• 구강회복응용과학지
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• 제30권1호
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• pp.81-92
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• 2014

상악 전치부에 임플란트를 이용해 심미적으로 수복 하는 것은 많은 어려움이 따른다. 이는 치조골 흡수와 치간 유두 수축 등과 같은 임플란트 주변 경, 연조직 문제와 금속지대주 및 금속도재관의 변연노출과 낮은 광투과도 등의 보철적 한계 때문이다. 이에 본 증례에서는 경, 연조직의 증대술 및 성형술, 발치 후 즉시 식립 등과 함께 임시수복물의 장기간 사용 및 수정으로 임플란트 주위 연조직의 형태와 건강을 형성한 후, 맞춤형 인상 코핑을 사용하여 이를 최종 모형에 재현하였다. 또한 맞춤형 지르코니아 지대주와 완전 도재관을 이용해 최종 수복함으로써 기능적이고 심미적인 결과를 얻었기에 이를 보고하고자 한다.

• The Journal of Advanced Prosthodontics
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• 제10권1호
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• pp.65-72
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• 2018

PURPOSE. The aim of this in vitro study was to investigate the fracture resistance under chewing simulation of implant-supported posterior restorations (crowns cemented to hybrid-abutments) made of different all-ceramic materials. MATERIALS AND METHODS. Monolithic zirconia (MZr) and monolithic lithium disilicate (MLD) crowns for mandibular first molar were fabricated using computer-aided design/computer-aided manufacturing technology and then cemented to zirconia hybrid-abutments (Ti-based). Each group was divided into two subgroups (n=10): (A) control group, crowns were subjected to single load to fracture; (B) test group, crowns underwent chewing simulation using multiple loads for 1.2 million cycles at 1.2 Hz with simultaneous thermocycling between $5^{\circ}C$ and $55^{\circ}C$. Data was statistically analyzed with one-way ANOVA and a Post-Hoc test. RESULTS. All tested crowns survived chewing simulation resulting in 100% survival rate. However, wear facets were observed on all the crowns at the occlusal contact point. Fracture load of monolithic lithium disilicate crowns was statistically significantly lower than that of monolithic zirconia crowns. Also, fracture load was significantly reduced in both of the all-ceramic materials after exposure to chewing simulation and thermocycling. Crowns of all test groups exhibited cohesive fracture within the monolithic crown structure only, and no abutment fractures or screw loosening were observed. CONCLUSION. When supported by implants, monolithic zirconia restorations cemented to hybrid abutments withstand masticatory forces. Also, fatigue loading accompanied by simultaneous thermocycling significantly reduces the strength of both of the all-ceramic materials. Moreover, further research is needed to define potentials, limits, and long-term serviceability of the materials and hybrid abutments.

• 대한치과기공학회지
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• 제41권3호
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• pp.187-193
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• 2019

Purpose: The purpose of this study was to compare two-dimensional fitness of the monolithic zirconia prosthesis by using different type of scanner. Methods: No. 26 abutment tooth of FDI system was selected for the study. Using the extraoral scanner and intraoral scanner, the abutment tooth was scanned 10 times and the scanned files were saved as STL files. CAD/CAM system was used to produce the monolithic zirconia prosthesis. marginal and internal gap of the monolithic zirconia prosthesis were measured by digital microscope(x160) and applied silicone replica technique was applied. t-test, a statistical software, was used to perform data analysis. Results: Marginal gap $mean{\pm}SD$ of the monolithic zirconia prosthesis was $33{\pm}7.5{\mu}m$ with extra oral scanner and $34.7{\pm}11.1{\mu}m$ with intraoral scanner. axial gap mean was $40.5{\pm}3.5{\mu}m$ with extra oral scanner and $44.6{\pm}11.6{\mu}m$ with intraoral scanner. occlusal gap mean was $110.1{\pm}25.4{\mu}m$ with extra oral scanner and $64{\pm}9.7{\mu}m$ with intraoral scanner. Conclusion: In this study, fabricating zirconia prosthesis with different type of scanner was clinically applicable.

