• 대한치과보철학회지
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• 제29권2호
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• pp.129-145
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• 1991

The purpose of this study was to analyze the stresses and displacements of various esthetic restorations and abutment teeth. The finite element models of central incisor were divided into four groups according to the types of restoration. Three load cases were applied; 1) 45 degrees on the incisal edge, 2) horizontal force on the labial surface, and 3) 26 degrees diagonally on the lingual surface. Material property, geometry, and load conditions of each model were inputed to the two dimensional finite element program and stresses and displacements were analyzed. Results were as follows; 1. In the cases of porcelain fused gold ann and porcelain laminate venner, stresses were equally distributed in supporting abutment tooth. 2. The metal coping of porcelain fused gold u and collarless porcelain fused gold crown functioned as a good stress distributor. 3. When the horizontal load applied, the highest tensile and compressive stresses were seen in the cervical margin of restoration and the dentin of the abutment tooth. 4. The highest displacement of restoration was seen when load was applied at an mee of 26 degrees diagonally in lingual surface of tooth in centric occlusion. 5. The influence of loading direction on the stresses and displacements in the restoration was greater than that of various design. 6. The possibility of fracture was highest in porcelain jacket crown.

• 대한치과보철학회지
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• 제25권1호
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• pp.161-179
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• 1987

To study the mechanical behaviors of the margins of porcelain-fused-to-metal crown on the posterior teeth, 5 types of margins on the lower first molar were chosen, and then the finite element models were constructed. 50kg forces were applied to the porcelain on the axial wall supported by the metal vertically. The displacements and stresses of the porcelain-fused-to-metal crown were analyzed to investigate the influence of the type of margins. The results were as follows; 1. High tensile stresses were exhibited on the porcelain of the portion of the coronal line angle insufficient metallic support. 2. In case metal coping had a good supporting form to vertical force, uniform compressive stresses were exhibited on their supporting form. 3. Tensile stresses in the inframetallic margin on the series of the shoulder with a bevel margins were decreased in the bevel portion. 4. Principal stresses on the metal of the chamfer marginal portion were decreased comparing with the series of the shoulder margins. 5. The noticeable compressive stress gradients were exhibited between axial cement layer and metal on the series of the shoulder margins. 6. The principal stresses on the marginal cement layer were higher than that of the occlusal surface and axial wall.

• 대한치과기공학회지
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• 제21권1호
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• pp.115-121
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• 1999

This investing was carried out to evaluate the alteration of stress distribution on teeth and esthetic crowns. Analyzing the stress distribution by the two-dimensional finite element methods, a model of lower 1st molar according to the porcelain fused metal crown an the porcelain fused glass ceramic core crown and the all glass ceramic crown. 1. The pattern of stress distribution showed no apparent differences. 2. The greatest von Mises values were concentrated around the central fossa of all esthetic crowns. The greatest Maximum principle value were concentrated around the interface between the base of esthetic crown and the abutment tooth. It was found that the apatite glass ceramic could be applicable for use in dental crown prosthesis.

• 대한치과보철학회지
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• 제57권4호
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• pp.439-447
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• 2019

임플란트 식립 시 자연치와 임플란트 사이의 간격은 치주 조직 보존 및 심미에 중요한 요소이다. 또한 고정성 치아 수복 시 치아의 비정상적 위치 이동과 경사 이동은 의도적 근관치료를 필요로 할 수도 있고 저작효율에 불리하게 작용하기도 한다. 본 증례에서는 치열이 불균일하고 붕괴된 교합을 가진 환자에서 완전구강회복을 시행하기에 앞서 치아재배열을 위한 교정치료를 진행하였다. 환자는 통증이나 소리와 같은 측두하악관절장애 증상 및 불편감이 없으므로 교정치료를 진행하는 데 무리가 없었다. 임플란트 식립 전부터 시작한 교정치료를 임플란트 임시 보철물 시적 후에도 진행하였고 전치부 보호 및 심미를 위하여 교합고경을 전치부 기준 2 mm 거상하였다. 교정치료 완료 후 임플란트 및 자연치에 도재전장금관(Porcelain-fused-to-metal crown, PFM crown) 혹은 브릿지(bridge)로 최종 수복하였다. 환자의 치열 개선 및 무치악부 수복으로 기능적, 심미적으로 만족할 만한 결과를 보였다.

• Imaging Science in Dentistry
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• 제43권2호
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• pp.123-128
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• 2013

Double tooth is a dental anomaly consequent to fusion of two or more teeth or gemination of a single tooth. This report describes a unique case of double tooth in relation to a mandibular lateral incisor exhibiting the presence of four root canals. The role of conventional radiography and advanced three-dimensional imaging techniques in the better assessment of complex root canal systems and their aid in endodontic management has also been highlighted.

• 대한심미치과학회지
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• 제10권2호
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• pp.15-20
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• 2001

The spaced dentition is a common clinical finding. The careful analysis of clinically spaced dentition is a necessity for effective treatment planning. Spaced dentition often exists in the presence of intact teeth. Therefore, special care should be taken in order to obtain the most successful esthetic effect and to prevent overtreatment as well. The aesthetic restorative dental treatment using the porcelain laminate veneers is getting more popular than the complex orthodontic treatment, and prosthetic solutions that require sacrifice of sound tooth structure. The physical strength of porcelain laminate veneers is not as good as porcelain fused metal crowns, and more researches are needed in the field of bonding between composite cement and porcelain laminate veneer. However, the esthetic results from this unprepared porcelain laminate veneers were satisfactory with Authentic (Ceramay, Germany) pressable ceramic technique and resin cement (Rely X Veneer, 3M). This article deals with 2 cases of unprepared porcelain laminate veneers on anterior teeth.

