• 제목/요약/키워드: Set and Statement

검색결과 95건 처리시간 0.023초

경호수행을 위한 태권도정신 활용의 질적 접근 (The Approach of Qualitative on Application of Taekwondo Spirit in Security Attendance)

  • 박영만;전용태
    • 시큐리티연구
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    • 제18호
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    • pp.39-54
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    • 2009
  • 본 연구는 경호수행에서의 태권도 정신의 중요성과 의미를 규명하는데 있다. 이러한 목적을 달성하기 위하여 우선 연구대상자를 2년 이상 태권도를 지속적으로 수련해온 경호원으로 경호 수행 중의 경험을 충실히 답변할 수 있도록 평직원에서 관리자직급까지로 설정하고 유목적표집법을 이용 9명의 대상자를 표집 하였다. 이러한 연구의 과정을 통하여 도출되어진 결론은 다음과 같다. 첫째, 태권도 수련을 통하여 체득된 예의, 염치, 인내, 극기, 백절불굴의 다섯 가지 태권도정신은 경호원의 경호임무 수행에 있어서 긍정적인 영향을 미치고 있다. 경호원들은 평상시 태권도 수련 중에 요구되는 예의, 염치, 인내, 극기, 백절불굴의 정신을 태권도수련을 통하여 수양함으로써 몸과 마음으로써 태권도정신을 획득하게 된다고 진술하였다. 이렇게 체득된 태권도정신은 경호임무 수행 중에 얻게 되는 각종 스트레스와 위해상황의 발생, 조직 내의 갈등과 같은 부정적 상황을 지혜롭게 극복할 수 있는 중요기재가 되어주었다. 둘째, 일상에서 요구되는 바른 마음가짐, 정신적 건강, 유연한 사회적 태도를 함양할 수 있는 바탕을 태권도정신이 제공해준다는 신념을 가지고 있었다. 따라서 경호대상과 경호원간, 또는 상급자 경호원과 하급자 경호원간의 위계질서가 반드시 요구되는 경호경비 조직 내에서 필요로 하는 자세를 배울 수 있는 기회를 얻을 수 있었다.

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상악 구치부 임플랜트 보철수복시 치관/치근비에 따른 응력 분포에 대한 유한 요소 분석 (FINITE ELEMENT ANALYSIS ON MAXILLARY MOLAR IMPLANT UNDER DIFFERENT C/R RATIO)

  • 김진호;김형섭;최대균;권긍록
    • 대한치과보철학회지
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    • 제44권5호
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    • pp.561-573
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    • 2006
  • Statement of the problem: In cases of low bone level in maxilla followed by extraction due to severe periodontitis or enlarged maxillary sinus, crown-root ratio of implant prosthesis will increase. The prognosis of these cases is not good as expected. Purpose : The purpose is to compare stress distribution due to crown-root ratio and effect of splinting between two implants in maxillary molar area under different loads Material and methods: Using ITI($4.1{\times}10$ mm) implant. two finite element models were made(model S: two parallel implants, model A: one of two is 20 degree inclined). Each model was designed in different crown-root ratio(0.7:1, 1:1, 1.25:1) and set cement type gold crown to make it splinted or non-splinted clinical situations. After that, 300 N force was loaded to each model in four ways.(load 1 : middle of occlusal table, load 2 : middle of buccal cusp, load 3 : middle of lingual cusp, load 4 : horizontal load to middle of buccal cusp), and stress distribution was analyzed. Results: On all occasions, stress was concentrated on neck of implant near cortical bone. In the case of inclined implant, stress was increased compared with parallel implants. Under load 1, 2, 3, stress was not increased even when crown-root ratio increases, but under load 4, when crown-root ratio increases, stress also increased. And more stress was concentrated under load 1 than load 2, 3. When crown-root ratio was same, stress under load 1, 2, 3 decreased when splinting, but under load 4, stress did not really decrease. Conclusion: Under vertical load, stress distribution related to crown-root ratio did not change. But under horizontal load, stress increased as crown-root ratio increases. Under vertical load, splinting decreased stress but under horizontal load, effect of splinting was decreased as condition of implant changes for the worse such as increase of crown-root ratio, inclined implant.

