• 한국결정성장학회지
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• 제33권6호
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• pp.276-281
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• 2023

적층제조 공정의 높은 설계자유도에 의해 기존 공정으로 성형이 어려운 형상이 적용된 제품의 제작이 가능해짐에 따라 복잡한 구조를 갖는 기능성 구조에 대한 연구자들의 관심이 증가되고 있다. 타이타늄 합금으로 제작되는 인체 삽입형 임플란트의 경우, 뼈와의 친화성을 확보하기 위해 다차원 격자구조를 적용하여 강도 및 탄성계수를 뼈와 유사한 수준으로 조절하고 있다. 따라서 격자구조의 설계 변수에 따른 기계적 특성에 대한 데이터 베이스 확보 및 관련 시뮬레이션 기술 개발은 개인 맞춤형 인플란트 제작을 효율적으로 수행할 수 있게 할 것이라 생각된다. 따라서 본 연구에서는 Ti-6Al-4V 합금 소재를 적용하여 설계변수별 격자구조체를 제작하고 이에 대한 탄성계수를 측정하였으며 그 결과를 시뮬레이션과 비교하여 정확한 탄성계수 예측을 위한 유한요소해석 방안을 제시하였다.

• 대한소아치과학회지
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• 제30권2호
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• pp.217-228
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• 2003

뇌와 두개골의 조화로운 성장 발육은 성장 중인 두개골과 이 뼈들을 연결하는 두개봉합부들 그리고 발육중인 뇌사이의 일련의 상호작용에 의해 이루어진다. 두개봉합부의 조기융합으로 알려진 craniosynostosis는 이러한 상호균형적인 관계가 파괴될 때 야기될 수 있다. Bone morphogenetic protein의 하나인 Bmp2는 골 각각의 형태와 골격의 상대적인 비례성을 조절하는데 관여하고 있으며, Bmp의 하부 유전자로 알려져 있는 Msx2 homeobox 유전자의 돌연변이는 Boston-type craniosynostosis를 야기한다 이와 함께 Dlx5 homozygote mutant mouse의 표현형은 두개골 골화의 지연을 포함한 다양한 두개안면의 이상을 나타낸다. 이러한 사실들은 Bmp2, Msx2, Dlx5 유전자들이 두개봉합부의 형태발생과정에 중요하게 작용할 수 있음을 시사하고 있다. Mouse 두개봉합부의 초기형태발생과정에 위 유전자들의 기능을 알아보기 위해, 태생기 동안의 시상봉합부에서의 Bmp2, Msx2, Dlx5 유전자들의 발현양상을 in situ hybridization 방법을 이용하여 분석하였다. Bmp2 mRNA는 osteogenic front에서 강하게 발현되었으며, parietal bone의 골막에서도 관찰되었다. Msx2 mRNA는 시상봉합부의 미분화 간엽조직에서 강하게 발현되었으며, osteogenie front 및 dura mater에서도 관찰되었다. Dlx5 mRNA는 osteogenic front와 parietal bone에서 강하게 발현되었다. 두개봉합부에서의 Bmp signaling의 역할을 알아보기 위해 태생 15.5일 mouse의 두개골을 이용하여 in vitro 실험을 시행하였다. Bmp2-soaked beads를 osteogenic fronts에 올려놓고 48시간 기관배양한 결과 BSA 대조군에 비해 Bmp2 beads 주위 조직의 두께와 세포수가 증가하였으며 Msx2와 Dlx5 유전자들의 발현을 유도하였다. 그러나 FGF2 beads주위로는 이들 유전자들의 발현이 관찰되지 않았다. 이러한 결과들을 종합해 볼 때, Bmp2 유전자는 두개골 성장과 두개봉합부의 초기 형태발생을 조절하는데 중요한 역할을 담당하고 있으며, Bmp signaling은 Msx2, Dlx5 유전자들을 조절함으로써 두개골의 골화와 두개봉합부의 유지에 관여하고 있음을 제시해 주고 있다.

• Imaging Science in Dentistry
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• 제32권1호
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• pp.1-10
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• 2002

