• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.519-523
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• 2004

This study investigates micro-structural and mechanical properties of trabecular bone in human femoral head with and without osteoporosis using Micro-CT and finite element-model. 15 cored trabecular bone specimens with 20min of diameter were obtained from femoral heads with osteoporosis (T-score > -2.5 ) resected for total hip arthroplasty, and 5 specimens were removed from femoral head of cadavers, which has no history of musculoskeletal diseases. A high-resolution micro-CT system was used to scan each specimen to obtain histomorphometry indices. Based on obtained micro-images(pixel size=21.31㎛), a FE-model was created to determine mechanical property indices. While non-osteoporosis group had increases trabecular thickness, bone volume, bone volume fraction, degree of anisotropy and trabecular number compared with those of non-osteoporotic group, the non-osteoporotic group showed decreases in trabecular separation and structure model index. Regarding the mechanical property indices, reaction force, apparent stress and young's modulus were 1ower in osteoporotic group than in non-osteoporotic group. Our data shows salient deteriorations in trabecular micro-structural and mechanical properties in human femoral head with osteoporosis.

• Animal Systematics, Evolution and Diversity
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• v.21 no.1
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• pp.111-122
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• 2005

A study on marine sponges was conducted by SCUBA diving at Ulleungdo Island and Gageodo Island, Korea during the period from July 2000 to October 2001. Two species, Clathria (Clathria) gombawuiensis n. sp. and Clathria (C) gageoensis n. sp., are new to the fauna of sponges. Clathria (C) gombawuiensis n. sp. closely relates to Clathria (C) conica Levi, 1963 based on the type of spicules, but differs in size of spicules and growth form, Clathria (C) conica has not small toxa. Clathria (C) gageoensis n. sp. is similar to Clathria (C) hexagonopora Levi, 1963, but it differs in size of spicules and growth form, also Clathria (C) hexagonopora has not small toxa.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.3
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• pp.215-222
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• 2014

Purpose: The aim of this study was to investigate differences between the morphology of the mandibular symphysis and four facial skeletal types. Materials and Methods: 40 cone-beam computed tomographies were selected and classified in to 4 groups according to their vertical and anterior-posterior skeletal patterns. The bone volume ($mm^3$) of the symphysis, the cross sectional area corresponding to the 4 mandibular incisors' axis: the cross sectional area of total bone ($mm^2$), the area of the cancellous bone ($mm^2$) and the thickness (mm) of labial and lingual alveolar bone at 2 mm, 3 mm under the cemento-enamel junction (CEJ) were measured. General linear model (GLM), Kruskal-Wallis test and Tukey honestly significant difference (HSD) test were subsequently used for statistical analysis. Results: The lingual cortical bone thickness of the lateral incisors at 2, 3 mm under CEJ was greater in the Class I low angle group than the other 3 groups (P < 0.05). There were no statistically significant differences in the volume of the mandibular incisor bony support, cross-sectional area of total bone and cancellous bone at the mandibular incisor' axis. Conclusion: Patients in Class I, low angle group have a thicker lingual mandibular symphysis than Class I, high angle patients.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.862-865
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• 2005

해면골에 대한 평가는 일반적으로 골밀도를 기준으로 평가하지만, 골밀도는 뼈의 특성을 70-80% 정도만 설명하는 것으로 알려져 있다. 이에 따라 골밀도로 설명이 되지 않는 나머지 특성을 뼈 미세구조의 형태학적 특성을 이용하여 설명하려는 노력이 생체역학 분야에서 오랫동안 있어 왔다. 본 연구는 CAD/CAM 분야의 feature extraction 기술을 이러한 생체역학 분야에 접목함으로써 뼈의 미세구조 평가를 위한 새로운 형태학적 지수 개발의 가능성을 탐색하고자 한다.

• Animal Systematics, Evolution and Diversity
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• v.21 no.2
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• pp.233-241
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• 2005

Two new marine sponges of family Tedaniidae, Tedania (Tedon iu) songakensis n. sp. and Tedania (Tedonia) sasuensis n. sp. were collected from Jeju Island and Chuja Island, Korea between 2004 and 2005. T. (T.) songakensis n. sp. is similar to T (T.) purpurescen Bergquist and Fromont, 1988 based on its type of spicules, but is distinguished from growth form and size of small onychaetes. The growth form of this species is massive, and is compared with thin encrusting of Tedania (T.) purpurescen. The onychaetes of the new species is twice as long as that of T. (T.) purpurescen. T. (T.) sasuensis n. sp. is closely related to T. (T.) connectens (Bronsted, 1924) in type of spicules. However, it is different in size of onychaetes and growth form. The large onychaetes of new species is larger than that of T (T.) connectens. The small onychaetes of new species is smaller than that of T. (T.) connectens. The growth form is massive in new species, but thick encrustins in T.(T.) connectens. And T. (T.) songakensis n. sp. is similar to T. (T.) sasuensis n. sp. in growth form. However, the former is widely different from the latter in shape, color and size of all spicules.

