• 대한심미치과학회지
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• 제22권1호
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• pp.9-21
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• 2013

심미의 기준은 시대와 문화 그리고 개개인의 주관적인 관점에 따라 각기 다를 수 있다. 하지만 심미적인 부위를 수복하는 치과의사로서 일반적으로 따라야 할 원칙과 기준들이 있으며 수복물의 형태와 주변치아와의 조화 등을 위해 캐드캠의 몇몇 기능들은 아주 유용한 것으로 보이며, 전통적인 작업 방식에 비해 효율성도 높은 것으로 보인다. 또한 전치부 임플란트에서 치은이 얇은 경우 기계적인 문제를 줄이면서도 지르코니아 등의 도재를 사용하기 위한 한 방법인 링크 지대주에 대해 함께 알아보려 한다.

• 구강회복응용과학지
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• 제33권2호
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• pp.114-118
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• 2017

목적: 이 연구의 목적은 타이타늄 구성요소를 가진 지르코니아 지대주가 내부연결 임플란트에 사용되었을 때 나사 풀림에 대해 알아보는 것이다. 열순환 후 타이타늄 소켓을 가진 지르코니아 지대주와 타이타늄 지대주의 나사 풀림과 제거력을 비교 분석하였다. 연구 재료 및 방법: 내측연결 임플란트와 내측연결 타이타늄 지대주, 타이타늄 소켓을 가진 외측연결 지르코니아 지대주를 준비하였다. 내부연결형 임플란트에 5개의 타이타늄 지대주를(대조군), 타이타늄 소켓을 가진 5개의 지르코니아 지대주(실험군)를 각각 연결하고 30 Ncm의 토크로 조인 후 열순환 처리 전후의 지대주 나사 제거력을 측정하였다. 각 시편들은 열순환 장치의 수조에서 $5^{\circ}C$와 $55^{\circ}C$의 물에 60초씩 교대로 2,000회의 열순환을 시행하였다. 각 시편의 나사 풀림을 조사하고 열순환 전후에 나사 제거력을 통계학적으로 분석하였다. 결과: 두 그룹 모두에서 열순환 후 지대주 나사 풀림을 보이지 않았다. 열순환 전후의 나사 제거력 차이는 대조군에서 $-1.34{\pm}2.53Ncm$, 실험군에서 $-1.26{\pm}2.06Ncm$ 로 나타났다. 독립표본 T 통계분석 결과 두 군간에 유의한 차이를 보이지 않았다(P > 0.05). 결론: 이 실험의 결과 내에서 내부연결 임플란트를 위한 지르코니아 지대주 내 타이타늄 소켓이 열순환 후 지대주 나사풀림에 타이타늄 지대주와 비교하여 유의한 영향을 나타내지 않았다.

• The Journal of Advanced Prosthodontics
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• 제9권4호
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• pp.271-277
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• 2017

PURPOSE. This in vitro study aimed to evaluate the effect of implant connection design (external vs. internal) on the fit discrepancy and torque loss of zirconia and titanium abutments. MATERIALS AND METHODS. Two regular platform dental implants, one with external connection ($Br{\aa}nemark$, Nobel Biocare AB) and the other with internal connection (Noble Replace, Nobel Biocare AB), were selected. Seven titanium and seven customized zirconia abutments were used for each connection design. Measurements of geometry, marginal discrepancy, and rotational freedom were done using video measuring machine. To measure the torque loss, each abutment was torqued to 35 Ncm and then opened by means of a digital torque wrench. Data were analyzed with two-way ANOVA and t-test at ${\alpha}=0.05$ of significance. RESULTS. There were significant differences in the geometrical measurements and rotational freedom between abutments of two connection groups (P<.001). Also, the results showed significant differences between titanium abutments of internal and external connection implants in terms of rotational freedom (P<.001). Not only customized internal abutments but also customized external abutments did not have the exact geometry of prefabricated abutments (P<.001). However, neither connection type (P=.15) nor abutment material (P=.38) affected torque loss. CONCLUSION. Abutments with internal connection showed less rotational freedom. However, better marginal fit was observed in externally connected abutments. Also, customized abutments with either connection could not duplicate the exact geometry of their corresponding prefabricated abutment. However, neither abutment connection nor material affected torque loss values.

• 대한치과보철학회지
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• 제53권4호
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• pp.345-351
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• 2015