Purpose: To observe the histopathological changes following irradiation on the wound healing after tooth extraction in the rachitic rats. Materials and Methods: In order to carry out this study, the rats were divided into four groups: Group 1 (normal diet/non-irradiation group), Group 2 (normal diet/irradiation group), Group 3 (rachitogenic diet/non-irradiation group), and Group 4 (rachitogenic diet/irradiation group). Rachitic changes were induced with rachitogenic diet No. 2 (high calcium, low phosphorus, and Vitamin D deficient diet) for 5 weeks. After the extraction of both maxillary first molars of the rats in Group 2 and 4, the head and neck of the rats were irradiated with single absorbed dose of 10 Gy. The rats were sacrificed at the 1st, 5th, 10th, and 15th day after tooth extraction. The specimens including the extraction wound were sectioned, stained with the hematoxylin-eosin and Masson's trichrome method and examined under the light microscope. Results: In the Group 2, the amount of newly formed bone trabeculae on the periphery of extraction socket and osteoblastic activity were reduced. In the Group 3, epithelial fusion was not revealed on the 5th day after toothe extraction and growth rate of osteoid formation was reduced. In the Group 4, necrotized tissue at the outer surface of extraction socket and destructive changes on the alveolar bones were noted on the 10th day. Epithelial fusion was not revealed and large amounts of osteoclast were noted on alveolar bone on the 15th day. Conclusion: The healing process of wound after tooth extraction was retarded by irradiation and especially in the rachitic rats.

• 대한수의학회지
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• 제45권4호
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• pp.465-467
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• 2005

The sacrum fused with ilium in a chinese water deer (Hydropotes inermis) was observed. The sacrum consists of four sacral vertebrae which was fused each other. In the ventral part of the fused pelvis, on the left, there was a 20.19 mm gap at the dorsolateral part of the sacroiliac articular part which is in between the promontory and the cranial border of the first ventral sacral foramen. On the right, there was a 14.34 mm gap at the dorsal part of sacroiliac articulation. In the dorsal view of the fused pelvis, the wing of sacrum and the wing of ilium were fused tightly, so that the boundary of the two bones was not recognizable. The left and right second dorsal sacral foramina and the third dorsal sacral foramen on the left were small. The third dorsal and ventral sacral foramina on the right were not formed.

• Imaging Science in Dentistry
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• 제51권2호
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• pp.217-222
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• 2021

Ewing sarcoma in the head and neck is rare, and metastasis from other bones to the mandible accounts for 0.7% of cases. This report presents a case of oral metastasis in a 24-year-old male patient diagnosed with Ewing sarcoma of the femur (p53 gene mutation and EWSR1-ERG fusion). The chief complaint was numbness in the mandible and pain for 1 month and a hardened, ulcerated exophytic lesion in the right retromolar region. Imaging exams revealed an unspecified thinning of the cortical bone of the inferior alveolar canal in the right mandibular ramus, associated with erosion of the alveolar bone. Histopathological analysis confirmed metastasis of Ewing sarcoma. The patient presented an aggressive disease progression and died 1 month after the oral diagnosis. It is important to recognize the signs and symptoms compatible with rare clinical outcomes, leading to an early diagnosis that can improve patients' quality of life and survival.

• 한국재료학회지
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• 제22권6호
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• pp.292-297
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• 2012

In order to improve osseointegration of dental implants with bone we studied an implant with holes inside its body to deliver bioactive materials based on a proposed patent. Bioactive materials can be selectively applied through holes to a patient according to diagnosis and the integration progress. After the bioactive material is applied, bone can grow into the holes to increase implant bonding and also enhance surface integration. In order to improve the concept and study the effect of bioactive material injection on implant integration, design optimization and integration research were undertaken utilizing the finite element method. A 2-dimensional simulation study showed that when bone grew into the holes after the bioactive material was injected, stress vertically distributed in the upper part of the implant was relieved and mild stress appeared at the opening of the injection holes. This confirmed the effect of the bioactive material and the contribution of the injection holes, but the maximum stress increased ten-fold at the opening. In order to reduce the maximum stress, the size, location, and the number of holes were varied and the effects were studied. When bioactive materials formed an interface layer between the implant and the mandible and four holes were filled with cortical and cancellous bones all the stress concentrated opposite to the loading side without holes disappeared. The stresses at the four outlets of the holes was mildly elevated but the maximum stress value was ten-fold greater compared to the case without the bioactive material.

• Journal of Korean Neurosurgical Society
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• 제47권4호
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• pp.313-315
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• 2010

Osteochondromas are common, benign tumors in the long bones, but osteochondromas are rare in the vertebrae. Most vertebral osteochondromas arise from the cervical or upper thoracic spine. However, lumbar osteochondromas have rarely been reported. In this report, a rare case of a lumbar osteochondroma arising from the spondylolytic L3 lamina in a 57-year-old woman is presented. She also had a ruptured disc and lumbar canal stenosis at L4-5-S1. The osteochondroma was completely removed and a posterior lumbar interbody fusion and instrumentation were performed. Considering the rarity of osteochondromas in the lumbar vertebrae, especially the L3 vertebra, it is possible that the pre-existing lumbar spondylolysis or spondylolisthesis was one of the factors affecting the occurrence or progression of the osteochondroma.

