• 한국산학기술학회논문지
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• 제22권4호
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• pp.124-130
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• 2021

치과보철물의 심미적 결과를 조절하는 중요한 요인은 반투명도이며, 지르코니아 착색제의 건조 정도가 반투명도에 어떠한 영향을 미치는지 알아보고자 한다. 실험을 위해서 지르코니아 블록별로 원형 시편을 총 90개 제작하였다. 그 다음 지르코니아 시편을 착색제로 180초 침적 후 미건조(0초), 중간건조(30초), 완전건조(30분)의 건조시간(Dry time)을 부여한 후 지르코니아 소결로를 이용하여 원형 시편을 소결하였다. 분광광도계(Spectrophotometer CM-3600A, Konica Minolta, Japan)를 이용하여 흑색표준타일과 백색표준타일 위에 시편을 놓고, 표준광원 D65의 조건에서 정반사광 제거방식으로 지르코니아 원형 시편을 각각 측정하였다. 시편당 총 3번씩 반복측정하였다. 지르코니아의 건조시간에 따른 반투명도를 비교 분석하기 위하여 One-way ANOVA를 시행하였다. 지르코니아 종류별, 착색제에 따라 반투명도는 통계적으로 차이가 있었고(P < 0.001), 건조시간에 따라서는 통계적으로 차이는 없었다(P > 0.922). 그러나, 완전건조인 상태일 때, 반투명도 값이 작은 것으로 나타나 건조가 잘 될수록 지르코니아 색상이 투명하다는 것을 알 수 있었다.

• 대한치과기공학회지
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• 제43권2호
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• pp.62-68
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• 2021

Purpose: This study examined the correlations between the satisfaction and effectiveness of practical training and theory lectures under two conditions: face-to-face lectures and non-face-to-face online lectures. Methods: A survey of 436 public health student, whereafter SPSS 20.0 (IBM) was used on the data to conduct frequency, descriptive statistics, and exploratory factor analyses. The Cronbach's α value was estimated in a reliability analysis, and a simple regression analysis was conducted to verify the study hypothesis. Results: It was found that the students preferred pre-recorded lectures online for both practical training and theory, claiming that when compared with face-to-face lectures, these non-face-to-face lectures meant a shorter commute and the ability to repeat the content. However, it was admitted that technical issues such as facilities or access difficulties and lower concentration could be a problem. The hypothesis that course satisfaction affects lecture effectiveness was verified, with both the practical training and theory lectures found to have a statistically significant positive (+) effect. The explanatory power of student satisfaction on the effectiveness of the theory component was slightly higher than that of the practical training component, with the students having more positive perceptions on the necessity of face-to-face lectures in practical training than they did for those in theoretical instruction. Conclusion: Providing non-face-to-face online theory courses and face-to-face practical training courses could increase student satisfaction and lecture effectiveness.

• 대한치과기공학회지
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• 제43권2호
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• pp.48-55
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• 2021

Purpose: This study aimed to analyze deformation according to post-curing of complete arch artificial teeth for temporary dentures printed with a digital light processing (DLP) printer. Methods: An edentulous model was prepared and an occlusal rim was produced. The edentulous model and occlusal rim were scanned using a model scanner. A complete denture was designed using a dental computer-aided design, and the denture base and artificial tooth were separated. Ten complete arch artificial teeth were printed using a 3D printer (DLP). Complete arch artificial teeth was classified into the following three groups: a group no post-curing (NC), a group with 10 minutes post-curing (10M), and a group with 20 minutes post-curing (20M). Specimens were scanned using a model scanner. The scanned data were overlapped with the reference data. Statistical analysis was performed using one-way ANOVA analysis of variance, Kruskal-Wallis test, and Mann-Whitney U test (α=0.05). Results: Regarding the overall deviation of complete arch artificial teeth, the NC group showed the lowest mean deviation of 111.13 ㎛ and the 20M group showed the highest mean deviation of 131.03 ㎛. There were statistically significant differences among the three groups (p<0.05). Conclusion: The complete arch artificial tooth showed deformation due to post-curing. In addition, the largest shrinkage deformation was observed at 10 minutes of post-curing, whereas the least deformation was observed at 20 minutes.

