치과용 금합금의 표면처리에 따른 교정용 브라켓의 전단결합강도 변화

민지현,황현식,김종철 대한치과교정학회 2000 대한치과교정학회지 Vol.30 No.4

치과용 금합금에 브라켓을 부착하는 경우 자연치에 비하여 낮은 결합강도를 보이며, 잦은 브라켓 탈락이 나타나고 있는 바, 본 연구는 여러 가지 금합금 표면처리 방법이 교정용 레진 접착제와 금합금 간의 전단결합강도에 미치는 영향을 평가하여 금합금과 브라켓 간의 부착강도 증진방법을 모색하고자 시행하였다. 치과용 금합금으로 주조된 240개의 시편을 표면처리 유무 및 방법에 따라 무처리, 샌드블라스팅 단독처리, 샌드블라스팅과 주석도금 병용처리, 그리고 샌드블라스팅과 중간접착제 병용처리의 4가지 경우와, Ortho-one, Panavia 21, Superbond C&B의 3가지 레진접착제의 조합에 의해 12군으로 나누어 브라켓을 부착하였다. 시편을 증류수에 담아 37℃ 항온 수조 속에서 24시간 동안 보관한 후, 만능물성 시험기를 이용하여 전단결합강도를 측정한 후 다음과 같은 결과를 얻었다. 1.치과용 금합금의 표면을 처리하지 않은 경우에 비하여 표면처리한 군에서 통계적으로 유의하게 높은 전단결합강도가 나타났다. 2.샌드블라스팅 단독처리에 비하여 주석도금 병용처리를 시행한 경우 Panavia 21에서만 유의한 결합강도 증가가 나타났다. 3.샌드블라스팅 단독처리에 비하여 중간접착제 병용처리를 시행한 경우 모든 접착제에서 유의한 결합강도 증가가 나타났다. 4.사용된 레진접착제에 따른 전단결합강도를 비교한 결과 Superbond C&B가 가장 높고 그 다음으로 Panavia 21, Ortho-one 순으로 나타나는 양상을 보였다. 이상의 결과는 금합금 표면에서 브라켓 부착강도를 증가시키기 위해서는 레진접착제 종류에 관계없이 샌드블라스팅과 중간접착제 병용처리가 필요함을 시사하였다. The dental gold alloy shows a lower bond strength than the natural teeth in bracket bonding, and this can be a possible source of subsequent bond failure. This study aims to evaluate the effect of various gold alloy surface treatment techniques on shear bond strength between the orthodontic adhesives and the gold alloy and to find ways of increasing the bond strength. Two hundred and forty specimens made of the dental fold alloy were divided into twelve groups based on the combination of surface treatment methods(non-surface treatment, sandblasted, sandblasted plus tin-plated, and sandblasted plus intermediate adhesive) and adhesive systems (Ortho-one, Panavia 21, Superbond C&B). The specimens with bonded brackets were placed in distilled water at 37℃ for 24 hours and shear bond strength was measured by a universal testing machine. The results were as follows: 1.All surface-treated groups showed a significantly higher shear bond strength than non-surface-treated groups. 2.The sandblasted plus tin-plated group showed a significantle higher shear bond strength than the sandblasted group only when Panavia 21 was involved. 3.The sandblasted plus intermediate adhesive group showed a significantly higher shear bond strength than sandblasted group regardless of the type of adhesive used. 4.Of the three resin adhesive types, the Superbond C&B showed the highest bond strength, followed by Panavia 21 and Ortho-one. These findings suggest that a combination of sandblasting and intermediate resin treatment is desirable in order to enhance bracket bond strength regardless of adhesive types.

전기 도금법을 이용한 CoPtCu 나노선 제조 및 자기적 특성 연구

민지현,우준화,안부현,조지웅,류홍링,지혜민,이주헌,김영근,고영동,정진석 한국자기학회 2006 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

발반사마사지가 무용전공 학생들의 변비완화에 미치는 효과

민지현,김민정,강경호 한국피부미용향장학회 2010 한국피부미용향장학회지 Vol.5 No.1

Evaluation of physical property and cytotoxicity of resin infiltrant based on a triethylene glycol dimethacrylate (TEGDMA)

민지현,오지연,김기림 한국치위생학회 2019 한국치위생학회지 Vol.19 No.2

Objectives: The resin infiltration technique is a promising alternative therapy for arresting the early dental caries. However, there are very few reports on the safety and biocompatibility of this technique. We evaluated various properties of resin infiltrant (RI) based on a triethylene glycol dimethacrylate (TEGDMA).The water sorption (Wsp) and water solubility (Wsl) was assessed. Additionally, the cytotoxicity of RI against both animal and human fibroblast cell lines was investigated. Methods: The RI of the Icon®, the first product developed for resin infiltration, is mainly composed of TEGDMA in the resin matrix. The Wsp and Wsl for the RI were measured in accordance with ISO 4049 specifications. Fourier-transform infrared spectroscopy (FTIR) was used for analyzing the polymerization before and after curing of RI. The cytotoxicity of RI against the mouse fibroblasts (L929) and human gingival fibroblasts (hTERT-hNOF) was evaluated using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and the data were analyzed using one-way analysis of variance. Results: Wsp and Wsl of the RI specimens were 53.37 μg/mm3 and 10.6 μg/mm3, respectively. FTIR analysis revealed a slightly higher degree of curing with longer irradiation time. The degree of conversion for RI was high (80.9%) after 40 seconds of light curing. There was a significant decrease in the viability of L929 and hTERThNOF cells at RI extraction solution concentrations above 50%, respectively, compared to that in the negative control ( p < 0.05). Conclusions: Even though the RI exhibited positive effect on the early prevention of dental caries, the clinicians should also consider the toxicity of RI on periodontal tissues.

