• Nuclear Engineering and Technology
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• 제20권4호
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• pp.241-245
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• 1988

핵연료봉의 PCI 파손은 원자로의 운전제한과 밀접한 관계가 있기 때문에, 출력급증 조건에서 핵연료봉의 PCI 파손을 지배하는 파손인자들의 거동을 검토하는 것은 매우 중요하다. 본 연구에서는 피복관에서의 원주방향 응력, 원주방향 변형도, 원주방향 주름 높이, 크립 변형율 및 변형도 에너지등의 파손인자들에 대한 거동특성을 핵연료봉 성능해석용 전산코드인 FEMAXI-IV를 이용하여 출력급증량 및 출력증가율의 운전인자들의 함수로 검토하였다.

• Journal of Ship and Ocean Technology
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• 제7권4호
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• pp.1-15
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• 2003

The motion of passively floating body, whose keel can have a contact with seabed soil, is under the consideration. The body simulates ice ridge floating in shallow water. The force of seabed soil reaction applied to the grounded keel is estimated taking into account soil embankment near the grounded keel. Two-dimensional trajectories of body motion, the shape of the grooves in seabed and the height of soil embankment are calculated when the motion of the body is caused by semidiurnal $M_2$ tide. The influence of wave amplitude and bottom slope on the shapes of body trajectory and the grooves are analyzed.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.45.1-45.7
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• 2016

Background: We evaluated and compared the outcomes of different ossification processes in patients with alveolar cleft in whom correction was performed using endochondral bone graft or intramembranous bone graft. Methods: The patients were divided into two groups: the endochondral bone (iliac bone or rib bone) graft group and the intramembranous bone (mandibular bone) graft group. Medical records and radiologic images of patients who underwent alveolar bone grafting due to alveolar cleft were analyzed retrospectively. Through postoperative and follow-up radiologic images, the height of the interdental bone septum was classified into four types based on the highest point of alveolar ridge. Then, the height of the interdental bone septum and the area of the bone graft were evaluated according to the type of bone graft. In addition, the occurrence of complications and the need for an additional bone graft, the result of postoperative orthodontic treatment, and the eruption of impacted teeth were investigated. Results: Thirty patients were included in this study. There was no significant difference in the change of the interdental bone height and the area of the bone graft according to the type of bone. There was no significant difference in the success rate of the surgery according to the type of bone. One patient underwent an additional bone graft surgery during the follow-up period. Conclusions: The outcomes of alveolar bone grafting were not significantly different according to the type of bone graft. If appropriate to the size of the recipient site, the chin bone is a useful graft material in alveolar cleft, as is the iliac bone.

• Journal of Periodontal and Implant Science
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• 제35권1호
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• pp.251-261
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• 2005

Alveolar ridge defects may limit or restrict placement of implants. The purpose of this study was to evaluate clinical and histopathologic results which occur following guided bone regeneration using platelet-rich plasma, bovine bone powder and e-PTFE membrane in the localized alveolar bone defects. Ten patients who required guided bone regeneration in implant placemnet, were slelected. Alveolar crest height and width were measured at baseline and, afer 2nd surgery 5 months later At 5 months , we obtained histopathological results as follows: 1. Alveolar crest height was an average of $8.20{\pm}3.74$ mm preoperatively and decreased to an average of $7.40{\pm}1.84$ mm postoperatively. There was no significant difference. 2. Alveolar crest width was an average of $4.25{\pm}2.03$ mm preoperatively and significantly increased to an average of $7.20{\pm}2.44$ mm postoperatively (P<0.01) 3. The change of Alveolar crest height and width were $0.80{\pm}1.40$ mm, $2.95{\pm}1.09$ mm 4. Histopathological evaluations revealed new bone formation with graft material and laminated bone containing the presence of osteocyte-like cell In conclusion, guided bone regeneration using platelet-rich plasma, bovine bone powder and e-PTFE membrane would provide a viable therapeutic alternative for implant placement in the localized alveolar defect or implant failure

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.32.1-32.8
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• 2018

Background: The free vascularized fibula flap presents many advantages such as sufficient length of the bony segment, good vascularization, better quality of the bone, and a long vascular pedicle, but it is also associated with some disadvantages with regard to prosthetic rehabilitation because of its limited height. Improvement in bone height is necessary for ideal dental implant treatment of reconstructed mandibles. Case presentation: For two squamous cell carcinoma patients, mandibular bone reconstruction was performed secondarily with the peroneal flap after tumor resection. Since the bone height was insufficient at the time of implant treatment, occlusion reconstruction by dental implant was performed after vertical distraction osteogenesis. Conclusions: Vertical distraction osteogenesis is a suitable treatment option for alveolar ridge deficiency resulting from fibula transplantation for mandibular reconstruction following tumor surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제49권6호
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• pp.347-353
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• 2023

This case report presents inferior alveolar nerve (IAN) repositioning as a viable approach for implant placement in the mandibular molar region, where challenges of severe alveolar bone width and height deficiencies can exist. Two patients requiring implant placement in the right mandibular molar region underwent nerve transposition and lateralization. In both cases, inadequate alveolar bone height above the IAN precluded the use of short implants. The first patient exhibited an overall low alveolar ridge from the anterior to posterior regions, with a complex relationship with adjacent implant bone level and the mental nerve, complicating vertical augmentation. In the second case, although vertical bone resorption was not severe, the high positioning of the IAN within the alveolar bone due to orthognathic surgery raised concerns regarding adequate height of the implant prosthesis. Therefore, instead of onlay bone grafting, nerve transposition and lateralization were employed for implant placement. In both cases, the follow-up results demonstrated successful osseointegration of all implants and complete recovery of postoperative numbness in the lower lip and mentum area. IAN repositioning is a valuable surgical technique that allows implant placement in severely compromised posterior mandibular regions, promoting patient comfort and successful implant placement without permanent IAN damage.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권6호
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• pp.570-578
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• 2006

