• 대한치과기공학회지
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• 제44권3호
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• pp.67-75
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• 2022

Purpose: This study aimed to comparatively evaluate the stress distribution of bones surrounding the implant system to which both titanium and polyetheretherketone (PEEK) abutments are applied using a three-dimensional finite element analysis. Methods: The three-dimensional implant system was designed by the computer-aided design program (CATIA; Dassault Systemes). The discretization process for setting nodes and elements was conducted using the HyperMesh program (Altair), after finishing the design of each structure for the customized abutment implant system. The results of the stress analysis were drawn from the Abaqus program (Dassault Systèmes). This study applied 200 N of vertical load and 100 N of oblique load to the occlusal surface of a mandibular first molar. Results: Under external load application, the PEEK-modeled dental implant showed the highest von Mises stress (VMS). The lowest VMS was observed in the Ti-modeled abutment screws. In all groups, the VMS was observed in the crestal regions or necks of implants. Conclusion: The bones surrounding the implant system to which the PEEK abutment was applied, such as the cortical and trabecular bones, showed stress distribution similar to that of the titanium implant system. This finding suggests that the difference in the abutment materials had no effect on the stress distribution of the bones surrounding implants. However, the PEEK abutments require mechanical and physical properties improved for clinical application, and the clinical application is thought to be limited.

• Journal of Periodontal and Implant Science
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• 제46권6호
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• pp.362-371
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• 2016

Purpose: The increasing demand for esthetically pleasing results has contributed to the use of ceramics for dental implant abutments. The aim of this study was to compare the biological response of epithelial tissue cultivated on lithium disilicate ($LS_2$) and zirconium oxide ($ZrO_2$) ceramics. Understanding the relevant physicochemical and mechanical properties of these ceramics will help identify the optimal material for facilitating gingival wound closure. Methods: Both biomaterials were prepared with 2 different surface treatments: raw and polished. Their physicochemical characteristics were analyzed by contact angle measurements, scanning white-light interferometry, and scanning electron microscopy. An organotypic culture was then performed using a chicken epithelium model to simulate peri-implant soft tissue. We measured the contact angle, hydrophobicity, and roughness of the materials as well as the tissue behavior at their surfaces (cell migration and cell adhesion). Results: The best cell migration was observed on $ZrO_2$ ceramic. Cell adhesion was also drastically lower on the polished $ZrO_2$ ceramic than on both the raw and polished $LS_2$. Evaluating various surface topographies of $LS_2$ showed that increasing surface roughness improved cell adhesion, leading to an increase of up to 13%. Conclusions: Our results demonstrate that a biomaterial, here $LS_2$, can be modified using simple surface changes in order to finely modulate soft tissue adhesion. Strong adhesion at the abutment associated with weak migration assists in gingival wound healing. On the same material, polishing can reduce cell adhesion without drastically modifying cell migration. A comparison of $LS_2$ and $ZrO_2$ ceramic showed that $LS_2$ was more conducive to creating varying tissue reactions. Our results can help dental surgeons to choose, especially for esthetic implant abutments, the most appropriate biomaterial as well as the most appropriate surface treatment to use in accordance with specific clinical dental applications.

• 구강회복응용과학지
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• 제20권1호
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• pp.1-8
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• 2004

STATEMENT OF PROBLEM: Tensile strength of metal crown cemented with provisional cement have shown clinically difference between metal abutment of implant and natural abutment. PURPOSE: This study was tested to compare the tensile strength of provisional cement on the natural abutment and metal abutment. MATERIAL AND METHODS: Out of the 20 premolars that were selected for this experiment, each 10 were prepared of abutments by chamfer and rounded shoulder margin and then duplicated to produce 20 metal abutments that were same to natural teeth. Then, crowns were fabricated to fit the total 40 natural & metal abutments to be cemented by cavitec, to be added of regular, repetitive vertical load, and to be measured of tensile strength by using Universal Test Machine. RESULTS: There was statistically significant difference in the tensile strength between the crowns cemented to the natural & metal abutments, but no statistically significant difference was observed between the chamfer and the shoulder gingival margin of the each abutments. CONCLUSIONS: Tensile strength of metal teeth is greater about 2 more times than that of natural teeth when it is cemented with Cavitec.

