• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.71-76
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• 2009

Purpose: Many researches showed loss of alveolar bone in fresh extraction socket and even in case of immediate implant placement. The aim of this study was to evaluate the effect of non-resorbable barrier membrane on the change of buccal and lingual alveolar bone in immediate implant placement into periapically infected extraction sockets. Materials and methods: Immediate implants were placed into artificially induced periapical lesion of mandibular premolars after complete debridement using buccal bone defect made by a 6mm trephine bur in 4 mongrel dogs. Before flap repositioning, a non-resorbable barrier membrane was placed on the buccal defect in the experimental group. No membrane was placed in the control group. In 12 weeks after placement, the dogs were sacrificed and undecalcified histologic specimens were prepared. The vertical distance from the smooth-rough surface interface(SRI) to gingiva, 1st bone contact and bone crest were measured in buccal and lingual side. The horizontal thicknesses of gingiva and bone at 0, 1, 2 and 3mm below SRI were measured. Results: The buccal bone was resorbed more than lingual bone in both groups and there was statistical significance(p<0.05). The distances from SRI to 1st bone contact were $2.45{\pm}2.35\;mm$ in experimental group and $4.49{\pm}3.10\;mm$ in control group. In all vertical level, lingual bone was thicker than buccal bone(p<0.05). Conclusion: Buccal bone was reduced more than lingual bone in immediate implant placement into periapically infected extraction sockets. Placement of non-resorbable barrier membrane reduced the buccal bone resorption. However there was no statistical significance.

• Applied Microscopy
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• v.25 no.4
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• pp.115-123
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• 1995

This study was carried out to observe the functional ultrastructures of photoreceptor cells in frog(Rana catesbeiana) retina using transmission electron microscope. The photoreceptor cells are divided into two types-rod and cone cells-consist of outer and inner segment. The long outer segment of rod cell contains dense stacks of membrane and formed vertical and horizontal folds. The outer segment of cone cell is small, and vertical and horizontal folds are not exist. The electron dense cytoplasm of rod cell contains compact mitochondria, Golgi complexes, and endoplasmic reticula. The inner segment of cone cell shows low electron density and contains a large lipid droplet in the upper part of inner segment. In addition, cone cell contains many mitochondria, Golgi complexes. rough endoplasmic reticula, ribosomes and numerous glycogen particles. It is believed that these ultrastructural characteristics are closely associated with photoreceptive function of photoreceptor cells in frog retina.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.5
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• pp.444-450
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• 2007

In general, labiolingual or buccolingual widths of residual alveolar bone are insufficient in edentulous area, because of alveolar resorption. Horizontal augmentation is bone graft procedure with a view to reinforcing horizontally insufficient bone quantity for installation of implants. The standard method is taking appropriate amount of block bone from intraoral or extraoral autogenous bone, and solid fixation with screws or mini-plate on labial or buccal side of residual alveolar bone. The purpose of this study is to discuss clinical usefulness of horizontal augmentation with autogenous block bone by observation and analysis of course of 41 implants installed to 12 patients by horizontal augmentation in Seoul National University Bundang Hospital from July, 2002 to December, 2005. The mean age of patients is 52.7, from 19 to 70, and the number of men and women is each 2 and 10. Block bone was taken from symphysis, body, ramus of mandible or iliac bone. And 6 types of implants were installed simultaneously or not, the diameters of implants are from 3.3 to 5.5mm, the lengths are from 8 to 15mm. The operator added artificial bone grafting material and optionally covered with membrane. The mean periods of observation after operation and final prosthetics were 28.6 and 17.0 months. As a result, 40 among 41 implants survived, the survival rate was 97.6%. Average 0.9mm crestal resorption was observed at final point of time by periapical view of each patients. Major complication related to the procedure was numbness in 7 patients.

