• 대한치과기공학회지
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• 제29권1호
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• pp.93-101
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• 2007

The purpose of this study is to evaluate the effect of three different oblique mechanical loading to occlusal surfaces of posterior implant partial dentures on the stress distributions in surrounding bone, using 3-dimensional finite element method. A 3-dimensional finite element model of a posterior implant partial dentures composed of three unit implants, simplified 3 gold alloy crown and supporting bone was developed according to the design of AVANA self tapping implant for this study. Three kinds of surface distributed oblique loads(300 N) are applied to following occlusal surfaces in the three crowns; 1) All occlusal surfaces in the three crown(load of 300 N was shared to three crown), 2) Occlusal surface of centered crown (load of 300 N was applied to a centered crown), 3) Occlusal surface of proximal crown(load of 300 N was applied to a distal proximal crown). In the results, 141 MPa of maximum von Mises stress was calculated at third loading condition and 98 MPa of minimum von Mises stress was calculated at first loading condition. From the results, location and type of occlusive loading conditions are important for the safety of supporting bone.

• 구강회복응용과학지
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• 제27권2호
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• pp.209-222
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• 2011

상실된 상악 전치부는 고정성 보철물이나 가철성 보철물 또는 임플란트 보철 등 다양한 방법을 통하여 수복할 수 있다. 이 중 적절하게 제작된 회전삽입로 국소의치는 경제적, 해부학적 한계를 가진 환자에서 기능적, 심미적으로 우수한 결과를 보일 수 있다. 회전삽입로 국소의치는 일반적 국소의치의 일직선 삽입로와는 달리 국소의치의 한 쪽 유지장치부가 먼저 장착된 뒤 회전하면서 반대쪽의 유지부가 삽입되어 의치가 안착된다. 이 때 언더컷 속에 위치하는 견고한 부연결장치에서 유지력을 획득하고 회전삽입로와 평행하게 긴 수로형 혹은 구미형(dovetail) 레스트 시트에서 지지 및 파지를 얻으므로 일반적인 가요성 유지암 및 파지암을 생략할 수 있어 심미적으로 우수하고 위생 관리에도 유리하다. 그러나 회전삽입로 국소의치에서 한번 제작된 견고한 유지부는 정교한 조절이 불가능해 상대적으로 기공작업이 어렵고 정밀한 보철물 디자인이 필요하므로 임상적인 성공을 위해서는 회전삽입로 국소의치의 원리에 대한 깊은 이해가 필요하다. 이번 증례보고는 회전삽입로 국소의치를 장착한 후 장기적인 유지관리의 어려움을 겪은 증례를 소개하고 이를 예방할 수 있는 이론적, 기공적 주의사항을 보고하고자 한다.

• 대한치과보철학회지
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• 제42권4호
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• pp.412-424
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• 2004

Statement of problem: Several prosthetic options are available for the restoration of multiple adjacent implants. A passively fitting prosthesis has been considered a prerequisite for the success and maintenance of osseointegration. Passivity is a particular concern with multiple implants because of documented inaccuracies in the casting and soldering process. One way to avoid this problem is to restore the implants individually, however, the restorations of individual adjacent impants requires careful adjustment of interproximal contacts. Purpose: The purpose of this study was to compare the stress distribution pattern and amount surrounding Bicon implants with individual crowns and splinted restorations. Material and method: A photoelastic model of a human partially edentulous left mandible with 3 Bicon implants($4{\times}11mm$) was fabricated. For non-splinted restorations, individual crowns were fabricated on 3 abutments ($4{\times}0.65mm,\;0^{\circ}$, 2.0 mm post, Bicon Inc., Boston, USA) After the units were cemented, 4 levels of interproximal contact tightness were evaluated: open, ideal ($8{\mu}m$ shim stock drags without tearing), medium($40{\mu}m)$), and heavy($80{\mu}m$). Splinted 3-unit fixed partial dentures were fabricated and cemented to the model. Changes in stress distribution under simulated non-loaded and loaded conditions(7.5, 15, 30 lb) were analyzed with a circular polaricope. Results: 1. Stresses were distributed around the entire body of fin in Bicon implants. 2. Splinted restorations were useful for distribution of stress around implants especially with higher loads. 3. By increasing the contact tightness between the individually restored three implants, the stress increased in the coronal portion of implants. Conclusions: Ideal adjustment of the contact tightness was important to reduce the stresses around individually restored Bicon implants.