• 대한치과기공학회지
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• 제43권4호
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• pp.168-174
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• 2021

Purpose: This study was conducted to investigate alloys spectrophotometrically including yttrium of nickel-chromium (Ni-Cr) alloys, which are used as substitutes for the regulation of beryllium and provide helpful improvements in Ni-Cr alloys. Methods: Four groups of specimens (ZN, ZY, SN and EM) were prepared for analysis. Color parameters were measured with a spectrophotometer, and color difference (∆E^*) was calculated. The t-test and one-way analysis of variance test were used to determine significant difference, and the Tukey test was used to identify where the differences were. To measure the spectroscopic reflectivity, the spectroscopic reflectance was measured and converted into CIE L^*, a^*, b^* color system. Results: The ∆E^* value of each metal ceramic group after opaque firing of Ni-Cr alloy with and without yttrium was <2, and the total group color difference (∆E^*) was below 1 in the dentin ceramic all experimental group. However, the a^* and b^* values of the metal ceramic groups were higher than that in the lithium disilicate all ceramic group, and the chroma was higher than the natural tooth. The brightness of all experimental groups was similar to that of the shade guide sample. Conclusion: Yttrium added to Ni-Cr alloys showed similar CIE L^*, a^*, b^* values to Ni-Cr alloys that did not contain yttrium, indicating that yttrium had no effect on color in metallic ceramic systems.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.221-221
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• 2022

방재성능목표란 홍수, 호우 등으로부터 재해를 예방하기 위한 방재정책 등에 적용하기 위하여 처리 가능한 시간당 강우량 및 연속강우량의 목표로, 각 지자체별로 지역특성 및 경제여건 등을 고려하여 지역별 방재성능목표를 설정한다. 지역별 방재성능목표 기준을 설정하기 위해 전국을 168개 티센망으로 분류하고 69개 지점 확률강우량을 활용하여 지방자치단체별 확률강우량을 산정하고, 지방자치단체별 티센면적 비율을 감안하여 각 지자체별 방재성능목표 설정 기준을 마련한다. 이때 확률강우량 산정에 기상청에서 제공하는 종관기상관측(ASOS) 자료를 이용하는데, 종관기상관측(ASOS, Automated Synoptic Observing System)이란 종관규모의 날씨를 파악하기 위하여 정해진 시각에 모든 관측소에서 같은 시각에 실시하는 지상관측으로, 종관규모는 일기도에 표현되어 있는 고기압이나 저기압의 공간적 크기 및 수명을 말하며, 해당 지역의 현재 기상 실시간 제공 및 기상예보에 활용한다. 그러나 ASOS 자료로 산정한 확률강우량을 토대로 설정한 지역별 방재성능목표는 지배관측소개소 및 면적 비율에 따라 강우량이 실제 해당 지역에 내린 강우량에 비해 작거나 크게 산정되어 실제 강우량을 반영하지 못하는 문제가 발생한다. 이에 지진·태풍·홍수·가뭄 등 기상현상에 따른 자연재해를 막기 위해 실시하는 지상관측인 방재성능관측(AWS, Automatic Weather System)을 1997년부터 약 510여개 지점에 설치하여 기상관측자료를 구축하고 있으나, 관측자료가 30년 미만이므로 자료의 일관성 및 신뢰도 확보 등의 문제로 이용하고 있지 않다. 실제로 ASOS 관측소와 AWS 관측소의 시간 강우량 최댓값 차이가 큼에도 불구하고 행안부는 지역별 방재성능목표 수립을 위한 강우량 산정에서 AWS 관측소의 기록은 반영하지 않고 ASOS 관측소 기록만 적용하여 실제 해당 지역의 강우량을 반영하는 방재 대책을 수립하지 못하는 실정이다. 따라서 소규모 유역 및 재해영향평가 등의 경우 인근 지역에 AWS 관측소가 있을 경우, 해당지역의 기상 특성을 대변하는 자료로 보유관측년수가 30년 이상인 AWS 자료의 적극적인 활용이 필요할 것으로 판단된다.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3625-3634
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• 2014

본 연구는 치과기공사의 건강관련 삶의 질 관리에 필요한 자료를 제시함으로써 치과기공사의 건강 위험 예방 및 관리를 위한 기초자료를 제공하고자 실시되었다. 조사대상은 대전지역 30개 치과기공소와 해당 업체에 근무하는 치과기공사 141명으로 하였으며, 2011년 12월 20일부터 2012년 1월 31일까지 작업환경을 측정함과 동시에 구조화된 자기기입식 설문지를 이용하여 설문조사를 실시하였다. 수집된 자료의 분석결과 건강지수 총점은 개인수준 요인인 근무시간과 흡연상태에 따라 통계적으로 유의미한 차이를 보였으며, 신체적 건강지수는 개인수준 요인인 흡연상태와 운동습관에 따라 통계적으로 유의미한 차이를 보였다. 정신적 건강지수는 개인수준 요인인 근무시간과 흡연상태에 따라 통계적으로 유의미한 차이를 보였다. 집단수준의 예측변수에서는 유의미한 변수가 나타나지 않았다. 결론적으로 치과기공사의 건강관련 삶의 질 수준은 집단수준 요인보다 개인수준 요인에 더 큰 영향을 받는 것으로 나타났다.

