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Seoul-Hee Nam,Man-Seok Han 한국자기학회 2023 Journal of Magnetics Vol.28 No.4
Fluoride compounds are major substances that inhibit the growth of oral bacteria, increase the hardness of the tooth surface, and promote recalcification. However, caution must be exercised regarding fluoride exposure, as it may cause side effects to the human body due to its toxicity if swallowed. Accordingly, this study was conducted to evaluate the residual amount of fluoride remaining in saliva after using mouthwashes containing high and low fluoride concentrations. After rinsing with five commercially available high-fluoride mouthwashes according to the manufacturer’s instructions, the fluoride concentration remaining in saliva was quantitatively evaluated over time through Fluorine (19F) NMR (magnetic field: 9.4 Tesla) immediately, 1 minute, and 2 minutes later. When gargling with DH 2000 ppm fluoride, the residual salivary fluoride content was 30.3960% immediately after gargling, 0.0041% after 1 minute, and 0.0020% (0.0401 ppm) after 2 minutes; when gargling with EB 1000 ppm, it was 16.5001 % immediately after gargling, 10.6269 % after 1 minute, and 0.0034% after 2 minutes; and when gargling with BS 1000 ppm, it was 17.1169 % immediately after gargling, 13.2337% after 1 minute, and 0.0019% (0.0188 ppm) after 2 minutes. When gargling with LIS 220 ppm, the residual salivary fluoride content was 56.3716 % immediately after gargling, 0.0842% after 1 minute, and 0.0180% (0.0396 ppm) after 2 minutes; and when gargling with R 90 ppm, it was 0.0302% immediately after gargling, 0.0151 % after 1 minute, and 0.0077% (0.0069 ppm) after 2 minutes. Even when mouthwashes containing various fluoride concentrations were used, only the fluoride content of existing normal saliva remained after 2 minutes, confirming that swallowing the saliva is safe and does not affect the human body.
An Evaluation of the Repetitive Tooth Bleaching with Nonthermal Atmospheric Pressure Plasma
Seoul Hee Nam,Gyoo Cheon Kim,Jin Woo Hong 대한구강생물학회 2016 International Journal of Oral Biology Vol.41 No.4
This study was undertaken to achieve a high bleaching efficacy with plasma, through longer application and reparative bleaching processes, by different shade evaluation methods. Extracted human teeth were divided into 6 groups (n=10). All teeth were treated in pairs. Low concentration of 15% carbamide peroxide (CP) was applied, with and without plasma, for 10, 20, and 30-min tooth bleaching, respectively. The bleaching procedure was repeated once daily for four days. The teeth were maintained in a moist environment provided by artificial saliva. The Vitapan Classical shade guide and Commission Internationale de L’Eclairage (CIELAB) color system were collectively used to measure the bleaching efficacy. Color evaluation was statistically analyzed using Student t-test and one-way analysis of variance (ANOVA) complemented by Tukey’s test. Combining the plasma with 15% CP showed significantly greater color changes compared to bleaching without plasma (p<0.05). A high bleaching efficacy with plasma is proportional to the repetitive application and the treatment time. A 30-min application with plasma provided the best bleaching. Repetitive bleaching showed lower probability of color relapse of the bleached tooth. The color change by shade guide correlated with the changes in CIELAB color system. A value of 1 color change units (CCU) conversion factor for overall color change (ΔE) values comparisons was 3.724 values. The two measuring methods provide a more accurate correspondence of color change. The repetitive and longer application for tooth bleaching, combined with plasma, has a strong bleaching effect and produces whiter teeth
Seoul Hee Nam,Hae June Lee,Jin Woo Hong,Gyoo Cheon Kim KOREAN ACADAMY OF ORAL BIOLOGY 2014 International Journal of Oral Biology Vol.39 No.4
Nonthermal atmospheric pressure plasma has attracted great interest for biomedical applications. The plasma consists of charged particles, radicals, and a strong electric field as the fourth state of matter. This study evaluated the change in the surface roughness after tooth bleaching by plasma in combination with a low concentration (15%) of carbamide peroxide, specifically whether the application of plasma produced detriments, such as demineralization and structural change, with the goal of efficient and safe tooth bleaching. After being combined with plasma and 15% carbamide peroxide, the hydroxyapatite surface was significantly smoother with a low roughness average value. Tooth bleaching with 15% carbamide peroxide alone produced an irregular surface and increased the surface roughness with high roughness average value. Tooth bleaching with plasma resulted in no significant variations in hydroxyapatite in terms of change in surface roughness and surface topography. The application of tooth bleaching with plasma is not deleterious to dental hard tissue, implicating it as a safe tooth bleaching technique.
