• 대한치과보철학회지
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• 제43권6호
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• pp.727-735
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• 2005

Statement of problem. Platform switching in implant prosthesis has been used for esthetic and biological purpose. But there are few reports for this concept. Purpose. The purpose of this study is evaluation of platform switching in wide implant by three dimensional finite element analysis. Materials and Methods. The single implant and prosthesis was modeled in accordance with the geometric designs for Osstem implant system. Three-dimensional finite element models were developed for (1) a wide diameter 3i type titanium implant 5 mm in diameter, 13 mm in length with wide cemented abutment, titanium alloy abutment screw, and prosthesis (2) a wide diameter 3i type titanium implant 5 mm in diameter, 13 mm in length with regular cemented abutment, titanium alloy abutment screw and prosthesis(platform switching) was made for finite element analysis. The abutment screws were subjected to a tightening torque of 30 Ncm. The amount of preload was hypothesized to 650N, and round and flat type prostheses were loaded to 200 N. Four loading offset point (0, 2, 4, 6 mm from the center of the implants) were evaluated. Models were processed by the software programs HyperMesh and ANSA. The PAM-CRASH 2G simulation software was used for analysis of stress. The PAM-VIEW and HyperView were used for post processing. Results. The results from experiment were as follows; 1. von Mises stress value is increased in order of bone, abutment, implant and abutment screw. 2. von Mises stress of abutment screw is lower when platform switching. 3. von Mises stress of implant is lower when platform switching until loading offset 4 mm. 4. von Mises stress of abutment is similar between each other. 5. von Mises stress of bone is slightly higher when platform switching. Conclusion. The von Mises stress pattern of implant components is favor when platform switch ing but slightly higher in bone stress distribution than use of wide abutment. The research about stress distribution is essential for investigation of the cortical bone loss.

• 구강회복응용과학지
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• 제23권1호
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• pp.21-30
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• 2007

Despite of the successful clinical performance of implants, it is still lacking of the knowledge of changes in implant occlusion. The purpose of this study was to evaluate the changes of infraocclusal contact after clinical occlusal function of implant. Twenty patients(38 implants) were recalled during 10 months after placement of implant prosthesis. Occlusion changes were investigated at placement, placement 1 months, 4 months and 10 months serially with silicone bite material and T-Scan II sensor. Bony changes were also evaluated with periapical radiographs. The changes of silicone thickness and T-Scan II sensored areas were statistically analyzed with repeated measured ANOVA and the Scheffe's post-hoc test at the 95% significance level. The following results have been made based on this study: 1. Alveolar bone loss was within 0.20mm and it was generally concluded within physiologic level. 2. There were no statistically significant differences in the thickness changes of silicone material at 1 month and 4 months of occlusal function. However, there was statistically significant difference at 10 months of occlusal function (p<0.05). 3. There was no statistically significant difference in changes of occlusal contact area in T-Scan II at 1 month and 4 months of occlusal function, but there was statistically significant difference at 10 months of occlusal function (p<0.05). Conclusively, as time goes by, implant occlusion to be formed infraocclusion was to be far close and increased occlusal contact. However, it was not observed destructive bone resorption in periapical radiographs and any other side effects.

• Structural Engineering and Mechanics
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• 제57권4호
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• pp.717-731
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• 2016

In orthopedic surgery and more especially in total arthroplastie of hip, the fixing of the implants generally takes place essentially by means of constituted surgical polymer cement. The damage of this materiel led to the fatal rupture and thus loosening of the prosthesis in total hip, the effect of over loading as the case of tripping of the patient during walking is one of the parameters that led to the damage of this binder. From this phenomenon we supposed that a remain of bone is included in the cement implantation. The object of this work is to study the effect of this bony inclusion in the zones where the outside conditions (loads and geometric shapes) can provoke the fracture of the cement and therefore the aseptic lousing of the prosthesis. In this study it was assumed the presence of two bones -type inclusions in this material, one after we analyzed the effect of interaction between these two inclusions damage of damage to this material. One have modeled the damage in the cement around this bone inclusion and estimate the crack length from the damaged cement zone in the acetabulum using the finite element method, for every position of the implant under the extreme effort undergone by the prosthesis. We noted that the most intense stress position is around the sharp corner of the bone fragment and the higher level of damage leads directly the fracture of the total prosthesis of the hip.