• 구강회복응용과학지
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• 제24권1호
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• pp.57-65
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• 2008

연구목적 : 본 연구에서는 rotational freedom을 측정할 수 있는 기구를 개발하여 시중에서 유통되고 있는 국산 임플란트 및 다양한 국적의 임플란트들의 기계적인 가공오차들을 측정하여 다양한 임플란트 시스템의 component간의 기계적인 안정성을 평가하고자 한다. 또한 본 연구에서는 더 나아가 최근에 임플란트 abutment로 각광을 받고 있는 각종 ceramic abutment의 절삭 가공오차에 관한 항목을 측정하여 임플란트 제조사 및 임상의들에게 올바른 정보를 제공하고자 한다. 연구재료 및 방법 : 국내에서 유통되는 외부연결구조의 외국산 임플란트 시스템(Nobel Biocare, Anthorgyr)과 국산 시스템(Neobiotec)과 내부연결구조의 임플란트 시스템(외국산:Nobel Biocare, Anthorgyr, Straumann, Frident Dentsply, 국산:Dentium) 별로 임플란트 fixture, abutment, analog를 서로 교차 연결하여 회전각도측정기(rotational angle measuring device)로 freedom of rotational angle을 측정하였다. 국산 외부연결구조의 지르코니아 abutment(ZirAce)를 외부연결구조의 임플란트 시스템(Neobiotec, Nobel Biocare, Anthorgyr)의 fixture와 analog와 교차연결하여 freedom of rotational angle을 측정하였다. 연구결과 : 국산 외부연결구조의 임플란트 시스템은 약 2.67도(fixture와 abutment 연결시), 내부연결구조의 임플란트는 약 4.3도(fixture와 abutment 연결시)의 rotational freedom을 보였다. 국산 지르코니아 abutment는 외국산 및 국산 외부연결구조 임플란트 시스템과 상관없이 3도 이하(fixture와 연결시)의 결과를 보였다. 결 론 : 시제품으로 제작된 디지털 회전각도측정기는 높은 분해능을 갖고 있었으며, 국산 임플란트의 기계적 가공오차는 외국산 임플란트와 거의 유사했다. 국산 세라믹 abutment의 기계적 가공오차는 fixture 제조회사별로 다르게 나타났지만 같은 회사의 절삭가공된 금속 abutment와 비교시 가공오차가 더 적었다.

• 치위생과학회지
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• 제15권1호
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• pp.54-59
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• 2015

본 연구는 시중에 널리 사용되는 치과용 지르코니아 코어를 이용하여 서로 다른 형태의 지대치를 대상으로 작업모형을 제작한 후, 치과용 스캐너를 통해 3차원 디지털 모형을 전환한 데이터를 토대로 지르코니아 코어를 제작하였으며, 각 실험군별 변연 적합도를 측정하여 비교분석하고자 하였다. 이와 같은 결과로 형태가 다른 지대치가 CAD/CAM system으로 치과 보철물 제작 시 적합도의 영향여부를 비교하였다. 제한된 조건 하에서 수행된 본 연구에서 다름과 같은 결과를 보였다. 지대치의 형태가 다른 작업모형으로 제작된 지르코니아 코어의 변연 적합도는 큰 차이가 없었다(p>0.05). 작업모형의 부위를 4등분으로 나누어 측정한 변연 적합도 또한 통계적으로 유의한 차이를 보이지 않았다. 결론적으로 3종류의 다른 지대치 모두 유사한 지르코니아 코어의 변연 적합도를 보였으며, 측정된 결과는 선행연구에 비추어 볼 때 임상적으로 허용 가능한 수치($100{\sim}120{\mu}m$)를 초과하는 실험군은 없었다. 이와 같은 결과를 토대로 다른 형태의 지대치를 사용하여 제작되었더라도 지르코니아 코어의 변연 적합도에 큰 영향을 주지 않을 것으로 생각된다.

• The Journal of Advanced Prosthodontics
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• 제9권3호
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• pp.152-158
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• 2017

PURPOSE. The purpose of this study was to evaluate the influence of different coping thicknesses and veneer ceramic cooling rates on the failure load of zirconia-ceramic crowns. MATERIALS AND METHODS. Zirconia copings of two different thicknesses (0.5 mm or 1.5 mm; n=20 each) were fabricated from scanning 40 identical abutment models using a dental computer-aided design and computer-aided manufacturing system. Zirconia-ceramic crowns were completed by veneering feldspathic ceramics under different cooling rates (conventional or slow, n=20 each), resulting in 4 different groups (CONV05, SLOW05, CONV15, SLOW15; n=10 per group). Each crown was cemented on the abutment. 300,000 cycles of a 50-N load and thermocycling were applied on the crown, and then, a monotonic load was applied on each crown until failure. The mean failure loads were evaluated with two-way analysis of variance (P=.05). RESULTS. No cohesive or adhesive failure was observed after fatigue loading with thermocycling. Among the 4 groups, SLOW15 group (slow cooling and 1.5 mm chipping thickness) resulted in a significantly greater mean failure load than the other groups (P<.001). Coping fractures were only observed in SLOW15 group. CONCLUSION. The failure load of zirconia-ceramic crowns was significantly influenced by cooling rate as well as coping thickness. Under conventional cooling conditions, the mean failure load was not influenced by the coping thickness; however, under slow cooling conditions, the mean failure load was significantly influenced by the coping thickness.