정부R&D투자가 기업 규모별 R&D지출에 미치는 영향 분석 (Effectiveness of Government R&D on Firm's R&D Spending)

  • 정준호;김재수;최기석;이병희
    • 한국콘텐츠학회논문지
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    • 제16권10호
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    • pp.150-162
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    • 2016
  • 정부의 R&D투자가 실제적으로 기업의 R&D투자를 진작시키는데 영향을 주고 있는지에 대해서 아직 합의된 결과가 도출되지 않았다. 한편 2016년도의 주요부처 정부R&D 예산이 삭감된 가운데 대기업에 대한 정부R&D투자는 줄이고 중소 중견기업에 대한 투자를 늘리기로 하여 이러한 정책이 향후 효과가 있을지에 대한 실증 분석이 요구된다. 이를 위해 국가과학기술지식정보서비스(NTIS)와 공시된 재무제표를 이용하여 2012년부터 2014년까지 1301개의 데이터를 기초로 이원고정효과모형과 이원확률효과모형을 사용하였다. 표본은 상장기업만을 대상으로 했으며 기업규모별(대기업, 중견기업, 중소기업)로 정부R&D투자가 기업R&D투자에 미치는 영향을 분석하였다. 분석결과 대기업에 대한 정부R&D투자는 다소 유의한 범위를 벗어나기는 하였으나 구축효과가 있는 것으로 나타났고, 유의하게 중견기업과 중소기업은 보완효과가 있는 것으로 나타났다. 이러한 연구결과는 현재 정부 정책의 방향이 합당함을 보이고 있다. 이는 정부의 제약된 자원을 효율적으로 배분하여 중소 중견기업의 자체 R&D투자를 유도하고 나아가 글로벌 강소기업의 혁신에 도움이 될 것으로 기대된다.

국제항공화물운송계약(國際航空貨物運送契約)의 법률관계(法律關係) -화주(貨主)의 권리의무(權利義務)를 중심(中心)으로- (Legal Relations of the Contract of International Carriage of Goods by Air)

