• 대한치과교정학회지
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• 제22권3호
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• pp.509-529
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• 1992

Skeletal Class III malocclusion is one of the most difficult type to treat and stabilize. For a child with developing skeletal Class III malocclusion, the treatment objective would be to stimulate maxillary growth, particulary one who has markedly deficient maxilla, and to restrain excessive mandibular growth. In order to stimulate the maxillary growth, maxillary protraction appliance is the one of the effective orthopedic appliances in skeletal Class III. The purposes of this study were as follows ; evaluation of the skeletal and dental changes of the maxillary protraction in children with Class III Maxillary deficiency , comparison of the clinical effects between the group with RPE and labiolingual intraoral appliances , comparison of the clinical effects and stability related to the ages of the patients : stability of the maxillary protraction about 1 year after retention. The subjects consisted of 60 children between the ages of 8 and 13.4 who were diagnosed as Class III with maxillary deficiency and were treated with Face Mask (Delaire Type) from the Dept. of Orthodontics Yong Dong Severance Hospital, Yonsei University. 48 children wore the RPE and 12 children wore Labiolingual Appliance. Lateral Cephalograms were taken for each patient at before and after correction of anterior cross-bite in 60 children, and after an observation period of 10 to 14 months in 19 children. X and Y coordinate of 10 landmarks were analyzed using a horizontal line through sella and rotated $6^{\circ}$ down anteriorly as the horizontal reference axis, and a perpendicular verticual line through sella as the vertical reference axis. Each of the 31 measurents (10 verticals, 10 horizontals, 2 angles and 9 others) was statistically analyzed using SPSS/PC statistics. The results are as follows; 1. After maxillary protraction the maxilla and maxillary teeth moved downward and forward, while the mandible and mandibular incisor rotated downward and backward. 2. Maxillary protraction with rapid palatal expansion appliance was more effective than with labiolingual appliance. 3. More downward movement of the posterior palatal plane obserbed with maxillary protraction doing the midpalatal suture opening than with protraction after finishing the palatal expansion 4. The clinical effects of protraction and changes of the retention periods were not statistically significant among the age groups. 5. During the retention period, maxilla and maxillary teeth, and mandible and mandibular teeth moved downward and forward, however the mandibular changes were larger than the maxillary changes.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권4호
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• pp.411-419
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• 2000

Purpose: This study was aimed at analysis of the changes in the condyle position in subjects with mandibular setback osteotomies Method: Twenty patients were evaluated retrospectively for their changes in the condyle position who underwent surgical mandibular setback using bilateral sagittal split osteotomies with a manual condyle repositioning technique and rigid fixation. The cephalometric and panoramic analysis was performed preoperatively, 1 week, 6 months, and 1 year postoperatively. And postoperative noise, temporomandibular joint pain, and mouth opening were clinically examined 2 months, 4 months, 6 months, 8 months, 10 months, and 12 months postoperatively. Result: The condyles rotated posteriorly and laterally immediately after surgery, and they returned to the preoperative position during follow-up period but it is not significant. The statistical analysis (Paired t-test) showed no significant effects in postsurgical stability. The changes in the condyle position didn't have a significant harmful influence on temporomandibular joint disorder. Conclusion: A careful surgical mandibular setback using manual condyle repositioning and fixation technique will move condyle minimally and that will decrease the relapse and temporomandibular joint disorder.

• The Journal of Advanced Prosthodontics
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• 제1권2호
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• pp.102-106
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• 2009

STATEMENT OF PROBLEM. Screw loosening has been a common complication and still reported frequently. PURPOSE. The purpose of this study was to evaluate abrasion of the implant fixture and TiN coated abutment screw after repeated delivery and removal with universal measuring microscope. MATERIAL AND METHODS. Implant systems used for this study were Osstem and 3i. Seven pairs of implant fixtures, abutments and abutment screws for each system were selected and all the fixtures were perpendicularly mounted in liquid unsaturated poly-esther with dental surveyor. After 20 times of repeated closing and opening test, the evaluation for the change of inner surface of implant and TiN-coated abutment screw, and weight loss were measured. Mann-Whitney test with SPSS statistical software for Window was applied to analyze the measurement of weight loss. RESULTS. TiN-coated abutment screws of Osstem and 3i showed lesser loss of weight than non-coated those of Osstem and 3i (P < .05, Mann-Whitney test). CONCLUSION. Conclusively, TiN coating of abutment screw showed better resistance to abrasion than titanium abutment screw. It was concluded that TiN coating of abutment screw would reduce the loss of preload with good abrasion resistance and low coefficient of friction, and help to maintain screw joint stability.