• Animal Systematics, Evolution and Diversity
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• v.21 no.2
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• pp.243-250
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• 2005

A taxonomic study on the marine sponges was conducted with materials which were collected from Ulleung Island and Chuja Island, Korea by SCUBA diving during the period of July 2000 to May 2005. Among them, two species, Mycale (Aegogropila) jukdoensis n. sp. and Mycale (Mycale) chujaensis n. sp. are new to science. M. (A.) jukdoensis n. sp. seems closely to M. grandis based on the shape of spicules, but our new species has two categories of subtylostyles and also larger sigmas and raphides than those of M. grandis. And anisochelae I of M. (A.) jukdoensis n. sp. is smaller than that of M. grandis. M. (M.) chujaensis n. sp. is similar to M. sulgata in the growth form and size of microscleres. However, the new species has two categories of subtylostyles instead of one type in M. sulgata.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.447-451
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• 2003

A new method for analyzing the bone-remodeling process using quasi-molecular dynamics was proposed in this study. The effect of pressure due to bone marrow, which could not be considered in previous methods, was also considered in this method. Bone-remodeling response of the 2D vertebral body of lumbar spine to a uniaxial compressive displacement of 1.8564mm. corresponding to approximately 2kN of compressive load, was studied. Converged shape change of the cortical shell and rearrangement of cancellous bone structure matched well with a normal shape of the vertebral body. The calculated responses in the spinal elements also shows closed results compared with experimental results.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.699-721
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• 1996

브로네마르크가 골유착성 임플랜트를 소개한 이래로, 현재 골유착성 임플랜트에 의한 치료는 안전하고 안정적인 방법으로 여겨지고 있다. 골유착성 임플랜트를 이용한 초기의 치료는 무치악 환자의 저작기능 회복에 중점을 두어 왔다. 그러나 현재는 환자와 시대의 요구에 따라서 심미성이 주요한 관심사가 되었다. 그래서 표준 지대주보다 더 심미적인 지대주 시스템들이 개발되었다. 다양한 직경의 임플랜트 고정체에 관한 임상가들의 요구에 의해 직경 이 큰 고정체가 생산되기 시작했으며, 5mm의 직경을 갖는 고정체가 그 예이다. 골유착성 임플랜트를 사용하여 보철치료를 할 때, 골과 고정체의 계면은 보철물과 지대주에 가해지는 교합력을 인접골에 전달하게 되며, 이것은 계면에 생물학적인 반응을 야기할 수 있다. 임플랜트의 형태는 골흡수와 같은 바람직하지 않은 반응을 일으키지 않도록 고안되어야 하며, 임플랜트 자체가 교합력을 견딜 수 있어야 한다. 그러므로 골유착성 임플랜트 시스템을 임상에 사용하려고 할 때 이것의 생역학적 분석은 반드시 필요하다. 본 연구에서는 삼차원 유한요소분석적 방법을 사용하여 3.75mm직경을 갖는 고정체에 표준 지대주, 이세티콘 지대주, 마이러스콘 지대주를 연결한 모델과 5mm 직경을 갖는 고정체에 표준 지대주를 연결한 모델에 각각 수직하중, 경사하중, 수평하중을 가했을 때의 응력분포를 비교하였다. 본 연구의 결과는 다음과 같다. 1. 모든 모델에서 금나사의 경부, 금원주, 지대주에 응력의 집중이 일어났다. 2. 임플랜트 고정체에서는 고정체 상방 2/3, 그리고 지대주와 접촉하는 고정체 상면에서 응력의 집중이 관찰되었다. 3. 골에서는 상부 피질골에 응력의 집중이 관찰되었으며, 해면골에서는 두드러진 응력의 집중을 보인 부위는 없었으나 고정체의 근단부 주위 해면골에서의 응력값이 비교적 높았다. 4. 5mm 직경의 고정체를 사용하지 않은 모델 중에서, 표준 지대주를 사용한 경우가 가장 응력분산에 유리하였으며 마이러스콘 지대주를 사용한 경우가 가장 불리하였다. 5. 3가지 하중 조건하에서 수평하중과 경사하중의 경우가 수직하중의 경우보다 더 높은 응력값이 관찰되었다. 6. 응력값은 골에서보다 임플랜트 내부에서 훨씬 높았다.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.47-57
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• 2010

An undisturbed healing process without micromotion at the implant-bone interface is essential for achievement of osseointegration of dental implant. Therefore, initial stability was advocated as prerequisite for successful clinical outcome. Adequate bone quality and quantity were important to achieve initial stability and to prevent early failures. However there were few published data available regarding the effect of design change in implant geometry on initial stability of the implants. The purpose of the current study was to assess the initial stability of various designs of implants when placed into artificial bone materials of varying qualities and shapes of insertion holes. Within the scope of this study, the following results were drawn. Bone quality was major importance to achieve initial stability. Initial stability was higher on GS II which had additional design feature of double thread. With a tapered design of implant such as GS III showed a higher initial stability than straight one. An insertion hole with the similar shape of implant would lead to reduce a compression force on cortical bone and enhance a bone anchorage on cancellous bone.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.701-702
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• 2007