• Steel and Composite Structures
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• 제27권6호
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• pp.727-745
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• 2018

The design criteria and the corresponding performance levels characterize the response of extended stiffened end-plate beam-to-column joints. In order to guarantee a ductile behavior, hierarchy criteria should be adopted to enforce the plastic deformations in the ductile components of the joint. However, the effectiveness of thesecriteria can be impaired if the actual resistance of the end-plate material largely differs from the design value due to the potential activation of brittle failure modes of the bolt rows (e.g., occurrence of failure mode 3 in the place of mode 1 per bolt row). Also the number and the position of bolt rows directly affect the joint response. The presence of a bolt row in the center of the connection does not improve the strength of the joint under both gravity, wind and seismic loading, but it can modify the damage pattern of ductile connections, reducing the gap opening between the end-plate and the column face. On the other hand, the presence of a central bolt row can influence the capacity of the joint to resist the catenary actions developing under a column loss scenario, thus improving the joint robustness. Aiming at investigating the influence of these features on both the cyclic behavior and the response under column loss, a wide range of finite element analyses (FEAs) were performed and the main results are described and discussed in this paper.

• 대한치과보철학회지
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• 제47권2호
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• pp.125-135
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• 2009

연구목적: 임플란트 치료에서 흔히 발생하는 기계적인 문제점을 하나가 지대주나사의 풀림과 파절이다. 일반적으로 나사 연결의 안정성을 위해서는 지대주나사의 조임회전력에 의한 전하중을 나사의 탄성한계까지 증가시킬 필요가 있다. 그러나 저작운동에 의한 기능부하는 전하중이 가해진 지대주나사에 추가적인 인장력을 가하게 되어 나사의 풀림이나 파절의 가능성을 높인다. 이러한 풀림이나 파절을 방지하면서 동시에 최대의 결합 강도를 가지는 조임회전력을 찾는 연구가 필요하다. 본 연구는 지대주나사의 조임회전력이 임플란트-지대주 연결부 안정성에 미치는 영향을 3차원 유한요소 분석을 통하여 확인하고자했다. 연구 재료 및 방법: External butt joint를 가진 임플란트를 기반으로 3차원 유한요소 해석모형을 설계하였다. 조임회전력에 따른 지대주나사의 전하중을 이론치, 실험치 및 해석치를 비교하여 해석모형을 검증하였다. 검증한 해석모형에서 대해 조임회전력을 10 Ncm, 20 Ncm, 30 Ncm, 그리고 40 Ncm로 각각 적용하고 지대주에 30도 경사지게 250 N의 외부하중을 가하여 유산요소 해석을 실시하였다. 그 결과를 통해 지대주나사의 최대 등가응력을 계산하고 고정체와 지대주 연결부의 응력분포 및 이개거리(gap distance)를 산출하였다. 결과 및 결론: 본 연구조건 하에서 다음과 같은 결과를 얻었다. 1. 전하중은 조임회전력이 클수록 증가하였다. 2. 조임회전력 적용 후 최대 등가응력은 지대주나사 경부에서 발생하였으며, 나사산 체결부에서는 주로 경부쪽 네 개의 나사산에 응력이 집중되었다. 3. 외부하중을 가했을 때에도 조임회전력을 적용했을 때와 동일하게 최대 등가응력은 주로 지대주나사 경부에서 발생하였으나, 10 Ncm의 조임회전력을 적용한 경우에서는 지대주나사 두부밑면에서 발생하였다. 4. 외부하중을 가했을 때 10 Ncm와 20 Ncm의 조임회전력을 적용한 경우에서는 연결부 이개(joint opening) 현상이 관찰 되었다. 5. 조임회전력이 40 Ncm인 경우에는 경사하중에 의해 지대주나사의 경부에 발생하는 최대등가응력이 나사의 소재인 티타늄 합금의 허용응력을 초과하였다. 이상의 결과로 볼 때, 조임회전력은 고정체와 지대주 연결부의 안정성에 영향을 미치는 것이 확인되었다. 임플란트 지대주나사는 임상에서 발생하는 기능 하중을 고려하여 고정체와 지대주 연결의 안정성을 유지할 수 있는 적정 조임회전력의 크기가 제안되어야 한다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제19권2호
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• pp.157-166
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• 1997

