• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.3
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• pp.196-204
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• 2002

For the study of its stability when the screw has been fixed after sagittal split ramus osteotomy(SSRO) of the mandible, the methods of screw arrangement are classified into two types, triangular and straight. The angles of screws to the bone surface are classified as perpendicular arrangements, the $60^{\circ}$ anterioinferior screw, known as triangular, and the most posterior screw, called straight arrangement, thus there are four types. The finite element method model has been made by using a three dimensional calculator and a supercomputer. The load directions are to the anterior teeth, premolar region, and molar region, and the bite force is 1 Kgf to each region. The distribution of stress, the von-Mises yield strength, and safety of margin refer to the total sum of transformed energy have been studied by comparison with each other. The following conclusion has been researched : 1. When shear stress is compared, in the triangular arrangement in the form of "ㄱ", the anterosuperior screw is seen at contributing to the support of the bone fragment. In the straight arrangement, substantial stress is seen to be concentrated on the most posterior angled screw. 2. When the von-Mises yield strength is compared, it seemed that the stress concentration on the angled anteroinferior screw is higher, it shows a higher possibility of fracture than any other screw. In the straight arrangement, stress appeared to be concentrated on the most posteriorly angled screw. 3. When the safety margins of the transfomed energy are compared, the energy conduction is much greater in the case of the angled screw than in the case of the perpendicular screw. The triangular arrangement in the form of "ㄱ" shows a superior clinical sign to that of the straight arrangement. Judging from the above results, when the screw fixation is made after SSRO in practical clinical cases, two screws should be inserted in the superior border of mandibular ramus and a third screw of mandibular inferior border should be inserted in the form of triangular. All screws on the bony surface should be placed perpendicularly-$90^{\circ}$ angles apparently best promote bony support and stability.

• Journal of Korean Foot and Ankle Society
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• v.9 no.1
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• pp.1-8
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• 2005

Purpose: We compared the bony arrangements of the forefoot in 2 different years, 1982 and 2004, to determine any changes with time period of 22 years. Materials and Methods: The radiographs of 200 normal Korean adults, 100 male and 100 female volunteers, were evaluated both in 1982 and 2004. The radiographic results were evaluated with as follows; hallux valgus angle (HVA), intermetatarsal angle (IMA), morphology of metatarsal head and relative anterior protrusion of the metatarsals and the phalanges. The mean ages were 38 years (23-52years) in 1982, and 37 years (24-50years) in 2004. Results: The mean of HVA decreased from 15.6 degrees in 1982 to 14.3 degrees in 2004 (p=0.047), and the mean of IMA increased from 8.0 degrees in 1982 to 9.4 degrees in 2004 (p=0.031). The morphology of metatarsal head and relative anterior protrusion of the metatarsals and the phalanges were not different between the two study years. Conclusion: Comparing with those of 1982 measurements, we found an increase of IMA and a decrease of HVA. A prospective study may be needed to illuminate course of the changes.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.170-179
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• 2000

The rh-BMP-4 is a subgroup of TGF-${\beta}$ superfamily. The application of rh-BMP in alveolar bony defect was reported to new alveolar bone and new cementum formation. For minimized complications following tooth replantation, a operator must replant a tooth fast at the pertinent position. This study was to evaluate the effect of rh-BMP-4 on periodontal regeneration and root resorption following tooth replantation in rats. The 50 Sprague-Dawley rats weighting about 130gm were used in this study. The animals were divided into three groups. Group 1 ; immediate replantation after extraction : Group 2 ; replantation stored teeth extraction of first molar, the removal of periodontal ligament with collagenase, and etching with citric acid : Group 3 ; replantation stored teeth with treated rh-BMP-4 in mesial root. Experimental animals were sacrificed 3, 7, 14 days after replantation by heart infusion. The maxillae were removed, fixed, demineralized, dehydrated, infiltrated and embedded with JB-4 mixture. For light microscopic observation, 5 micron sections were cut and stained with toluidine blue. The results of this study were as follows : 1. After experimental 3 days, all groups were observed dead space between periodontum and root. 2. After experimental 7 days, group 1 and group 3 were observed filling periodontal fibers between alveolar bone and root but group 2 were not. 3. After experimental 7 days, group 3 were observed appearance of attached cementoblast like cell on root surface. Group 1 were observed regular arrangement of fibroblasts and collagen fibers at ${\times}400$ observation. 4. After experimental 14 days, all group were observed filling periodontal fibers between alveolar bone and root. Group 1 were observed normal arrangement of periodontal fibers. Group 3 were observed less abnormal arrangement of periodontal fibers. Group 2 were not observed functional normal arrangement of periodontal fibers. 5. After experimental 14 days, group 2 and 3 were observed several root resorption and irregular root surface but group 1 were not. These results suggest that the rh-BMP-4 can stimulate cementogenesis and enhance to attach collagen fibers.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.6
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• pp.486-489
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• 2009