  • 이강빈
    • 항공우주정책ㆍ법학회지
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    • 제1권
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    • pp.193-222
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    • 1989
  • The purpose of this study is to review the rights and duties of cargo owners, the party to the contract of international carriage of goods by air under the Warsaw Convention System and the IATA conditions. It is generally known that air freight is the most-cost mode of transportation. However, should there be considerations of total distribution cost, the use of air freight leads exporters to be advantageous in physical distribution. The Warsaw Convention System defined and limited the rights and duties of cargo owners and air carriers paticipating in the international carriage of goods, but it does not regulate every aspect of air transportation. Therefore, the unregulated parts are governed by national laws and by individual contracts of carriage. The International Air Transport Association(lATA), a worldwide organization of airlines, has formulated model conditions of contract for the carriage of cargo. These models are not uniformly followed but they serve as a basis for many of the individual standard form of contracts prepared by air carriers. The contract of air carriage of goods is a contract of adhesion, 'the consignor recognizing and accepting the conditions laid down by the carrier'. There are consignors and carriers as the parties to the contract of international carriage of goods. In addition to his basic right, implied in Warsaw Convention Article 18 and 19, to require devery of the goods in good condition and at the date agreed upon, the consignor has the right to dispose the goods in the course of the journey up to the moment when the consignee is entitled to require delivery. If it is impossible to carry out the orders of the consignor, the carrier must so inform him forthwith. The right conferred on the consignor ceases at the moment when that of the consignee begins in accordance with Warsaw Convention Article 13. Nevertheless, if the consignee declines to accept the air waybill or the goods, or if he cannot be communicated with, the consignor resumes his right of disposition. Unless it is otherwise agreed, it is the duty of the carrier to give notice to the consignee as soon as the goods arrive. The consignee is entitled, on arrival of the goods at the place of destination, to require the carrier to hand over to him the air waybill and to deliver the goods to him, on payment of the charges due and on complying with the conditions of carriage set out in the air waybill. The air waybill is supposed to be made out by the consignor. If the carrier makes it out, he is deemed, subject to proof to the contrary, to have done so on behalf of the consignor, whether there is one air waybill or several, each must be made out in three original parts. The first is for the carrier, the second is for the consignee, and the the third is handed to the consignor when the shipment has been accepted. The consignor is responsible for the correctness of the particulars and statement concerning the cargo appearing in the air waybill. Each of the original parts of the air waybill has evidential value and possession of his part is a condition for the exercise by the consignor or consignee of his rights under the contract of carriage. Hague Protocol set forth in Article 9 that nothing in this. Convention prevents the issue of a negotiable air waybill, but Montreal Additional Protocol No. 4 deleted this article. All charges applicable to a shipment are payable in cash at the time of acceptance thereof by the carrier in case of a prepaid shipment or at the time of delivery thereof by the carrier in case of a collect shipment. The carrier shall have lien the cargo for unpaid charges and, in the event of non-payment thereof, shall have the right to dispose of the cargo at public or private sale and pay itself out of the proceeds of such sale any and all such amounts. In conclusion, the Warsaw Convention System has the character of ambiguity in various respects, not only in the part of the forms of documents but also in conditions of contract. Accordingly, the following propositions might be considered: (1) If the carrier does not obey the orders of the consignor for the disposition of the goods without proper reasons, he will be liable strictly for any damage which may be caused thereby to the cargo owner. The special agreement and carrier's conditions of carriage which limit unreasonably the consignor's right of disposition of the goods will be nullified. (2) The instrument of the Warsaw Convention System which is not yet in force(Montreal Additional Protocol No. 4) would considerably simplfy the processing and keeping of computerized records of the carriage. Until this instrument enters into force, the airlines will be faced with practical problems preventing them to substitute computerized data processing techniques for the formal issuance of the documents. Accordingly, Montreal Additional Protocol No. 4 should become effective as soon as posisble. From a practical point of view in the international trade, the issuance of negotiable air waybill should be permitted for the security of the bank.

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TENSILE BOND STRENGTH BETWEEN ELASTOMERIC IMPRESSION MATERIALS AND TRAY RESINS DEPENDING ON THE THICKNESS OF THE TRAY ADHESIVE

  • Kim, Tae-Won;Moon, Hong-Seok;Lee, Keun-Woo;Chung, Moon-Kyu
    • 대한치과보철학회지
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    • 제44권6호
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    • pp.699-711
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    • 2006
  • Statement of problem. Elastomeric impression materials have been widely used to obtain an accurate impression. However there have not been enough studies on the influence of the thickness of the tray adhesives on the bonding strength between the trays and the elastomeric impression materials. Purpose. In order to understand the relationship between the thickness of the tray adhesive and the tensile bond strength and to suggest the thickness at which the bonding strength is strongest, tensile bond strength related to the thickness of adhesives of 3 different elastomeric impression materials were tested. Materials and methods. 3 impression materials, $Permlastic^{(R)}$. Regular Set(Kerr Corp., Romulus, Michigan, U.S.A.), $Impregum^{TM}$ $Penta^{TM}$(3M ESPE, Seefeld, Germany), and Aquasil Ultra Monophase Regular Set Smart Wetting.(Dentsply Caulk, Milford, Delaware, U.S.A.), were used in this study, and tray adhesives from the same manufacturers of the impression materials were used, which were Rubber Base Adhesive, Polyether Adhesive, and Silfix, respectively. The tray specimens were prepared by autopolymerizing the tray material(Instant Tray Mix, Lang, Wheeling, Illinois, U.S.A.), and a PVC pipe was used to house the impression material. In group A, tray adhesives were applied in multiple thin layers of 1 to 5 and in group B, adhesives were applied only once, in the thickness equivalent to several applications. Lightness($L^*$) of the adhesion surface was measured with a spectrophotometer(CM-3500d, Konica Minolta, Sakai, Osaka, Japan). The tensile bond strength of the elastomeric impression material and the tray resin was measured with universal materials testing machines(Instron, Model 3366, Instron Corp, Nowood, Massachusetts, U.S.A.). A formula between the number of adhesive application layers and the lightness of the adhesion surface was deduced in group A, and the number of adhesive layers in group B was estimated by applying the lightness($L^*$) to the deduced formula. Results. 1. In group A, a statistically significant increase in tensile bond strength appeared when the number of application layers increased from 1 to 2 and from 4 to 5, and no significant difference was present between 2, 3, and 4 layers in Permlastic. In Impregum, the tensile bond strength was significantly increased when the number of adhesive layers increased from 1 to 3, but no significant difference after 3 layers. In Aquasil, the tensile bond strength significantly increased as the number of application layers increased up to 4 but showed no significant difference between 4 and 5. 2. In group B, the tensile bond strength was decreased when the thickness of the adhesive increased in Permlastic. Impregum showed an increased tensile bond strength when the thickness of the adhesive was increased. In Aquasil, the tensile bond strength increased as the number of adhesive application layers increased up to approximately 2.5 layers but it sharply decreased after approximately 4.5. Conclusion. From the study, the common idea that it is better to apply a thin and single coat of tray adhesive needs correction in more detailed ways, and instructions on some of the tray adhesives should be reconsidered since there were several cases in which the tensile bond strength increased according to the increase in the thickness of the adhesives.

