• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.72-72
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• 2018

A dynamic fatigue characteristic of dental implant system has been evaluated with applying single axial compressive shear loading based on the ISO 14801 standard. For the advanced dynamic fatigue test, multi-directional force and motion needed to be accompanied for more information of mechanical properties as based on mastication in oral environment. In this study, we have prepared loading and motion protocol for the multi-directional fatigue test of dental implant system with single (Apical/Occlusal; AO), and additional mastication motion (Lingual/Facial; LF, Mesial/Distal; MD). As following the prepared protocol (with modification of ISO 14801), fatigue test was conducted to verify the worst case results for the development of highly stabilized dental implant system. Mechanical testing was performed using an universal testing machine (MTS Bionix 858, MN, USA) for static compression and single directional loading fatigue, while the multi-directional loading was performed with joint simulator (ADL-Force 5, MA, USA) under load control. Basically, all mechanical test was performed according to the ISO 14801:2016 standard. Static compression test was performed to identify the maximum fracture force with loading speed of 1.0 mm/min. A dynamic fatigue test was performed with 40 % value of maximum fracture force and 5 Hz loading frequency. A single directional fatigue test was performed with only apical/occlusal (AO) force application, while multi directional fatigue tests were applied $2^{\circ}$ of facial/lingual (FL) or mesial/distal (MD) movement. Fatigue failure cycles were entirely different between applying single-directional loading and multi-directional loading. As a comparison of these loading factor, the failure cycle was around 5 times lower than single-directional loading while applied multi-directional loading. Also, the displacement change with accumulated multi-directional fatigue cycles was higher than that of single directional cycles.

• 한국치위생학회지
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• 제15권1호
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• pp.137-146
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• 2015

Objectives: This study was obtained to identify current education status of the community dental hygiene practice. Methods: It was designed cross section and self-reported on-line questionnaire(Survey monkey). It was performed probability sampling by targeting 82 dental hygiene schools(each one faculty member) in charge of community dental hygiene curriculum and 254 community health centers's community dental hygienists whom was working at oral health section. The response rate was 60% and 53%, respectively. The questionnaire consisted of time, duration, practice group, evaluation method, and practice contents including 63 learning objectives of dental hygiene. Results: Nearly half of these schools conduct such community field work practice in the spring semester of the junior year. This practice was mainly progressed based on average 4 students as one team per each one school for 7-8 hours a day during the period of more than 5 weeks(p<0.05). However, in case of both school and community health center, almost half of feedback after practice was not achieved and there was a difference in needs for practice education between schools and community health center. Conclusions: We should be considered that a sufficient consultation for the practice environment and its contents between schools and community health centers. It was considered that development of a standardized practice manual reflecting such requirement.

• Journal of Periodontal and Implant Science
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• 제27권1호
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• pp.19-43
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• 1997

The barrier membranes for GTR procedure could be affected bY bacterial contamination after exposure to oral environment. This study was done to evaluate whether the tetracycline impregnated barrier membranes could inhibit bacterial attachment and penetration into membranes. The resorbable membrane(polylactic and polyglycolide copolymer, $Resolute^{(R)}$, W.L Gore and Associates, Inc..USA) and the non-resorbable membrane(e-PTFE; Gore-TexTM, W.L. Gore & Associates, Inc.,USA) were cut into 4mm discs and trated with 5% tridodecylmethylammonium chloride solution in ethanol and dried in air. The membranes were immersed in tetracycline(TC) solution (100mg/ml, pH 8.0) and dried. To the maxillary canine-premolar region in six periodontally healthy volunteers, removable acrylic devices were inserted, on which 8 cylindrical chambers were glued with TC impregnated and non-impregnated discs, the membrane discs were examined for bacterial attachment and penetration, and structural changes under SEM and LM. From the 1st day to the 7th day, membranes showed bacterial plaque formation composed of cocci and rods. Thereafter, filamentous bacteria appeared and the plaque thickness increased. The TC impregnated e-PTFE membranes showed less bacterial attachment and delayed in bacterial plaque maturation than non-treated membranes. As for bacterial penetration, the TC impregnated e-PTFE membranes showed superficial invasion and infrequent presence of bacteria in unexposed inner surface at the 4th week. while the non-treated e-PTFE membranes showed deep bacterial invasion at the 2nd week and frequent presence of internal bacteria at the 4th week. The resorbable membranes started to be resorbed at the 2nd week and were perforated at the 4th week, regardless of TC treatment. In conclusion, bacterial plaque formation and penetration was efficiently delayed in TC impregnated e-PTFE membranes, whereas resorbable membranes were similar in bacterial invasion due to membrane degradation and perforation, regardless of TC treatment.

