• 대한치과보철학회지
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• 제51권4호
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• pp.292-299
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• 2013

연구 목적: 의료환경의 변화에 따라 새로운 의료관리에 대한 필요성과 함께 의료기관의 원가관리에 대한 관심이 증가되었다. 본 연구는 치과의료기관에서 빈번하게 제공되는 치과 임플란트 서비스를 직원의 활동에 근거하여 자원 또는 원가를 배부하는 활동기준원가(Activity-Based Cost, ABC) 방법을 적용하여 원가를 산정하기 위해 시행되었다. 연구 대상 및 방법: 수도권 소재의 A 치과의료기관을 대상으로 치과 임플란트 원가산정을 실시하였다. 해당 기관의 총비용을 확인하기 위해 1사분기 세무회계자료를 사용하였고 기관 내에서 이루어지는 활동을 파악하기 위하여 활동분석표 작성을 요청하였다. 자료를 바탕으로 치과 임플란트에 해당하는 직접원가와 간접원가를 분리하고, 간접원가의 왜곡을 최소화하기 위해 원가동인(Cost driver)을 파악하여 활동별로 비용을 배분하는 활동기준원가 분석을 실시하였다. 결과:치과 임플란트 원가를 직접비와 간접비로 나누어 비교한 결과 각각 35.8%, 49.5%로 나타났다. 치과 임플란트 1개당 원가는 1,579천원 정도로 산정되었고, 임플란트 수술 및 시술 전 후 활동이 포함된 보철 시술 진료영역에 47만원(30%)이 소요되어 가장 많은 부분을 차지하였다. 연수 및 치과학 교육 등의 활동도 기타 진료에 비해 상대적으로 높은 비중을 나타내었다. 결론: 과학적인 치과 임플란트의 수가 산정을 위해서 치과 임플란트와 관련된 직접적인 진료 술식 이외에 시술 전 후 준비활동 등에 대한 고려가 충분히 이루어져야 한다. 임플란트 시술 전 후의 활동 및 교육, 연수활동 등은 간접비에 포함되는 부분이나 진료의 질을 담보하고 환자의 만족도를 향상시키기 위해 반드시 필요할 활동으로 이러한 활동들을 고려한 합리적 수가 산정이 필요하다.

• 대한치과보철학회지
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• 제33권3호
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• pp.539-549
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• 1995

The purpose of this study was to determine the accuracy of 3 implant impression methods by using strain gauge. The models used for this study were partially edentulous mandibular acrylic resin casts Model A, with two abutment analogs in #46,47 extraction site, represented two implant parallel to to the adjacent natural tooth. Model B represent an anterior implant parallel to the adjacene natural tooth and a posterior implant exhibiting a 15-degree lingual inclination. Master framework were fabricated on the master model, and 3 strain gauges were attached to a master framwork to determine the passivity of fit of the framework to sample casts made by the three impression techniques. The master framework was attached to each sample cast with gold screws, which were tightened with the torque driver to ensure a consistent toque application of 10 Ncm. Universal Digital Measuring System UCAM-5BT was used for strain measuring. Impression techniques studid were : 1. unsplinted tapered impression coping, polyvinyl siloxane, stock tray 2. unsplinted squared impression coping, polyether, custom tray 3. squared impression coping splinted with Duralay resin, polyether, custom tray Through analysis on data from this study, the following conclusions were obtained. 1. There were no statistically significant differences between the mean strain recorded from the sample casts made with the tree impression. But only strain values of model A(parallel group) Y-axis was signifcantly differed between Technique 1 and 3(P<0.05). 2. There was no statistically significant difference between model A(parallel group) and model B(15-degree divergent group).

