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방기숙,이성재,김수남,이홍수,이용근 韓國保健敎育學會 1996 보건교육건강증진학회지 Vol.13 No.2
Human teeth vary widely in color. Practitioner and patients are concerned with preventing and correcting discolored or dark teeth to achieve and maintain stain-free, white teeth. Tooth brushing cannot alter tooth color but it can remove adhering films and stains. The esthetics of natural dentition can be improved by bleaching and this process can be applied to intrinsically and extrinsically stained teeth. The need for a brighter, more attractive smile has made rapid growth in the market for tooth whiteners. There is no doubt these products work as whiteners, at least on mild to moderate stains, but the safety of these products are unclear. In this experiment, the effect of tooth whitener application on the color and microhardness of extracted human enamel was measured. RMS, RMT and NWT were used as tooth whiteners, and tooth past(ETQ) and hydrogen peroxide solution(HPO) were used as controls. 35 caries-free extracted human molars were embedded and polished with the exposed enamel diameter of 4 mm. The tooth whiteners and control agents were applied according to the manufacturers' instructions or clinically simulated procedures for eight weeks, and measurements were repeated every two weeks. Value(L*) difference was measured using Differential Colorimeter(Model TC-6FX, Denshoku Co., Japan), and microhardness was measured using microhardness tester(Mitsuzawa Seiki Co., Japan). The results were as follows ; 1. After application of agents for eight weeks, the Vickers hardness increased significantly in the ETQ, RMS and RMT application group(p<0.01), and that decreased significantly in NWT application group(p<0.01), but in HPO application group there was no significant change. The change in microhardness was greatest in NWT application group(p<0.0l). 2. After application of tooth whiteners and controls for eight weeks, the value change of toothpaste application group was significantly lower than those of other agents groups(p<0.01), and there was no significant difference in value(L*) change among tooth whitener groups(p>0.01) 3. The application of tooth paste and paste type tooth whitener made gradual value change, but hydrogen peroxide gel type tooth whitener and hydrogen peroxide solution made rapid value change during initial application period.
이용근,이흥수,이성재,방기숙,오상엽 원광대학교 생체재료·매식연구소 1996 원광생체재료·매식 Vol.5 No.2
Human teeth vary widely in color. Practitioner and patients are concerned with preventing and correcting discolored or dark teeth to achieve and maintain stain-free, white teeth. Tooth brushing cannot after tooth color but it can remove adherent films and stains. Esthetics of natural dentition can be improved by bleaching and this process can be applied to intrinsically and extrinsically stained teeth. The need for a brighter, more attractive smile has made rapid growth in the marker for tooth whiteners. There is no doubt these products work as whiteners, at least on mild to moderate stains, but the safety of these products are unclear. In this experiment, the effect of tooth whitener application on the color of extracted human enamel was measured. RMS, RMT and NWT were used as tooth whiteners, and tooth paste(ETQ) and hydrogen peroxide solution(HPO) were used as controls. 35 caries-free extracted human molars were embedded and polished with the exposed enamel diameter of 4 mm. The tooth whiteners and control agents were according applied to the manufacturers' instructions of clinically simulated procedures for eight weeks, and measurements were repeated every two weeks. CLELAB color difference(ΔE^*) was measured using Differential Colorimeter(Model TC-6FX, Denshoku Co., Japan). The results were are follows ; 1. After application of tooth whiteners and controls for eight weeks, the color change of all groups were not significantly different from each other (p>0.01). But after application of agents for 2 weeks and four weeks, the color difference of NWT applied group and HPO applied group were significantly higher than those of others(p<0.01). 2. The application of tooth paste and paste type tooth whitener made gradual color change, but hydrogen peroxide gel type whitener and hydrogen peroxide solution made rapid color change during initial application period.