• 구강회복응용과학지
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• 제30권4호
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• pp.315-323
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• 2014

과도한 치아의 마모는 수직 교합 고경의 감소를 야기하여 구강 및 저작계의 병적 변화를 일으킬수 있으며, 이 경우 새로운 교합 설정과 수직 고경 회복 시 정확한 진단과 분석이 필수적이다. 이에 본 증례에서는 고딕 아치 트레이서를 통해 거상된 수직고경에서의 중심위를 기록한 후 전악 수복을 시행하였다. 본 증례는 70세 남자 환자로서 이가 시리고 아파서 음식을 먹지 못한다는 주소로 내원하였다. 전반적인 치아 마모에 의한 수직고경의 감소를 보여 면밀한 모형분석을 통해 수직고경의 거상을 결정하였다. 거상된 수직고경에 맞춰 고딕 아치 트레이서를 이용하여 중심위 채득 후 임시 보철물을 장착하였다. 4개월 동안 임시 보철물을 통해 적절한 교합을 형성하였으며 이를 이용하여 최종 보철을 제작하였다. 치료를 통해 기능적, 심미적으로 만족할 만한 결과를 얻었기에 이를 보고하는 바이다.

• 구강회복응용과학지
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• 제30권2호
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• pp.176-183
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• 2014

심하게 흡수된 치조제는 기능적인 하중을 견디기 어렵고 구강 조직의 유해 변화와 더불어 환자의 의치 적응을 어렵게 한다. 환자의 불편감을 해소하고 의치의 안정성과 유지력을 증가시키기 위해 임플란트를 이용한 피개의치가 치료 방법으로 선택될 수 있다. 로케이터 부착장치는 사용상의 편리성이 높으며 다양한 유지력을 갖는 남자부를 보유함으로써 임상에서 볼 형태 부착장치대용으로 많이 사용되고 있다. 본 증례는 77세 여자환자로서 낮은 수직고경과 심한 치조제 흡수를 보이는 상하악 무치악 상태였다. 이에 하악에 4개의 임플란트를 식립하고, 상악은 총의치, 하악은 로케이터 부착장치를 이용한 임플란트 피개의치로 수복하여 기능 및 심미적으로 만족할 만한 결과를 얻었기에 이를 보고하고자 한다.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.41-59
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• 1991

This study was performed to elucidate the distribution and correlation of immunoglobulin G subclasses with the degree of inflammation in the experimentally induced rat pulp and periapical pathoses. The pulp exposures were made in 108 mandibular 1st molars of 54 rats and the teeth were left open to the oral environment The animals were sacrified at 3, 7, 15, 30, 60 and 90 days after pulp exposure, and examined microscopically and radiographically Seventy one specimens were routinely sectioned at the thickness of 4 - $6{\mu}$ and stained with Hematoxylin - eosin for histologic examination, with toluidine blue for mast cells, and with the primary antibodies against rat IgG subclasses by using the Avidin - Biotin complex method. The following results were obtained: 1. As the degree of inflammation of rat pulp and periapeces intensified, the number of IgG subclass containing cells per unit area, especially IgG2a and IgG2c, decresased. 2. The IgG2c cells were most predominantly found in the lesions with slight inflammation, IgG1 cells in mild or severe inflammation, and IgG2a cells in moderate inflammation. 3. IgG subclass containg cells were more predominantly observed in the periapical granuloma than periapical abscess or cyst(p<0.01). 4. IgG2a containing cells were predominant in pulp inflammation, IgG1 containing cells in periapical granuloma, IgG2a cells and IgG1 cells in periapical abscess, and IgG2a cells were significantly predominant in periapical cyst. 5. The number of IgG subclass containing cells and mast cells in periapical tissue decreased with time lapse after pulp exposure. And correlation index between mast cells and IgG1, IgG2a, IgG2b was stastically high.

• 대한치과교정학회지
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• 제12권1호
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• pp.15-20
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• 1982

저자는 비교적 최근내 개발되어 시판되고있는 3가지 교정용 접착제를 교정을 위해 발치한 25개씩의 소구치에 접착하여 24시간후에 인장강도를 측정한 결과, 다음과 같은 결론을 얻었다. 각 제품의 평균인장강도는 교정력과 구강내에서 발생할 수 있는 외력의 합인 $29kg/cm^2$ 보다 높았으며, 제품C는 제품B, A보다 통계학적으로 높은 인장강도를 보이나, 제품B와 제품A는 통계학적으로 유의한 차가 없었다. 접착제가 떨어진 양상은 접착제가 치아와 bracket에 부분적으로 붙어서 떨어진 것이 가장 많았고 $(68\%)$, 접착제가 bracket에만 붙어서 떨어진 것 $(22.7\%)$, 접착제가 치아에만 붙어서 떨어진 것$(9.3\%)$순으로 나타났다.