• 한국위성정보통신학회논문지
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• 제8권2호
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• pp.36-43
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• 2013

본 논문에서는 고전압에서 동작하는 DDIC(display driver IC) 칩의 정전기 보호소자로 사용되는 GG_EDNMOS 소자의 고전류 특성 및 더블 스냅백 메커니즘이 분석되었다. 이온주입 조건을 달리하는 매트릭스 조합에 의한 수차례의 2차원 시뮬레이션 및 TLP 특성 데이타를 비교한 결과, BJT 트리거링 후에 더블 스냅백 현상이 나타났으나 웰(well) 및 드리프트(drift) 이온주입 조건을 적절히 조절함으로써 안정적인 ESD 보호성능을 얻을 수 있었다. 즉, 최적의 백그라운드 캐리어 밀도를 얻는 것이 고전압 동작용 정전기보호소자의 고전류 특성에 매우 중요한 영향을 주는 임계인자(critical factor)임을 알 수 있었다.

• 대한치과기공학회지
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• 제35권3호
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• pp.201-207
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• 2013

Purpose: In this study, the loosening torque test was conducted with three implant products that are produced, approved and sold in Korea, which are manufactured in different fixture and abutment tightening methods (internal submerged type, internal morse taper type, and external type) to examine the loosening torque of the screw according to the method of tightening the implant fixture and abutment. Methods: In the loosening torque test, the three types of fixtures and abutments with different tightening methods were tightened by rotating them clockwise with a $30N{\cdot}cm$ force using a driver equipped with an electric torque meter. The results of the test are as follows. Results: The loosening torque values of the internal submerged type, internal morse taper type and external type implants were $24.10{\pm}0.742N{\cdot}cm$, $29.10{\pm}1.710N{\cdot}cm$, and $26.60{\times}1.636N{\cdot}cm$, respectively. Conclusion: The screw loosening torque values of the three fixture and abutment tightening methods were analyzed via Kruskal Wallis test layout, and they were significantly different (p<0.05).

• The Journal of Advanced Prosthodontics
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• 제10권5호
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• pp.381-387
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• 2018

PURPOSE. Cement-retained implant prostheses can lack proper retrievability during repair, and residual cement can cause peri-implantitis. The purpose of this in vitro study was to evaluate the influence of abutment height and convergence angle on the retrievability of cement-retained implant prostheses with lingual slots, known as retrievable cement-type slots (RCS). MATERIALS AND METHODS. We fabricated six types of titanium abutments (10 of each type) with two different heights (4 mm and 6 mm), three different convergence angles ($8^{\circ}$, $10^{\circ}$, and $12^{\circ}$), a sloped shoulder margin (0.6 mm depth), a rectangular shape ($6mm{\times}6.5mm$) with rounded edges, and a rectangular ledge ($2mm{\times}1mm$) for the RCS. One monolithic zirconia crown was fabricated for each abutment using a dental computer-aided design/computer-aided manufacturing system. The abutments and crowns were permanently cemented together with dual-curing resin cement, followed by 24 hours in demineralized water at room temperature. Using a custom-made device with a slot driver and torque gauge, we recorded the torque ($N{\cdot}cm$) required to remove the crowns. Statistical analysis was conducted using multiple regression analysis and Mann-Whitney U tests (${\alpha}=.05$). RESULTS. Removal torques significantly decreased as convergence angles increased. Multiple regression analysis showed no significant interaction between the abutment height and the convergence angle (Durbin-Watson ratio: 2.186). CONCLUSION. Within the limitations of this in vitro study, we suggest that the retrievability of cement-retained implant prostheses with RCS can be maintained by adjusting the abutment height and convergence angle, even when they are permanently cemented together.

• 구강회복응용과학지
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• 제26권4호
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• pp.419-432
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• 2010