• 대한소아치과학회지
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• 제36권1호
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• pp.119-125
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• 2009

두 개의 치아가 하나로 붙은 것처럼 보이는 경우, 쌍생인지 융합인지 여부를 결정할 수 없을 경우에 이중치(double tooth)라는 용어를 사용한다. 이중치는 유치에 더 호발하나 영구치에도 약 0.1% 발생율을 보이며 심미적인 문제와 우식의 호발, 치주적 문제, 치열의 문제를 보일 수 있다. 이러한 이중치의 치료는 여러 전문 분야의 협진을 필요로 한다. 우선, 순측과 구개측의 중심구는 치아우식에 민감하므로 조기에 열구를 전색하는 것이 필요하며, 영구 치열에서는 융합치를 외과적으로 구강 내 또는 구강 외에서 분리한 후 교정적으로 배열할 수 있으며, 치관 모양을 다듬기 위하여 수복 치료가 필요할 수 있다. 한 개의 근관을 가진 경우는 순면구의 모양을 다듬고, 근원심 크기를 감소시킨 후 복합레진을 적용하는 방법도 있으나 불가피하게 발치해야 하는 경우도 있다. 이 경우 교정 및 보철 치료가 필요하며 임플란트 매식술도 고려된다. 그러나 이러한 치료의 선택은 임상적 상황에 맞추어 이루어져야한다. 이번 증례들에서도 심미적인 문제와 교합의 문제를 발견할 수 있었으며, 첫 번째 증례에서는 이런 문제를 해결하기 위하여 교정적, 근관치료, 레진 수복술, 외과적인 구강내 절제술을 이용하여 치료하였으나, 치근단 흡수가 관찰되었다. 두 번째와 세 번째 증례에서는 3차원 전산화 단층 촬영을 이용하여 정확한 치아의 내부와 외부 구조를 파악할 수 있었으며, 일반 방사선 사진으로는 판단이 어려운 근관 분리 여부와 근관의 융합 정도와 융합 위치 등을 진단할 수 있었다.

• 대한소아치과학회지
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• 제35권2호
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• pp.195-204
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• 2008

치아 우식증과 침식증의 진단과 본 연구는 교정용 밴드 사용의 대안으로 제시된 직접 부착 술식이 보철 치료를 받은 치아상에서도 적절한 결합 강도를 갖으면서 임상적으로 유용하게 사용될 수 있는지를 평가하고, 불산과 포세린 전처리제의 사용 여부에 따른 결합 강도와 접착 파절 양상의 차이에 대해 알아보고자 시행하였다. 사람의 상하악 소구치 치관 20개를 대조군으로, 소구치의 협면을 복제한 포세린 치관 80개를 실험군으로 나눈 후, 대조군은 37% 인산으로 산부식한 후 Transbond $XT^{(R)}$를 이용하여 금속 브라켓을 접착하였고, 실험군들은 모두 포세린 치관에 통상적으로 sandblasting 처리를 하되, 9.6% 불산으로 4분간 부식처리를 함께 한 군, 포세린 전처리제를 적용한 군, 마지막으로 sandblasting과 불산 그리고 포세린 전처리제를 모두 적용한 군으로 20개씩 나눈 후 금속 브라켓을 접착하였다. 각 군간 전단 결합 강도와 접착 파절 양상을 비교하여 관찰한 결과, 포세린 치관에 금속 브라켓을 접착할 시, 기존의 비심미적인 밴드를 사용하지 않더라도 sandblasting과 불산 그리고 포세린 전처리제를 이용한 직접 부착 술식으로 임상적으로 유용하게 사용될 수 있음을 알 수 있었다.

• 대한치과기공학회지
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• 제26권1호
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• pp.115-128
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• 2004

In this study, optical and mechanical properties were investigated with 4 kinds of commercial dental enamels. As a result of EDS analysis $SiO_2,\;Na_{2}O,\;Al_{2}O_3\;and\;K_{2}O$ were the main components of commercial dental enamels. In case of H specimen, content of $SiO_2\;and\;K_2O$ were more than that of another specimens. Starting powder and fired specimens were glass ceramics which were consist of amorphous phase and leucite (crystalline) phase. Crystallization did not occurred during firing process, since the XRD peak intensity was similar between starting powder and fired specimens. As a result of differential thermal analysis, $T_g$ and crystalline temperature was varied with composition in the range of $548\sim576^{\circ}C$ and $735\sim780^{\circ}C$ respectively. 0.5mm thickness dental enamel specimens showed sufficient translucent properties. However, transmittance and reflectance were lower than 5% result from scattering due to the refractive index difference between glass and crystalline phase. 3 point bending strength was in the range of 73.9$\sim$101.8MPa which was similar or slightly higher than enamel of natural teeth and Vickers hardness was higher than enamel of natural teeth more than 100.

• Imaging Science in Dentistry
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• 제45권3호
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• pp.187-192
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• 2015

Cleidocranial dysplasia (CCD) is a rare congenital disorder, typically characterized by persistently open skull sutures, aplastic or hypoplastic clavicles, and supernumerary teeth. Mutations in the gene encoding the runt-related transcription factor 2 (RUNX2) protein are responsible for approximately two thirds of CCD patients. We report a 20-year-old CCD patient presenting not only with typical skeletal changes, but also complex dental anomalies. A previously undiagnosed odontoma, 14 supernumerary teeth, a cystic lesion, and previously unreported fused primary teeth were discovered on cone-beam computed tomography (CBCT) scans. Mutation analysis identified the causal c.578G>A (p.R193Q) mutation in the RUNX2 gene. At 20 years of age, the patient had already missed the optimal period for dental intervention. This report describes the complex dental anomalies in a belatedly diagnosed CCD patient, and emphasizes the significance of CBCT assessment for the detection of dental anomalies and the importance of early treatment to achieve good outcomes.