• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권3호
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• pp.276-279
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• 2001

저자등은 Gardner 증후군과는 연관없이 단독으로 하악의 우각 하연부 내측에서 특이하게 발생한 치밀골 형태의 외골종과 상악의 잔존 치조능상에서 매우 드물게 전체적으로 균일한 해면골 형태의 조직학적 소견을 보이며 발생한 외골종을 치험 하였기에 문헌 고찰과 함께 증례들을 보고하였다.

• 한국재료학회지
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• 제22권6호
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• pp.285-291
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• 2012

Hydroxyapatite (HA) is well known as a biocompatible and bioactive material. HA has been practically applied as bone graft materials in a range of medical and dental fields. In this study, two types of dense hydroxyapatite ceramics were prepared from natural bones and synthetic materials. The biocompatibility of HA ceramics for supporting osteoblast cell growth and cytotoxicity using an in vitro MG-63 cell line model were respectively evaluated. Artificial hydroxyapatite shows relative density of 93% with 1-2 ${\mu}m$ after sintering, but a hydroxyapatite compact derived from bovine bone has low sintered density of 85% with a small content of MgO. Irrespective of the starting raw materials, both types of sintered hydroxyapatite displayed similar biocompatibility in the tests. FE-SEM observations showed that most MG-63 cells had a stellar shape and formed an intercellular matrix containing fibers on sintered HA. The cells were well attached and grown over the HA surface, indicating that there was no toxicity.

• 한국세라믹학회지
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• 제55권6호
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• pp.590-596
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• 2018

To improve the injection behavior of brushite cement, dense ${\beta}-Ca_3(PO_4)_2$ (${\beta}-TCP$) granules were added to the starting material. The spherical ${\beta}-TCP$ granules prepared by spray-drying and subsequent sintering at $1000{\sim}1200^{\circ}C$ accounted for fractions of from 0.5 to 0.7 of the total ${\beta}-TCP$. The injection behavior was evaluated by measuring the injected mass divided by the loaded mass of paste in the syringe pump. The injected amount was increased with the increase in the fraction and sintering temperature of ${\beta}-TCP$ granules, except at $1200^{\circ}C$. The increase in the fraction of ${\beta}-TCP$ and its sintering temperature resulted in a decrease in the plastic limit, which is the volume of water required to liquefy the compact. The rest water could be utilized in the cement with the reduced plastic limit for improved injectability. The amounts of rest water assigned for powdery phase were estimated, and correlated with the injectability of paste.

• 대한치과의사협회지
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• 제55권3호
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• pp.208-214
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• 2017

Purpose: This study was performed to survey the incidence and imaging characteristics of the antral exostoses in a Korean population. Materials and methods: The cone-beam computed tomographic images of 5,268 patients were reviewed for the presence of antral exostoses. Incidence, location, shape, structure and dimension were evaluated. Gender and side difference were analyzed by chi-squared test. Results: Ninety eight antral exostoses were found in 78 (1.5%) out of 5,268 patients. Gender and sides showed no statistically significant differences. Antral exostoses was often found in the lateral wall and floor of the maxillary sinus, accounting for 58.2% and 38.8% of the exostoses, respectively. Most exostoses had broad base and were composed of spongy bone surrounded by compact bone. The mean dimension was 9.1(W)*4.9(D)*5.3(H) mm. Conclusion: Antral exostoses is not uncommon in a Korean population. The identification of antral exostoses is clinically significant to avoid unnecessary examination and treatment. It also needs to be examined carefully in the implant planning or sinus lift procedure.

• 대한한방부인과학회지
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• 제19권1호
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• pp.47-68
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• 2006

Purpose : This study was carried out to investigate the effects of Gagamdokhwalgisang-Tang on the morphometric changes of femur, and on the hormones and cytokines associated with bone metabolism in overiectomized rats. Methods : Twenty-four female Sprague-Dawley rats were divided into sham operated group(normal) ovariectomized group(control), and treated with extract of GD group(treated). Each group was evaluated the changes of body weight at 0, 3, 6, 8 weeks after ovariectomy. Morphometric analysis(femur weight, femur/body weight ratio, femur ash weight femur ash/body weight ratio cross sectional area of compact bone and concellous bone of femur) and histopathological examination were performed at 8 weeks after ovariectomy. Estrogen, Alkaline Phosphatase(ALP) and cytokine(Tumor necrosis $factor-{\alpha}$, $Interleukin-l{\beta}$, Inerleukin-6) assay were performed at 8 weeks after ovariectomy. Results : 1. The body weight of control and treated group was significantly increased(p<<0.001) compared with the normal group at 8 weeks. 2. The femur weight and femur/body weight ratio of treated group were significantly increased(p<<0.05, p<<0.01) compared with the control group at 8 weeks. 3. The femur ash weight showed no significantly different changes, but femur ash/body weight ratio of treated group was significantly increased(p<<0.05) compared with the control group at 8 weeks. 4. In the cross sectional area of cancellous bone of femoral body, the treated group was significantly increased(p<<0.001) compared with the control group at 8 weeks. 5. The serum estrogen level of treated group showed no significantly different changes compared with the control group at 8 weeks. 6. The serum ALP activity of treated group was significantly decreased(p<<0.01) compared with the control group at 8 weeks. 7. The serum Tumor necrosis $factor-{\alpha}(TNF-{\alpha})$ level of treated group was significantly decreased(p<<0.05) compared with the control group at 8 weeks. 8. The serum $Interleukin-l{\beta}(IL-1{\beta})$ level of treated group was significantly decreased(n<<0.001) compared with the control group at 8 weeks. 9. The serum Interleukin-6(IL-6) level of treated group was significantly decreased(P<<0.01)compared with the control group at 8 weeks. Conclusion : These results indicate that GD inhibits bone resorption in ovariectomized rats. And the major inhibitory mechanism may be related to the inhibitory effects of GD on the secretion of $TNF-{\alpha}$, $IL-1{\beta}$ and IL-6 in the pathogenesis of osteoporosis in estrogen deficient rats.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.52.1-52.8
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• 2019