현재 임상적으로 여러 형태의 토크 조절기가 사용되고 있고, 토크 조절기에 따라 오차율이 다양하게 보고되고 있는데 제조회사에서 권장하는 적절한 조임력으로 나사가 조여지지 않을 경우 나사 풀림과 이에 따른 파절이 발생하여 결과적으로 보철물과 임플란트 매식체에 합병증이 야기될 수 있으므로 토크 조절기의 정확성이 필수적이다. 본 연구에서는 일정 토크 수준이 넘으면 핸들의 앞 부위가 꺾여지도록 만들어진 토크 최대값 제한 장치(TLD, torque limiting device), 눈금자가 표시되어 있는 활 형태로 조임력의 크기를 조절할 수 있는 토크 표시 장치(TID, torque indicating device), 콘트라앵글 핸드피스 형태에 조임력의 크기를 조절하거나 이미 정해진 조절기를 끼워서 사용하는 콘트라앵글 토크 조절장치(CA, contraangle torque device), 기계적인 토크 발생장치를 이용하여 적정 회전력을 가하는 전자 토크 조절기(ETC, electronic torque controller)등 네 종류의 토크 조절기를 이용하여 제조회사의 지시대로 나사를 조인 후 풀림 토크값을 측정하고 각각의 차이값을 구하여 토크 조절기의 정확도를 비교, 분석하고자 하였다. 콘트라앵글 토크 조절장치(CA)가 가장 측정값에 근접한 결과를 보였으며 토크 최대값 제한 장치(TLD)를 제외한 나머지 세 종류의 토크 조절기의 정확도는 서로 통계적으로 유의한 차이를 보이지 않지만, 토크 최대값 제한 장치(TLD) 의 경우 유의하게 낮은 정밀성을 보였으므로 이는 토크 부여 시 회전 속도에 따른 오차발생 가능성을 보여준다. 토크 표시 장치 (TID), 콘트라앵글 토크 조절장치 (CA) 와 같은 수동 토크 조절기는는 전자식 토크 조절기와 오차 범위 내에서의 유사한 정밀성을 보여주고 있으며 이는 임상에서 보다 주의 깊게 장치를 사용한다면 효과적인 전하중 부여가 가능함을 의미한다.

• 대한치과보철학회지
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• 제42권6호
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• pp.628-640
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• 2004

Statement of problem. Wear as a result of repeated closing/opening cycles may decrease the friction coefficient of screw head, threads, and other mating components and, consequently, resistance to opening gradually decreases. It may cause screw loosening, which is one of the most common failures in implant prosthesis. Purpose. The purpose of this study is to evaluate the changes on the head and thread surface of the abutment screws after repeated closing and opening through the examination of tested screws in SEM(scanning electron microscope). Materials and methods. Five species of abutments were selected (3i-three, Avana-two) respectively by two pieces. The implant fixtures were perpendicularly mounted in liquid unsaturated polyesther(Epovia, Cray Valley Inc.) with dental surveyor. Each abutment was secured to the implant fixture by each abutment screw with recommended torque value using a digital torque controller. The abutment screws were repeatedly tightened and removed 20 times with a digital controller. FESEM (field emission scanning electron microscope, Netherland, Phillips co., model:XL 30 SFEG) was used to observe changes of each part caused by repeatedly closing/opening expeiment. First, the Photomicrographs of pre-test screws provided by each manufacturer were taken. The changes of each screw were investigated after every fifth closing and opening experiment with FESEM. Scaning electron microscope photomicrographs of each screw were taken four times. Results. As the number of closing and opening was increased, the wear or distortion of hexed or squared slot that contacted with the driver tip was more severely progressed. Wear or distortion of hexed slot was more severe than that of squared slot and it was more remarkable in the titanium screw than in the gold screw. All the tested screws showed that the width in the crest of their screw thread decreased gradually as the test was proceeded. Conclusions. Conclusively, we recommend the clinical use of gold screw, a periodic exchanges of abutment screws and avoiding repeated closing/opening unnecessarily. We also suggest a more careful manipulation of the abutment screw and screw-driver and using of abutment screw with an acute-angled slot design rather than an obtuse-angled one. Finally, it is suggested that the new slot design and the surface treatment for enduring wear or distortion should be devised.

