• Journal of Korean Dental Science
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• 제15권1호
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• pp.84-91
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• 2022

An all-on-4 restoration allows edentulous patients to use a fixed prosthesis with a minimum number of implants. These implant-supported fixed complete dentures have traditionally been fabricated as screw-retained or cement-retained prostheses. However, it is difficult to passively fit the long-span full-arch prosthesis using the screw-retained type restoration, and predictable retrievability is not obtained with the cement-retained type. This case report describes a prosthesis fabricated using a combination of the two retention types. The screwmentable method allows the implant-supported fixed complete denture to achieve a passive fit at the connection with retrievability. In addition, a framework with an optimized size was designed by using digital dental technology.

• The Journal of Advanced Prosthodontics
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• 제2권1호
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• pp.4-6
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• 2010

PURPOSE. The aim of this article is to analyze the preference for treatment modality of dentists. MATERIAL AND METHODS. Data of 20,038 patients was involved. Data analysis were done by distribution according to the various kinds of prosthesis, including complete denture, removable partial denture, fixed partial denture, implant-supported dental prosthesis as well as distribution according to the professional titles of the dentists finishing the treatment, including resident and professors. RESULTS. The number of cases of dental prosthesis increased year by year. 61.06% of the patients accepted fixed partial denture restoration. The number of patients who accepted implant supported restoration is also increasing year by year. The number of complete denture, implant-supported dental prosthesis finished by professors was larger than that done by residents, while it was contrary for removable partial denture, fixed partial denture, and the difference was statistically significant (P < .05). CONCLUSION. Professors and residents have some difference in the categorization of prosthesis finished. Fixed partial denture and implant-supported dental prosthesis are preferred.

• The Journal of Advanced Prosthodontics
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• 제11권5호
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• pp.280-285
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• 2019

PURPOSE. The present study was designed to examine the clinical fit of fixed dental prosthesis fabricated by the milling-sintering method using a presintered cobalt-chromium alloy. MATERIALS AND METHODS. Two single metal-ceramic crowns were fabricated via milling-sintering method and casting method in each of the twelve consecutive patients who required an implant-supported fixed prosthesis. In the milling-sintering method, the prosthetic coping was designed in computer software, and the design was converted to a non-precious alloy coping using milling and post-sintering process. In the casting method, the conventional manual fabrication process was applied. The absolute marginal discrepancy of the prostheses was evaluated intraorally using the triple-scan technique. Statistical analysis was conducted using Mann-Whitney U test (${\alpha}=.05$). RESULTS. Eight patients (66.7%) showed a lower marginal discrepancy of the prostheses made using the milling-sintering method than that of the prosthesis made by the casting method. Statistically, the misfit of the prosthesis fabricated using the milling-sintering method was not significantly different from that fabricated using the casting method (P=.782). There was no tendency between the amount of marginal discrepancy and the measurement point. CONCLUSION. The overall marginal fit of prosthesis fabricated by milling-sintering using a presintered alloy was comparable to that of the prosthesis fabricated by the conventional casting method in clinical use.

• 대한치과보철학회지
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• 제55권2호
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• pp.180-186
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• 2017

완전 무치악 환자에서 임플란트를 이용한 치료 방법은 환자의 삶의 질 개선에 크게 기여하였으나, 잔존골 상태나 경제력 등에 의해 임플란트의 식립 개수에 제한을 받는 상황이 종종 나타난다. 이러한 경우 일반적으로 임플란트 피개의치나 임플란트 융합 국소의치 형태로 치료계획을 세울 수 있지만, 정확한 설계를 바탕으로 양측성 캔틸레버 형태의 고정성 보철물 역시 고려해 볼 수 있다. 본 증례에서는 심한 치조골 흡수를 보이는 완전 무치악 환자에서 상악 총의치 및 하악 임플란트 지지 고정성 캔틸레버 보철물 제작을 통해 기능적, 심미적으로 양호한 결과를 얻었기에 보고하고자 한다.