Treatment of condylar fracture is still controversial, but the indication of surgical mangement is increased due to improved fixation methods and surgical techniques. In this article, we report our clinical and radiological results with the use of lag screw osteosynthesis for fixation of fractured mandibular condyle. 12 case of condyle fracture treated by open reduction and fixation with lag screw were monitored for an average of 10 months (range from 6 months to 19 months) postoperatively. The obtained results are as follows : 1. Postoperative maximum mouth opening is achieved over 40mm except one patient. 2. Although slight crepitus and deviation of mandible during mouth opening were found, Temporomandibular joint problem is satisfactory in all but one patient. 3. Distal migration of screw and resorption of fractured fragment were found in each 2 patients, but good functional recovery was achieved in all. According to the above results, we think that lag screw osteosynthesis is relatively indicated in level III or IV condylar fracture.

• 대한치과의사협회지
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• 제46권5호
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• pp.308-314
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• 2008

The risk of temporomandibular joint disorder (TMD) can be increased during dental treatment due to excessive mouth opening and change of occlusion. The aim of this study is to find the relationship between dental treatment and TMD in the patients who developed TMD after dental treatment. The subjects of this study were 21 patients, who developed TMD after dental treatment and were treated with active TMD therapy in Seoul National University Bundang Hospital from June 2003 to February 2007. The subjects were examined with preceding dental treatment, symptom, diagnosis, treatment method of TMD and prognosis of TMD. The obtained results were as follows. 1. Preceding dental treatments were : Implant treatment, 14 cases ; Tooth extraction, 3 cases and others. 2. TMD symptoms were : pain on TMJ, 12cases : Sound on TMJ, 3cases ; Mouth opening limitation, Headache and others. 3. Diagnoses of TMD were : Synovitis and/or capsulitis, 10 cases ; 8 cases of Internal derangement and others. 4. Most TMD were treated by stabilization splint. 5. Prognoses of TMD were : Improvement, 6cases ; sustained 11 cases. In conclusion, the risk of TMD is increased during implant treatment. Prognoses of TMD after dental treatment were bad. It might be that these patients were non-cooperative and have distrust of dental treatment. Because the overloading on TMJ is possible in dental treatment of patients with underlying TMD, prior explanation and knowledge TMJ treatment are very important in these cases.

• 대한두개안면성형외과학회지
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• 제9권2호
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• pp.51-54
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• 2008

Purpose: The choice of open versus closed reduction for mandibular subcondylar fracture is a debatable issue. To evaluate the advantage of open approach to closed method with IMF(intermaxillary fixation), we conducted a retrospective study to compare the outcomes of each method. Methods: From 2002 to 2006, 29 patients with mandibular subcondylar fractures were treated by open or closed reduction. 17 patients were treated by open reduction and 12 patients by closed reduction and IMF. Each group was assessed for duration of mandibular immobilization, incidences of buccal palsy, malocclusion, TMJ(temporomandibular joint) pain, and deviation of the mandible on mouth opening. Results: All cases showed accurate reduction in anatomical position, no significant displacement and no deviation on mouth opening during the follow-up period. IMF period is statistically shorter in open reduction (p<0.05). Differences in incidence of other complications were not significant statistically. Conclusion: As there are significant independent morbidities associated with IMF which requires postoperative rehabilitation, prolonged temporomandibular immobilization should not be overlooked. Some patients with poor compliances will not tolerate IMF in nonsurgical treatment. In the aspect of patient's convenience and early recovery by short IMF period, open reduction would be recommended as a better treatment method.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권1호
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• pp.55-65
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• 2005

Most patients with temporomandibular disorder can be treated conservatively. However, open TMJ surgery can be needed in some patients. We analysed the patients with TMD which open surgery has performed since 1998. Open surgery was carried out in 8 patients. Age ranged from 22 to 61 years, with a mean of 42.8years. All patients were male. Final diagnosis was obtained based upon clinical, radiographic and operative finding as follows; habitual luxation, bony ankylosis, traumatic arthritis, disc displacement with destructive change, disc displacement and adhesion. Etiologic factors included trauma(4), infection(2), and unknown(2). Open surgery included arthroplasty with either of condylectomy, eminectomy, meniscoplasty, capsurrohaphy. All patients were recovered uneventfully without severe complications. Some mouth opening limitation and mouth opening deviation remained. Postoperative aggressive physical therapy and careful follow up were performed. In conclusion, open TMJ surgery must be considered in organic disease such as ankylosis, tumor and TMD without favorable recovery after long-term conservative therapy.

