• Journal of Korean society of Dental Hygiene
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• v.16 no.4
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• pp.525-530
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• 2016

Objectives: The purpose of the study is to investigate remineralization effect according to application cycle of fluoride varnish in preschool children. Methods: The study subjects were fifty six children (92 teeth) having one or more early dental caries lesion. Fluoride varnish was applied to the primary area of maxillary and anterior mandibular teeth with the interval of one month, three months, and six months. Results: Dft index was 3.54 in male and 3.44 in female. The fluorescence loss(${\Delta}F$) value due to early caries lesions showed a significant difference in experiment groups I and II after the application of fluoride varnish, but there was no significant difference in experiment group III. After fluoride varnish application, there was a significant change in experimental group I and III. The maximum fluorescence loss(${\Delta}Fmax$) from early caries lesions showed a significant difference after application of the fluoride varnish in all three experiment groups of I, II, and III(p<0.001). Conclusions: Fluoride varnish should be recommended and applied to the children of high risk caries group in every three months.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1983-1985
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• 2005

This paper describes moisture content, dielectric strength and dielectric properties of thermally accelerating aged insulating paper as varnish treatment. Kraft, nomex paper were impregnated with diluted varnish, varnish and solvent were diluted in the ratio of 40wt%, in vacuum condition, and then completely dried. To analysis of papers were influenced by varnish treatment, we applied thermal stress, and then measured moisture content, dielectric strength and relative permittivity, $tan{\delta}$ as varnish impregnated papers.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.461-470
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• 2013

In order to examine the anticariogenic effect after fluoride varnish was applied to sound enamel and artificial caries enamel, anterior teeth of healthy cattle were used and divided into four groups such as group 1 (sound enamel), group 2 (application of fluoride varnish to sound enamel), group 3 (artificial caries enamel) and group 4 (application of fluoride varnish to artificial caries enamel). Remineralization on the surface of enamel and changes of crystalline structure after demineralization were observed by using a field emission scanning electron microscope (FE-SEM). Quantitative analysis of Ca and P was measured by using the energy dispersive X-ray spectrophotometer (EDS). The following conclusions were obtained: 1)Surface pattern of enamel was the roughest in group 3 due to the defects caused by porosity and microcracks. Group 4, group 1 and group 2 were followed in order; 2) It was found that pattern of crystalline structures in a group of application of fluoride varnish and a group of no application showed bigger change in artificial caries enamel than that in sound enamel. In other words, groups 4 and 1 showed a similar pattern; 3) The contents of Ca and P were higher in groups of application of fluoride varnish (group 2 and group 4) than in groups of no application of fluoride varnish (group 1 and group 3). Taken results of this study together, in the case of application of fluoride varnish, crystalline structure was changed by remineralization even in the sound enamel. In particular, porous structures showed a smooth and uniform pattern due to the recalcification in the artificial caries enamel. In addition, according to results of EDS analysis, the contents of Ca and P were increased and it had great anticariogenic effects which inhibit decalcification of sound enamel and artificial caries enamel.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.266-276
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• 2020

The purpose of this study was to compare the remineralization effect of 38% silver diamine fluoride (SDF) and 5% sodium fluoride (NaF) varnish on artificially induced enamel caries. The present study standardized the physiochemical characteristics of the tooth structure using bovine teeth, realized the wash-off action of agents using a saliva, reproduced an environment similar to mouth through pH-cycling, and comparatively assessed the remineralization effect of 38% SDF and 5% NaF varnish in a non-destructive method using micro-CT. And the remineralized enamel surface structure was analyzed by scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS). In both SDF and NaF varnish, mineral density (△Hounsfield unit value) and the volume of enamel restored to normal mineral density through remineralization gradually increased with time. And the SDF showed a much higher level of increase in mineral density at all depths and remineralized volume than NaF varnish. According to SEM analysis, the surface roughness decreased in the order of artificial saliva, NaF varnish and SDF. In addition, EDS analysis showed that silver ion was precipitated on the enamel surface in SDF group. In conclusion, SDF had a greater remineralization effect than NaF varnish on demineralized enamel.

• Journal of the Korea Furniture Society
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• v.11 no.1
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• pp.45-51
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• 2000

It was thought that the stiffness of a coated specimen became lower than that of the solid wood because the stiffness of the dried film of coating material is lower than that of the solid wood. The authors were trying to compare the effect of lacquer varnish and rhus lacquer on the resonant frequency of the solid woods for the violin, spruce and maple. Vibration modal shape of coated specimens were same to those of solid woods, but the frequency became lower at each mode as were expected regardless of coat. frequency decrement of coated specimen was getting larger at upper mode in both European violin woods, however, rhus lacquer coated spruce specimens were less affected than lacquer varnish coated specimens.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.3
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• pp.193-201
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• 2006

Thermal performance model was developed for a cross-flow aluminum heat exchanger with relatively short passage. Appropriate heat transfer coefficient and friction factor equations for laminar channel flow were obtained considering developing regions. The heat exchanger was analyzed using the unmixed cross-flow ${\epsilon}$-NTU relationship considering leak-age between streams. Thermal contact between corrugations and plates was also considered. Tests were separately conducted for two samples - one made of non-treated aluminum sheets, and the other made of varnish-treated ones. The samples were made by stacking corrugations and plates one after another. The model adequately predicted the thermal performance and pressure drop of the non-treated heat exchanger. The thermal performance of the varnish-treated one was $7{\sim}12%$ overpredicted, and the pressure drop of the varnished-treated heat exchanger was $5{\sim}15%$ underpredicted. The air leakage ratio of the non-treated heat exchanger was $23{\sim}26%$. The ratio decreased to less than $10%$ with the varnish treatment.