• Journal of Korean Dental Science
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• 제16권2호
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• pp.105-114
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• 2023

The axial contour and proximal contact of the prosthesis affect periodontal health, food impaction, and patient satisfaction. This narrative review provides a summary of articles regarding the axial contour and proximal contact of a fixed dental prosthesis on periodontal health and physiologic function. By acquiring a comprehensive understanding of the axial contour and proximal contact of teeth and prostheses, as well as their functional significance, the virtual design of fixed dental prosthesis can be optimized to maintain periodontal health and promote physiologic function effectively.

• 대한치과보철학회지
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• 제51권3호
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• pp.221-225
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• 2013

임시 보철물의 적절한 관리는 보철의 성공에 있어서 중요한 요소이다. 상악 전치 결손부 임시 보철물은 장경간의 결손부가 존재하거나, 타원형의 악궁을 가진 환자에서 자주 탈락하게 된다. 이는 상악 전치부가 구치부에 비해서 수평적인 힘에 더 많이 노출되며, 부가적으로 전방 캔틸레버 효과가 임시 보철물의 유지를 저해하고, 상악 전치부 임시 보철물은 하악의 기능 운동시 적절한 전방 유도를 제공하여야 하기 때문이다. 또한 임시 보철물의 최대 감합위에서 교합접촉은 지점선의 반대편에 위치하게 되어 그 자체로 임시 보철물의 탈락을 야기한다. 본 증례에서는 임시 임플란트를 이용하여 상악 전치부 보철물에 대한 전술한 유해 작용을 피할 수 있었고, 발치 후 치유기간 동안 환자에게 편안함과 만족감을 부여하였으므로 이를 보고하는 바이다.

• The Journal of Advanced Prosthodontics
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• 제12권2호
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• pp.67-74
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• 2020

PURPOSE. This study evaluated the influence of prosthesis weight and number of implants on the bone tissue microstrain. MATERIALS AND METHODS. Fifteen (15) fixed full-arch implant-supported prosthesis designs were created using a modeling software with different numbers of implants (4, 6, or 8) and prosthesis weights (10, 15, 20, 40, or 60 g). Each solid was imported to the computer aided engineering software and tetrahedral elements formed the mesh. The material properties were assigned to each solid with isotropic and homogeneous behavior. The friction coefficient was set as 0.3 between all the metallic interfaces, 0.65 for the cortical bone-implant interface, and 0.77 for the cancellous bone-implant interface. The standard earth gravity was defined along the Z-axis and the bone was fixed. The resulting equivalent strain was assumed as failure criteria. RESULTS. The prosthesis weight was related to the bone strain. The more implants installed, the less the amount of strain generated in the bone. The most critical situation was the use of a 60 g prosthesis supported by 4 implants with the largest calculated magnitude of 39.9 mm/mm, thereby suggesting that there was no group able to induce bone remodeling simply due to the prosthesis weight. CONCLUSION. Heavier prostheses under the effect of gravity force are related to more strain being generated around the implants. Installing more implants to support the prosthesis enables attenuating the effects observed in the bone. The simulated prostheses were not able to generate harmful values of peri-implant bone strain.

• 대한치과보철학회지
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• 제29권1호
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• pp.1-11
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• 1991

A two dimensional finite element method was used to analyze the changes in mechanical behavior of the supporting structures when a fixed prosthesis replaced a mandibular 1st molar. In the unrestored situation as the degree of bone resorption increased, there was a corresponding increase in stress in the periodontium. Tilting of the molar abutment induced the additional stress on the mesial side of the root. The presence of a fixed prosthesis markedly reduced the magnitude and distribution of stress in the periodontium. The mechanical advantage obtained by a fixed prosthesis was greater in the situation of a tilted 2nd molar with reduced bone support than with the higher bone levels.

