• 대한소아치과학회지
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• 제49권1호
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• pp.25-34
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• 2022

이 연구의 목적은 상악 측절치 과잉치의 해부학적인 특징과 정상 측절치와의 관계에 대해 정량적 분석을 시행하는 것에 있다. 43명의 44개의 상악 측절치 과잉치를 대상으로 전산화 단층 방사선사진을 이용하여 측절치 과잉치의 위치, 형태, 방향 및 측절치 과잉치와 인접한 영구전치와의 관계를 관찰하였다. 또한 측절치 과잉치와 인접한 측절치 및 반대측 측절치의 크기를 비교하기 위해 각각의 치관 근원심 폭경을 계측하였고, 치아성숙도를 비교하기 위해 Nolla stage를 이용하여 각 치아의 치근 발육 정도를 평가하였다. 측절치 과잉치는 90.9%의 비율로 정위 방향으로 존재하였고, 84.1%가 보충형의 형태로 존재하였다. 측절치 과잉치는 인접한 측절치나 반대측의 측절치에 비해 치관의 크기가 통계적으로 유의하게 작았고(p < .0001), 치근 발육 단계에서는 통계적 유의미한 차이를 보이지 않았다. 결론적으로, 상악 측절치 과잉치는 정상측절치와 매우 유사하지만 치관 크기에 있어서 차이를 보인다. 상악 측절치 과잉치가 존재하는 경우, 교정적 혹은 심미적인 문제를 줄이기 위해 측절치와 과잉치를 정확하게 구분하여 치료하는 것이 중요하다.

• 대한기계학회논문집A
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• 제39권7호
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• pp.665-671
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• 2015

유성 기어박스의 진동기반 고장진단 기법은 조립 및 제작공차와 하중조건에 의해 결정되는 진동 변조특성에 따라 성능을 달리하는 특성을 갖는다. 이 논문에서는 풍력발전기에 장착되어 있는 유성 기어박스의 고장을 효과적으로 진단하기 위해 진동 변조특성을 고려한 고장진단기법을 제안하고자 한다. 리샘플링된 진동신호에 대한 대역 필터링을 사용함으로써 유성기어박스의 진동 변조특성을 규명하고자 하였으며, 진동추출 윈도우함수의 최적위치를 선정하여 활용함으로써 가변적 진동 변조현상에서도 강건한 고장진단을 수행할 수 있도록 하였다. 제안된 고장진단기법의 검증을 위해 2kW 급 풍력발전기 테스트베드가 설계되었으며 기어 치 부분파손이 모사 제작되어 기어박스에 장착되었다.

• 구강회복응용과학지
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• 제17권3호
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• pp.145-154
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• 2001

In the past, many dentist were interested mainly in the mechanical aspects such as tooth preparation and retainer types for making dental restoration. But, these days, the concept of restorative treatment emphasizes the importarce of gnatic system and masticatory muscles in addition to oral cavity. So, the current considerations for the fixed prosthodontic treatment include the stabilization of temporomandibular joint and neuromuscualr system and the relationship of periodontal ligament and occlusion. To achieve the above objectives, occlusal splint has been used as one of the mouth preparations for restorative treatment. The objectives of occlusal splint are as follows; 1. To use as preliminary application for periodontal-occlusal treatment 2. To provide proper vertical dimension 3. To control abnormal habits and parafunction 4. To treat the temporomandibular disease and myofascial pain 5. To establish the new therapeutic position In some cases, the patients had improper vertical dimension and occlusal interferences caused by prostheses reconstucted using centric relation recorded without considering the health of TMJ and manticatory muscle. And these prosthesis act as primary source that cause pathologic phenomenon in periodontal ligament, muscles and TMJ. Physiologically, in order to make the treatment occlusion guided by proper centric relation method, the method should be guided after the use of occlusal splint for some period. The main objective of prosthetic treatment is to maintain the function and health of stomatognathic system. So, one of the most important things that have to be performed by clinicians is a clinical ability to do the correct diagnosis and treatment planning based on the stomatognatic function and occlusion.

