• Structural Engineering and Mechanics
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• 제28권2호
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• pp.239-257
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• 2008

Double-sided punched metal plate timber fasteners present projections on both sides, which offer improved joint fire resistance and better joint aesthetics. In this paper, 3-D nonlinear finite element models were developed to simulate double-sided nail plate fastener timber joints. The models, incorporating orthotropic elasticity, Hill's yield criterion and elasto-plasticity and contact algorithms, are capable of simulating complex contact between the tooth and the timber and between the base plate and the timber in a fastener. Using validated models, parametric studies of the double-sided nail plate joints was undertaken to cover the tooth length and the tooth width. Optimal configuration was assumed to have been attained when increase in nail plate tooth width did not result in a raise in joint capacity, in conjunction with the optimum tooth length. This paper presents the first attempt to model and optimise tooth profile of double-sided nail plate fastener timber joints, which offers rational designs of such fasteners.

• 치과방사선
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• 제2권1호
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• pp.53-57
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• 1972

The author measured the length of crown, root and tooth on the films which was taken by intraoral bisecting technic with mesh plate on the films. The films were taken from the dry skulls, dentiform and patients who had to be removed their upper incisors and the other patients who adimitted for dental care. From this serial experiment the results was made as follows: 1. By using the film and mesh plate in the oral cavity, the real tooth length can be measured easily on the film surfaces. 2. It can be avoided the film distortion in the oral cavity when taking the film using the mesh plate and film together. 3. When measuring the film, length of crown was elongated and length of root was shortened. 4. When using the well-trained bisecting technic, the real tooth length can be measured directly on the intraoral film.

• 대한치과보철학회지
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• 제28권1호
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• pp.43-61
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• 1990

The laser reflexion method is a new technique which permits precise contactless measurement and observation of tooth mobility as well as tooth movement. The purposes of this study were to clarify the reliability of the laser reflexion method in clinical application and to measure the abutment tooth movement according to clasp design. This study was designed to determine 1) How much a bending movement of the impression plate stand affects the position of the reflexion pattern and how precise the patient bites into plate 2) Which clasp design causes greater movement of the abutment tooth. Under medium and maximum bite forces, tests were performed on central loading position which was 13mm distal to terminal abutment tooth of distal extension removable partial denture. The movement in the mesiodistal and buccolingual directions was measured. The Duncan's New Multiple-Range test was used to compare the means for the four castings under each direction-load combination; and the paired sample t-test was for medium and maximum bite forces. From this experiment, the following results were obtained. 1. The Roach clasp, the combination clasp, the RPI clasp, and the Akers clasp did not significantly differ in their effects on buccolingual movement of the abutment tooth. 2. The direction of abutment tooth movement was not significantly altered by clasp design and all abutment tooth movements were oriented distobuccally. 3. Under medium bite force, the Akers clasp caused greater distal movement of the abutment tooth than did the combination clasp and the RPI clasp. Under maximum bite force, the Akers clasp caused greater distal movement of the abutment tooth than did the RPI clasp. 4. The testing apparatus and procedures used in this study(laser reflexion method) proved to be reliable in clinical application.

• 대한치과교정학회지
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• 제31권1호
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• pp.97-105
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• 2001

교정 치료 시 많은 경우 상악 전치부를 상당량 견인하게 되며 이 때 치아의 이동량과 전방 피질골의 개조량이 동일하게 일어나지 않는다면 치주적인 문제가 발생할 수 있게 된다. 이에 본 연구에서는 상악 전치가 후방 견인될 때 치아의 이동량과 피질골의 개조량의 관계를 알아보기 위하여 성장이 완료된 만 18세 이상의 성인 여자환자 56명을 대상으로 치료 전후의 측모두부 방사선 사진을 계측하였다. 연구대상 56명은 전치의 후방견인 시 경사이동이 주로 일어난 환자(26명 )와 치체 이동이 동반된 환자(30명)로 나누었으며 치료 전후의 측모두부방사선 사진을 true horizontal plane 을 기준으로 하여 중첩하였다. Tip-Group(경사이동된 군)에서는 수평적인 bone remodeling/tooth movement ratio가 1:1.63, Torque-Group(치체 이동이 동반된 군)에서는 1:1.66이었다. 두 군 모두에서 치아의 이동량과 골의 개조량이 동일하지 않았기 때문에 경사 이동 시에는 치근첨이 구개측피질골판에서 멀어지고 순측피질골판에 가까워지며, 치체이동이 동반된 군에서는 치근이 순측피질골판에서는 멀어지고 구개측피질골판에 접근하게 된다. 따라서 상악의 전방 피질골의 두께가 매우 얇은 환자에서는 상악 전치의 후방견인량에 제한이 있게 되며 골격적 부조화가 심한 경우에는 악교정수술을 동반한 치료를 고려하고, 교정적 절충치료가 필요한 경우 술자는 그 치료한계를 명확히 인식해야할 것이다.