• 대한치과의사협회지
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• 제55권12호
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• pp.842-849
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• 2017

The term, 'crossed occlusion' implies clinical situation in which the residual teeth in one arch have no contact with those in the antagonistic arch, resulting in the collapse of occlusal vertical dimension. The treatment goal of this pathologic condition is restoration of the collapsed vertical dimension and stabilization of abnormal mandibular position. Previously, konus removable prostheses or tooth supported overdentures were suggested to solve crossed occlusion. Nowadays, dental implants have been used for definitive support to solve this problem. In this case report, a 65 years old female patient had a crossed occlusion, in which the maxillary posterior residual teeth and mandibular anterior residual teeth cross. Interim removable and fixed dental prostheses were used to confirm the proper vertical and horizontal jaw relation. After that, the mandibular posterior edentulous region was restored with implant-supported fixed dental prostheses. Computer tomography guided implant surgery was performed according to the concept of the restoration-driven implant placement. The maxillary anterior edentulous region was restored with Kennedy class IV removable prosthesis, considering the patient's economic status. The patient's jaw position and prostheses have been well maintained at the follow-up after 6 months of definitive restoration. The antero-posterior crossed occlusion problems appeared to be effectively solved with the combination of removable in one arch and implant-supported fixed prostheses in the other.

• 대한치과보철학회지
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• 제52권1호
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• pp.42-47
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• 2014

광범위한 치아 상실과 마모로 인한 교합면의 파괴로 수직고경이 감소된 경우 안모의 변화, 전방 유도의 상실로 인한 반대 교합을 보일 수 있으며, 또한 턱관절의 문제를 발생 시킬 수도 있다. 이러한 경우 교합 수직 고경의 증가를 통한 전악 수복을 고려할 수 있으며, 적절한 환자의 수직 고경 평가가 필요하다. 본 증례는 80세의 남자 환자로 전반적인 보철계획을 주소로 내원하였으며, 치아상실 및 마모에 따른 전치부의 반대 교합과 교합 수직 고경의 감소가 관찰되었다. 진단 모형과 방사선 사진, 임상적 검사를 이용하여 교합 관계를 분석하여 교합 수직 고경 증가를 결정하였다. 진단 wax up을 시행하였고 임시 보철물을 제작하였다. 3개월의 적응 기간 후 상악 고정성 보철물과 하악 임플란트 지지 피개의치로 최종 수복하였다. 장착 후 8개월경과 관찰 중이며 양호한 심미적 기능적 개선을 보였다.

• 구강회복응용과학지
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• 제22권1호
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• pp.75-87
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• 2006

The purpose of this study was to investigate the effects of prostheses misfit, cantilever on the stress distribution in the implant components and surrounding bone using three dimensional finite element analysis. Two standard 3-dimensional finite element models were constructed: (1) 3 ITI implant supported, 3-unit fixed partial denture and (2) 3 ITI implant supported, 3-unit fixed partial denture with a distal cantilever. variations of the standard finite element models were made by placing a $100{\mu}m$ or $200{\mu}m$ gap between the fixture, the abutment and the crown on the second premolar and first molar. Total 14 models were constructed. In each model, 244 N of vertical load and 244 N of $30^{\circ}$ oblique load were placed on the distal marginal ridge of the distal molar. von Mises stresses were recorded and compared in the crowns, abutments, crestal compact bones, and trabecular bones. The results were obtained as follows: 1. In the ITI implant system, cement-retained prostheses showed comparatively low stress distributions on all the implant components and fixtures regardless of the misfit sizes under vertical loading. The stresses were increased twice under oblique loading especially in the prostheses with cantilever, but neither showed the effects of misfit size. 2. Under the oblique loading and posterior cantilever, the stresses were highly increased in the crestal bones around ITI implants, but effects of misfit were not shown. Although higher stresses were shown on the apical portion of trabecular bones, the effects by misfit were little and the stresses were increased by the posterior cantilever. 3. When the cement loss happened in the ITI implant supported FPD with misfit, the stresses were increased in the implant componets and supporting structures.