• 한국중재학회지:중재연구
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• 제23권4호
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• pp.55-76
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• 2013

This study aims to analyze the main features of Mongolian arbitration system compared with Korean Arbitration Law which was revised under the UNCITRAL Arbitration Model Law. On the basis of this comparative study, certain differences are suggested: First, the environment of Mongolian arbitration is still insufficient in terms of its operation and usage at the international level. Second, the Mongol National Arbitration Court has established Ad-hoc Arbitration Rules and has promoted Ad-hoc Arbitration although it is an institutional arbitration organization. Third, the arbitration objects are defined as the types of tangible and intangible assets in Mongolia which are different from those of the Korean Arbitration Law. Accordingly, court and officer disputes, family disputes, labor-management relations, and criminal matters are covered by the arbitration objects. Fourth, Mongol Arbitration Law specifies the following persons disqualified for arbitrator appointment: the member of the Constitutional Court, judge, procurator, inquiry officer, investigator, court decision enforcement officer, attorney, or notary who has previously rendered legal service to any party of the disputes, and any officials who are prohibited by laws to be engaged in positions above the scope of their duties. Fifth, the arbitrator selection and appointment criteria should be documented, and the arbitrator should have the ability to resolve the disputes independently and fairly and achieve concord from both parties. Sixth, if there is no agreement between the parties, the arbitration language should be Mongolian, and the arbitral tribunal has no power to decide on it. Seventh, despite the agreement for a documentary hearing between the parties, there should be provided opportunities for an oral hearing if either of the parties requires it. Eighth, if the parties do not understand the language of the arbitration, the parties can directly ask the translation service. They should also keep secrets in the process of arbitration. Ninth, the cancellation of arbitral award is allowed by the application of the parties, not by the authority of the court. Except for the nine differences above, the Mongolian arbitration system is similar to that of the Korean Arbitration Law. This paper serves to contribute to the furtherance in trade relationship between Mongolia and Korea after the rapid and efficient resolution of disputes.

• 대한치과보철학회지
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• 제41권2호
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• pp.160-168
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• 2003

Statement of problem : Direct denture reline resins tend to discolor during service in the oral environment by intrinsic and extrinsic factor. Purpose : This study was designed to evaluate the color stability of direct denture reline resins. Material and methods : Mild Rebaron(GC Corp., Japan), Meta Base M(Sun medical Co., Japan), Mild Rebaron LC(GC Corp., Japan) and as a control group, Vertex SC(Dentimex Zeist, Holland) were chosen for this study. Ten specimens of each direct denture reline resins were fabricated. Treatment methods designed for this study were the coffee staining test(7days) and the accelerated aging test(100hours). The color changes before and after treatment were measured by Tristimulous colorimeter(Yasuda seiki seisakusho, Ltd. Japan) and analyzed. Results All the direct denture reline resins subjected to the coffee staining test and the accelerated aging test showed noticible difference in color change. After coffee staining test, Meta Base M showed the highest color change followed by Vertex SC. Mild Rebaron LC and Mild Rebaron. There were no statistical differences between Meta Base M and Vertex SC and between Mild Rebaron LC and Mild Rebaron(p>0.05). After accelerated aging test. Mild Rebaron LC showed the highest color change followed by Vertex SC, Meta Base M and Mild Rebaron. There were no statistical differences only between Mild Rebaron and Mata Base M(p>0.05) but among the others, there were statistical differences(p<0.05). Conclusion : Within the limitation of this study, all the direct denture reline resins subjected to the extrinsic and intrinsic factors showed noticible difference in color change, and there were differences among manufacturers.

• 대한소아치과학회지
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• 제1권1호
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• pp.57-61
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• 1974

The Study reported here was designed to analyze the prevalence of Dental Caries in the primary teeth of monozygote twins, and to ascertain and compare the intrapair differences with the intrapair differences in control pairs. The prevalence of dental caries in the primary teeth of 40 pairs of presumably monozygote twins, based on phenotypic analysis, was studied. The age range was from 3 to12 years. The control group consisted of pairs that included a twin chosen at random and an unrelated child of the same sex and age, so that for each pair of twins there was a corresponding control pair. The clinical examination was carried out by an operator using an oral mirror and sharp explorers, and with good lighting. 40 pairs of twins were examined with a total of 4,950 primary tooth surfaces (990 primary teeth) and 40 control pairs with a total of 4,935 primary tooth surfaces (987 primary teeth). Five surfaces were considered for each tooth. After the def individual index was determined, the ratio between this index and the number of examined surfaces was established in each case, the cer (Caries experience rate) index. The def and cer averages were determined for the subjects and the controls. All intrapair differences in twin and control groups were compared following the paired sampling method. The following conclusions were made: 1. Intrapair differences in the control group were significantly greater than in twins, when defs, ds, es, fs, and cer were compared. 2. The genotype appeared to be a determining factor in dental caries susceptibility or resistance, although the environment played an important role as well. 3. Intrapair differences in American children were significantly greater than in Korean when defs, es, fs, and cer were compared, but ds was equal.