• 대한치과기공학회지
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• 제38권1호
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• pp.23-36
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• 2016

Purpose: The purpose of this study is to suggest direction for dental technicians and management of dental laboratories to contribute to the improvement of oral health of citizens with high-quality dental prosthesis by researching operational status and management satisfaction of dental laboratories. Methods: In order to investigate operational status and management satisfaction of dental laboratories, this study conducted a questionnaire survey by mailing questionnaires to heads of dental laboratories designated as clinical training workshops of Department of Dental Technology of G University and a total of 158 questionnaires were used for analysis. Results: As for gender, males were 142 persons (89.9%) and females were 16 persons (10.1%). For location of the laboratories, number of laboratories in metropolitan cities was 94 (59.5%) while small and that in mid-sized cities was 64 (40.5%). As for the satisfaction with job, those who have managed dental laboratories for 23-30 years ($1.92{\pm}77$), transact with 7-12 dental clinics ($1.70{\pm}75$), had monthly income of 4-8 million won ($1.74{\pm}.80$) and had 8-10 employees ($2.33{\pm}.68$) were the highest in their satisfaction. As for satisfaction with management, those who have managed their business for 15-20 years ($2.86{\pm}.52$), transact with more than 20 dental clinics ($2.00{\pm}.04$), had monthly income of less than 4 million won ($2.00{\pm}.85$) and had less than 3 employees ($2.00{\pm}.62$) were the highest in their satisfaction. As for monthly income, those with less than 2 million won were 24 persons (15.2%), 2-4 million were 64 persons (40.5%), 4-6 million were 40 (25.3%), 6-8 million were 14 (8.9%) and over 8 million won were 16 persons (10.2%). As for number of employees, those with less than 3 employees were 32perosns (20.3%), 4-7 were 82 (51.9%), 8-10 were 26 (16.5%) and more than 11 were 10 persons (6.3%). As for severance payment, 84 persons practiced it according to Labor Standard Act (53.2%) and 34 practice it to a proper degree (21.5%) while 20 did not practice it at all (12.7%) and 20 persons did not respond to the question (12.7%). Conclusion: Although dental laboratories have rapidly expanded in number from 473 in 1986 to 2,400 in 2015, dental technician circles are facing difficulty in their management due to fierce competition and low profitability. Therefore, in order to improve this problem, it is necessary to readjust prices for dental prosthesis to realistic ones.

• 대한치과기공학회지
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• 제24권1호
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• pp.9-18
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• 2002

The aim of this study is to propose effective measures for shortage of manpower of dental technology laboratory in Gangwon province by means of examining not only the history of Gangwon association, present condition of transference of members of Gangwon association from 1990, of missing members and annual rate of participation in repair education with setting object of study into Gangwon association under the influence of the Korean Dental Technology Association but also the present condition of opening and closing laboratory, amount of business connection and condition of shortage of manpower and its field with setting object of study into 28 dental technology laboratories. Results from this study are like followings : First, Gagnwon association was established in 1984 as the eleventh in the line of the board, reorganization of board is conducted 8 times up to the eighth in the line of the board in 2001. board is composed of 16 persons including president and operated its term as 3 years. Second, a number of representative and ordinary member of Gangwon association has increased gradually from 1992 to 2001. in aspect of annual rate of participation in repair education, representative's is more higher than ordinary member's overall. the worst rate of whole members' is shown as 47.9% and the its best rate is shown as 92.0%. in addition, 70$\sim$80% rate of participation into repair education is shown most frequently as 8 times of whole 20 times from 1992 to 2001. Third, 29 authorized dental technology laboratories have registered in Gangwon association until march 2002 within 9 cities and counties. in consideration of establishment location. Gangneung city has most amount as 7 laboratories(24.1%), Wonju city has 5(17.2%), Samcheok city and Sokcho city, each has 4(13.8%), Chuncheon city has 3(10.3%), Donghae city and Taeback city, each has 2(6.9%) and Yangyang and Yongwol county, each has 1(3.4%). Fourth, amount of work personnel of laboratory in Gangwon province is 1$\sim$10 persons as the maximum value. 23 laboratories(82.1%) have their own work personnel as amount of 5 and below. in aspect of main business, most of laboratories focus on the Porcelain and Crown. and 16 laboratories(57.1%) have their own expensive equipments such as Milling. its also suggests that 16 laboratories(57.1%) suffer their shortage of working personnel. specifically, 6 laboratories(21.4%) suffer the highest shortage especially in Denture field, Fifth, whole number of Gangwon association is up to 101 members (28 representatives and 73 ordinary members) until December 31th 2001. amount of immune from repair education of Gangwon association until October 2001 is up to 10 persons, and missing members from 1997 is up to 18 persons, suspension of business is up to 4 persons. in aspect of transference from 1990, transfer-in is up to 21 persons and transfer out is up to 16 persons.