• The Journal of Advanced Prosthodontics
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• 제13권3호
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• pp.152-159
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• 2021

Purpose. The aim of this study was to investigate to what extent cyclic load affects the screwless implant-abutment connection for Morse taper dental implants. Materials and Methods. 16 implants (SICvantage max) and 16 abutments (Swiss Cross) were used. The screwless implant-abutment connection was subjected to 10,000 cycles of axial loading with a maximum force of 120 N. For the pull-off testing, before and after the same cyclic loading, the required force for disconnecting the remaining 6 implant-abutment connections was measured. The surface of 10 abutments was examined using a scanning electron microscope 120× before and after loading. Results. The pull-off test showed a significant decrease in the vertical force required to pull the abutment from the implant with mean 229.39 N ± 18.23 before loading, and 204.30 N ± 13.51 after loading (P<.01). Apart from the appearance of polished surface areas and slight signs of wear, no visible damages were found on the abutments. Conclusion. The deformation on the polished abutment surface might represent the result of micro movements within the implant-abutment connection during loading. Although there was a decrease of the pull-off force values after cyclic loading, this might not have a notable effect on the clinical performance.

• 대한치과보철학회지
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• 제45권6호
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• pp.753-759
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• 2007

Statement of problem. In distal extension removable partial denture, the preservation of health of abutment teeth is very important, but abutment teeth are subjected to unfavorable stress under unilateral loading specially. Purpose. The purpose of this study was to investigate the biomechanical effects of mandibular removable partial dentures with various prosthetic designs under unilateral loading, using strain gauge analysis. Material and methods. Artificial teeth of both canines were anchored bilaterally in a mandibular edentulous model made of resin. Bilateral distal extension removable partial dentures with splinted and unsplinted abutments were fabricated. Group 1: Clasp-retained mandibular removable partial denture with unsplinted abutments Group 2: Clasp-retained mandibular removable partial denture with splinted abutments by 6-unit bridge. Group 3: Bar-retained mandibular removable partial denture Strain gauges were bonded on the labial plate of the mandibular resin model, approximately 2 mm dose to the abutments. Two unilateral vertical experimental loadings (30N and 100N) were applied subsequently via miniature load cell that were placed at mandibular left first molar region. Strain measurements were performed and simultaneously monitored from a computer connected to data acquisition system. For within-group evaluations, t-test was used to compare the strain values and for between-group comparisons, a one-way analysis of variance (ANOVA) was used and Tukey test was used as post hoc comparisons. Results. The strain values of group 1 and 2 were tensile under loadings. In contrast, strain values of group 3 were compressive in nature. Strain values increased as the applied load in increased from 30N to 100N (p<.05) except for right side in group 1. Under 30N loading, in left side, group 1 showed higher strain values than groups 2 and 3 in absolute quantity (p<.05). And group 2 showed higher strain values than group 1 (p<.05). In right side, group 1 and 2 showed higher strain values than group 3 in absolute quantity (p<.05). Under 100N loading in left side, group 1 showed higher strain values than groups 2 and 3 in absolute quantity (p<.05). And group 2 showed higher strain values than group 1 (p<.05). In right side, group 1 and 2 showed higher strain values than group 3 in absolute quantity (p<.05). Under 30N loading, group 2 and 3 showed higher strain values in right side than in left side. Under 100N loading, right side strain values were higher than left side ones for all groups. Conclusion. Splinting of two isolated abutments by bridge reduced the peri-abutment strain in comparison with unsplinted abutments under unilateral loading. Bar-retained removable partial denture showed the lowest strain of three groups, and compressive nature.