개발사업의 경관영향 검토를 위한 주요 조망점 선정 방법에 관한 연구 (The Method of Selecting Landscape Control Points for Landscape Impact Review of Development Projects)

  • 신지훈;신민지;최원빈
    • 한국조경학회지
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    • 제46권1호
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    • pp.143-155
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    • 2018
  • 2006년 자연환경보전법 개정에 따라 자연경관심의 제도가 도입되었다. 자연경관심의제도는 자연경관 내 개발사업 및 개발계획 시행 시 사업의 규모와 형태 배치로 인한 스카이라인과 경관보전, 경관자원, 조망축 등의 항목을 검토하는 제도이다. 그러나 경관영향평가를 위한 조망점의 선정은 모든 평가마다 기준의 일관성이 미흡하여 영향 평가 결과의 정확도와 신뢰도가 크게 저하되고 있는 실정이다. 이처럼 조망점의 위치에 따라 지각되는 경관의 모습이 현저하게 변화하게 되고, 불명확한 선정기준은 경관영향평가 결과에도 시각적 영향이 과소평가되므로 합리적인 선정기준이 필요하다. 본 연구는 개발사업 진행으로 인한 경관 변화가 예상될 때 경관영향을 평가하기 위한 객관적이고 합리적인 조망점 선정기준을 제시하고, 궁극적으로는 개발사업에 대한 경관영향 검토 및 향후 경관 모니터링을 위한 기초적인 분석방법을 제시하는데 목적을 갖고 있다. 환경영향평가서의 자연경관 내 시행되는 개발사업 중 단일건축물 및 소규모 개발을 하는 사례를 조사하고, 그 중 점적 개발사업 4곳을 대상으로 경관영향평가 부분을 분석하여 주요 조망점 선정과정에 대해 제안하였다. 기존 가시지역 분석방법의 결과인 지형 변화에 따라 가시지역 범위를 반영하지 못하는 한계를 극복하기 위해 조망 대상물 기준 가시지역 분석방법은 가시 범위를 확대하여 영향력이 높은 유효한 조망점을 선정할 수 있는 가능성을 판단하였다.

군(軍) 보고서 등장 문장과 관련 법령 간 비교 시스템 구축 방안 연구 (A Study on the Establishment of Comparison System between the Statement of Military Reports and Related Laws)