• 구강회복응용과학지
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• 제31권2호
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• pp.126-133
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• 2015

염증에 의해 파괴된 치주조직은 외과적 방법만으로 조직의 완전한 재생과 심미수복을 이루는 것이 어렵다. 특히, 임플란트와 관련된 문제라면 심미성의 향상을 얻기가 더욱 어렵다. 23세 여자 환자가 비심미적인 전치부 임플란트 보철물을 개선하고자 내원하였다. 개인 치과의원에서 수차례 치조골 이식술과 연조직 이식술을 받았으나 실패한 상태였다. 염증을 제거하고 심미성을 향상시키기 위해 유리치은이식술 시행 후 골유도재생술과 혈관개재 골막결합조직 이식술(vascularized interpositional periosteal connective tissue graft)을 이용한 치조제증대술을 시행하였다. 심미적 보철물 제작을 위해 임플란트 지지형 보철물 대신 인접 자연치를 이용한 전통적인 고정성 보철물을 선택하였다. 상악 전치부 치열에서 비심미적인 임플란트 보철물을 외과적 그리고 보철적 접근을 통한 다각적 방법을 병용함으로써 더 우수한 심미성을 회복한 증례를 소개하고자 한다.

• 대한치과보철학회지
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• 제29권1호
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• pp.167-213
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• 1991

The successful replacement of missing teeth has been one driving aim behind the emergence of implant dentistry as both a technology and clinical vocation for over four decades. To date, a multitude of dental implant devices had been designed and utilized in the patient population. Most of these devices have been designed without support of the engineering criteria. The long-term success of any dental implant is dependent upon the optimization of stresses which occurs during oral function and parafunction. Although many studies have examined the biologic interactions between dental implants and living tissue, few studies have been reported on the biomechanical aspects of dental implants. The purpose of this study was to analyze the stress distribution of osseointegrated prosthesis on certain conditions, such as amount of load, location of load, length of fixtures, number of fixtures used, arch shape, bone quality, etc. Three dimentional finite element analysis was used for this study. FEM models were created using commercial software(Super SAP. for IBM 16 bit AT computer. All elements were 8-node brick, isoparametric. Mandible and prosthesis was modeled with 780 elements and 1074 nodes. The results were as follows : 1. In case of cantilever extension, there was a compressive stress at the base of the first implant and a tensile stress at the base of the second implant. 2. The stresses were linearly proportional to the amount of load. 3. The stresses were linearly proportional to the length of cantilever. 4. There was a stress concentration at the neck of the implant and bone under horizontal loads.

• 대한치과보철학회지
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• 제56권1호
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• pp.88-94
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• 2018

최근 치과치료의 영역에서 디지털 임플란트 시스템은 그 영역을 넓혀 나가고 있다. 디지털 장비들의 기술적 발전에 힘입어 한계점들이 하나 둘씩 극복되었다. 초기 단일치아 수복 정도에나 사용되었던 디지털 임플란트 시스템은 임플란트 수술에서부터 보철물 제작까지 무치악의 영역에서도 사용되고 있다. 본 증례에서는 50세의 하악 무치악 환자가 임플란트를 이용한 교합 재건을 원하였다. 하악의 임플란트 수복을 위해서 "All-on-4" 개념의 디지털 임플란트 시스템 사용을 계획하였고, 무절개 수술을 위한 가이드 장치를 제작하여 수술을 시행하였다. 수술 후, 전악 보철을 디지털 장비를 이용하여 제작하였다. 전체 치료 과정에서 기존의 아날로그 방식(인상채득, 납형 제작, 주조 등)을 가능한 배제하고 디지털 시스템을 이용하여 기공과정 및 임상과정을 최소화하기로 계획하였고 만족할만한 결과를 얻었기에 보고하는 바이다.