다기능성 CoPtAu 합금 나노와이어의 제작

민지현,이주헌,우준화,조문규,김영근 한국자기학회 2007 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

치아미백의 부작용과 해결방법

민지현 청주대학교 보건의료과학연구소 2017 보건의료과학연구 Vol.5 No.2

This study was performed to review current knowledge on the method to prevent relapse the tooth staining after tooth bleaching. ‘Pubmed’, ‘MedLine’, and ‘Google scholar’ databases were searched electronically with key words of tooth bleaching, restain, rebound, relapse, prevent stain, stability, maintenance of whitening. There were several studies about the side effect of the tooth bleaching. However there were some studies after the 2000s about the solution method for the side effect of tooth bleaching. More studies need to conduct to solve the side effect of the tooth bleaching.

치면세균막 제거 전후 착색된 치아의 색 평가

민지현 청주대학교 보건의료과학연구소 2019 보건의료과학연구 Vol.7 No.2

This in vitro study aimed to evaluate the color for the discolored tooth before and after removal of dental plaque. Eight bovine enamel specimens per beverage group were subjected to an 8-day pH-cycling model, which used six Korean children's beverages and a remineralizing solution. The surfaces of the enamel specimens were photographed and evaluated the color at the following times. (1) sound teeth before the pH-cycling, (2) simply cleaned teeth after pH-cycling (bacterial membrane remain on the tooth surface), (3) ultrasonic cleaned teeth (complete removal of bacterial membrane from tooth surface). The color change (ΔE) was investigated between a simply cleaned teeth and a sound teeth (ΔESC), and ultrasonic cleaned teeth (ΔEUC) and sound teeth . The largest group with ΔESC and ΔEUC was in the coca-cola group, and the group showed a statistically significant difference for the ΔESC and ΔEUC between the other drink groups (p<0.05). There was also a significant difference between ΔESC and ΔEUC values in the coca-cola group (p<0.05). However, this was not a clinically detectable color difference. In conclusion, dental bacterial membranes do not clinically affect tooth color evaluation.

미디어 이용이 청소년의 외모 지상주의에 미치는 영향

민지현 한국방송학회 2007 한국방송학회 학술대회 논문집 Vol.- No.-

생체 시료 중 카테콜 아민류, 세로토닌 및 대사물질들의 HPLC/ECD 동시 정량분석

민지현,한영희,Min, Ji-Hyun,Hahn, Young-Hee 대한약학회 2011 약학회지 Vol.55 No.4

Simultaneous monitoring of catecholamines and serotonin with their appropriate extraction from the biological samples is required in order to understand thoroughly the regulation of the central and peripheral nervous system. In the present research the segmented gradient elution with the solid phase extraction using a C18 cartridge rather than the previous isocratic elution with alumina extraction is successfully employed to determine norepinephrine (NE), epinephrine (E), dopamine (DA), serotonin (5HT), 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5HIAA) simultaneously within 20 minutes using 3,4-dihydroxyhydrocinnamic aicd as the internal standard (IS). Linearities were obtained in the concentration range between $5{\times}10^{-6}M$ and $1{\times}10^{-4}M$ for all 7 compounds with detection limits of 0.6~1.9 ${\mu}M$. The present HPLC/ECD method yielded reasonable accuracy (relative error; -1.4~1.1%) and precision (relative standard deviation; 0.4~1.9%) for 9 measurements of the standard solution consisting of NE, E, DA, 5HT, DOPAC and 5HIAA compounds. Recoveries of catecholamines, serotonin and their metabolites from human serum were in the range of 57%~86%. While the concentrations of NE and 5HT in the serum of normal Sprague-Dawley rat were found as $1.4{\times}10^{-6}M$ and $2.6{\times}10^{-6}M$, respectively, the contents of NE and 5HT in the serum of the stressed rat were increased 5.6 times and 1.4 times more, respectively.

고등학교 급식식단의 엽경채류 식재료 사용 빈도 및 조리방법 분석 연구

민지현,이종경,김현정,윤기선 한국식품위생안전성학회 2016 한국식품위생안전성학회지 Vol.31 No.4

This study was conducted to extract the factors affecting the microbial safety of leaf and stem vegetables in the high school foodservice and to provide information for supplying the safe foodservice menu. The lunch and dinner menu (1,945 data) of the total 6 high schools at the Central and the South Region in March, June, September, and December were collected. The frequency analysis and the multiple correspondence analysis (MCA) based on the 3 factors (potentially hazardous food (PHF), leafy and stem vegetables in the menu, the cooking methods) were conducted. The most frequent PHF was the menu of blanched vegetables, salads, seaweeds and fried chicken. The most frequent consumed leaf and stem vegetables were spinach, chive, lettuce, Western cabbage, perilla leaf, iceberg lettuce, chicory, leek and broccoli. MCA based on the leaf and stem vegetables, the region, and the cooking method (cooked/non-cooked) showed that garlic stem and spinach were more used in the Central Region, while water dropwort were more used in the South Region. Iceberg lettuce, Bok choy and leek were included frequently in the PHF menu. Plant products frequently used in PHF menu requires the food safety system such as Good Agricultural Practice (GAP) to reduce the microbial risk. The menu database according to raw materials based on cooking methods (heating or mixing) as well as the development and verification of menu based on the microbial safety will be contributed to provide the safer foodservice menu.