  • 정지인;김민태;김우주
    • 지능정보연구
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    • 제26권3호
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    • pp.109-125
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    • 2020
  • 군(軍)에서 방위력개선사업(이하 방위사업)은 매우 투명하고 효율적으로 이루어져야 함에도, 방위사업 관련 법 및 규정의 과도한 다양화로 많은 실무자들이 원활한 방위사업 추진에 어려움을 겪고 있다. 한편, 방위사업 관련 실무자들이 각종 문서에서 다루는 법령 문장은 문장 내에서 표현 하나만 잘못되더라도 심각한 문제를 유발하는 특징을 가지고 있으나, 이를 실시간으로 바로잡기 위한 문장 비교 시스템 구축에 대한 노력은 미미했다. 따라서 본 논문에서는 Siamese Network 기반의 자연어 처리(NLP) 분야 인공 신경망 모델을 이용하여 군(軍)의 방위사업 관련 문서에서 등장할 가능성이 높은 문장과 이와 관련된 법령 조항의 유사도를 비교하여 위법 위험 여부를 판단·분류하고, 그 결과를 사용자에게 인지시켜 주는 '군(軍) 보고서 등장 문장과 관련 법령 간 비교 시스템' 구축 방안을 제안하려고 한다. 직접 제작한 데이터 셋인 모(母)문장(실제 법령에 등장하는 문장)과 자(子)문장(모(母)문장에서 파생시킨 변형 문장) 3,442쌍을 사용하여 다양한 인공 신경망 모델(Bi-LSTM, Self-Attention, D_Bi-LSTM)을 학습시켰으며 1 : 1 문장 유사도 비교 실험을 통해 성능 평가를 수행한 결과, 상당히 높은 정확도로 자(子)문장의 모(母)문장 대비 위법 위험 여부를 분류할 수 있었다. 또한, 모델 학습에 사용한 자(子)문장 데이터는 법령 문장을 일정 규칙에 따라 변형한 형태이기 때문에 모(母)·자(子)문장 데이터만으로 학습시킨 모델이 실제 군(軍) 보고서에 등장하는 문장을 효과적으로 분류한다고 판단하기에는 제한된다는 단점을 보완하기 위해, 실제 군(軍) 보고서에 등장하는 형태에 보다 더 가깝고 모(母)문장과 연관된 새로운 문장 120문장을 추가로 작성하여 모델의 성능을 평가해본 결과, 모(母)·자(子)문장 데이터만으로 학습시킨 모델로도 일정 수준 이상의 성능을 확인 할 수 있었다. 결과적으로 본 연구를 통해 방위사업 관련 군(軍) 보고서에서 등장하는 여러 특정 문장들이 각각 어느 관련 법령의 어느 조항과 가장 유사한지 살펴보고, 해당 조항과의 유사도 비교를 통해 위법 위험 여부를 판단하는 '실시간 군(軍) 문서와 관련 법령 간 자동화 비교 시스템'의 구축 가능성을 확인할 수 있었다.

의료서비스 마케팅을 위한 품질지각과 만족에 관한 연구 (A Study on Qulity Perceptions and Satisfaction for Medical Service Marketing)