• The Journal of Advanced Prosthodontics
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• 제13권6호
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• pp.396-407
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• 2021

PURPOSE. Zirconia has exceptional biocompatibility and good mechanical properties in clinical situations. However, finite element analysis (FEA) studies on the biomechanical stability of two-piece zirconia implant systems are limited. Therefore, the aim of this study was to compare the biomechanical properties of the two-piece zirconia and titanium implants using FEA. MATERIALS AND METHODS. Two groups of finite element (FE) models, the zirconia (Zircon) and titanium (Titan) models, were generated for the exam. Oblique (175 N) and vertical (175 N) loads were applied to the FE model generated for FEA simulation, and the stress levels and distributions were investigated. RESULTS. In oblique loading, von Mises stress values were the highest in the abutment of the Zircon model. The von Mises stress values of the Titan model for the abutment screw and implant fixture were slightly higher than those of the Zircon model. Minimum principal stress in the cortical bone was higher in the Titan model than Zircon model under oblique and vertical loading. Under both vertical and oblique loads, stress concentrations in the implant components and bone occurred in the same area. Because the material itself has high stiffness and elastic modulus, the Zircon model exhibited a higher von Mises stress value in the abutments than the Titan model, but at a level lower than the fracture strength of the material. CONCLUSION. Owing to the good esthetics and stress controllability of the Zircon model, it can be considered for clinical use.

• 대한치과보철학회지
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• 제43권5호
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• pp.611-621
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• 2005

State of problem: Zirconia all-ceramic restoration fabricated with CAM system is on an increasing trend in dentistry. However, evaluation of the marginal and internal fits of zirconia bridge seldomly have been reported. Purpose: This study was to evaluate the at of margin and internal surface in posterior 3-unit zirconia bridge framework fabricated with CAM system(DeguDent, Germany). Material and Method: Preparations of secondary premolar and secondary molar on artificial resin model were performed for fabrication of 3-unit posterior bridge framework. Fits of 5 zirconia bridge framework were compared with 5 precious ceramo-metal alloy framework(V-GnathosPlus, Metalor, Switzerland), and prepared margins were designed to chamfer and shoulder finishing line. Each framework was cemented to epoxy resin model with reinforced glass ionomer(FujiCEM, GC Co., Japan), embedded in acrylic resin and sectioned in two planes, mesio-distal and buccolingual. Samples were divided into six pieces by sectioning and had two pieces of each surface(i.e mesial, distal, buccal and lingual surface) per abutment, so there were eight measuring points in each abutment. External gap was measured at the margin and internal gaps were measured at the margin, axial and occlusal surface. Gaps were observed under the measuring microscope(Compact measuring microscope STM5; Olympus, Japan) at a magnification of $\times100$. T-test were used to determine the statistic significance of the different gaps between zirconia and metal framework. Results and Conclusion: 1. External and internal marginal gaps of zirconia and metal framework were in clinically acceptable range. External marginal gaps were not different significantly between zirconia$(81.9{\mu}m)$ and metal $(81.3{\mu}m)$ framework and internal marginal gaps of zirconia $(44.6{\mu}m)$ were smaller than those of metal framework $(58.6{\mu}m)$. 2. Internal axial gaps of zirconia framework$(96.7{\mu}m)$ were larger than those of metal frame-work$(78.1{\mu}m)$ significantly and adversely, internal occlusal gaps of zirconia frame-work$(89.4{\mu}m)$ were smaller than those of metal framework $(104.9{\mu}m)$ significantly. 3. There were no significant differences in external and internal marginal gaps between chamfer and shoulder finish line when zirconia frameworks were fabricated.

• Restorative Dentistry and Endodontics
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• 제43권1호
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• pp.9.1-9.6
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• 2018

The objective of this case report is to introduce a simple technique for simultaneously taking a closed-mouth impression and functionally generated path (FGP) for a full coverage crown restoration. A monolithic zirconia crown was the restoration of choice. An alginate impression of the abutment tooth was taken to fabricate a custom-made closed-mouth impression tray covering the abutment tooth and the adjacent teeth. The tray had an FGP table and an abutment tray in cameo and intaglio surfaces, respectively. The impression was taken with silicone impression material after adjusting the abutment tray and inscribing the FGP using self-curing acrylic resins. Plaster casts were made from the impression, and a zirconia crown was fabricated. The crown was cemented to the abutment tooth with minimal adjustments. This simple technique resulted in a well-fitting crown that accounted for mandibular movements. Using the custom closed-mouth impression tray incorporating an FGP table simultaneously aids in fabricating an accurately fitting restoration that incorporates harmonious mandibular movements using a single impression capture.

• 대한심미치과학회지
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• 제17권1호
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• pp.42-49
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• 2008