• 대한영양사협회학술지
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• 제8권4호
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• pp.372-386
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• 2002

The purposes of this study were to find factor which influence on the selection criteria of food supplier. Questionnaire were distributed to 52 general hospitals with more than 400 beds located in Seoul and Kyongin province, and responded questionnaires were collected from 44 dietetic departments (84.6%) and 18 purchasing departments (34.6%). The main results of this study can be summarized as follows: (1) supplier selection criteria include quality, service, cost and supplier competency. (2) With having been met with tight competition and market opening, hospitals plan a strategy to improve quality, service and they tend to have more interest in various supplier selection criteria. (3) Purchasing departments estimate more highly the rate of reflection in considering supplier selection criteria than the rate of importance about cost criteria, which reveals that purchasing departments sensitively respond to cost cutdown. (4) When selecting suppliers, a significant(p<.01) influence of stability of supplier industry environment on the selecting criteria such as the importances of quality, service, and supplier quality are recognized only after recognizing the stability of food delivery industry. Food supplier industry secures stability more quickly through major companies' participation in food distribution industry and this will reveal the importance of supplier selection criteria. (5) Suppliers which are selected by the quality criteria, service criteria, supplier quality criteria make efforts to communicate with foodservice departments, to give more proper information about substitute food, new product, and to make commitments, while suppliers which are decided by cost criteria do not establish supportive relationships with foodservice departments.

• 대한두개안면성형외과학회지
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• 제15권2호
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• pp.53-58
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• 2014

Background: Maxillomandibular fixation (MMF) is usually used to treat double mandibular fractures. However, advancements in reduction and fixation techniques may allow recovery of the premorbid dental arch and occlusion without the use of MMF. We investigated whether anatomical reduction and microplate fixation without MMF could provide secure immobilization and correct occlusion in double mandibular fractures. Methods: Thirty-four patients with double mandibular fractures were treated with open reduction and internal fixation without MMF. Both fracture sites were surgically treated. For bony fixations, we used microplates with or without wire. After reduction, each fracture site was fixed at two or three points to maintain anatomical alignment of the mandible. Interdental wiring was used to reduce the fracture at the superior border and to enhance stability for 6 weeks. Mouth opening was permitted immediately. Results: No major complications were observed, including infection, plate exposure, non-union, or significant malocclusion. Five patients experienced minor complications, among whom the only one patient experienced a persistant but mild malocclusion with no need for additional management. Conclusion: This study showed that double mandibular fractures correction with two-or three-point fixation without MMF simplified the surgical procedure, increased patient comfort, and reduced complications, due to good stability and excellent adaptation.

• 터널과지하공간
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• 제34권2호
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• pp.169-184
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• 2024

본 연구에서는 심부 지하공간의 안정성을 평가하고자 심부 응력조건을 반영한 암석블록의 이축압축실험을 통하여 지하공동에서 손상 발생시 발생하는 음향방출 및 미소변형의 특성을 분석하였다. 음향방출 특성 분석 결과 지하공동에서 손상 발생 직전에 음향방출 신호의 주파수, 카운트, 에너지, 진폭 특성이 급격히 증가하였다. 특히 주파수와 카운트는 손상 전후에서 특성 차이가 크게 나타나 원형 공동의 손상 특성 분석에 적합한 음향방출 인자인 것으로 나타났다. 이미지상관기법 적용결과 실험 중 공동 주변에 변형이 집중되었음을 변형률의 공간적 분포를 통해 알 수 있었으며, 실험 종료 지점에서는 스폴링 현상이 발생하였음을 확인할 수 있었다. 본 연구에서 제시된 원형 공동 손상시 음향방출 및 미소변형 특성은 심지층 활용을 위한 지하공동 안정성 평가의 기초자료로 활용될 것으로 기대된다.

• 한국안전학회지
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• 제31권3호
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• pp.8-15
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• 2016

The purpose of this study is to design a model with the structural stability so as not to lose the operational function due to structural plastic or fail of a sliding blast door by blast pressure to this aim, a numerical simulation was performed using full-size experiments and M&S (Modeling & Simulation) of the sliding blast door. The sliding blast door ($W3,000{\times}H2,500mm$) under the blast load is in the form of a sliding type 2-way metal grill, which was applied by a design blast pressure (reflected pressure $P_r$) of 17 bar. According to the experimental results of a real sliding blast door under blast load, the blast pressure reached the sliding blast door approximately 4.3 ms after the explosion and lasted about 4.0 ms thereafter. The maximum blast pressure($P_r$) was 347.7 psi (2,397.3 kPa), it is similar to the UFC 3-340-02 of Parameter(91 %). In addition, operation inspection that was conducted for the sliding blast door after real test showed a problem of losing the door opening function, which was because of the fail of the Reversal Bolt that was installed to prevent the shock due to rebound of the blast door from the blast pressure. According to the reproduction of the experiment through M&S by applying the blast pressure measurement value of the full-size experiments, the sliding blast door showed a similar result to the full-size experiment in that the reversal bolt part failed to lose the function. In addition, as the pressure is concentrated on the failed reversal bolt, the Principal Tensile Failure Stress was exceeded in only 1.25 ms after the explosion, and the reversal bolt completely failed after 5.4 ms. Based on the result of the failed reversal bolt through the full-size experiment and M&S, the shape and size of the bolts were changed to re-design the M&S and re-analyze the sliding blast door. According to the M&S re-analysis result when the reversal bolt was designed in a square of 25 mm ($625mm^2$), the maximum pressure that the reversal bolt receives showed 81% of the principal tensile failure stress of the material, in plastic stage before fail.