• Restorative Dentistry and Endodontics
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• v.36 no.4
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• pp.290-299
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• 2011

Objectives: The usage of fluoride varnish for a moderate to low caries-risk group has not been well validated. This study aimed to evaluate the preventive and therapeutic efficacies of fluoride varnish on the initiated root caries. Materials and Methods: Ten premolars were sectioned into quarters, further divided into two windows, one of which was painted with Fluor Protector (1,000 ppm fluoride, Ivoclar Vivadent). An initial lesion with a well-preserved surface layer was produced by pH cycling. Scanned line analysis using energy dispersive spectrometry determined the weight percentages of Ca and P in the demineralized layer. Scanning Electron microscopy and confocal laser scanning microscopy (CLSM) evaluated the varnish-applied root surfaces. Results: The mean lesion depth (SD) was 12.3 (2.6) ${\mu}m$ (single cycling) and 19.6 (3.8) ${\mu}m$ (double cycling). Double cycling extended the lesion depth, but induced no more mineral loss than single cycling (p < 0.05). The mean weight percentages of Ca and P between groups with and without varnish were not significantly different (p < 0.05). A CLSM showed varnish remained within 15 ${\mu}m$ of the surface layer. Conclusions: When a mild acid challenge initiated root tissue demineralization, the application of low-concentration fluoride varnish did not influence the lesion depth or the mineral composition of the subsurface lesion.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.97-105
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• 1990

When conventional root canal treatment is failed or contraindicated, retrograde root canal filling following apicoectomy is a valuable procedure, aimed at hermetically sealing the root canal against leakage of irritants from the canal into the periapical tissue. In this in vitro investigation, to analyze apical microleakage electrochemically in teeth with different retrograde filling materials and preparation types, single - rooted tooth was cut 2mm from the apex and each Class I and Slot preparation was prepared. Experimental groups : Group 1. Amalgam filling with cavity varnish in Class I preparation Group 2. Scotchbond 2+Silux filling in Class I preparation Group 3. Gutta percha filling with ZOE cement in Class I preparation Group 4. Amalgam filling with cavity varnish in Slot preparation Group 5. Scotchbond 2+Silux filling in Slot preparation Each specimens was immersed in 1% solution of KCl, and applied a potential of 9V external power supply. Measurements of the current flow were obtained at 1, 2, 3, 7, 9, 12, 14, 18, 21, 25 and 28 day after immerson. Marginal microleakage were compared and evaluated. The results were as follows ; 1. The group filled with composite resin with dentin bonding agent shows lower apical microleakage value than the group filled with amalgam following varnish application (P<0.01). 2. In the group filled with gutta percha, apical microleakage value was the hightest 3. There was no significant difference between Class I cavity and Slot type cavity regardless of the used materials.

• Korean Journal of Dental Materials
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• v.44 no.1
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• pp.21-31
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• 2017

The purpose of this study was to fabricate a biocompatible fluoride varnish with sustained fluoride release, and to compare it with commercial fluoride varnishes. For the experimental fluoride varnish, bis-GMA (BG) or two types of rosin (KR-610: K0, KR-612: K2) were used as bases. Either ethyl acetate or ethanol was added as solvent and 5 wt% NaF was used. 5 mg of experimental F- varnishes and 2 commercial products, Cavity shield (CS) and Flor-opal (FO), were applied on a labial surface of bovine teeth ($10mm{\times}7mm$). The amount of fluoride release was measured at 1 hr, 2 hrs, 3 hrs, 4 hrs, 8 hrs, 12 hrs, 1 day, 3 days, 5 days, 10 days, 15 days, 20 days and 30 days. MTT test was done with diluted F- varnishes using ethanol. Statistical analysis was done with one-way ANOVA and Duncan multiple range test (${\alpha}=0.05$). BG showed the highest fluoride release at 1 hr (P<0.05), while that of K0 was highest at 2 hrs (P<0.05). From 1 day to 5 days, experimental fluoride varnishes showed higher fluoride release than the commercial products (P<0.05), and there were no significant differences after 5 days (P>0.05). For MTT test, K0 and FO showed higher cell viability than other experimental groups (P<0.05), with no significant differences with K2 (P>0.05). Considering the sustained fluoride release and cell viability of the experimental rosin-based fluoride varnishes compared with commercial products, it will be appropriate for clinical application.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.3
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• pp.77-83
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• 2010

In this study, we analyzed the combustion characteristics of four different floor covering materials(wood, monorium, laminatedpaper, and varnish-laminated paper) with regard to their ignitibility, thermal characteristics and flame retardancy by using an ignition temperature tester, a dual cone calorimeter, a thermogravimetric analyzer and limited oxygen index, for their fire risk assessment. According to the result, monorium had the lowest ignition temperature of $325^{\circ}C$ and the laminated paper and the varnish-laminated paper promptly ignited before 7s. Further, the wood showed the largest total heat release of $100MJ/m^2$, and the varnish-laminated paper showed the highest peak heat release rate. From the thermogravimetric analysis, it was shown that all specimens underwent rapid weight loss at $300{\sim}400^{\circ}C$. The limit oxygen indices of the laminated paper and the varnish-laminated paper were in the range of 20~21%, while it was 34% for wood. This study enabled us to confirm that wood, laminated paper and varnish-laminated paper have a relatively short ignition time and are easy to burn but they all have low heat release. In contrast, wood showed the lowest fire risk among them and had excellent flame retardancy but with high heat release.