• Fisheries and Aquatic Sciences
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• 제19권4호
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• pp.20.1-20.12
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• 2016

The osteological development in Sebastes koreanus is described and illustrated on the basis of 32 larvae [6.11-11.10 mm body length (BL)] and a single juvenile (18.60 mm BL) collected from the Yellow Sea. The first-ossified skeletal elements, which are related to feeding, swimming, and respiration, appear in larvae of 6.27 mm BL; these include the jaw bones, palatine, opercular, hyoid arch, and pectoral girdle. All skeletal elements are fully ossified in the juvenile observed in the study. Ossification of the neurocranium started in the frontal, pterotic, and parietal regions at 6.27 mm BL, and then in the parasphenoid and basioccipital regions at 8.17 mm BL. The vertebrae had started to ossify at ~7.17 mm BL, and their ossification was nearly complete at 11.10 mm BL. In the juvenile, although ossification of the pectoral girdle was fully complete, the fusion of the scapula and uppermost radial had not yet occurred. Thus, the scapula and uppermost radial fuse during or after the juvenile stage. The five hypurals in the caudal skeleton were also fused to form three hypural elements. The osteological results are discussed from a functional viewpoint and in terms of the comparative osteological development in related species.

• 대한족부족관절학회지
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• 제23권4호
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• pp.189-195
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• 2019

Purpose: The aim of this study is to evaluate if the Ilizarov external fixation procedure with axial compression can help to obtain fusion across the ankle joint in patients with a high risk of nonunion. Materials and Methods: From January 2006 to December 2015, the study reviewed 17 patients who underwent ankle arthropathy with a high risk of nonunion and who underwent ankle fusion using the Ilizarov external fixator with axial compression and auto bone grafting. After the lateral surface of the ankle joint was exposed through a lateral trans-fibular approach, massive removal of the articular cartilage and excision of any loose or avascular bone were done. With the cortical bone harvested from the pelvis as corticocancellous bone blocks, we inserted the two cortical blocks longitudinally into the anterior and posterior part of the free ankle space from lateral to medial to make the rectangular chamber to fill the cancellous bones. After the Ilizarov external fixator was equipped, we tightened the frame by 5 mm to compress the bone graft space. We accessed the American Orthopaedic Foot and Ankle Society (AOFAS) AnkleHindfoot score both preoperatively and postoperatively. Results: The average age at the time of operation was 63.4 years (range, 47~78 years). The mean frame time was 17.4 weeks (range, 15~23 weeks). The average follow-up period was 3.7 years (range, 2~6 years). Osseous fusion was obtained in 15 patients (88.2%). There were two stable pseudarthroses among the rheumatoid arthritis patients, and we continued their follow-up. The mean AOFAS AnkleHindfoot score improved from 48.5 to 73.7 points. Conclusion: Ankle arthrodesis using the Ilizarov external fixation with axial compression and auto bone grafting on the ankle arthropathy that had difficult conditions to achieve union is considered one of the useful methods with a correspondingly low incidence of complications.

• 대한족부족관절학회지
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• 제7권1호
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• pp.13-20
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• 2003

Purpose: We analysis the outcome and complications of treatment of lesser toe brachymetatarsia. Materials and Methods: We analysed 28 patients 35 cases of lesser toe brachymetatarsia. Mean post operative follow up period was 2 years 8 months. All of the patients were female and mean age at operation was 21 years old. 2 cases of third metatasal bone and 33 cases of fourth metatarsal bone were operated. 8 metatarsal bones were treated using one staged lengthening with tricortical bone graft and 27 metatarsal bones were treated using callotasis with monofixator. Results: The average amount of lengthening was 13.3mm(12mm-15mm) in one staged lengthening, while 14.4mm(4mm-23mm) in callotasis. Average percentile increase was 28.9%(26%-34%) in one staged lengthening and 32%(18%-46%) in callotasis. The average healing index of callotasis was 76 days/cm (41 days/cm-166 days/cm). Satisfied outcomes in 4 cases of 8 cases (50%) after one staged lengthening and 17 cases of 27 cases (63%) after callotasis. 6 complications in 4 cases were occurred after one staged lengthening; insufficient length gain in 3 cases, fracture on the junction of graft bone and metatarsal bone in 1 case, plantar bowing deformity in 1 case and bony fusion of metatarsophalangeal joint in 1 case. 17 complications in 10 patients were occurred after callotasis ; metatarsophalangeal joint stiffness in 8 cases, metatarsophalangeal joint subluxation in 2 cases, overlengthened metatarsal bone in 2 cases, tapering of callus in 1 case, fracture of callus in 1 case, premature consolidation of callus in 1 case, osteomyelitis of metataral head in 1 case and plantar bowing deformity in 1 case. Conclusion: Although one staged lengthening and gradual lengthening using callotasis are effective treatment for lesser toe brachymetatarsia, complications not rarely occured after lengthening. Insufficient lengthening are most common complication after one staged lengthening while metatarsophalangeal joint stiffness lire most common complication after callotasis.