목적: 이 실험의 목적은 전치부 임플란트에 적용되는 지르코니아 지대주의 적절한 축벽의 두께를 평가하는 것이었다. 재료 및 방법: 시편들은 4가지의 서로 다른 두께로 제작되었으며, 일정하게 제작하고자 CAD/CAM 시스템을 이용하여 소결전 지르코니아 블록을 가공한 후 소결하였다. 가공된 시편들은 두께에 따라 Group 1 (0.5 mm), Group 2 (0.8 mm), Group 3 (1.0 mm), Group 4 (1.2 mm)의 4가지 그룹으로 분류되었다. 임플란트 시스템은 외부연결형(US, Osstem, Pussan, Korea) 을 이용하였다. 지대주 시편들은 시멘트 유지형 지대주를 복제하여 제작되었다. 크라운은 1.5 mm 의 두께로 CAD/CAM을 이용하여 제작되었다. 제작된 지대주 시편들을 임플란트에 고정시킨 후 레진시멘트(RelyXTM UniCem, 3M ESPE AG, Seefeld, Germany)를 이용하여 크라운을 합착하였다. 지르코니아 지대주의 파절을 측정하기 위해 만능시험기로 임플란트 장축에 30도의 각도로 힘을 가하였다. 결과: Group 1, Group 2, Group 3와 Group 4의 파절강도는 각각 $236.00{\pm}67.55N$, $599.00{\pm}15.80N$, $588.20{\pm}33.18N$, $97.83{\pm}98.13N$이었다. Group 1이 다른 그룹에 비해 통계학적으로 유의성 있게 낮은 강도를 보여주었다(independent Mann-Whitney U-test, P<.05). 나머지 Group 2, Group 3와 Group 4는 서로 통계학적으로 유의성을 보여주지 않았다(independent Mann-Whitney U-test, P>.05). 결론: 지르코니아 지대주는 파절에 저항하기 위해 적절한 두께를 필요로 한다. 이 실험의 결과로 판단할 때, 지르코니아 지대주가 전치부 임플란트에 적용되기 위해서는 0.8 mm 이상의 두께를 가져야 된다고 추천된다.

• The Journal of Advanced Prosthodontics
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• 제7권6호
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• pp.475-483
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• 2015

PURPOSE. The objective of this study was to evaluate the influence of various cement types on the stress distribution in monolithic zirconia crowns under maximum bite force using the finite element analysis. MATERIALS AND METHODS. The models of the prepared #46 crown (deep chamfer margin) were scanned and solid models composed of the monolithic zirconia crown, cement layer, and prepared tooth were produced using the computer-aided design technology and were subsequently translated into 3-dimensional finite element models. Four models were prepared according to different cement types (zinc phosphate, polycarboxylate, glass ionomer, and resin). A load of 700 N was applied vertically on the crowns (8 loading points). Maximum principal stress was determined. RESULTS. Zinc phosphate cement had a greater stress concentration in the cement layer, while polycarboxylate cement had a greater stress concentration on the distal surface of the monolithic zirconia crown and abutment tooth. Resin cement and glass ionomer cement showed similar patterns, but resin cement showed a lower stress distribution on the lingual and mesial surface of the cement layer. CONCLUSION. The test results indicate that the use of different luting agents that have various elastic moduli has an impact on the stress distribution of the monolithic zirconia crowns, cement layers, and abutment tooth. Resin cement is recommended for the luting agent of the monolithic zirconia crowns.

• 대한치과기공학회지
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• 제46권2호
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• pp.21-27
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• 2024

Purpose: This study aimed to analyze the stress distribution and deformation in implant abutments made from titanium (Ti-6Al-4V), zirconia, and polyetheretherketone (PEEK), including their screws and fixtures, under various loading conditions using finite element analysis (FEA). Methods: Three-dimensional models of the mandible with implant abutments were created using Siemens NX software (NX10.0.0.24, Siemens). FEA was conducted using Abaqus to simulate occlusal loads and assess stress distribution and deformation. Material properties such as Young's modulus and Poisson's ratio were assigned to each component based on literature and experimental data. Results: The FEA results revealed distinct stress distribution patterns among the materials. Titanium alloy abutments exhibited the highest stress resistance and the most uniform stress distribution, making them highly suitable for long-term stability. Zirconia abutments showed strong mechanical properties with higher stress concentration, indicating potential vulnerability to fracture despite their aesthetic advantages. PEEK abutments demonstrated the least stress resistance and higher deformation compared to other abutment materials, but offered superior shock absorption, though they posed a higher risk of mechanical failure under high load conditions. Conclusion: The study emphasizes the importance of selecting appropriate materials for dental implants. Titanium offers durability and uniform stress distribution, making it highly suitable for long-term stability. Zirconia provides aesthetic benefits but has a higher risk of fracture compared to titanium. PEEK excels in shock absorption but has a higher risk of mechanical failure compared to both titanium and zirconia. These insights can guide improved implant designs and material choices for various clinical needs.

• The Journal of Advanced Prosthodontics
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• 제6권3호
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• pp.233-240
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• 2014

