• Journal of Korean society of Dental Hygiene
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• v.8 no.1
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• pp.13-22
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• 2008

This study compared tooth's remineralization using enamel surface artificially demineralized with 0.1M lactate and HCL solution using Vicker's Hardness Number(VHN) to compare CPP-ACP and remineralization of nano-sized Carbonate Apatite's initial caries. Using pH circulation models divided into 0% nano-CA, 5% nano-CA, 10% nano-CA, 10% CPP-ACP and D.W. they were treated for 5 minutes, three times a day for 14 days to get the following results. 1. There were no significant differences among the initial surface hardness of samples demineralized surface of front tooth in 5 groups. and all 5 groups' surface hardness reduced significantly after demineralization of enamel. 2. When inquiring into hardness changes through pH circulation model, the highest hardness change was in 5% nano-CA group. Also. 10% nano-CA and 10% CPP-ACP groups increased significantly. but there was no significant difference statistically. In generalizing the above experiment results, nano-sized Carbonate Apatite showed remineralization, and compared to 10% CPP-ACP group, 5% nano-CA had remineralization to artificial caries. thus implies that when we develop method to contact with tooth of nano-CA in the future, it is expected to gain synergy effect on function of saliva, a natural remineralization material.

• Journal of Biosystems Engineering
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• v.29 no.4
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• pp.347-356
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• 2004

치아인회석, 키토산, 시아노아크릴레이트 등의 생분해성 생체재료를 이용해 새로운 생체흡수성 골시멘트를 개발하고자 하였다. 이들 골시멘트들에 대해서 중합온도, 응고시간 등의 조작특성과 압축강도, 전단강도 등의 물성을 분석하였다. 특히, 치아인회석과 키토산의 미립가루와 부틸 시아노아크릴레이트의 강력접착제를 이용한 시멘트(B)에 대해서는 직접 접촉방법과 XTT 방법을 통해 세포독성을 분석하였고, 또한 쥐를 이용한 동물실험에서 시멘트(B)의 처리그룹에 따라 생체적합성을 분석하였다. 시아노아크릴레이트를 이용한 골시멘트의 최대중합온도는 약 33$^{\circ}C$, 조작(응고)시간은 3-6분, 압축강도는 약 15-25㎫, 전단강도는 약 0.4-l.7 ㎫를 나타내었다. 첨가제로 사용된 Lipiodol은 골시멘트의 주사성과 강력접착제의 초기 중합지연도를 높였고, 특히 송진가루는 시아노아크릴레이트의 초기중합을 지연시켰다. 시아노아크릴레이트를 이용한 시멘트(B)의 세포독성을 분석한 결과, 대부분의 처리 그룹에서 낮게 나타났고, 특히 키토산과 치아인회석을 사용한 경우 각각 세포 독성이 더 낮게 나타났다. 그리고 골시멘트(B)의 동물 생체적합성 실험의 방사선상 및 조직학적 분석에서도 뼈 형성 및 결합이 우수하게 나타났다.

• Journal of the Korean Ceramic Society
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• v.20 no.1
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• pp.55-62
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• 1983

the preliminary work on the prepartion of fine hydroxyapatite powder and the synthesis of dense hydroxyapatite ceramic from the powder were investigated for the development of artificial bone and tooth materials for implants. The effects of the process variables such as compositions of the raw materials the initial pH of the solutions and sintering temperature on the physical properties were investigated in order to determine the optimum conditions for the fabrication of tooth implant material. As the initial pH of the solutions was increased in the range of 10-11.6 the initial particle size of precipitates was decreased thus the sinterability of precipitates was improved. It was found that the composition of calcium rich of 1.75 in Ca/P mole ratio exhibited better sinterability and mechanical strength of the apatite ceramics for example the highest value of Vicker's hardness obtained from the compositions of 1.75 in Ca/P mole ratio was 764±30 Kg/mm2 compared to the maximum value of 600 kg/mm2 obtained from the compositions of 1.67 in Ca/P mole ratio.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.115-121
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• 1999

This investing was carried out to evaluate the alteration of stress distribution on teeth and esthetic crowns. Analyzing the stress distribution by the two-dimensional finite element methods, a model of lower 1st molar according to the porcelain fused metal crown an the porcelain fused glass ceramic core crown and the all glass ceramic crown. 1. The pattern of stress distribution showed no apparent differences. 2. The greatest von Mises values were concentrated around the central fossa of all esthetic crowns. The greatest Maximum principle value were concentrated around the interface between the base of esthetic crown and the abutment tooth. It was found that the apatite glass ceramic could be applicable for use in dental crown prosthesis.

• Journal of the Korean Magnetic Resonance Society
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• v.6 no.2
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• pp.84-88
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• 2002

Dating and dosimetry using electron spin resonance (ESR) in 20th Century developed at both Yamaguchi University and Osaka University have been reviewed with emphasis on new prospects and strategies in 21th century. Natural radiation have been generating radicals that accumulated in archaeological and geological materials. ESR detects these radicals and the ESR signal intensity is proportional to the radiation dose and therefore the age. The assessment of the total dose of natural radiation and the annual dose rate give their ESR ages. The ESR dating of stalactites and stalagmites ant Akiyoshi cave in Yamaguchi prefecture in 1975 was extended to anthropological dating using bones and tooth enamel excavated in Greek Petralona cave. Fossils of shells and corals gave the ages of marine terraces and sea-level changes. Quartz grains gave the ages of geothermal alteration and fault movements. Future ESR dating of ices at outer planets anf their satellite are also investigated as basic studies for ices od $H_2O,\;CO_2,\;SO_2$ as well as terrestrial hydrates in laboratory. Atomic bomb radiation dosimetry at Hiroshima and Nagasaki using ESR lead to the dosimetry of personnel, Chemobyl and JCO criticality accidents. Monitoring of radiation dose with sensitive materials with tissue equivalence are being developed. finally a new scanning ESR imaging apparatus (a near field microwave microscope) developed in our laboratory gave ESR images of Radicals from fossils to Si-CVD and diamond films as summarized in my book in 2002.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.355-362
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• 1987

본 실험의 목적은 치아 회분이 입자 크기에 따라 골형성에 어떠한 영향을 주며 순수 합성수산화 apatite인 calcitite와는 어떠한 차이가 있는가를 평가하기 위하여 수행하였다. 이를 위하여 200mesh와 40mesh의 치아 회분말과 40mesh calcitite를 잡종견의 신선한 발치와에 매식후 1주, 2주, 3주, 4주에 각각 희생하여 임상, X-선상 및 현미경적으로 관찰한 바 다음과 같은 결론을 얻었다. 1. 모든 경우에 조직의 거부반응이 없었다. 2. 40mesh치아 회분의 경우가 200mesh의 치아회분의 경우 보다 골 형성 능력이 현저히 높았다. 3. 40 mesh 치아회분과 calcitite 모두 비교군에 비하여 골 형성이 지연되었다. 4. 40 mesh 치아 회분과 calcitite의 골 형성 능력은 유사하였다.