in the sputtering gas.

정수처리 공정에서 철과 망간 잔류 농도에 관한 연구

최미리,서규태,문병현,이택순 7개 국립대학교 환경연구 논문집 공동발행 위원회 2003 공업기술연구 Vol.3 No.-

This study was to investigate the cause of the color and turbidity in a small-scale water treatment plant using lakes water as water supply source. Water qualities in aqueducts, in depth of the lakes and in each process were measured. And effects of prechlorination on each unit operation in the water treatment, especially on iron and manganese removal, were studied. The concentration of iron and manganese was 0.13, 0.08 mg/L in the surface water and 1.93 and 0.433 mg/L in 15 m depth of the lake. Higher iron concentration of the inlet was measured to 5.35 mg/L which was caused by the steel aqueduct corrosion. The optimun coagulation dosages of Poly Aluminum Chloride(PAC) and Liquid Aluminum Sulfate (LAS) were 17.5 mg/L and 35 mg/L. Pretreatmnet of raw water with CaCOl improved the removal efficiencies of iron and manganes. However, more efficient method for removing iron and manganes was required.

급성 췌장염을 동반한 임신성 급성 지방간 1 예

강미선;박상훈;박지영 서희영;허란;김상현 인제대학교 백병원 2011 仁濟醫學 Vol.32 No.-

Acute fatty liver of pregnancy (AFLP) was first described as a specific clinical entity in 1940 and thought to be universally fatal. Maternal mortality in the past approached 75 percent. However early diagnosis and prompt delivery have dramatically improved the prognosis, and maternal mortality rate is now less than 18 percent. A early diagnosis, a prompt delivery, and a intensive supportive care have improved maternal and perinatal outcome. We report a 30—year—old woman at 37 weeks gestation who have multiple complications including acute pancreatitis in AFLP. She was complicated with acute renal failure, disseminated intravascular coagulation, duodenal ulcer bleeding, spontaneous bacterial peritonitis, pulmonary edema and acute pancreatitis.