• 한국디지털건축인테리어학회논문집
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• 제13권2호
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• pp.35-43
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• 2013

The green building is one of biggest factors to go the goal of energy saving and environmental conservation, "reduction of energy consumption, friendly energy technology, recycling of resource, and environmental pollution reduction technology. The purpose of these green buildings realized by the energy-saving technology such as the thermal bridge breaker(or thermal bridge block). Thermal bridges are localized elements that penetrate insulated portions of building envelope that results in heat loss. The purpose of this paper is to describe the technical interactions for patents of a thermal bridge breaker(TTB) used in green building practices, and be subject to investigation to TTB in the leading countries, that is, United State, Europe Union, Japan, and Korea. As a result, there are four TTB categories(roof, wall-slab connection, opening, footing) in house or building. The TTB categories is remarkable technology that is apparatus in slab-wall joints and sealing element of opening frame in walls.

• Imaging Science in Dentistry
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• 제38권2호
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• pp.89-93
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• 2008

Purpose: To evaluate the difference of the movement of the mandibular condyles between trans cranial and panoramic TMJ radiographs to view the movement of the mandibular condyles. Materials and Methods: Thirty-four paired transcranial and panoramic TMJ radiographs of patients were used to evaluate the movement of the mandibular condyle. The distances, from the most superior point of the mandibular condyle to the most inferior point of the articular eminence on both radiographs, were measured. The measurements were taken at closed state and maximum opening state of each radiograph on both side. Differences between matched pairs were analysed by paired t-test, with significance established at P<0.05. Results and Conclusion: The mean distance, from the most superior point of the mandibular condyle to the most inferior point of the articular eminence on both radiographs, was statistically different at each side (P<0.05). At closing state, the mean distance measured on panoramic TMJ radiographs was longer than on transcranial radio-graphs (0.85 mm at right side, 1.20 mm at left side). But at maximum opening state, the mean distance on transcranial radiographs was longer (1.00 mm at right side, 0.62 mm at left side) than panoramic TMJ radiographs.

• Journal of Oral Medicine and Pain
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• 제46권3호
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• pp.93-97
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• 2021

The limited mouth opening, also known as trismus, can result from temporomandibular joint disorders, infection, neoplasm, trauma, and abnormal anatomic structure like coronoid hyperplasia. Head and neck cancer patients often complain of limited mouth opening, which is usually induced by myofibrotic contracture of masticatory muscle. But clinicians should consider any reasons such as infection or cancer growth and metastasis if trismus gets worse or pain develops. We report the case of the patient, who was diagnosed with myxofibrosarcoma on nasal cavity. He had suffered from trismus after concurrent chemoradiotherapy. However, pain had developed and trismus had worsened. He was diagnosed with infratemporal space abscess and myositis of masticatory muscles.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권5호
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• pp.336-342
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• 2017

Synovial chondromatosis is a rare benign lesion originating from the synovial membrane. It presents as adhesive or non-adhesive intra-articular cartilaginous loose bodies. Although the causes of synovial chondromatosis have not been fully elucidated, inflammation, external injury, or excessive use of joints have been suggested as possible causes. Synovial chondromatosis has been reported to occur most frequently at large joints that bear weights, with a rare occurrence at the temporomandibular joint (TMJ). When synovial chondromatosis develops at TMJ, clinical symptoms, including pain, joint sounds, and mouth opening may common. Moreover, synovial chondromatosis rarely spreads to the mandibular condyle, glenoid cavity, or articular eminence of TMJ. The goal of this study was to discuss the methods of surgery and other possible considerations by reviewing cases of patients who underwent surgery for synovial chondromatosis that extended to the temporal bone.