• Restorative Dentistry and Endodontics
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• v.32 no.3
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• pp.180-190
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• 2007

The purpose of this study was to evaluate the abrasion resistance of surface penetrating sealant which was applied on a composite resin restoration and to provide proper time to reapply sealant on composite resin surface. Two hundred rectangular specimens, sized $8\times3\times2mm$, were made of Micronew (Bisco, Inc., Schaumburg, IL, U.S.A) and divided into two groups; F group (n = 10) was finished with coarse and medium grit of Sof-Lex discs and BisCoverwas applied B group (n = 190) after finishing with discs. B group was again subdivided into nineteen subgroups From B-1 group to B-18 group were subjected to toothbrush abrasion test using a distilled water-dentifrice slurry and toothbrush heads B-IM group was not subjected to toothbrush abrasion test. Average surface roughness (Ra) of each group was calculated using a surface roughness tester (Surfcorder MSE-1700: Kosaka Laboratory Ltd., Tokyo, Japan) . A representative specimen of each group was examined by FE-SEM (S-4700: Hitachi High Technologies Co., Tokyo, Japan). The data were analysed using cluster analysis, paired t-test, and repeated measure ANOVA. The results of this study were as follows; 1. Ra off group was $0.898{\pm}0.145{\mu}m$ and B-IM group was $0.289{\pm}0.142{\mu}m$. Ra became higher from B-1 group $(0.299{\pm}0.48{\mu}m$ to B-18 group $(0.642{\pm}0.313{\mu}m$. 2. Final cluster center of Ra was $0.361{\mu}m$ in cluster 1 $(B-IM\simB-7)$, $0.511{\mu}m$ in cluster 2 $(B-8\simB-14)$ and $0.624{\mu}m$ in cluster 3 ($(B-15\simB-18)$. There were significant difference among Ra of three clusters. 3 Ra of B-IM group was decreased 210.72% than Ra of F group. Ra of B-8 group and B-15 group was increased 35.49% and 51.35% respectively than Ra of B-IM group. 4. On FE-SEM, B-IM group showed the smoothest resin surface. B-8 group and B-15 group showed vertically shallow scratches , and wide and irregular vertical scratches on composite resin surface respectively. Within a limitation of this study, finished resin surface will be again smooth and glazy if BisCover would be reapplied within 8 to 14 months after applying to resin surface.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.592-599
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• 2002

Objective : The purpose of this study was to evaluate the effects of several light curing methods and several adhesives on the microleakage of composite resin restorations in primary teeth. Materials and methods : In 150 extracted human primary anterior teeth, O-shaped cavities were prepared in the labial surface ; the cavity diameter and depth were 1.6mm. The cavities were filled with light-activated composite resin, Compoglass. Four kinds of adhesives were used. Each filling materials were polymerized with three light cure methods. The restorations were polished using Sof-Lex discs(3M Co., USA). The samples were thermocycled 1,000 times between $5^{\circ}C$ and $55^{\circ}C$ with a 1-minute dwell time. Then, they were immersed in a 2% methylene blue solution(pH 7) for 12hours. Subsequently they were sectioned labio-lingually through the center of the restoration with a diamond saw at low speed with a water coolant, and evaluated by stereomicroscopy. Microleakage analyses were done, using scores from 0 to 4. Results : Results showed the least microleakage in Compoglass group(P<0.05). There were less microleakage in SBMP group among the adhesive groups, but no significant difference was observed(P>0.05). And there were no significant differences among the groups depending on curing methods(P>0.05).

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.5691-5695
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• 2015

Background: Continuous surveillance of pattern of blood stream infection is necessary in febrile neutropenia (FN)especially with the recent escalating trend in the management of pediatric cancer patients towards intensified regimens and with the increase in infections caused by resistant organisms limiting the choice of antibiotics. Aim: To monitor change in pattern of blood stream infections (BSI) in FN pediatric cancer patients. Materials and Methods: Surveillance of FN episodes with positive BSI was prospectively monitored and compared to a previous surveillance in the same pediatric oncology unit. Results: A total of 232 BSI positive episodes were documented in 192 patients during a 6 months period. The results of recent surveillance analysis showed an increase in intensified regimens of chemotherapy, antimicrobial resistance, fungal infections, and prolonged duration of episodes when compared to previous surveillance, with p value sof <0.001, 0.005, 0.021, and <0.001, respectively. There was an apparent decrease in the crude mortality but this was not statistically significant, to 6% in 2011 from 10 % in 2006. Conclusions: The pattern of BSI at our institution is still inclining towards gram positive organisms but is showing a shift towards more antibiotic resistance and fungal infections.

