• Imaging Science in Dentistry
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• 제35권3호
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• pp.179-183
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• 2005

Metastatic tumors to the jaw bones are uncommon. The most common metastatic tumors to the jaw bones are the breast, lung and kidney. In the jaw bones, the common location of the lesions is the mandible, and the posterior area of the mandible is more commonly affected. The radiographic appearance is quite variable. In this report, a very rare case of metastatic gastric adenocarcinoma to the mandible is presented. The patient had undergone a gastrectomy 3 years ago.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.425-428
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• 2000

In this paper the impact force which occurs on each tooth of jaw-bones while masticating is calculated through the rigid body dynamic analysis. This analysis is done by ADAMS. The impact force calculated in this paper is required for the structural stress analysis of implant system which is needed for the implant system design. The analysis results show that the impact time decreases as the impact force increases, the largest impact force occurs on the front tooth and the impact force is almost normal to the tooth surface together with slight tangential force.

• 한국CDE학회논문집
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• 제7권1호
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• pp.27-33
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• 2002

MDO(Multidisciplinary Design Optimization) methodology is a new technology to solve a complicate design problem with a large number of design variables and constraints. The design of a dental implant system is a typical complicate problem, and so it requires the MDO methodology. Actually, several analyses such as rigid body dynamic analysis and structural stress analysis etc. should be carried out in the MDO methodology application to the design of a dental implant system. In this paper, as a first step of MDO methodology application to the design of a dental implant system, the impact force which is applied on the tooth in masticating is calculated through the rigid body dynamic analysis of upper and lower jaw-bones. This analysis is done using ADAMS. The impact force calculated through the rigid body dynamic analysis can be used for the structural stress analysis of a dental implant system which is needed for the design of a dental implant system. In addition, the rigid body dynamic analysis results also show that the impact time decreases as the impact force increases, the largest impact force occurs on the front tooth, and the impact force is almost normal to the tooth surface with a slight tangential force.

• Imaging Science in Dentistry
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• 제32권4호
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• pp.231-234
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• 2002

The odontogenic myxoma is an infiltrative benign tumor of bone that occurs almost exclusively in the jaw bones and comprises 3% to 6% of odontogenic tumors. This neoplasm is thought to arise from the primitive mesenchymal structures of a developing tooth, including the dental follicle, dental papilla, or periodontal ligament. Radiographically the odontogenic myxoma may produce several patterns: unicystic, multilocular, pericoronal, and radiolucent-radiopaque, making the differential diagnosis difficult. In this report, two cases of the odontogenic myxoma in the jaw bones are presented. The first case involved only the mandible, while the second case involved the maxilla. Both cases presented extensive multilocular radiolucencies characteristic of odontogenic myxoma.

• Journal of Korean Dental Science
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• 제8권2호
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• pp.65-73
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• 2015

Purpose: Parathyroid hormone (PTH) therapy has drawn attention, as an alternative to anti-resorptive drugs since PTH accelerates bone density by anabolic action. The purpose of this study was to identify the effect of intermittent PTH administration on jaw bones of rat undergone bilateral ovariectomy. Materials and Methods: Nine female Sprague-Dawley rats were divided into three groups. PTH group was ovariectomized (OVX) to induce osteoporosis and PTH $30{\mu}g/kg$ was administered 1 week after the surgery. In OVX group, ovariectomy was performed and only vehicle was administered by subcutaneous injection 3 times per week. Control group was subjected to sham surgery. The animals were sacrificed 8 weeks after the surgery and specimens were obtained from ilium and upper and lower jaw bones. Histological investigation was carried out by using an optical microscope and micro-computed tomography was taken to examine structural property changes in each bone sample. Result: In the ilium, the bone volume ratio (bone volume/total volume, BV/TV) of PTH, OVX and control groups was $53.75%{\pm}7.57%$, $50.61%{\pm}12.89%$, $76.20%{\pm}5.92%$ (P=0.061) and bone mineral density (BMD) was $1.12{\pm}0.09$, $0.88{\pm}0.48$, $1.38{\pm}0.07g/cm^3$ (P=0.061). In the mandible, BV/TV of PTH, OVX and control groups was $64.60%{\pm}12.17%$, $58.26%{\pm}9.63%$, $67.54%{\pm}14.74%$(P=0.670) and BMD was $1.21{\pm}0.17$, $1.19{\pm}0.13$, $1.27{\pm}0.18g/cm^3$ (P=0.587). In the maxilla, BV/TV of PTH, OVX and control groups was $61.19%{\pm}8.92%$, $52.50%{\pm}11.22%$, $64.60%{\pm}12.17%$ (P=0.430) and BMD was $1.20{\pm}0.11$, $1.11{\pm}0.16$, $1.21{\pm}0.17g/cm^3$ (P=0.561). No statistically significant difference was found in any variables in all groups. Histological observation revealed that the ilium in OVX group demonstrated sparsely formed trabecular bones compared with other groups. However, upper and lower trabecular bones did not present significant differences. Conclusion: Intermittent administration of PTH appears to affect the microstructure of rat jaw bones, but statistical significance was not found. However, the measurements in this study partly implicated the possible anabolic effect of PTH in vivo.