• 터널과지하공간
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• 제22권3호
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• pp.214-220
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• 2012

터널 굴착에 의해 발생되는 주변 지반의 변위는 터널의 안정성 평가를 위해 중요한 정보가 된다. 실제 시공중 계측에 의해 획득되어 지는 변위량은 불가피하게 계측전 발생한 변위를 포함하지 못하게 된다. 따라서, 계측이 이루어진 시점을 고려하여 계측전 발생한 변위량을 예측하는 것은 매우 중요하다. 본 연구에서는 초기 계측이 이루어진 시점에 따라 계측전 변위 예측의 정확도를 굴착면과 계측지점의 이격거리만을 고려하여 통계적 기법으로 고찰하였다. 또한, 계측 오차가 변위 예측결과에 미치는 영향을 몬테카를로 시뮬레이션을 통하여 살펴보았다. 연구결과 초기 계측이 이루어진 이격거리가 커질수록 전체 변위 이력곡선의 예측 정확도는 급격히 감소하였으며, 계측오차가 커질수록 예측 정확도가 낮아지는 경향을 확인하였다.

• 동의생리병리학회지
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• 제26권5호
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• pp.630-640
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• 2012

Recently, the range of meridian muscle has expanded to muscular membranes, tendons and sinews as well as muscles, comprehending the modern manual therapy and its theories. So, in this study, the movement of body is explained through the assignment of meridian muscles into 3 Yins and 3 Yangs, and the modern manual therapy is understood with body's movement principles rather than with simple muscular movements. For this, the ground that the meridian muscles can expand to muscular membranes, tendons and sinews is researched in newest papers and studies rather than in the conventional studies that have analyzed the meridian muscles just in anatomic viewpoints. And, to find out how it can be applied to the actual clinic, its relationship with modern manual therapies such as Positional Release Therapy and Muscle Energy Techniques which are in the spotlight lately is also researched, getting the following results: Modern manual therapy is to keep the mutual balance of Yin-Yang meridian muscles after all and secure the stability of body to relieve the pains due to the stagnation of energy and blood. In the main body, they can be allotted into the opening of Great Yang/Great Yin, the closing of Bright Yang(陽明)/Small Yin, and the pivoting of Small Yang/Growing Yin (厥陰). The bending and stretching of meridian muscles as well as the movement of body can be explained according to the principle of opening, closing and pivoting. When the body is divided into 3 Yins and 3 Yangs, the viewpoint of Yin-Yang-Inside-Outside can be applied to the protagonist and antagonist muscles, giving a theoretic basis to the modern manual therapy. In the process to understand Positional Release Therapy and Muscle Energy Techniques in the viewpoint of Meridian Muscle, it turned out that the meridian muscle theory of Oriental Medicine which used to be known only in documents can well explain the movement mechanism of human body. The stress reaction through the reciprocal inhibition in Positional Release Therapy and Muscle Energy Techniques can also be understood with Yin-Yang-Inside-Outside.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권5호
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• pp.331-335
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• 2017

Clinical limitations following closed reduction of an intracapsular condylar fracture include a decrease in maximum mouth opening, reduced range of mandibular movements such as protrusion/lateral excursion, and reduced occlusal stability. Anteromedial and inferior displacement of the medial condyle fragment by traction of the lateral pterygoid muscle can induce bone overgrowth due to distraction osteogenesis between the medial and lateral condylar fragments, causing structural changes in the condyle. In addition, when conventional maxillomandibular fixation (MMF) is performed, persistent interdental contact sustains masticatory muscle hyperactivity, leading to a decreased vertical dimension and premature contact of the posterior teeth. To resolve the functional problems of conventional closed reduction, we designed a novel method for closed reduction through protrusive MMF for two weeks. Two patients diagnosed with intracapsular condylar fracture had favorable occlusion after protrusive MMF without premature contact of the posterior teeth. This particular method has two main advantages. First, in the protrusive position, the lateral condylar fragment is moved in the anterior-inferior direction closer to the medial fragment, minimizing bone formation between the two fragments and preventing structural changes. Second, in the protrusive position, posterior disclusion occurs, preventing masticatory muscle hyperactivity and the subsequent gradual decrease in ramus height.