• Journal of Embryo Transfer
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• v.19 no.1
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• pp.67-73
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• 2004

본 연구는 우리나라 고유의 유전자원인 재래산양의 체내수정란 생산기술을 확립하고자 수행하였다. 흡입법(aspiration)과 세절법(slicing)에 의해 난소 한 개당 회수된 난자의 수는 3.9개와 4.1개를 나타내어 slicing방법이 aspiration방법보다는 많은 숫자의 난자를 회수하였으나 유의적인 차이는 나타내지 않았다. 회수된 난자의 등급별 분포는 aspiration방법에서 Grade I, Grade II, Grade III, Grade IV의 비율이 10.3%, 20.5%, 38.5%, 30.8%를 나타내었으며, slicing법에서는 9.8%, 22.0%, 39.0%, 29.3%를 나타내어 Grade III과 Grade IV의 비율이 70% 이상을 차지하였다. 회수된 난자를 체외성숙 시킨 결과 Grade I과 Grade II에서는 85% 이상이 metaphase H (MII)까지 도달하였으나, Grade III과 Grade IV는 40% 이하의 체외성숙율을 나타내었다. 체외수정용 배양액으로 BO를 사용하였을 경우 Grade I 및 II에서 84.4%의 난분할율을 나타내어 TALP를 사용하였을 때의 58.8%보다 높은 난할율을 보였다. 또한 배양액의 종류별 체외발달율에 있어서는 상실배 및 배반포기배로의 발달은 mSOF를 배양액으로 이용하였을 경우 15.0%의 발달율을 나타내었으며, 체외배양 시 항산화물질인 glutathione (GSH)을 첨가함으로서 26.8%의 상실배 및 배반포배로의 발달율을 나타내었다.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.599-605
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• 2000

Among the effects of tooth bleaching on composite resins, degree of color change and dye deposition onto composite resins after office bleaching were investigated in vitro. Seventy two disc-shaped resin samples were fabricated with hybrid type composite resin, Z-100 under 3 different environments(24 samples for each environment) characterized by 3 kinds of light-curing intensity and duration($250mW/cm^2$-20sec., $250mW/cm^2$-40sec., $550mW/cm^2$-20sec.). As control, one-third samples of each group were not treated with bleaching agent. The remaining two-thirds samples of each group were treated with bleaching agent(bleaching group). Then, before thermocycling procedure in coffee bath, the half of the samples treated with bleaching agent were polished(polishing group) with polishing system. SofLex, but the other half(not-polishing group) and control group were not polished. Another 72 samples were also made with microfilled type composite resin. Sillux Plus and treated according to the experimental procedures mentioned above. The color of each resin sample was measured before bleaching, after bleaching, and after thermocycling preceded by bleaching. And color difference was evaluated. It was concluded as follows: 1. The amount of color change of resin samples after office bleaching was not statistically significant(p>0.05). But the samples which were treated with bleaching agent showed more color change than that of control group. 2. After thermocycling in coffee bath, the amount of color change of resin samples between control and bleaching group was not statistically significant(p>0.05). 3. After thermocycling in coffee bath, the polishing procedure of resin samples showed no statistically significant difference(p>0.05) between polishing and not-polishing group in the aspect of color change.

• Proceedings of the KACD Conference
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• 2008.05a
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• pp.177-183
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• 2008

It was reported that esthetic composite resin restoration reinforces the strength of remaining tooth structure with preserving the natural tooth structure. However, it is unknown how much the strength would be recovered. The purpose of this study was to compare the fracture resistance of three types of undermined cavity filled with composite resin with that of non-cavitated natural tooth. Forty sound upper molars were allocated randomly into four groups of 10 teeth. After flattening occlusal enamel. undermined cavities were prepared in thirty teeth to make three types of specimens with various thickness of occlusal structure (Group $1{\sim}3$). All the cavity have the 5 mm width mesio-distally and 7 mm depth bucco-lingually. Another natural 10 teeth (Group 4) were used as a control group. Teeth in group 1 have remaining occlusal structure about 1 mm thickness, which was composed of mainly enamel and small amount of dentin. In Group 2, remained thickness was about 1.5 mm, including 0.5 mm thickness dentin. In Group 3, thickness was about 2.0 mm, including 1 mm thickness dentin. Every effort was made to keep the remaining dentin thickness about 0.5 mm from the pulp space in cavitated groups. All the thickness was evaluated with radiographic Length Analyzer program. After acid etching with 37% phosphoric acid, one-bottle adhesive (Single $Bond^{TM}$, 3M/ESPE, USA) was applied following the manufacturer's recommendation and cavities were incrementally filled with hybrid composite resin (Filtek $Z-250^{TM}$, 3M/ESPE, USA). Teeth were stored in distilled water for one day at room temperature, after then, they were finished and polished with Sof-Lex system. All specimens were embedded in acrylic resin and static load was applied to the specimens with a 3 mm diameter stainless steel rod in an Universal testing machine and cross-head speed was 1 mm/min. Maximum load in case of fracture was recorded for each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA) and a Tukey test at the 95% confidence level. The results were as follows: 1. Fracture resistance of the undermined cavity filled with composite resin was about 75% of the natural tooth. 2. No significant difference on fracture loads of composite resin restoration was found among the three types of cavitated groups. Within the limits of this study, it can be concluded the fracture resistance of the undermined cavity filled with composite resin was lower than that of natural teeth, however remaining tooth structure may be supported and saved by the reinforcement with adhesive restoration, even of that portion consists of mainly enamel and a little dentin structure.