PURPOSE. To evaluate the effects of different abutment geometries in combination with varying luting agents and the effectiveness of different cleaning methods (prior to re-cementation) regarding the retentiveness of zirconia copings on implants. MATERIALS AND METHODS. Implants were embedded in resin blocks. Three groups of titanium abutments (pre-fabricated, height: 7.5 mm, taper: $5.7^{\circ}$; customized-long, height: 6.79 mm, taper: $4.8^{\circ}$; customized-short, height: 4.31 mm, taper: $4.8^{\circ}$) were used for luting of CAD/CAM-fabricated zirconia copings with a semi-permanent (Telio CS) and a provisional cement (TempBond NE). Retention forces were evaluated using a universal testing machine. Furthermore, the influence of cleaning methods (manually, manually in combination with ultrasonic bath or sandblasting) prior to re-cementation with a provisional cement (TempBond NE) was investigated with the pre-fabricated titanium abutments (height: 7.5 mm, taper: $5.7^{\circ}$) and SEM-analysis of inner surfaces of the copings was performed. Significant differences were determined via two-way ANOVA. RESULTS. Significant interactions between abutment geometry and luting agent were observed. TempBond NE showed the highest level of retentiveness on customized-long abutments, but was negatively affected by other abutment geometries. In contrast, luting with Telio CS demonstrated consistent results irrespective of the varying abutment geometries. Manual cleaning in combination with an ultrasonic bath was the only cleaning method tested prior to re-cementation that revealed retentiveness levels not inferior to primary cementation. CONCLUSION. No superiority for one of the two cements could be demonstrated because their influences on retentive strength are also depending on abutment geometry. Only manual cleaning in combination with an ultrasonic bath offers retentiveness levels after re-cementation comparable to those of primary luting.

• 구강회복응용과학지
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• 제26권2호
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• pp.97-109
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• 2010

연구목적 : 본 연구는 임플랜트 지대주에 동적하중을 가하기 전, 후의 풀림토크 변화를 측정함으로써 수종의 지대주에 가해진 단기간의 교합력이 임플랜트-지대주의 안정성에 영향을 미치는지를 연구하고자 하였다. 재료및 방법 : 임플랜트 고정체는 외부육각구조를 사용하였고, 티타늄합금 지대주, 지르코니아 지대주, 주조 금합금 지대주인 UCLA plastic abutment를 사용하였다. 초기 풀림회전력을 측정하고, 하중을 $10^5$ 회 가한후, 풀림회전력을 측정하였다. 초기 풀림회전력 상실률, 하중후 풀림회전력 상실률, 동적하중에 의한 풀림회전력 상실률을 계산하였다. 결과 : 초기 풀림회전력, 동적 하중후 풀림회전력, 초기 풀림회전력 상실률, 동적 하중후 풀림회전력 상실률, 동적 하중에 의한 풀림회전력 상실률은 각 지대주간 유의한 차이를 나타내지 않았다. 또한, 각 지대주 내에서 동적 하중 전후의 풀림회전력은 통계적으로 유의한 차이를 나타내지 않았다. 결론 : Titanium, zirconia, UCLA 지대주의 초기 나사풀림은 지대주간 유의한 차이가 없음을 알 수 있었고, 초기의 저작력은 하중전후 나사풀림에 큰 영향을 주지 않는다고 생각된다. 또한, UCLA, zirconia, titanium 지대주의 선택시 초기 나사풀림과 관련하여 특정 종류의 지대주 선택을 기피할 필요는 없다고 생각된다.

• 대한치과기공학회지
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• 제36권4호
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• pp.231-237
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• 2014

Purpose: This study was performed fracture strength test by conducted change of abutment and coping shape for suggesting monolithic all ceramic crown which has thin thickness and superior strength of the occlusal surface. Methods: The specimens on the four kinds abutment was made according to thickness of occlusal surface and angle of axis surface. And All ceramic coping specimens of 6 different kinds was made by the CAD/CAM Method. Compression strength test using the UTM and the verification of compression-stress situation using the 3D finite element method were conducted under optimum conditions. Results: 516C specimen was showed the strongest compression-fracture strength, followed by 516FR, 516F45, specimens. Did not show significant differences between 516FR and 516F45. 516C of the universal testing machine the specimen's surface that are within the vertical load is small, finite element method of a uniformly distributed load, so the value received suggests otherwise. Conclusion: In conclusion, abutments of monolithic ziconia ceramic when having a same thickness of the occlusal, as the angle of occlusal edge is small, the stress is well dispersed and it can endure well in the fracture.

• The Journal of Advanced Prosthodontics
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• 제13권4호
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• pp.216-225
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• 2021

PURPOSE. The aim of this study is to evaluate the effects of canine guidance occlusion and group function occlusion on the degree of stress to the bone, implants, abutments, and crowns using finite element analysis (FEA). MATERIALS AND METHODS. This study included the implant-prosthesis system of a three-unit bridge made of monolithic zirconia and hybrid abutments. Three-dimensional (3D) models of a bone-level implant system and a titanium base abutment were created using the original implant components. Two titanium implants, measuring 4 × 11 mm each, were selected. The loads were applied in two oblique directions of 15° and 30° under two occlusal movement conditions. In the canine guidance condition, loads (100 N) were applied to the canine crown only. In the group function condition, loads were applied to all three teeth. In this loading, a force of 100 N was applied to the canine, and 200-N forces were applied to each premolar. The stress distribution among all the components of the implant-bridge system was assessed using ANSYS SpaceClaim 2020 R2 software and finite element analysis. RESULTS. Maximum stress was found in the group function occlusion. The maximum stress increased with an increase in the angle of occlusal force. CONCLUSION. The canine guidance occlusion with monolithic zirconia crown materials is promising for implant-supported prostheses in the canine and premolar areas.