Effective and Long-lasting Tooth Bleaching by Non-Thermal Atmospheric Pressure Plasma
Seoul Hee Nam,Jin Woo Hong,Gyoo Cheon Kim 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10
The problem associated with bleached teeth is to return to the original tooth color over time. Because the long-term color stability after tooth bleaching is very important, novel technique is requested. This study is to evaluate the long-term color stability of tooth bleached by nonthermal atmospheric pressure plasma with 15% hydrogen peroxide (HP) or 15% carbamide peroxide (CP). Extracted human teeth were assigned to 4 groups (n = 10): Group 1 was treated with plasma activated 15% HP; Group 2 with 15% HP alone; Group 3 with plasma-activated 15% CP gel; and Group 4 with 15% CP alone. A low-frequency driven helium plasma jet was used. After a 30-min application, teeth were immersed in artificial saliva, and color was assessed using the CIELAB system over 6 months, with the overall color changes (ΔE) calculated relative to baseline. Hydroxyl radical concentration (·OH) was detected using methylene blue (MD) dye. Statistical analyzes were performed with Student’s t-test, one-way analysis of variance, and post-hoc Duncan tests. Results: Combination treatment of plasma and 15% HP/CP resulted in higher color stability than 15% HP/CP alone throughout the whole observation period (p < 0.05). The activity of ·OH in combined plasma and low concentration 15% HP/CP was enhanced, relative to bleaching agents alone (p < 0.05). Long-term color stability of tooth bleaching using plasma with 15% HP/CP was retained for 6 months. Tooth bleaching with plasma is an important factor for ·OH production, which is key to the bleaching effect.
Hee Jeong Seo,Hyang-Do Ham,Hyung Yong Jin,Woo Hyung Lee,Hyun Sub Hwang,Soon-Ah Park,Yong Sung Kim,Suck Chei Choi,Seoul Lee,Kyung Jae Oh,Byung Sook Kim,Byung Rim Park,Moon Young Lee 대한생리학회-대한약리학회 2010 The Korean Journal of Physiology & Pharmacology Vol.14 No.4
The hypothalamic-pituitary-adrenal (HPA) axis is the primary endocrine system to respond to stress. The HPA axis may be affected by increased level of corticotrophin-releasing factors under chronic stress and by chronic administration of monosodium glutamate (MSG). The purpose of this study was to investigate whether chronic MSG administration aggravates chronic variable stress (CVS)-induced behavioral and hormonal changes. Twenty-four adult male Sprague-Dawley rats, weighing 200∼220 g, were divided into 4 groups as follows: water administration (CON), MSG (3 g/kg) administration (MSG), CVS, and CVS with MSG (3 g/kg) administration (CVS+MSG). In addition, for the purpose of comparing the effect on plasma corticosterone levels between chronic stress and daily care or acute stress, 2 groups were added at the end of the experiment; the 2 new groups were as follows: naïve mice (n=7) and mice exposed to restraint stress for 2 h just before decapitation (A-Str, n=7). In an open field test performed after the experiment, the CVS+MSG group significant decrease in activity. The increase in relative adrenal weights in the CVS and CVS+MSG group was significantly greater than those in the CON and/or MSG groups. In spite of the increase in the relative adrenal weight, there was a significant decrease in the plasma corticosterone levels in the CVS+MSG group as compared to all other groups, except the naïve group. These results suggest that impaired HPA axis function as well as the decrease in the behavioral activity in adult rats can be induced by chronic MSG administration under CVS rather than CVS alone.
Seoul-Hee Nam,Man-Seok Han,Bo-Kyoung Song Korean Magnetics Society 2018 Journal of Magnetics Vol.23 No.4
The purpose of this study is to investigate the stability of natural teeth whitening by analyzing the change on the tooth enamel surface and major mineral components, as well as tooth whitening using a natural material, such as fruit juice. Only the buccal surfaces of 20 premolar teeth extracted were assigned to 5 groups (n=4). For Group 1, normal saline was applied; for Group 2, strawberry and baking soda were mixed at a ratio of 3:1; for Group 3, lemon and baking soda were mixed at a ratio of 3:1; and for Group 4, baking soda and water were mixed at a ratio of 3:1. About 1 ml of each material was applied on the enamel surface using a toothbrush. For Group 5, 5 mm whitening toothpaste was applied using a toothbrush. Color changes using the CIELAB, pH measurement using a pH meter, surface morphology using scanning electron microscopy (SEM), and mineral content using electromagnetic wave (X-ray) photoelectron spectrometer (XPS) were measured. The whitening effect was highest in the teeth applied with lemon compared to the whitening toothpaste. The pH value was lowest with the lemon application, which showed a distinctly rough surface and porosity. The Ca and P values were lowest in the tooth surface whitened with lemon. It was confirmed that tooth whitening with natural fruit juice increased the roughness of the tooth surface due to the acidic low pH. It also caused enamel demineralization and posed harm to the teeth.
Change in the Salivary Fluoride Concentration through Nuclear Magnetic Resonance Spectroscopy
Seoul-Hee Nam,Man-Seok Han,Bo-Kyoung Song Korean Magnetics Society 2018 Journal of Magnetics Vol.23 No.4
Fluoride application has an excellent effect for the prevention of dental caries, and 1.23 % acidulated phosphate fluoride (APF) gel is the most commonly used fluoride formulation for professional fluoride application. There has been a problem, however: its excessive intake may cause toxicity in the human body. The purpose of this study was to evaluate the amount of residual fluoride present in the saliva in the mouth over time by measuring it with <SUP>19</SUP>F NMR spectroscopy after the topical application of 1.23 % APF gel. After 30-minute application, a very small amount of fluoride (0.000482 %) remained in the saliva in the mouth, indicating that there was no effect on the human body. Therefore, this study demonstrated that clinical fluoride application using 1.23 % APF gel is safe.