• Journal of Korean Dental Science
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• 제15권2호
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• pp.152-161
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• 2022

Mandibular implant overdenture is a good treatment option for complete edentulous patients with restoring removable prosthesis. Mandibular implant overdenture with two implants and locator attachments is widely used. It is tissue-supported overdenture that is made with the concept of conventional complete denture fabrication. There are two patients who provided impressions by open mouth technique and closed mouth technique in each case. In both cases, mandibular implant overdentures were restored with functionally and aesthetically satisfying results.

• 대한치과보철학회지
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• 제45권5호
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• pp.633-643
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• 2007

Statement of problem: Recently there are on an increasing trend of using implants-especially in edentulous mandible of severly alveolar bone recessed. Purpose: The aim of this study was to analyze the displacement and stress distribution of various mandibular implant-retained overdenture models supported by two implants in interforaminal region under the occlusion scheme load. Material and method: FEA models were made by the 3D scanning of the edentulous mandibular dentiform. The three models were named as Model M1, M2, and M3 accord ing to the position of implants: M1, Lt. incisor area, M2, Canine area, and M3, 1st Premolar area. Inter-implant angulation model was named as M4. Conventional complete denture was named M5 and used as a control group. Ball implant and Gold matrice were used as a retentive anchors. The occlusion type loads were applied horizontally over each tooth. Results: 1. In mandibular implant retained overdenture Canine Protected Occlusion type load resulted in higher levels of stress to the implants and female matrices than other types of loads. 2. The overdenture model M1, with implants in lateral incisor areas resulted in lower stress concentration to the implants and female matrices than other models. 3. In mandibular implant retained overdenture the stresses of the implant and female matrice were lower in mesially inclined implant than these of parallel installed implant. Conclusion: Lateral incisor areas could be the best site for the implants in mandibular implant-retained overdenture. The mandibular implant retained overdenture models mentioned above showed to the lowest stress to the implants and female matrices.

• 대한치과보철학회지
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• 제28권1호
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• pp.63-94
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• 1990

The purpose of this study was to analyze the displacement and the magnitude and the mode of distribution of the stresses in the lower overdenture, the mucous membrane, the abutment tooth and the mandibular supporting bone when various denture base materials, such as acrylic resin and 0.5mm metal base, and various denture base designs were subjected to different loading schemes. For this study, the two-dimensional finite element method was used. Mandibular arch models, with only canine remaining, were fabricated. In the first denture base design, a space, approximately 1mm thick, was prepared between the denture and the dome abutment. In the second denture base design, contact between the denture and the dome abutment was eliminated except the contact of the occlusal third of the abutment. In order to represent the same physiological condition as the fixed areas of the mandible under loading schemes, the eight nodes which lie at the mandibular angle region, the coronoid process and the mandibular condyle were assumed to be fixed. Each model was loaded with a magnitude of 10 kgs on the first molar region(P1) and 7 kgs on the central incisal region (P2) in a vertical direction. Then the force of 10 kgs was applied distributively from the first premolar to the second molar of each model in a vertical direction(P3). The results were as follows. : 1. When the testing vertical loads were given to the selected points of the overdenture, the overdenture showed the rotatory phenomenon, as well as sinking and the displacements of alveolar ridge, abutment and lower border of mandible under the metal base overdenture were less than those under the acrylic resin overdenture. 2. The maximum principal stresses(the maximum tensile stresses) being considered, high tensile stresses occured at the buccal shelf area, the posterior region of the ridge crest and the anterior border region of the mandibular ramus. 3. The minimum principal stresses(the maximum compressive stresses) being considered, high compressive stresses occured at the inferior and posterior border region of the mandible, the mandibular angle and the posterior border region of the mandibular ramus. 4. The vertical load on the central incisal region(P2) produced higher equivalent stress in the mandible than that on any other region(P1, P3) because of the long lever arm distance from the fixed points to the loading point. 5. Higher equivalent stresses were distributed throughout the metal base overdenture than the resin base overdenture under the same loading condition. 6. The case of occlusal third contact of the abutment to the denture produced higher equivalent stresses in the abutment, the mandibular area around the abutment and the overdenture than the case of a 1mm space between the denture and the abutment. 7. Without regard to overdenture base materials and designs, the amounts and distribution patterns of equivalent stresses under the same loading condition were similar in the mucous membrane.