  • 유동근
    • 간호행정학회지
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    • 제2권1호
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    • pp.97-114
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    • 1996
  • INSTRODUCTION Service quality is, unlike goods quality, an abstract and elusive constuct. Service quality and its requirements are not easily understood by consumers, and also present some critical research problems. However, quality is very important to marketers and consumers in that it has many strategic benefits in contributing to profitability of marketing activities and consumers' problem-solving activities. Moreover, despite the phenomenal growth of medical service sector, few researchers have attempted to define and model medical service quality. Especially, little research has focused on the evaluation of medical service quality and patient satisfaction from the perspectives of both the provider and the patient. As competition intensifies and patients are demanding higher quality of medical service, medical service quality and patient satisfaction has emerged as a critical research topic. The major purpose of this article is to explore the concept of medical service quality and its evaluation from both nurse and patient perspectives. This article attempts to achieve its purpose by (1)classfying critical service attibutes into threecategories(satisfiers, hygiene factors, and performance factors). (2)measuring the relative importance of need criteria, (3)evaluating SERVPERF model and SERVQUAL model in medical service sector, and (4)identifying the relationship between perceived quality and overall patient satisfaction. METHOD Data were gathered from a sample of 217 patients and 179 nurses in Seoul-area general hospitals. From the review of previous literature, 50 survey items representing various facets of the medical service quality were developed to form a questionnaire. A five-point scale ranging from "Strongly Agree"(5) to "Strongly Disagree"(1) accompanied each statement(expectation statements, perception statements, and importance statements). To measure overall satisfaction, a seven-point scale was used, ranging from "Very Satisfied"(7) to "Very Dissatisfied"(1) with no verbal labels for scale points 2 through 6 RESULTS In explaining the relationship between perceived performance and overall satisfaction, only 31 variables out of original 50 survey items were proven to be statistically significant. Hence, a penalty-reward analysis was performed on theses 31 critical attributes to find out 17 satisfiers, 8 hygiene factors, and 4 performance factors in patient perspective. The role(category) of each service quality attribute in relation to patient satisfaction was com pared across two groups, that is, patients and nurses. They were little overlapped, suggesting that two groups had different sets of 'perceived quality' attributes. Principal components factor analyses of the patients' and nurses' responses were performed to identify the underlying dimensions for the set of performance(experience) statements. 28 variables were analyzed by using a varimax rotation after deleting three obscure variables. The number of factors to be extracted was determined by evaluating the eigenvalue scores. Six factors wereextracted, accounting for 57.1% of the total variance. Reliability analysis was performed to refine the factors further. Using coefficient alpha, scores of .84 to .65 were obtained. Individual-item analysis indicated that all statements in each of the factors should remain. On 26 attributes of 31 critical service quality attributes, there were gaps between actual patient's importance of need criteria and nurse perceptions of them. Those critical attributes could be classified into four categories based on the relative importance of need criteria and perceived performance from the perspective of patient. This analysis is useful in developing strategic plans for performance improvement. (1) top priorities(high importance and low performance) (in this study)- more health-related information -accuracy in billing - quality of food - appointments at my convenience - information about tests and treatments - prompt service of business office -adequacy of accommodations(elevators, etc) (2) current strengths(high importance and high performance) (3)unnecessary strengths(low importance and high performance) (4) low priorities(low importance and low performance) While 26 service quality attributes of SERPERF model were significantly related to patient satisfation, only 13 attributes of SERVQUAL model were significantly related. This result suggested that only experience-based norms(SERVPERF model) were more appropriate than expectations to serve as a benchmark against which service experiences were compared(SERVQUAL model). However, it must be noted that the degree of association to overall satisfaction was not consistent. There were some gaps between nurse percetions and patient perception of medical service performance. From the patient's viewpoint, "personal likability", "technical skill/trust", and "cares about me" were most significant positioning factors that contributed patient satisfaction. DISCUSSION This study shows that there are inconsistencies between nurse perceptions and patient perceptions of medical service attributes. Also, for service quality improvement, it is most important for nurses to understand what satisfiers, hygiene factors, and performance factors are through two-way communications. Patient satisfaction should be measured, and problems identified should be resolved for survival in intense competitive market conditions. Hence, patient satisfaction monitoring is now becoming a standard marketing tool for healthcare providers and its role is expected to increase.

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노인요양시설에 있는 노인환자의 구강실태 및 치료수요도 (Oral health status and treatment need of institutionalized elderly patients)

  • 양순봉;문홍석;한동후;이호용;정문규
    • 대한치과보철학회지
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    • 제46권5호
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    • pp.455-469
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    • 2008
  • 문제제기: 노인요양시설은 치과진료영역 가운데 가장 취약한 상태에 놓여 있고 신체적, 정신적 장애로 인해 주관적 치료요구도를 파악할 수 없는 상태지만 이에 대한 기초적인 실태조사가 전무한 상태이다. 목적: 본 연구는 노인요양시설에서 노인환자들의 치아우식증에 의한 구강실태를 조사하고, 기능치아와 보철물로 이루어진 교합단위를 분석하여 그에 따른 치과치료수요도를 분석하는데 목적이 있으며 향후 적절한 진료방향을 수립하는데 기여하고자 한다. 연구재료 및 방법: 노인요양시설에서 758명의 노인환자와 D치과의원에 내원한 212명의 65세 이상인 노인을 대상으로 2000년 국민구강건강실태조사에서 작성된 치아우식검진지침에 입각하여 구강실태조사를 시행하였다. 결과: 노인요양시설의 노인에게서 고령으로 갈수록 대조군에 비해 악화되고 있는 구강상태를 알 수 있었고 매우 높은 치료수요를 파악할 수 있었다. 고찰: 노인환자의 구강건강관리를 위해서는 무엇보다도 이들을 보살피는 간병인과 간호 인력들이 가지고 있는 구강건강의 중요성에 대한 인식을 바꾸기 위한 노력이 절실히 필요한 상황이다. 이제는 무치악 환자에게 시행되고 있는 일회성 의치사업 일변도의 복지정책방향을 보건복지부와 일선 지방자치단체에서 사후관리를 원칙으로 한 전문가에 의한 무치악 환자의 의치사업으로 강화해야 하며 유치악의 노인환자들에 대한 정기적인 치과검진을 시행하고 이동진료 및 왕진시스템이 보완된 구강건강관리 및 보존, 수복진료 형태로의 전환을 고려할 시점이라 생각된다.