Background: A compact passive oxide layer can grow on tantalum (Ta). It has been reported that this oxide layer can facilitate bone ingrowth in vivo though the development of bone-like apatite, which promotes hard and soft tissue adhesion. Thus, Ta surface treatment on facial implant materials may improve the tissue response, which could result in less fibrotic encapsulation and make the implant more stable on the bone surface. The purposes of this study were to verify whether surface treatment of facial implant materials using Ta can improve the biohistobiological response and to determine the possibility of potential clinical applications. Methods: Two different and commonly used implant materials, silicone and expanded polytetrafluoroethylene (ePTFE), were treated via Ta ion implantation using a Ta sputtering gun. Ta-treated samples were compared with untreated samples using in vitro and in vivo evaluations. Osteoblast (MG-63) and fibroblast (NIH3T3) cell viability with the Ta-treated implant material was assessed, and the tissue response was observed by placing the implants over the rat calvarium (n = 48) for two different lengths of time. Foreign body and inflammatory reactions were observed, and soft tissue thickness between the calvarium and the implant as well as the bone response was measured. Results: The treatment of facial implant materials using Ta showed a tendency toward increased fibroblast and osteoblast viability, although this result was not statistically significant. During the in vivo study, both Ta-treated and untreated implants showed similar foreign body reactions. However, the Ta-treated implant materials (silicone and ePTFE) showed a tendency toward better histological features: lower soft tissue thickness between the implant and the underlying calvarium as well as an increase in new bone activity. Conclusion: Ta surface treatment using ion implantation on silicone and ePTFE facial implant materials showed the possibility of reducing soft tissue intervention between the calvarium and the implant to make the implant more stable on the bone surface. Although no statistically significant improvement was observed, Ta treatment revealed a tendency toward an improved biohistological response of silicone and ePTFE facial implants. Conclusively, tantalum treatment is beneficial and has the potential for clinical applications.

• 대한한방부인과학회지
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• 제18권3호
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• pp.32-50
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• 2005

Purpose : This study was carried out to investigated the effects of Saenghyeolbosu-Tang on the morphometric changes of femur, and on the hormones and cytokines associated with bone metabolism in ovariectomized rats. Methods : Twenty-four female Sprague-Dawley rats were divided into sham operated group(normal), ovariectomized group(control), and treated with extract of Saenghyeolbosu-Tang group(treated). Each group was evaluated the changes of body weight at 0, 3, 6, 8, weeks after ovariectomy. Morphometric analysis(femur weight, femur/body weight, femur ash weight, femur ash/body weight, cross sectional area of compact bone and cancellous bone of femur) and histopathological examination were performed at 8 weeks after ovariectomy. Estrogen and cytokines($TNF-{\alpha},\;IL-1{\beta}$, IL-6) assay were performed at 8 weeks after ovariectomy. Results : 1. The femur weight(g) of treated group(1.59${\pm}$0.08) was significantly increased(p<0.05)compared with the control group(1.50${\pm}$0.07) at 8 weeks. 2. The femur/body weight(g) of treated group(5.27${\pm}$0.36) was significantly increased(p<0.05) compared with the control group(4.78${\pm}$0.37) at 8 weeks. 3. In the cross sectional area of cancellous bone of femur(${mm^2}$) the treated group(1.60${\pm}$0.20)was significantly increased(p<0.01) compared with the control group(1.19${\pm}$0.19) at 8 weeks. 4. The serum estrogen level(pg/ml) of treated(83.67${\pm}$27.44) and control group(800.49${\pm}$22.27)showed no significantly different changes at 8 weeks. 5. The serum $TNF-{\alpha}$ level(pg/ml) of treated(33.71${\pm}$6.43) and control group(41.35${\pm}$8.47) showed no significantly different changes at 8 weeks. 6. The serum $IL-1{\beta}$ level(pg/ml) of treated group(53.78${\pm}$10.83) was significantly decreased(p<0.001) compared with the control group(79.80${\pm}$11.40) at 8 weeks. 7. The serum IL-6 level(pg/ml) of treated group(55.52${\pm}$9.02) was significantly decreased(p<0.01) compared with the control group(69.69${\pm}$7.95) at 8 weeks. Conclusion : This study shows that Saenghyeolbosu-Tang inhibits bone resolution in ovariectomized rats. These results may be related to the inhibitory effect of Saenghyeolbosu-Tang on the secretion of $IL-1{\beta}$ and IL-6 in the Pathogenesis of　osteoporosis.