Odontogenic Myxoma of the jaws is a rare benign tumor derived from embryonic mesenchymal elements of dental anlage. It appears to originate from the dental papilla, follicle or periodontal ligament. Odontogenic Myxoma of the maxilla is less frequent but behaves more aggressively than that of the mandible, because it spreads through the maxillary sinus. Radiographically, the tumors present as unilocular or multilocular radiolucent lesions with well-defined borders with fine, bony trabeculae. On gross examination, the tumor appears as a smooth, glistening, gelatinous, lobulated mass. On microscopic examination, these neoplasms exhibit loose arrangement of stellate-shaped cells. The intercellular substance is a mucinous and homogeneous matrix. We report a case of odontogenic myxoma of the maxilla observed in our clinic with good prognosis after partial maxillectomy.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.1
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• pp.44-48
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• 2011

Maxillary defects are inherently complex because they generally involve more than one midfacial component. In addition, most maxillary defects are composite in nature, and often require bony support, as well as a mucosal lining for reconstruction. Therefore, midfacial bone and soft tissue defects present a unique challenge because they require a complex arrangement of tissues in a relatively limited space. This might be difficult to achieve only with free osteocutaneous flaps. The use of bone grafts allows greater flexibility in a reconstruction but is limited by graft resorption. We report a case of a patient reconstructed with a lateral arm free flap, iliac bone graft, sagital split ramus osteotomy for the reconstruction of a right maxillary defect zygomatico-maxillary defect caused by a zygomatico-maxillary malignant tumor resection.

• The korean journal of orthodontics
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• v.9 no.1
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• pp.99-103
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• 1979

For the purpose of investigating the response of the periodontal tissue in relation to the experimental tooth movement, the rats were inhibited from collagen formation by adminstration of aminoacetonitrile. Findings were as follows: 1) In experimental group, the principal fibers of the periodontal ligament came to run parallel along the alveolar bone or root surface on the pressure side, while the decrease in density, irregular arrangement, and partial loss of principal fibers were observed on the tension side. 2) Sharpey's fibers at the alveolar bone decreased in number, and as the aminoacetonitrile administration continued, the capability of matrix formation decreased on the tension side, the narrowing of the alveolar septum and poor-bony trabeculation appeared on the pressure side. 3) In cementum, Sharpey's fibers were distributed irregularly. The formation of acellura cementum was decreased on the tension side, while the formative capability of cellular cementum was increased. 4) The degree of staining by Herovici technique decreased in the periodontal membrane. By PAS and ninhydrine -Schiff reaction it was appeared weakly positive in the region where the Sharpey's fibers existed.

• Ocean and Polar Research
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• v.43 no.4
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• pp.371-374
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• 2021

Triglopsis quadricornis Linnaeus, 1758 (Cottidae) is distributed in the Atlantic and Arctic and has four unique bony protuberances on its head. Here, we report the complete, circular, and annotated mitochondrial genome of T. quadricornis. The complete T. quadricornis mitochondrion was sequenced by high-throughput Illumina HiSeq platform. The sequences are 16,736 bp in size and contains 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, a control region, and large and small ribosomal subunits. The overall genomic structure of T. quadricornis mitochondrion was conserved with the gene arrangement of Megalocottus and Myoxocephalus species, and phylogenetic analysis supports their sister relationships. Most PCGs consist of TAA or TAG as a termination codon, whereas COII, ND4, and CYTB have T-- as a stop codon. This complete mitochondrial DNA information of T. quadricornis will provide an essential genomic resource to elucidate the phylogenetic relationship and evolutionary history of the family Cottidae.

• Applied Microscopy
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• v.31 no.3
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• pp.287-305
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• 2001

To investigate a role of cartilage canals in osteogenesis and growth of the vertebrae, in human fetuses ranging from 50 mm to 260 mm crown rump length were studied by electron microscopy. The initial appearance of cartilage canals of the vertebral body was observed at 60 mm fetus. In 80 mm fetus, primary ossification center in the vertebral body was first noted. The vertebral body showed calcified chondrocytes surrounded by a tone of hypertrophied chondrocytes and deep canals which terminated in calcified matrix. Most hypertrophied chondrocytes in the centrum showed in various stage of degeneration in disorderly arrangement. At the blind end of deep canal, osteogenic cells, osteoblasts and chondroclasts were observed. Resorption of unmineralized cartilage septa was undertaken by perivascular cells within cartilage canals. The ruffled border of the chondroclast was restricted to resorption site of calcified cartilagenous matrix. The periosteal bone formation was followed by the appearance of primary center of the centrum at 120 mm fetus. The osteoblasts of the perichondrium started to lay down a thin membranous bony lamella on the outer surface of the osseous trabeculae of the centrum. The processes of bone formation in the vertebral bodies were found to possess morphological similarities to that occurring at secondary center of the epiphysis of a long bone. These results indicate that the connective tissue cells within the cartilage canals proliferate and differentiate into osteoblasts at the site of endochondral ossification of the vertebrae.