A severely atrophic maxilla may disturb the proper implant placement. The various bone graft techniques are required for simultaneous or delayed implantation in the cases of atrophic alveolar ridges. We present 11 consecutive patients treated with simultaneous implantation using the autogenous inlay and/or onlay bone grafts from iliac crest to the floor of the maxillary sinus and the alveolar crest. In the cases of atrophic maxilla, a total 69 implants were simultaneously placed with autogenous iliac bone graft. 40 fixtures were inserted in the sinus floor simultaneously with subantral block bone graft, the other 29 fixtures were placed in the anterior or premolar areas with block or particulate bone graft. The vertical alveolar bone height was measured with Dental CT at the preoperation and 6 months postoperation. Moreover, the implant stability quotients (ISQ) were measured by $Osstell^{TM}$ during second implant surgery at 6 months later of first implantation. All implants were obtained successful osseointegration with the grafted bone. The mean vertical increases were 3.9mm in the anterior ridges and 12.8mm in the posterior ridges. During the second implant surgery, mean ISQ were 62.95 in the anterior ridge and 61.32 in the posterior ridge. We concluded that the simultaneous implantation with autogenous iliac bone graft were stable and available methods for severely atrophic maxilla.

• The Journal of Advanced Prosthodontics
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• 제6권5호
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• pp.361-371
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• 2014

PURPOSE. In case of large horizontal discrepancy of alveolar ridge due to severe resorption, cantilevered crown is usually an unavoidable treatment modality. The purpose of this study was to evaluate the clinical criteria for the placement of the aforementioned implant crown. MATERIALS AND METHODS. The mandible model with 2 mm thick cortical bone and cancellous bone was fabricated from CT cross-section image. An external connection type implant was installed and cantilevered crowns with increasing offset of 3, 4, 5, 6, and 7 mm were connected. Vertical load and $30^{\circ}$ oblique load of 300 N was applied and stress around bone and implant component was analyzed. A total of 14 cases were modeled and finite element analysis was performed using COSMOS Works (Solid works Inc, USA). RESULTS. As for the location of the vertical load, the maximum stress generated on the lingual side of the implant became larger according to the increase of offset distance. When the oblique load was applied at $30^{\circ}$, the maximum stress was generated on the buccal side and its magnitude gradually decreased as the distance of the offset load increased to 5 mm. After that point, the magnitude of implant component's stress increased gradually. CONCLUSION. The results of this study suggest that for the patient with atrophied alveolar ridge following the loss of molar teeth, von-Mises stress on implant components was the lowest under the $30^{\circ}$ oblique load at the 5 mm offset point. Further studies for the various crown height and numbers of occusal points are needed to generalize the conclusion of present study.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권5호
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• pp.421-428
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• 2011

Introduction: The purpose of this study was to evaluate the clinical result of vertical alveolar distraction, especially the distracted alveolar bone and installed implants. Materials and Methods: Twenty-one patients who have been received the vertical alveolar distraction and implant installation on 22 areas (3 maxilla and 19 mandible) using intraoral alveolar distraction device were examined. After consolidation period of 3-4 months, distraction devices were removed and 91 implants were installed in the distracted alveolar bone. The distracted bone and implants were evaluated clinically and radiographically. Results: Mean height of distracted alveolar bone was $7.5{\pm}3.2$ mm (range: 2.5-15.0 mm). Mean follow-up period after completion of the distraction was 3.1 years (range: 1.4-11.5 years). Mean resorption of distracted alveolar bone was $1.6{\pm}1.8$ mm. The success and survival rates of implants was 95.3% and 100%, respectively. Conclusion: Results of this study indicate that vertical alveolar distraction procedure is a useful and stable method for alveolar ridge augmentation and implantation.

• 대한치과보철학회지
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• 제37권6호
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• pp.819-824
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• 1999

The purpose of this article is to present a clinical case report for palateless complete denture. Despite the contravacy of palatal uncoverage in upper complete denture, palateless complete denture has some merits for upper edentulous patient. Following the uncovering of the palatal portion, the patient became easy to talk and restored the lost good tastes. He is happy despite of the decrease of the retention of the upper complete denture. Palateless complete denture is a compatible alternative fir upper edentulous patients in cases of gagging, large palatal torus and restoring the lost good tastes. The clinical points are as follows : 1. The remaning alveolar ridge should be ovoid and have enough width and height for the sup-port and retention. 2. The patient must have strong wish to the palateless complete denture. 3. Palatal beading made on the palatal peripheral border give good border sealing of the palatal flange and minimaized the prominence of the denture flange 4. The peripheral border of the palatal flange should be reduced as thin as possible for more comfort. 5. Upper artificial posterior teeth should be arranged over the alveolar ridge crest and inner incline of the buccal cusp relieved for denture stability while chewing. 6. For stability of palateless complete denture, bilateral balanced occlusion should be sttained. Palateless complete denture will restore the lost good tastes and more comfortable and physiologic to upper edentulous patients and a good alternative to full palatal coverage complete denture in the properly selected cases.