• 한국기계가공학회지
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• 제10권5호
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• pp.51-57
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• 2011

The lightweight and compact actuator with high power is required to perform motion with multiple degrees of freedom. To reduce the size and inertia of a robot manipulator, the mechanical transmission system is used. The shape memory alloy(SMA) is similar to the muscle-tendon-bone network of a human hand. However, there are some drawback and nonlinearity, such as the hysteresis and the stress dependence. In this paper, the design of the underactuated robot hand is studied. The 3-finger dexterous hand is driven by the SMA actuator using segmental mechanism. This digital approach enables to overcome the nonlinearity of SMA wire. The translational displacement of SMA actuator required to bend a phalanx of the underactuated robot hand is estimated and the bending angle of the underactuated robot hand according to input displacement of SMA actuator is predicted by the multi-body dynamic analysis.

• Applied Microscopy
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• 제31권2호
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• pp.109-116
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• 2001

홍화씨는 예로부터 국내에서 재배되어 한방 및 민간에서 특히 뼈에 우수한 작용이 있는 것으로 생각되어 오랫동안 복용되어 왔다. 최근 홍화씨를 성분분석한 바에 의하면 칼륨과 마그녜슘, 칼슘이 다량 함유되어 있어서 뼈의 발달과 유지에 도움이 있을 것이라고 추측된다. 그러나 아직까지 확실한 실험적 자료가 제시된 것은 별로 없다. 이에 저자들은 홍화씨 분말이 골다공증의 예방에 미치는 효과를 알아보기 위하여 본 실험을 실시하였다. 실험동물은 체중 230g의 12주령의 Sprague-Dawley Rats를 사용하였으며, 양쪽난소를 제거한 후 홍화씨 분말을 매일 0.3g씩 복용시키면서 1, 3, 5 및 7주 후에 경골을 채취하여 관찰하였다. 채취된 조직은 통상적인 주사전자현미경 시료제작법으로 고정과정을 거친 후 10% 질산으로 12시간 탈회하여 뼈의 단면을 노출시키고 탈수, 건조 및 금도금 과정을 거쳐 주사전자현미경(Hitachi, S-450)으로 관찰하여 촬영하였다. 관찰결과 난소적출 후 골소실이 일어나기 시작하여 7주 후에 대조군은 골수강에서 피질골까지의 두께의 감소와 골수강의 확장이 심하였으나, 홍화씨 분말을 투여한 실험군에서는 1주에서 7주까지 거의 같은 소견을 나타내었다. 이상의 결과를 종합해보면 홍화씨 분말은 여성호르몬 결핍으로 인한 골다공증의 예방에 효과가 있는 것으로 사료된다.

• Applied Microscopy
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• 제40권3호
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• pp.155-162
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• 2010

뼈는 단계별 (hierarchical) 구조를 가진 복합 재료이며 독특한 구조와 기계적 특성 때문에 재료공학 분야에서 많이 연구되어져 왔다. 뼈는 주로 hydroxyapatite, 콜라겐과 물로 구성된 층판형 유 무기 재료 복합체이다. 주요 무기물로써 hydroxyapatite로 잘 알려진 calcium phosphate를 통하여 뼈는 특유의 강도를 유지하게 된다. 본 실험에서는 광학 현미경(LM)과 투과전자현미경(TEM)을 이용하여 토끼와 닭 대퇴골의 구조를 연구하였다. 구성물질 분석은 대퇴골의 calcium, potassium, oxygen 분포 변화를 알아보는데 이용하였다. 실험은 두 구조 범위에 중점을 두었다: micro scale에서 치밀골의 배열을, nano scale에서 콜라겐 섬유와 apatite 결정을 관찰하였다. Micro scale에서 닭과 토끼 대퇴골 구조의 뚜렷한 차이점이 발견되었다. Nano scale에서는 apatite 결정의 모양과 크기 그리고 콜라겐의 배열을 비교 분석하였다. 그 결과 토끼와 닭은 종이 다름에도 불구하고 nano scale에서는 화학성분과 구조가 매우 유사한 것으로 나타났다.