• 대한소아치과학회지
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• 제35권2호
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• pp.339-344
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• 2008

상악 영구 견치의 매복에 비해 하악 영구 견치의 매복은 매우 드물게 일어난다. 치아가 매복된 경우 장애물 존재 여부와 매복 위치와 방향, 맹출 가능한 공간의 유무, 치근의 형성 단계 등의 요소에 따라 매복 치아의 발거 혹은 장애물의 제거 후 주기적 관찰, 맹출이 지연된 치아의 외과적 노출, 교정적 견인 등의 방법으로 치료하게 된다. 본 증례는 하악골의 골절 부위에 시행된 골간 강선 결찰과 미니 플레이트에 의해 하악 좌측 견치가 매복되어 있었던 경우로 CT 검사 결과 하악 정중부위 플레이트의 스크류가 맹출을 방해하고 있는 것으로 판단되어 전신 마취 하에 플레이트를 제거하였다. 이후 자연적인 맹출을 기대하였으나, 맹출력이 부족하여 교정적 견인으로 양호한 결과를 얻었기에 보고하는 바이다.

• 동력기계공학회지
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• 제15권4호
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• pp.48-53
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• 2011

Upon reviewing recent trends for robots, it can be seen that robots are gradually being miniaturized. However, most commercially available speed reducers have limitations in terms of structure and vibration when applied to small robots. In this respect, a tooth profile manufactured using thin plates was designed using balls and data analyzed related to numerical and FEM analysis. The speed reducer was manufactured to check their performance. The manufactured thin plate type speed reducer imposes less compressive stress on its tooth profile and balls, which can greatly increase feasibility.

• 대한치과의사협회지
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• 제55권10호
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• pp.725-732
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• 2017

Thin labial plate will be resorbed after extraction. Immediate implantation cannot prevent soft and hard tissue loss. Bone graft can be necessary in the immediate implantation after anterior tooth extraction. Slowly-resorbed or non-resorbable bone graft material have many advantages in esthetic area because of maintenance of volume. The clinicians should select the adequate cases of immediate implantation according to the indication and contraindication.

• 구강회복응용과학지
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• 제27권1호
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• pp.109-115
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• 2011

점차적으로 폭경이 증가하는 나사들을 이용하여 치조능확장술을 시행하고 임프란트를 식립하였다. 임상적으로 양호한 결과를 얻었으며 수술 중 협측 피질골판 골절은 발생하지 않았다. 임프란트 주변 결손부와 협측 피질골판 상방에 자가치아골이식재를 이식함으로써 부가적인 치조능 확장 효과와 동시에 협측 피질골판 흡수를 보상하였다. 치조능 폭경이 협소한 부위에 임프란트를 식립할 때 나사를 이용한 확장술은 성공적이고 예측 가능한 술식이며 자가치아골이식재는 치조능증대술과 골유도재생술을 위해 사용될 수 있다.

• 대한치과교정학회지
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• 제47권5호
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• pp.289-297
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• 2017

Objective: The objective of this study was to analyze the patterns of tooth movements when distalization of mandibular molars using a mini-plate took place. A finite element analysis was applied to analyze patterns of tooth movements. Methods: The model of the mandible and teeth were used to build a finite element analysis model, and a mini-plate was inserted in the mandibular ramus. Two different orthodontic forces were established for displacement of mandibular molars. Orthodontic forces were applied at the level of the bracket and at the level of the cemento-enamel junction in the mandibular canine respectively. Results: Applying orthodontic forces at the level of the cemento-enamel junction resulted in a greater biomechanical bodily movement in distalization of the mandibular molars compared to when the orthodontic forces were applied at the level of the bracket. Applying orthodontic forces to the cemento-enamel junction also resulted in unwanted greater extrusive movements in distalization of the mandibular molars compared to the bracket level. Conclusions: With considering the mode of orthodontic teeth movement, applying different vertical orthodontic forces for distalization of mandibular molars can lead to more effective distalization of teeth.

• 대한장애인치과학회지
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• 제8권2호
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• pp.134-138
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• 2012

In treatment of dentigerous cyst, complete enucleation, histopathologic examination and postoperative care are important to prevent the potential complications (mural ameloblastoma, squamous cell carcinoma). On the other hand, a maxillary impacted supernumerary anterior tooth are removed surgically, owing to the possibility of the cyst formation in future. After the cyst enucleation and extraction of the involved tooth, the wound area sutured and removable resin plate is then applied. In this operation, the postoperative bleeding and infection is likely to occur owing to postoperative accumulation of hematoma & seroma, psychologic stress and other contaminated factor. So, the authors established the immediate rubber & iodoform gauze drainage into the sutured wound of cyst enucleation & tooth extraction for the prevention of postoperative bleeding and infection. The removable resin splint are not used because of the poor cooperation and economic factor. The results were more favorable without the postoperative bleeding & wound infection in a cerebral palsy patient.