• 대한치과보철학회지
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• 제46권4호
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• pp.359-371
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• 2008

연구목적: 본 연구에서는 하악의 동일한 부위에 4개의 임플랜트를 식립하여 임플랜트 피개의치를 설계하는 경우, 바 구조와 이중관 구조 간의 응력분포에 대해 비교 분석하고자 하였다. 연구재료 및 방법: 하악골, 하악골에 식립한 4개의 임플랜트, 일차고정의 바 연결 상부구조, 이차고정의 이중관 상부구조를 삼차원 유한요소 모델링하였고, 상부 구조물에 최대 교두 감합위를 재현하는 수직하중과 측방운동시 작업측의 군기능을 재현하는 경사하중을 가하고, 최대 응력과 응력분포를 하악골, 임플랜트 지대주, 임플랜트 상부 구조물에서 분석하였다. 결과: 1. 악골에서의 최대 응력값은 경사하중을 제외하고 수직하중과 작업측 경사하중에서 이중관 구조가 바 구조에 비해 다소 적은 응력값을 보였다. 이중관 구조가 바 구조에 비해 비교적 악골 전체에 고르게 응력이 분포되었다. 2. 지대주에서는 모든 하중 조건에서 이중관 구조가 바 구조에 비해 낮은 응력값을 보였다. 응력 분포 양상은 두 구조에서 모두 비슷한 양상을 나타내었으며, 최후방 지대주의 원심면에 응력이 집중되었다. 3. 상부구조물에서는 모든 하중 조건에서 이중관 구조가 바 구조에 비해 높은 응력값을 나타냈다. 그러나, 바 구조에서는 바의 각 중심부와 지대주와의 연결부위, 지대주의 치경부에 응력이 집중된 반면, 이중관 구조에서는 상부 구조물 전체에 비교적 고른 응력 분포를 보였다. 결론: 본 연구 결과 이중관 구조가 바 구조보다 악골과 지대주에서는 더 낮은 응력을, 상부 구조물에서는 더 큰 응력을 나타냈다. 상부 구조물에 비교적 크게 전달되는 응력을 견딜 수 있는 상부구조물의 설계와 재료 선택만 이루진다면, 응력분포 면에서 이차고정을 하는 이중관 구조가 일차 고정하는 바 구조에 비해 유리하리라 생각된다.

• 구강회복응용과학지
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• 제31권3호
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• pp.242-252
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• 2015

무치악 환자에서는 치아가 상실되면서 주위 치조골의 개조와 흡수가 일어나고, 이에 따라 총의치의 유지력 감소, 저작 효율의 저하와 통증으로 인해 의치 사용에 어려움을 겪게 된다. 이를 개선하기 위해 하악에 2 - 4개의 임플란트를 식립하고 어태치먼트에서 유지 또는 지지를 얻는 피개의치가 바람직한 치료 방법으로 고려되고 있다. 본 증례들은 하악 완전 무치악 환자들을 악간 관계, 골흡수 정도, 안모지지 등을 평가하여 하악에 2개의 임플란트 식립을 고려하고, 다양한 종류의 어태치먼트를 이용한 임플란트 피개의치 수복을 계획하여 치료하였다. 주기적인 경과 관찰 결과 심미적, 기능적으로 만족할만한 결과를 얻었기에 이를 보고하는 바이다.

• The Journal of Advanced Prosthodontics
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• 제6권4호
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• pp.245-252
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• 2014

PURPOSE. To present a literature review on implant overdentures after a brief survey of bone loss after extraction of all teeth. MATERIALS AND METHODS. Papers on alveolar bone loss and implant overdentures have been studied for a narrative review. RESULTS. Bone loss of the alveolar process after tooth extraction occurs with great individual variation, impossible to predict at the time of extraction. The simplest way to prevent bone loss is to avoid extraction of all teeth. To keep a few teeth and use them or their roots for a tooth or root-supported overdenture substantially reduces bone loss. Jaws with implant-supported prostheses show less bone loss than jaws with conventional dentures. Mandibular 2-implant overdentures provide patients with better outcomes than do conventional dentures, regarding satisfaction, chewing ability and oral-health-related quality of life. There is no strong evidence for the superiority of one overdenture retention-system over the others regarding patient satisfaction, survival, peri-implant bone loss and relevant clinical factors. Mandibular single midline implant overdentures have shown promising results but long-term results are not yet available. For a maxillary overdenture 4 to 6 implants splinted with a bar provide high survival both for implants and overdenture. CONCLUSION. In edentulous mandibles, 2-implant overdentures provide excellent long-term success and survival, including patient satisfaction and improved oral functions. To further reduce the costs a single midline implant overdenture can be a promising option. In the maxilla, overdentures supported on 4 to 6 implants splinted with a bar have demonstrated good functional results.