• 한국환경보건학회지
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• 제44권1호
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• pp.55-62
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• 2018

Objectives: This study set out to measure the heavy metal concentrations in waste water produced in the casting pickling process at dental technical laboratories and examine the actual state of its treatment. Methods:The investigator measured the concentrations of each heavy metal at 55 dental technical laboratories using an inductively coupled plasma optical emission system. Results: The annual usage of electrolytes was under 10 L in 50 (90.9%), and was 10L or more in five (9.1%) laboratories. Among the laboratories, 15 (27.3%) commissioned the treatment of waste,12 (21.8%) treated the waste with general sewage,and 28 (50.9%) treated the waste in aseptic tank. The arithmetic $mean{\pm}standard$ deviation and the geometric mean of chrome(Cr) were $75.3{\pm}50.9$ and 58.3 mg/L; those of cobalt (Co) were $112.3{\pm}106.7$ and 66.1 mg/L; those of nickel (Ni) were $62.9{\pm}83.5$ and 8.9 mg/L; those of molybdenum (Mo) were $17.1{\pm}13.4$ and 12.0 mg/L; those of iron (Fe) were $31.5{\pm}44.1$ and 6.2 mg/L; those of lead (Pb) were $0.3{\pm}0.3$ and 0.3 mg/L; those of beryllium (Be) were $3.6{\pm}3.6$ and 2.0 mg/L. The hydrogen ion concentration was under pH 2 across all the samples. Conclusions: The findings show that the dental technical laboratories were not doing well with the separation, storage, collection, and treatment of the electrolytes they discarded, and that most of the electrolytes were introduced through the general sewage or aseptic tank. The causes of this include alack of perception among the practitioners at dental technical laboratories and contracted companies avoiding collection for economic reasons. There is a need for education to improve the perceptions of waste water treatment among the practitioners at dental technical laboratories. Environment-related departments should be stricter with legal applications in the central and local governments. It is also required to provide proper management of commissioned treatment.

• 한국산학기술학회논문지
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• 제14권1호
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• pp.328-335
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• 2013

본 연구는 치과기공사의 체형에 적합한 인간공학적인 작업 자세를 위한 작업대의 높이를 연구하고 개선방안을 제시하는 것이 목적이다. 이를 위해 경기지역과 충청도에 소재한 대학의 치기공과 3학년 학생 77명을 대상으로 학생의 신장과 몸무게 및 신체치수를 측정하였고 임상실습 시 가장 힘들었던 작업 자세에 대해 조사하였다. 또한 이를 실제작업환경과 비교 분석을 위해 수도권에 위치한 종합병원 치과기공실 2곳과 치과기공소 15곳을 직접 방문하여 의자를 포함한 책상 및 작업대 높이를 측정하여 측정값을 통계학적으로 분석 하였다. 특히 가장 많은 불편을 초래하는 원인 인자에 대해 세부적인 분석을 하였으며 이러한 분석 자료를 검토한 결과 다음과 같은 결론을 얻었다. 임상실습 시 가장 불편을 느끼는 작업대는 샌드작업대의 높이로 조사되었고 3학년 학생들의 성별과 불편한 작업대의 선택 항목간과 상관관계는 없는 것으로 분석되었다. 또한 샌드작업대가 불편했던 원인은 권장수치보다 낮은 샌드작업대의 높이 때문인 것으로 추정하였으며, 3학년 학생에게 적합한 샌드작업대의 최적의 높이는 권장치보다 다소 높은 것으로 분석되었다. 샌드작업대의 최적의 높이는 치기공과 3학년 학생의 키에 따라 다소 편차가 있었으며 개수대의 높이는 권장안보다 낮은 것으로 분석되었다. 또한 일반적으로 제시되는 권장안은 기본적으로 모든 작업자의 상이한 신장에 균일하게 적용되지 않음을 알 수 있었다.