• Journal of Welding and Joining
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• v.13 no.3
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• pp.8-17
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• 1995

LNG를 저장할 수 있는 탱크는 주로 지상식이거나 반지하식이며 그 용량은 매우 다양하다. 우리나라에서는 지상식 탱크가 평택 인수기지에 10만m$^{3}$급 Membrane Type 6기가 건설되었고 1기는 거의 완성단계이며, 현재 추가로 건설 중인 3기를 포함하면 총 10기의 탱크를 확보하게 된다. 또한 제2인수기지인 인천에도 동급 으로서 9%Ni강을 사용하는 Double Wall Type LNG 탱크 3기를 건설 중이다. 전세계적 으로 볼 때 LNG 저장 탱크의 78%는 지상식으로 Double Wall Type 또는 Membrane 저장 탱크 형식을 취하고 있으나, 최근에는 안전성 측면, 토지 가격의 상승, 토지의 합리적 이용 측면 등을 감안하여 LNG 탱크를 지하화, 대형화하는 추세이다. 본고에서는 Fig. 1과 같은 구조의 Double Wall Type LNG 저장탱크 중 초저온의 LNG에 직접 접하는 저 온용 재료(9%니켈강)로 만들어지는 내조 용접에 대해서 중점적으로 논하기로 하며, 특히 9% 니켈강 Shell Plate Horizontal Joint에 채용되는 Automatic Submerged ARC 용접에 대해 실제 현장 용접 시공상태를 나타내고자 한다.

• The Journal of the Korean dental association
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• v.9 no.6
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• pp.293-296
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• 1971

Histochemical observations on the effect of gold alloys crown margin in the periodontal membrane were caried out by use of rabbits. The animal were setted with gold alloys crown on the incisor teeth. The cervical margins were given extence into gingival sockets. The animals were sacrificed at the 30 days experimented period. Specimens of tissue were obtained from the mandibular incisor teeth with jaw. All tissues were fixed immediately in 10% neutral formalin solution. Different histochemical staining methods for the determination of fibrous components were the Mallory-Heidenhain Bielschowsky-Gomori, Gomori's aldehyde fuchsin. Periodic acid-Schiff reaction and Hematoxylin eosin stanin method. The results were as follows. The periodontal membrane is composed primarily of collagenous fibers and fibrous component run functional arrangement but in lower gold content groups, horizontal fiber groups were irregularly run. Elastic fibers were obligue run in experimental groups. There were no significant differences in reticularfibers in distribution.

• Structural Engineering and Mechanics
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• v.55 no.2
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• pp.349-364
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• 2015

Analytical solutions for modeling geotextile tubes during the filling process and approximation method to determine the densified tube shape are reviewed. The geotextile tube filling analysis is based on Plaut & Suherman's two-dimensional solution for geotextile tubes having a weightless and frictionless inextensible membrane resting on a rigid horizontal foundation subjected to internal and external hydrostatic pressures. The approximation for the densified tube shape developed by Leshchinsky et al. was adopted. A modified method for approximating the densified tube shape based on an areal-strain deformation analysis is introduced. Design diagrams useful for approximating geotextile tube measurements in the design process are provided.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.703-718
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• 2005

The purpose of this study was to evaluate the clinical efficacy of guided tissue regeneration(GTR) technique using chitosan nanofiber membrane and to compare it to the clinical efficacy following GTR using PLA/PLGA(copolymer of polvlactic acid and polylacticglycolic acid) membrane in mandibular class II furcation defects in human. The chitosan nanofiber membranes were applied to the mandibular class II furcation defects of 13 patients(test group) and PLA/PLGA membranes were applied to those of 11 patients(control group). Probing pocket depth, clinical attachment level, gingival recession, plaque index and gingival index were measured at baseline and 3 months postoperatively. Vertical and horizontal furcation defect depth were measured at surgery. Both groups were statistically analyzed by Wilcoxon signed Ranks Test and Mann-Whitney Test using SPSS program. The results were as follows: 1. Probing pocket depth, clinical attachment loss and gingival index were significantly reduced at 3 months postoperatively compared to values of baseline in both groups(p<0.05). 2. Gingival recession and plaque index were not significantly decreased at 3 months postoperatively compared to values of baseline in both groups. 3. No significant difference between two groups could be detected with regard to changes of probing pocket depth, gingival recession, clinical attachment level, plaque index and gingival index at 3 months postoperatively. In conclusion, chitosan nanofiber membrane is effective in the treatment of human mandibular class II furcation defects and a longer period study is needed to fully evaluate the outcomes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.4
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• pp.156-160
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• 2013