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.177-183
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• 2008

It was reported that esthetic composite resin restoration reinforces the strength of remaining tooth structure with preserving the natural tooth structure. However, it is unknown how much the strength would be recovered. The purpose of this study was to compare the fracture resistance of three types of undermined cavity filled with composite resin with that of non-cavitated natural tooth. Forty sound upper molars were allocated randomly into four groups of 10 teeth. After flattening occlusal enamel, undermined cavities were prepared in thirty teeth to make three types of specimens with various thickness of occlusal structure (Group $1{\sim}3$). All the cavity have the 5 mm width mesiodistally and 7 mm depth bucco-lingually. Another natural 10 teeth (Group 4) were used as a control group. Teeth in group 1 have remaining occlusal structure about 1 mm thickness, which was composed of mainly enamel and small amount of dentin. In Group 2, remained thickness was about 1.5 mm, including 0.5 mm thickness dentin. In Group 3, thickness was about 2.0 mm, including 1 mm thickness dentin. Every effort was made to keep the remaining dentin thickness about 0.5 mm from the pulp space in cavitated groups. All the thickness was evaluated with radiographic Length Analyzer program. After acid etching with 37% phosphoric acid, one-bottle adhesive (Single $Bond^{TM}$, 3M/ESPE, USA) was applied following the manufacturer's recommendation and cavities were incrementally filled with hybrid composite resin (Filtek $Z-250^{TM}$, 3M/ESPE, USA). Teeth were stored in distilled water for one day at room temperature, after then, they were finished and polished with Sof-Lex system. All specimens were embedded in acrylic resin and static load was applied to the specimens with a 3 mm diameter stainless steel rod in an Universal testing machine and cross-head speed was 1 mm/min. Maximum load in case of fracture was recorded for each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA) and a Tukey test at the 95% confidence level. The results were as follows: 1. Fracture resistance of the undermined cavity filled with composite resin was about 75% of the natural tooth. 2. No significant difference in fracture loads of composite resin restoration was found among the three types of cavitated groups. Within the limits of this study, it can be concluded the fracture resistance of the undermined cavity filled with composite resin was lower than that of natural teeth, however remaining tooth structure may be supported and saved by the reinforcement with adhesive restoration, even if that portion consists of mainly enamel and a little dentin structure.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.4
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• pp.719-741
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• 1997

This study was undertaken to compare by Atomic Force Microscope the effects of various finishing and polishing instruments on surface roughness of filling and veneering composite resins. Seven composite resins were studied : Silux Plus (3M Dental Products, U.S.A.), Charisma (Heraeus Kulzer, Germany), Prisma THP (L.D.Caulk, Dentsply, U.S.A.), Photoclearfil (Kuraray, Japan), Cesead (Kuraray, Japan), Thermoresin LC (GC, Japan), Artglass (Heraeus Kulzer, Germany). Samples were placed and polymerized in holes (2mm thick and 8.5mm in diameter) machined in Teflon mold under glass plate, ensuring excess of material and moulded to shape with polyester matrix strip. Except control group (Polyester matrix strip), all experimental groups were finished and polishied under manufacturer's instructions. The finishing and polishing procedure were : carbide bur (E.T carbide set 4159, Komet, Germany), diamond bur (composite resin polishing bur set, GC, Japan), aluminum-oxide disc (Sof-Lex Pop-On, 3M Dental Products, U.S.A.), diamond-particle disc (Dia-Finish, Renfert Germany), white stone bur & rubber point( composite finishing kit, EDENTA, Swiss), respectively. Each specimens were evaluated for the surface roughness with Atomic Force Microscope (AutoProbe CP, Park Scientific Instruments, U.S.A.) under contact mode and constant height mode. The results as follows : 1. Except Thermoresin LC, all experimental composite resin groups showed more rougher than control group after finishing and polishing(p<0.1). 2. A surface as smooth as control group was obtained by $Al_{2}O_{3}$ disc all filling composite resin groups except Charisma and all veneering composite resin groups except Thermoresin LC(p<0.05). 3. In case of Thermoresin LC, there were no statistically significant differences before and after finishing and polishing(p>0.1). 4. Carbide bur, diamond bur showed rough surfaces in all composite resin groups, so these were inappropriate for the final polishing instruments.