• 대한치과보철학회지
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• 제54권3호
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• pp.273-279
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• 2016

과도한 치아의 마모는 치수의 병적 변화, 교합 불균형과 기능 및 심미적 문제를 야기할 수 있다. 수직고경의 변화를 동반한 전악보철수복의 경우, 악관절 및 저작근의 통증이나 이상기능 등의 문제를 야기할 수 있으므로 정확한 진단 및 분석, 그리고 단계적인 치료접근이 요구된다. 본 증례는 34세 남자 환자로 전반적인 치아 마모와 부식으로 인해 기능적, 심미적 치아외형 상실을 가지고 있었다. 진단 평가결과 수직고경의 거상을 동반한 전악 보철 수복이 필요한 상태로 진단되었다. 치료계획에 의해 교합안정장치를 이용하여 턱관절을 안정화시킨 뒤 중심위를 채득하고, 거상된 수직고경 상에서 임시치아로 수복하여 경과 관찰하였다. 그 후 CAD-CAM (computer aided design-computer aided manufacturer)을 이용하여 단일구조 지르코니아를 이용한 보철 수복을 시행하였다. 최종 보철 수복 후 환자는 기능 및 형태적으로 매우 만족했으며, 더불어 심미적으로도 좋은 결과를 얻었기에 보고하는 바이다.

• 대한치과보철학회지
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• 제22권1호
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• pp.72-78
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• 1984

The notion that the axis of the shaft of the articulator must coincide the patient's mandibular transverse axis tells us the importance of locating the axis precisely. When using kinematic axis to transfer a cast to an articulator, the anatomic asymmetry of the contralateral points will result in certain distortion when the axis transferred to an articulator where the mechanical axis produces symmetry. In this study, after locating the true hinge axis point with Denar hinge axis locator, the discrepancies between true hinge axis point and arbitrary hinge axis point that was 13mm anterior from the posterior margin of center of trangus to the outer canthus of eye were measured. And the discrepancies between left and right true hinge axis point in the superoinferior and anteroposterior directions were measured. For this study, 20 dental students who have no missing teeth and no difficulties of mandibular movement were selected. Upper and lower cast of subjects were mounted on Denar Mark II articulator uisng Denar Slidematic face-bow and centric relation record for the measurement of discrepancies between left and right true hinge axis points. The results obtained as follows. 1. The mean distance from the arbitrary hinge axis point to the true hinge axis point was as follows. Right: horizontal distance; 1.99mm, vertical distance; 2.12mm, linear distance; 3.36 mm. Left: horizontal distance; 1.39mm, vertical distance; 2.06mm, linear distance; 2.09mm. Total: horizontal distance; 1.69mm, vertical distance; 2.09mm linear distance; 3.06 mm. 2. The 87.5% of true hinge axis points were within 5mm of the arbitrary hinge axis point. 3. The mean discrepancies between the right and left hinge axis point were 2.92mm in superoinferior direction and 4.74mm in anteroposterior direction. 4. When transferring the axis to the articulator, anatomic asymmetry between right: and left axis point produces in dislocation of cast on the articulator, and undesirable shift in esthetic tooth position will be resulted.

• The Journal of Advanced Prosthodontics
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• 제8권2호
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• pp.150-157
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• 2016

PURPOSE. The modified lateral-screw-retained implant prosthesis (LSP) is designed to combine the advantages of screw- and cement-retained implant prostheses. This retrospective study evaluated the mechanical and biological complication rates of implant-supported single crowns (ISSCs) inserted with the modified LSP in the posterior region, and determined how these complication rates are affected by clinical factors. MATERIALS AND METHODS. Mechanical complications (i.e., lateral screw loosening [LSL], abutment screw loosening, lateral screw fracture, and ceramic fracture) and biological complications (i.e., peri-implant mucositis [PM] and peri-implantitis) were identified from the patients' treatment records, clinical photographs, periapical radiographs, panoramic radiographs, and clinical indices. The correlations between complication rates and the following clinical factors were determined: gender, age, position in the jaw, placement location, functional duration, clinical crown-to-implant length ratio, crown height space, and the use of a submerged or nonsubmerged placement procedure. RESULTS. Mechanical and biological complications were present in 25 of 73 ISSCs with the modified LSP. LSL (n=11) and PM (n=11) were the most common complications. The incidence of mechanical complications was significantly related to gender (P=.018). The other clinical factors were not significantly associated with mechanical and biological complication rates. CONCLUSION. Within the limitations of this study, the incidence of mechanical and biological complications in the posterior region was similar for both modified LSP and conventional implant prosthetic systems. In addition, the modified LSP is amenable to maintenance care, which facilitates the prevention and treatment of mechanical and biological complications.