Objectives: Interest in bone graft material has increased with regard to restoration in cases of bone defect around the implant. Autogenous tooth bone graft material was developed and commercialized in 2008. In this study, we evaluated the results of vertical and horizontal ridge augmentation with autogenous tooth bone graft material. Materials and Methods: This study targeted patients who had vertical or horizontal ridge augmentation using AutoBT from March 2009 to April 2010. We evaluated the age and gender of the subject patients, implant stability, adjunctive surgery, additional bone graft material and barrier membrane, post-operative complication, implant survival rate, and crestal bone loss. Results: We performed vertical and horizontal ridge augmentation using powder- or block-type autogenous tooth bone graft material, and implant placement was performed on nine patients (male: 7, female: 2). The average age of patients was $49.88{\pm}12.98$ years, and the post-operative follow-up period was $35{\pm}5.31$ months. Post-operative complications included wound dehiscence (one case), hematoma (one case), and implant osseointegration failure (one case; survival rate: 96%); however, there were no complications related to bone graft material, such as infection. Average marginal bone loss after one-year loading was $0.12{\pm}0.19$ mm. Therefore, excellent clinical results can be said to have been obtained. Conclusion: Excellent clinical results can be said to have been obtained with vertical and horizontal ridge augmentation using autogenous tooth bone graft material.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.757-779
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• 2000

The aim of our study is to achieve complete periodontal tissue regeneration by the application of BMP and resorbable membrane. Three beagle dogs aged over one and half years and weighed 14 to 16 kg were used in this study. Mandibular 1st, 2nd premolars were extracted bilaterally. Horizontal furcation defects were induced around 3rd, 4th premolars bilaterally. BMP-4 were applied in the right side with resorbable membranes and only resorbable membranes were applied in the left side respectively. Each animal was sacrificed at 2, 4, and 8weeks, after regenerative surgery. Specimens were prepared with Hematoxylin-Eosin stain and Goldner's modified Masson Trichrome stain for light microscopic evaluation. The results were as follows: 1. At 2 weeks after regenerative surgery, downgrowth of junctional epithelium was observed both in the membraneapplied site and BMP-4-and-membrane-applied site. 2. At 4 weeks after regenerative surgery, resorbable membranes were completely resolved, therefore would not prevent downgrowth of junctional epithelium. New bone formation, new cementum formation and Sharpey's fiber were observed in BMP-4-andmembrane-applied site. 3. At 8 weeks after regenerative surgery, downgrowth of junctional epithelium was observed in the membrane-applied site. But, new cementum formation was observed in the same site. The extensive regeneration of new bone, new cementum and remarkable formation of Shapey's fiber were showed in BMP-4-and-membrane-applied site. 4. Resorbable membranes were resolved via the cell-mediated processes. 5. Periodontal tissue regeneration were better achieved in the BMP-4-andmembrane-applied site than in the membrane-applied site. Within the above results, BMP-4 may have the strong capability to form the new bone and resorbable membrane may be able to prevent the bony ankylosis. However, resolution rate of resorbable membrane may not be enough to protect rapid epithelial downgrowth for ideal periodontal regeneration. In conclusion, I suggest BMP-4 may have the strong possibility to be utilized in the clinical periodontal treat-

• Journal of Periodontal and Implant Science
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• v.27 no.2
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• pp.347-361
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• 1997

The present study investigates the effects of DFDB graft combined with Calcium sulfate membrane on the periodontal wound healing in dehiscence defects of dogs. Following the initiation of general anesthesia by I.V. administration of 30mg/kg of pentobarbital, first premolar was extracted and full-thickness flap was elevated from the second to the fourth premolar. The portion of premolars coronal to the alveolar crest was removed and mesial and distal roots separated to produce single rooted teeth. Exposed root canals were sealed with Caviton and covered completely with flaps sutured. Following the healing period of 12 weeks, the surgical sites were uncovered and $4{\times}4mm$ dehiscence defects were surgically created. Those defects with DFDB graft combined with Calcium sulfate membrane following root planing, were designated as test sites and those with flap surgery-only were designated as controls. 1. No foreign-body reaction or inflammation were observed in either groups. Calcium sulfate was completely resorbed in the test sites. 2. Significantly greater amounts of new cementum was observed in test sites compared with the controls. Significant amounts of functionally orientated collagens were observed in the test sites. 3. New bone formation was observed in significantly greater amounts in test sites. The results suggest that combined graft of DFDB and calcium sulfate is extremely biocompatible with a potential for new bone and cementum formation, and functional alignment of periodontal ligaments.