• 전자공학회지
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• 제37권8호
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• pp.50-59
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• 2010

$0.18-{\mu}m$ high voltage technology 13.5V high voltage well-based symmetric EDMOS isolated by MTI was designed and fabricated. Using calibrated process and device model parameters, the characteristics of the symmetric and asymmetric EDMOS have been simulated. The asymmetric EDMOS has higher performance, better $R_{sp}$ / BVDSS figure-of-merit, short-channel immunity and smaller pitch size than the symmetric EDMOS. The asymmetric EDMOST is a good candidate for low-power and smaller source driver chips. The low voltage logic well-based EDMOS process has advantages over high voltage well-based EDMOS in process cost by eliminating the process steps of high-voltage well/drift implant, high-temperature long-time thermal steps, etc. The specific on-resistance of our well-designed logic well-based EDMOSTs is compatible with the smallest one published. TCAD simulation and measurement results show that the improved logic well-based nEDMOS has better electrical characteristics than those of the conventional one. The improved EDMOS proposed in this paper is an excellent candidate to be integrated with low voltage logic devices for high-performance low-power low-cost chips.

• Journal of Periodontal and Implant Science
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• 제42권2호
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• pp.59-63
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• 2012

Purpose: This study evaluated the surface characteristics and bond strength produced using a novel technique for coating hydroxyapatite (HA) onto titanium implants. Methods: HA was coated on the titanium implant surface using a super-high-speed (SHS) blasting method with highly purified HA. The coating was performed at a low temperature, unlike conventional HA coating methods. Coating thickness was measured. The novel HA-coated disc was fabricated. X-ray diffraction analysis was performed directly on the disc to evaluate crystallinity. Four novel HA-coated discs and four resorbable blast medium (RBM) discs were prepared. Their surface roughnesses and areas were measured. Five puretitanium, RBM-treated, and novel HA-coated discs were prepared. Contact angle was measured. Two-way analysis of variance and the post-hoc Scheffe's test were used to analyze differences between the groups, with those with a probability of P<0.05 considered to be statistically significant. To evaluate exfoliation of the coating layer, 7 sites on the mandibles from 7 mongrel dogs were used. Other sites were used for another research project. In total, seven novel HA-coated implants were placed 2 months after extraction of premolars according to the manufacturer's instructions. The dogs were sacrificed 8 weeks after implant surgery. Implants were removed using a ratchet driver. The surface of the retrieved implants was evaluated microscopically. Results: A uniform HA coating layer was formed on the titanium implants with no deformation of the RBM titanium surface microtexture when an SHS blasting method was used. Conclusions: These HA-coated implants exhibited increased roughness, crystallinity, and wettability when compared with RBM implants.

• 구강회복응용과학지
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• 제36권3호
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• pp.158-167
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• 2020

목적: 치과 보철 진료 과정에서 사용 빈도가 높은 치과 임플란트 핸드 드라이버의 에탄올 용액을 이용한 감염 관리 효과에 대하여 연구하고자 하였다. 연구 재료 및 방법: 36개의 치과 임플란트 핸드 드라이버의 표면에 황색 포도상 구균을 접종 후 83% 에탄올 거즈로 30초 동안 닦아낸 군과 83% 에탄올 용액에 30초, 60초, 90초, 120초, 150초, 180초, 300초 동안 침적한 군으로 나누었다. 세균 집락 형성 단위 수의 측정 방법과 흡광도 분석 방법을 이용하여 실험군과 세균 접종 후 감염 관리를 시행하지 않은 양성 대조군 및 멸균 후 세균을 접종하지 않은 음성 대조군과의 비교를 통해 감염 관리 효과를 평가하였다. 결과: 세균 집락 형성 단위 수의 측정 결과와 흡광도 분석 결과에서 두 군 모두 양성 대조군에 비하여 통계적으로 유의한 차이를 나타냈다. 그리고 83% 에탄올 용액에 침적한 군에서 150초 이상의 침적을 시행하였을 경우 음성 대조군과 통계적으로 유의한 차이를 나타내지 않았다. 결론: 치과 임플란트 핸드 드라이버의 감염 관리를 위해 에탄올 용액을 단독으로 사용한 중등도 소독 방법은 임상적으로 멸균 상태에 대한 확신을 보장할 수 없으므로 멸균 전 사전 세척 과정으로서 에탄올 용액을 사용하는 것이 추천된다.