• 대한치과보철학회지
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• 제35권3호
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• pp.577-608
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• 1997

The purpose of this study is to evaluate the stress distribution in the bone around dental implants supporting mandibular overdenture according to the number of implant and the type of attachment. Two or four implants were placed in an edentulous mandibular model and three dimensional photoelastic stress analysis was carried out to measure the fringe order around the implant supporting structure and also to calculate principal stress components at cervical area of each implant. The attachments tested were rigid and resilient type of Dolder bar, Round bar, Hader bar and Dal-Ro attchment. The results were as follows ; 1. In 2-implant supported overdenture using Round bar, Hader bar, and Dal-Ro attachment, compressive stress pattern was observed on the supporting structure of implant on loaded side, while tensile stress pattern in unloaded side. 2. In 2-implant supported overdenture using Dolder bar, the rigid Dolder bar shared the occlusal loads between 2 implants in a more favorable manner than was exhibited by the resilient type, while the resilient type placed a more stress on the distocervical area of the implant on the loaded side. But compressive stress pattern was observed in both the loaded and unloaded sides in either case. 3. In 2-implant supported overdenture, rigid and resilient type of Dolder bar exhibited more cross arch involvement than the Round bar, Hader bar, or Dal-Ro attachment. 4. In 4-implant supported overdenture using resilient Dolder bar and Hader bar, stress turned out to be distributed evenly among the implants between loaded and unloaded side, but thor was no reduction in the magnitude of the stress in the surrounding structure of implant contratry to 2-implant supported overdenture. 5. The stress pattern at cervical area of implant was different with the number of implant or the type of attachment but the overload, harmful to surrounding structure of implant, was not observed.

• 대한치과보철학회지
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• 제38권1호
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• pp.98-107
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• 2000

Three linear strain gauges (KFR-02N-120-C1-23, Kyowa, Japan) were placed around the abutment of implant future and the maximum axial loads on the mandibular implants supporting over dentures were registered in experimental model when the overdenture was removed. The overdenture attachments used in this study were Round bar Hader bar, Dolder bar with and with out spacer. The retention of bar attachment was measured using universal testing machine while being con-trolled by Activating set and Deactivator except in case of the Hader bar. Simultaneously strains were recorded with the strain smart program in strain P-6000 series (Measurement group, Raleigh, USA). The maximum axial load was calculated and compared with each other. The results were as follows: 1. The amount and the timing of the maximum axial loads were different between the right and left implant in all attachment systems. 2. The retention of bar attachment except Hader bar could be adjusted but the controllability was different among the attachment systems. 3. The more the axial load, the higher the retention with Hader bar and Dolder bar without spacer. but the tendency of increase was not shown with round bar and Dolder bar with spacer.

• The Journal of Advanced Prosthodontics
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• 제4권4호
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• pp.254-258
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• 2012

Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar$^{(R)}$ is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar$^{(R)}$ was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar$^{(R)}$ system in a mandibular edentulous patient.

• 대한치과보철학회지
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• 제60권4호
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• pp.339-346
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• 2022

전통적인 총의치와 비교했을 때 하악 임플란트 피개의치는 2개의 임플란트로도 좋은 지지와 유지를 얻을 수 있다는 장점이 있다. 2개의 임플란트를 이용하여 하악 임플란트 피개의치를 제작할 때는 정확한 위치에 임플란트를 식립하는 것이 중요하다. 2개의 임플란트를 교합평면에 수직 방향으로, 견치 자리에 서로 평행하게 식립해야 피개의치의 장기적인 예후에 좋다. 하지만 무치악 환자에서 2개의 임플란트를 올바른 위치에 식립하는 것은 어려운 일이며, 이 때 서지컬 가이드를 이용한다면 보철적으로 유리한 위치에 임플란트를 식립하는데 도움을 받을 수 있다. 본 증례는 57세 남환으로 치주질환으로 인해 상, 하악의 모든 치아가 발거된 상태로 본원에 내원했다. 이에 상악은 전통적인 총의치, 하악은 2개의 임플란트를 이용한 임플란트 피개의치로 수복하여 기능 및 심미적으로 만족스러운 결과를 얻었으므로 이를 보고하고자 한다.