타이타늄 표면 코팅 처리에 따른 타이타늄도재관의 파절강도 비교 (A COMPARISON OF FRACTURE STRENGTHS OF PORCELAIN-FUSED-TO-TITANIUM CROWN AMONG TITANIUM SURFACE COATING TREATMENTS)

  • 김지혜;박상원;방몽숙;양홍서;박하옥;임현필;오계정;김현승;이광민;이경구
    • 대한치과보철학회지
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    • 제45권2호
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    • pp.203-215
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    • 2007
  • Statement of problem: Titanium and its alloy, with their excellent bio-compatibility and above average resistance to corrosion, have been widely used in the field of dentistry. However, the excessive oxidization of titanium which occurs during the process of firing on porcelain makes the bonding of titanium and porcelain more difficult than that of the conventional metal-porcelain bonding. To solve this problem related to titanium-porcelain bonding, several methods which modify the surfaces, coat the surfaces of titanium with various pure metals and ceramics, to enable the porcelain adhesive by limiting the diffusion of oxygen and forming the adhesive oxides surfaces, have been investigated. Purpose: The purpose of this study was to know whether the titanium-porcelain bonding strength could be enhanced by treating the titanium surface with gold and TiN followed by fabrication of clinically applicable porcelain-fused-to-titanium crown Material and method: The porcelain-fused-to-titanium crown was fabricated after sandblasting the surface of the casting titanium coping with $Al_2O_3$ and treating the surface with gold and TiN coating followed by condensation and firing of ultra-low fusing porcelain. To compare with porcelain-fused-to-titanium crowns, porcelain-fused-to-gold crowns were fabricated and used as control groups. The bonding strengths of porcelain-fused-to-gold crowns and porcelain-fused-totitanium crowns were set for comparison when the porcelain was fractured on purpose to get the experimental value of fracture strength. Then, the surface were examined by SEM and each fracturing pattern were compared with each other Result:Those results are as follows. 1. The highest value of fracture strength of porcelain-fused-to-titanium crowns was in the order of group with gold coating, group with TiN coating, group with $Al_2O_3$ sandblasting. No statistically significant difference was found among the three (P>.05). 2. The porcelain-fused-to-gold crowns showed the highest value in bonding strength. The bonding strength of crowns porcelain-fused-to-titanium crowns of rest groups showed bonding strength reaching only 85%-94% of that of PFG, though simple comparision seemed unacceptable due to the difference in materials used. 3. The fracturing patterns between metal and porcelain showed mixed type of failure behavior including cohesive failure and adhesive failure as a similar patterns by examination with the naked eye and SEM. But porcelain-fused-to-gold crowns showed high incidence of adhesive failure and porcelain-fused-to-titanium crowns showed high incidence of cohesive failure. Conclusion: Above results proved that when fabricating porcelain-fused-to-titanium crowns, treating casting titanium surface with gold or TiN was able to enhance the bonding strength between titanium and porcelain. Mean value of masticatory force was found to showed clinically acceptable values in porcelain bonding strength in all three groups. However, more experimental studies and evaluations should be done in order to get better porcelain bonding strength and various surface coating methods that can be applied on titanium surface with ease.