• 대한치과보철학회지
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• 제59권4호
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• pp.469-477
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• 2021

상악 전치부 임플란트의 성공적인 수복을 위해서는 pink esthetics와 white esthetics가 모두 충족되어야 한다. Pink esthetics 부분의 경우 적절한 임시보철물의 역할이 중요하고, white esthetics 부분의 경우에는 최종 보철물의 색상과 형태가 중요하다. 다층 지르코니아는 기존의 단일구조 지르코니아에 비해 절단 부위의 투명도가 높기 때문에 추가적인 도재 축성 없이 자연스러운 보철물 제작이 가능하다. 따라서 본 증례에서는 상악 전치를 상실한 환자에서 적절한 임시보철물을 통해 기능과 심미성을 충분히 회복한 후 다층 지르코니아를 통해 white esthetics를 달성하였다.

• 대한치과보철학회지
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• 제55권3호
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• pp.300-304
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• 2017

자연치열에 대합하는 완전 무치악 환자의 수복에서 임플란트를 이용한 고정성 보철물 또는 임플란트 피개의치는 좋은 치료법이다. 그러나, 완전 고정성 보철을 통한 치료는 충분한 골질, 골량이 뒷받침되어야 하기에 그 한계가 있다. 한편, 최근에는 임플란트 고정성 보철물과 함께 그것을 가철성 국소의치의 지대치로 사용하는 치료가 행해지고 있다. 본 증례보고는 자연치열에 대합되는 두 상악 완전 무치악 환자에 있어 임플란트 피개의치와 임플란트 고정성 보철물 및 가철성 국소의치를 이용한 치료 및 8년 경과관찰, 유지보수를 비교 고찰해 보고자 한다.

• 대한치과의사협회지
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• 제55권7호
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• pp.457-466
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• 2017

In the case of failed fixed implant prosthesis accompanied by abutment screw fracture, fractured screw fragment must be removed to use the existing implant fixtures. A 61-year-old male patient, who had a failed maxillary fixed implant prosthesis accompanied by three abutment screw fracture, hoped to reconstruct the maxillary implant prosthesis, while maintaining the existing implant fixtures. To use the existing implant fixtures, fractured screw fragments were removed. A maxillary implant overdenture using available existing implants was planned. Bar-attachment with Locator was used for implant splinting, denture stability, and retention. Final impression was taken after treatment of peri-implantitis. Jaw relation registration was taken to evaluate available interarch space for bar-attachment. After fabricating bar-attachment, centric relation was taken. Implant overdenture using bar-attachment with Locator was delivered after wax-denture evaluation. This case report showed that a satisfactory clinical result was achieved by implant overdenture using existing implant fixtures in a maxillary edentulous patient.

• 대한치과보철학회지
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• 제57권2호
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• pp.171-175
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• 2019

치조제가 심하게 흡수된 하악의 정확한 해부학적 구조를 채득하는 것은 매우 어렵다. 이 경우 보다 정확한 인상을 채득하기 위하여 수정모형 제작법을 통한 기능 인상 채득이 추천된다. 이를 위해서는 양측에 2개의 임플란트 크라운을 이용하여 적절한 고정원을 얻을 필요가 있다. 이를 통해 임플란트 피개의치에서는 불가능하였던 수정모형 제작법을 시행할 수 있다. 본 증례에서는 하악의 치조제가 심하게 흡수된 80세 여환을 하악 양측 견치 부위의 임플란트 크라운을 지대치로 한 가철성 국소의치를 이용하여 수복하였다. 가철성 국소의치의 금속구조물을 이용하여 개인 트레이를 제작하고 수정모형 제작을 위한 이차 인상을 채득하였다. 환자는 앞선 2회의 피개의치 실패 후 제작된 최종 보철물에 만족하였다. 치료 초기에 행해진 피개의치 치료에서는 부정확한 인상법에 따른 부적절한 보철물로 인해 술자와 환자 모두 만족하지 못했지만, 2개의 임플란트를 적절한 고정원으로 이용함으로써 성공적인 수복이 가능하였다.