• Reproductive and Developmental Biology
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• v.28 no.2
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• pp.127-132
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• 2004

This study was conducted to examine the effects of electric stimulation conditions on in vitro developmental ability of caprine embryos after somatic cell nuclear transfer. Recipient oocytes were surgically collected after superovulation by using CIDR and FSH, PMSG, hCG and estrous synchronization in Korean native goats. The caprine ear cells were cultured in vitro in serum-starvation condition (TCM-l99 + 0.5% FBS) for 3 to 5 days of cell confluence. The zona pellucida of in vivo and in vitro matured oocytes were partially drilled using laser system. Single somatic cell was individually transferred into the enucleated oocyte. The reconstructed oocytes were electrically fused with 0.3M mannitol. After the electofusion, embryos were activated by electric stimulation or Ionomycin + 6-DMAP. Nuclear transfer embryos were cultured in mSOF medium supplemented with 0.8% BSA 6∼7 days at 39 , 5% $CO_2$, 5% $O_2$, 90% $N_2$. The fusion rate of donor cells was 60.4% and 40.3 % in ear cell and fetal fibroblast, and cleavage rate were 40.6% and 48.2%, respectively. No significant difference was found in the fusion and cleavage rate in different donor cells. Nuclear transferred oocytes were fused by electric pulses of 1.30∼1.40, 2.30∼2.39 and 2.40∼2.46 ㎸/cm. There was no significant difference among different electric pulses in fusion rates (26.7, 34.8 and 43.8%). The cleavage rate was higher (p<0.05) in 1.30∼1.40 ㎸/cm (82.9%) than 2.30∼2.39 ㎸/cm (43.8%) and 2.40∼2.46 ㎸/cm. (51.8%). The fusion rates of recipient oocyte source were 1st (43.5% and 23.6%), 2nd (55.7％ and 39.2%) and 3rd (66.1% and 52.8%) in in vivo and in vitro oocytes. However, fusion ratee were significantly higher (p<0.05) in in vivo than in vitro oocyte. The cleavage rate of fused oocytes from in vivo and in vitro sources were 52.6% and 54.4%, respectively. No significant difference was found in the cleavage rate according to the recipient oocyte source. These results suggest that factors such as field pulse of electric stimulation and oocyte source could affect in vitro developmental ability of nuclear transplanted caprine oocytes.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.191-197
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• 2016

Historically, Korea old cattle had been consisted with various lines of coat color brindle, black and white-brown breeds or more. The two rare lines of black and white coat color are maintained for animal resources and preserved critically. The present study was carried out to evaluate potential usage of cysteamine supplementation during in vitro matration (IVM) and in vitro culture/production of embryo (IVP) by transvaginal ultrasound-guided follicle aspiration (Ovum Pick-Up: OPU) for the establishment of cryo-banking system. Immature slaughterhouse-derived cumulus-oocyte complexes (SL-COCs) were matured in IVM medium supplemented with 0, 0.1, 0.3 or 0.9 mM cysteamine, and then cultured in mSOF-BAS for 8 days after in vitro fertilization. The treatment of 0.1 mM cysteamine on SL-COCs showed higher rate of blastocyst, so OPU-derived COCs from rare breeds were matured in TCM media supplemented with or without 0.1 mM cysteamine, FSH and 5% FBS. The embryos were evaluated their developmental stages on day 8. During IVM, cysteamine treatment significantly increased the embryo production rate of slaughterhouse-derived COCs (19.6% vs. 30.5%). The presence of cysteamine during IVM of OPU-derived COCs from rare Korean cattle breeds (albino white and black line) also increased embryo production rates than those from SL-COCs (27.4% vs. 41.9% and 36.4%). With these results, cysteamine treatment during IVM is one of key factors IVP of blastocysts to establish banking system of endangered rare Koarean cattle with OPU derived transferable blastocysts.