• 대한치과의사협회지
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• 제23권12호통권199호
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• pp.1073-1081
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• 1985

• 구강회복응용과학지
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• 제29권3호
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• pp.209-223
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• 2013

하악 제 1대구치에 티타늄과 지르코니아 소재의 기성 지대주와 맞춤형 지대주를 이용해 지르코니아 크라운으로 수복한 경우를 3차원 유한요소법을 통해 응력 분포를 분석해 보고, 피로 파절 강도 및 파절 형태를 고찰해 보았다. 정상교합자의 CT scan을 재구성한 하악골 모형상에 제 1대구치 임플란트 지지 지르코니아 크라운으로 수복한 6가지 유한요소 모형을 제작하고, 협측 교두 중앙에 수직과 30도 각도로 100 N의 하중을 가하는 조건으로 응력분포를 분석하였다. 현재 임상적으로 사용되고 있는 4가지 지대주를 이용하여, 군당 10개의 시편을 제작하고, ISO 14801에 따라 피로파절 실험을 실시하였다. 지대주나 고정체의 재질에 따른 응력분포의 차이는 없었고 형태에 따른 응력크기의 차이만 보였다. 맞춤형 지대주 군이 전반적으로 낮은 크라운 응력을 나타내었으며, 지대주 일체형 지르코니아 임플란트는 계면 골조직의 응력이 가장 낮게 나타났다. 피로수명의 평균값은 7군이 가장 높았고, 1군, 2군, 3군의 순서로 낮게 나타났으며(P<0.05), 기성 지대주 군은 피로수명의 편차가 적게 나타났다. 구치부의 임플란트 수복 시에는 맞춤형 지대주의 사용이 상부 보철물의 파절저항성 향상에 유리하며, 심미적 요구도가 높은 경우에는 고정체와의 접합부를 티타늄으로 제작한 지르코니아 맞춤형 지대주의 사용을 고려해 볼 만 하다.

• Journal of Periodontal and Implant Science
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• 제49권1호
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• pp.58-58
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• 2019

• 대한치과보철학회지
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• 제43권1호
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• pp.95-104
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• 2005

Statement of problem. Higher stresses at the cervical bone around dental implants have been seen as a primary cause of the bone resorption at the site. Purpose : To determine the possibility of stress reduction by assembly of different abutment and implant in diameters. Material and methods. Abutments of several different diameters assembled on the top of XiVE$^{(R)}$ implants were axisymmetrically modeled for a series of finite element analyses. Abutments of 3.4, 3.8, 4.5, and 5.5 mm diameters were assumed to be sit on implants of the same or bigger diameters. All the abutments with an exception of 3.4mm dia, are technically possible to be assembled on bigger implants. Main consideration was given to the stresses at the cervical cortical bone induced by loads of parallel to the implant axis. Results and conclusions. 1. Higher stresses were observed at the cervical area of all the models of the same diameters of abutment and future. The peak stresses, which were shown to be a function of the fixture diameter, were from 1-1.85MPa. 2. Difference in the diameters of the abutments and the implants actually reduced the cervical bone stresses. 3. Downsizing of the abutment by one step resulted in 0.1MPa (5%) reduction of the stresses. In light of the relatively lower bone stress, however, this amount of stress reduction was decided to be biomechanically insignificant.

• 한국세라믹학회지
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• 제41권7호
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• pp.508-512
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• 2004

치과 임프란트의 상부구조물로 응용하기 위해 Zr $O_2$, $Y_2$ $O_3$, Nb$_2$ $O_{5}$를 각각 90.24, 5.31, 4.45mo1%씩 혼합한 정방정 지르코니아 고용체에 알루미나를 부피비로 10-90%를 10vo1%간격으로 첨가하여 (Y, Nb)-TZP/알루미나 복합체를 제조하였다. 최적의 기계적 물성은 알루미나를 10vo1% 첨가했을 때 이축 곡강도는 900MPa이었으며 파괴인성은 8.9MPam$^{1}$2/이었고 20$0^{\circ}C$ 오토크레이브하에서 10시간 열처리했을 때 저온열화가 관찰되지 않았다. 복합체를 임프란트 상부구조물로 제작하여 40명의 환자에게 총 65개를 시술한 후 2년 동안 관찰한 결과 부작용이나 나사의 풀림 또는 파절이 전혀 일어나지 않아 우수한 임상결과를 보였다.