• Imaging Science in Dentistry
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• 제51권4호
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• pp.461-466
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• 2021

Fibro-osseous lesions are a poorly defined category of conditions affecting the jaws and craniofacial bones, and include developmental lesions, reactive or dysplastic lesions, and neoplasms. Fibrous dysplasia and ossifying fibroma are the 2 main types of fibro-osseous lesions affecting the jaw, and ossifying fibroma is a true benign neoplasm of the bone-forming tissues with several well-recognized variants ranging from innocuous to extensively aggressive lesions. However, multiple simultaneous fibro-osseous lesions of the jaw bones involving all quadrants are exceedingly rare. One such case diagnosed by conventional radiography and computed tomography is discussed here.

• 한국수산과학회지
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• 제20권5호
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• pp.447-456
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• 1987

1986년 7월 14일 제주도 우도앞 해상에서 채포한 날치친어를 선상에서 인공수정시켜 실험실로 운반하여 부화${\cdot}$사육한 자치어의 성장에 따른 내부골격의 발달과정을 관찰한 결과를 요약하면 다음과 같다. 1. 두개골중에서 외후두골, 기저후두골, 부설골이 전장 5.06mm에서 처음으로 골화한다. 2. 척추골은 앞쪽에서 뒤로 골화가 진행되며, 신경극과 혈관극은 대응하는 추체에 앞서서 골화한다. 3. 미부봉상골은 하나의 가는 골로 이루어지며, 꼬리부분의 추체보다 먼저 골화한다. 4. 요대골은 지느러미를 지지하는 골중에서 가장 늦은 전장 7.23mm에 이르러 치음으로 골화한다. 5. 악골은 섭이와 관련하여 두부의 골중에서 비교적 빨리 골화하여 전장 7.23mm에 이르러 기본적인 형태를 갖춘다. 6. 대부분의 내부골격은 전장 20.01mm에서 골화가 거의 완료된다.

• 한국발생생물학회지:발생과생식
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• 제20권2호
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• pp.65-79
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• 2016

We observed the osteological development of larval and juvenile red spotted grouper (Epinephelus akaara) in order to generate data for the assessment of skeletal deformities and to inform phylogenetic systematics research. Larvae and juveniles were obtained from a aquafarm in Muan-gun, Jeolla-namdo Province, Korea. The average water temperature at the time of breeding was $23.0^{\circ}C$ and average water salinity was 33.0 psu. Freshly hatched fish larvae had not undergone any ossification, but ossification of the parasphenoid bone, which forms the base of the cranium, occurred as the juveniles reached an average body length (BL) of 2.49 mm. At the same time, ossification of the preopercle and opercle occurred in the operculum, and ossification of the maxilla, which forms the upper jaw, and the dentary bones, which form the lower jaw, began. In addition, ossification of the vertebra occurred by formation of 7 vertebral centra and the neural spine in the abdominal vertebra. When the juveniles reached an average (BL) of 5.22 mm, ossification of the nasal, lateral ethmoid, and alisphenoid bones occurred in the cranium; ossification of the endopterygoid and metapterygoid bones began in the palatine region; and ossification of the hypohyal and interhyal bones occurred in the hyoid arch. At an average (BL) of 20.9 mm, ossification of the basisphenoid bone in the cranium and the suborbital bone in the orbital region occurred. Ossification of the vertebra then occurred by the formation of long pairs of ribs from the third to the ninth abdominal vertebrae, completing osteological development.

• Imaging Science in Dentistry
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• 제49권3호
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• pp.235-240
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• 2019

Osteosarcoma is the most common primary bone tumor after plasma cell neoplasms. Osteosarcoma has diverse histological features and is characterized by the presence of malignant spindle cells and pluripotent neoplastic mesenchymal cells that produce immature bone, cartilage, and fibrous tissue. Osteosarcoma most frequently develops in the extremities of long bones, but can occur in the jaw in rare cases. The clinical and biological behavior of osteosarcoma of the jaw slightly differs from that of long-bone osteosarcoma. The incidence of jaw osteosarcoma is greater in the third to fourth decades of life, whereas long-bone osteosarcoma mostly occurs in the second decade of life. Osteosarcoma of the jaw has a lower tendency to metastasize and a better prognosis than long-bone osteosarcoma. Radiographically, osteosarcoma can present as a poorly-defined lytic, sclerotic, or mixed-density lesion with periosteal bone reaction response. Multi-detector computed tomography is useful for identifying the extent of bone destruction, as well as soft tissue involvement of the lesion. The current case report presents a fibroblastic osteosarcoma involving the left hemimandible with very unusual radiographic features.

• 한국수산과학회지
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• 제50권4호
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• pp.396-405
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• 2017

We observed the osteological development in larvae and juveniles of Korean spotted sleeper Odontobutis interrupta bred in the laboratory in April 2014. Immediately after hatching, the prelarvae, which were about 4.27 mm long, showed ossification of the premaxillary bones in the upper jaw and the dentary and articular bones in the lower jaw. At 7.11 mm, the larvae showed complete fusion of the post-cleithra and ossification of the scapulae with the appearance of one hole. At 8.65 mm, the larvae showed ossification of seven ribs from the third abdominal vertebra and an increase in the length of the neural spine and hemal spine. The number of caudal fin rays increased to 19. At 11.9 mm, the juveniles showed ossification of three procurrent rays on the side of the parhypural bone as well as ossification of two procurrent rays on the side of the epural bone, indicating the complete ossification of all spicules.