• 대한치과보철학회지
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• 제59권4호
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• pp.497-507
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• 2021

무치악 환자에서 잔존 치조골을 최대의 효율로 활용해 임플란트 고정성 보철물을 수복하는 치료법 중 하나로 All-on-6 개념을 사용할 수 있으나, 치료과정에서 복잡함과 번거로움이 동반된다. 나날이 발전해 온 디지털 시스템을 활용한다면 무치악 환자의 임플란트 식립부터 보철물 제작 및 수복까지 높은 효용성으로 활용할 수 있다. 본 증례에서는 76세 상악 무치악 환자의 일체형 나사 유지형 고정성 임플란트 보철 수복(1-piece design, screw retained implant fixed prosthesis)에 대해 진단부터 임플란트 식립 그리고 보철물 제작까지 전 과정에서 디지털 시스템을 활용하였다. 술전 진단에서 구강직접스캔(Direct intraoral scan)을 통해 환자의 정보를 데이터화 하였으며 이를 토대로 임플란트 식립 수술 가이드와 식립직후 장착할 즉시 임시보철물을 디자인 하였다. 최적의 잔존 치조골 위치에 식립된 6개의 임플란트 위치정보에 따라 정밀하게 제작된 즉시 임시보철물을 수복하여 술 후 사용 가능하도록 하여 환자의 불편감을 최소화하였다. 디지털 시스템을 활용하여 환자의 요구사항, 안정된 수직고경과 교합, 심미성을 고려하여 제작한 새로운 임시보철물을 거쳐 최종보철물을 디자인하고 제작하였다. 디지털 시스템을 활용하여 무치악 환자의 효율적이고 정확한 임플란트 식립부터 보철물 제작까지 전 과정에 있어서 복잡한 임플란트 치료과정을 단순화하여 환자의 불편감을 최소화시키고 기능적이고 심미적인 결과를 얻어 보고하는 바이다.

• 대한치과보철학회지
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• 제46권3호
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• pp.290-297
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• 2008

STATEMENT OF PROBLEM: Implant-supported fixed cantilever prostheses are influenced by various biomechanical factors. The information that shows the effect of implant number and position of cantilever on stress in the supporting bone is limited. PURPOSE: The purpose of this study was to investigate the effect of implant number variation and the effect of 2 different cantilever types on stress distribution in the supporting bone, using 3-dimensional finite element analysis. MATERIAL AND METHODS: A 3-D FE model of a mandibular section of bone with a missing second premolar, first molar, and second molar was developed. $4.1{\times}10$ mm screw-type dental implant was selected. 4.0 mm height solid abutments were fixed over all implant fixtures. Type III gold alloy was selected for implant-supported fixed prostheses. For mesial cantilever test, model 1-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 1-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 1-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with mesial cantilever were simulated. And then, 155N oblique force was applied to the buccal cusp of second premolar. For distal cantilever test, model 2-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 2-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 2-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with distal cantilever were simulated. And then, 206N oblique force was applied to the buccal cusp of second premolar. The implant and superstructure were simulated in finite element software(Pro/Engineer wildfire 2.0). The stress values were observed with the maximum von Mises stresses. RESULTS: Among the models without a cantilever, model 1-1 and 2-1 which had three implants, showed lower stress than model 1-2 and 2-2 which had two implants. Although model 2-1 was applied with 206N, it showed lower stress than model 1-2 which was applied with 155N. In models that implant positions of models were same, the amount of applied occlusal load largely influenced the maximum von Mises stress. Model 1-1, 1-2 and 1-3, which were loaded with 155N, showed less stress than corresponding model 2-1, 2-2 and 2- 3 which were loaded with 206N. For the same number of implants, the existence of a cantilever induced the obvious increase of maximum stress. Model 1-3 and 2-3 which had a cantilever, showed much higher stress than the others which had no cantilever. In all models, the von Mises stresses were concentrated at the cortical bone around the cervical region of the implants. Meanwhile, in model 1-1, 1-2 and 1-3, which were loaded on second premolar position, the first premolar participated in stress distribution. First premolars of model 2-1, 2-2 and 2-3 did not participate in stress distribution. CONCLUSION: 1. The more implants supported, the less stress was induced, regardless of applied occlusal loads. 2. The maximum von Mises stress in the bone of the implant-supported three unit fixed dental prosthesis with a mesial cantilever was 1.38 times that with a central pontic. The maximum von Mises stress in the bone of the implant-supported three-unit fixed dental prosthesis with a distal cantilever was 1.59 times that with a central pontic. 3. A distal cantilever induced larger stress in the bone than a mesial cantilever. 4. A adjacent tooth which contacts implant-supported fixed prosthesis participated in the stress distribution.