치면열구전색제의 조건에 따른 법랑질 결합강도에 관한 연구
이용근,이흥수,이성재,방기숙,최정민,류승호,강민석 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.1
In this study, the shear bond strengths and accompanying elastic modulus ratio, displacement at bond failure and work up to fracture of pit and fissure sealants to toothe enamel were analyzed by the following variables, those were acid etching, moisture content of the surface of enamel, dentin bonding agent(species and method), thermocycling, saliva contamination. One kind of chemically cured resin based pit and fissure sealant, two kinds of light cured resin based pit and fissure sealants and one kind of glass ionomer based pit and fissure sealant, and two kinds of dentin bonding agents were studied. The buccal surface of extracted premolars were ground flat with # 600 silicone carbide papers, and the ground surface was treated depending on the experimental conditions. After each treatment, each pit and fissure sealant was filled into plastic tube of 3mm diameter, which were laid on the surface of ground enamel surface, and were cured. Sealant bonded teeth specimens were immersed in 37℃ distilled water form 24 hours. The shear bond strength of sealant to enamel surface was measured with Universal testing machine with the cross head speed of 1mm/min. From the obtained load-deflection curves, modulus ratio, bond strength, displacement at bond failure and work up to fracture were analyzed. From this experiment, the following results were obtained : 1. Comparing the results of standard condition(i. e. acid etching, dry surface, no dentin bonding agent and 300 thermocyling), the elastic modulus ratio of chemically cured resinbased pit and fissure sealant was significantly higher than those of other materials(P<0.05), and the bond strength, displacement at bond failure and work up to fracture of glass ionomer based pit and fissure sealant were significantly lower than those of other materials(P<0.05). 2. The results of ANOVA with the variables of type of material, acid etching, moisture condition of the enamel surface, dentin bonding agents were as follows ; 1) variables showed significant main effect on the shear bond strength of pit and fissure sealant to enamel(P<0.01), 2) type of material, acid etching and moisture condition of enamel influenced the bond strength significantly(P<0.01), 3) type and application methods of dentin bonding agents influenced on the bond strength significantly(P<0.05). 3. There were statistically significant correlation between the work up to fracture and the bond strength, and between the work up to fracture and the displacement at bond failure(P<0.01), and in these cases the correlation coefficient was 0.87.
이기숙,김종덕,권혁방,Lee, Gy-Soog,Kim, Jong-Duk,Kwon, Hyuk-Bang 대한생식의학회 1990 Clinical and Experimental Reproductive Medicine Vol.17 No.2
These experiments were performed to know ultrastructural changes of the cumulus expansion in virot. SEM:In expanded oocyte-cumulus complex, the cell surface are characterized by the presence of many evaginations:they are relatively short and round shape. The mucous extracellular material were deposited between cumulus cells. TEM:In compact cumulus cells, golgi apparatus and rough endoplasmic reticulum developed. In expanded cumulus cells, rough endoplasmic reticulum decreased and the smooth endoplasmic reticulum increased. Also, there were numbers of mitochondria. Extracellular mucous material which is presumed to be hyaluronic acid appears when cumulus cell were expanded. In expanded cumulus cell, numbers of smooth endoplasmic reticulum help cumulus cell to develop in steroidogenic cell.
박기숙,김은정,한창환,이일우,이해방,강길선 한국생체재료학회 2003 생체재료학회지 Vol.7 No.2
Articular cartilage exhibits little intrinsic repair capacity, and new tissue engineering approaches are being developed to promote cartilage regeneration using cellular therapies. Bone marrow-derived mesenchymal stem cells (MSCs) are highly proliferative and multipotential cells that have been considered as ideal candidate cells for tissue engineering applications. In this study, we have characterized the chondrogenic potential of rabbit MSCs in porous polymeric scaffolds by poly(lactic acid-co-glycolic acid) (PLGA), poly(glycolic acid) (PGA) as three-dimensional constructs to support chondrogenic differentiation following transforming growth factor-1 (TGF-1 treatment. Rabbit MSCs were isolated by percoll gradient and adherent cell cultures were established. The cells were then passaged into an aggregate culture system in a defined medium. The defined medium included dexamethason and TGF-1, cells secreted an extracellular matrix (ECM) incorporating type II collagen, aggercan, and proteoglycans. In vitro, MSCs were seeded in polymeric scaffolds for 28 days. The chondrogenesis of MSCs-seeded polymer scaffolds culture was assessed by histology and RT-PCR for chondrogenic phenotype. In histological analysis from safranin-O staining, we confirmed that chondrogenic differentiated rabbit MSCs expressed chondrocyte-like morphologies. Also we observed that type II collagen expressed by RT-PCR. In conclusion, this study demonstrated that the biodegradable porous polymeric scaffolds were able to provide three-dimensional constructs for inducing chondrogenic differentiation of rabbit MSCs.