• 구강회복응용과학지
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• 제33권4호
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• pp.314-320
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• 2017

상악 전치부 같은 심미성이 요구되는 부위의 치료 시에는 주위조직과 조화를 이루며 미소선, 연조직 및 경조직의 형태뿐아니라 치아의 해부학적 형태와 비율을 고려하여야 한다. 심미분석은 교합평면과 수평적 기준선간의 적절한 평행성을 평가하는 안면분석, 절치 절연부의 위치와 교합평면과 구각선 사이의 조화로움을 평가하는 치아입술분석, 심미성뿐만 아니라 적절한 기능을 위한 형태와 외형을 평가하는 치아분석, 치은 변연의 이상적인 윤곽을 형성하는 치은분석 등의 방법이 있다. 상악의 치간 이개는 체계적인 진단과 치료 계획을 통해서 심미적으로 수복할 수 있으며 교정, 보철, 보존적인 치료방법이 사용될 수 있다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권4호
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• pp.338-347
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• 2001

Purpose: This is to review the cases of posterior maxillary segmental osteotomies to regain the interarch spaces for dental implants in the posterior mandible. Materials & Methods: Seven patients who presented with alveolar extrusion of upper posterior molars underwent segmental osteotomies by single-stage Kufner's buccal approach under the intravenous sedation and local anesthesia. The posterior maxillary cento-alveolar segments were repositioned upward using pre-fabricated palato-occlusal resin splints and immobilized with osteosynthesis microplates and screws. Dental implants were installated simultaneously. The regained spaces, tooth vitality, periodontal healing, relapse, tenderness on function, and complications including maxillary sinus involvements were evaluated periodically for over one year after the surgeries. Results: The single-tage procedures were completed within 80 minutes without any surgical complications. The posterior maxillary segments were repositioned upward to regain the interarch spaces ranging from 2.5 to 5.5mm. All teeth involved in the procedures keep their vitalities. The repositioned segments were maintained showing neither evidence of periodontal break-down nor tenderness to function. One patient whose segments had not been immobilized by osteosynthesis plate resulted in 2mm down-ward relapse in post-operative 8 months. A case of postoperative nasal bleeding from the posterior-lateral wall resulted in oroantral fistula and chronic maxillary sinusitis later. Conclusion: The extruded dento-alveolar segments of the posterior maxilla were repositioned properly by Kufner's one-stage segmental osteotomies. One microplate can be of help to keep the position until the osseous healing enough to support the masticatory force.

• The Journal of Advanced Prosthodontics
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• 제7권1호
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• pp.51-55
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• 2015

PURPOSE. Bone density at implant placement site is a key factor to obtain the primary stability of the fixture, which, in turn, is a prognostic factor for osseointegration and long-term success of an implant supported rehabilitation. Recently, an implant motor with a bone density measurement probe has been introduced. The aim of the present study was to test the objectiveness of the bone densities registered by the implant motor regardless of the operator performing them. MATERIALS AND METHODS. A total of 3704 bone density measurements, performed by means of the implant motor, were registered by 39 operators at different implant sites during routine activity. Bone density measurements were grouped according to their distribution across the jaws. Specifically, four different areas were distinguished: a pre-antral (between teeth from first right maxillary premolar to first left maxillary premolar) and a sub-antral (more distally) zone in the maxilla, and an interforaminal (between and including teeth from first left mandibular premolar to first right mandibular premolar) and a retroforaminal (more distally) zone in the lower one. A statistical comparison was performed to check the inter-operators variability of the collected data. RESULTS. The device produced consistent and operator-independent bone density values at each tooth position, showing a reliable bone-density measurement. CONCLUSION. The implant motor demonstrated to be a helpful tool to properly plan implant placement and loading irrespective of the operator using it.

• 대한소아치과학회지
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• 제41권1호
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• pp.64-71
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• 2014

과잉치는 정상치아의 수보다 증가되어 나타나는 치아로서 상악 중절치 사이의 과잉치를 정중과잉치라 부른다. 정중과잉치는 상악 전치의 맹출 장애를 포함하는 여러가지 병발증을 야기하지만 그 제거시기에 대해서는 아직 논란이 있다. 정중과잉치에 의해 발생하는 병발증을 피하기 위해 가능한 조기에 발견하여 제거해야 한다는 주장과 외과적 발거에 따른 인접 치아의 손상을 최소화하기위해 상악 영구 전치의 치근발육이 완성된 후 제거해야한다는 주장이 있다. 이에 저자는 정중과잉치로 인해 회전된 상악 중절치를 가진 세 명의 환자들에서 중절치가 치근발육 초기단계에 있을 때 정중과잉치를 제거함으로써 회전된 상악 영구중절치의 자연적인 개선이 보이는 바 이를 보고하고자 한다.