• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.2
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• pp.179-184
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• 2018

Resin infiltration has been used as a treatment option for the management of early caries lesions recently. However, the etching procedure with hydrochloric acid might be somewhat stressful for the clinicians due to safety problem especially for young children, leading to less utility. This study aims at searching for some alternative surface pretreatment methods of resin infiltration for the early caries lesions in primary anterior teeth by comparing penetration depth of various methods. No significant difference was found in penetration ratio between etched surface with 15% hydrochloric acid and 35% phosphoric acid. However, the penetration ratio was significantly higher in groups pretreated either with dental pumice or abrasive metal strip (p < .05). By the result of this study, etching with phosphoric acid as an alternative of hydrochloric acid was thought clinically acceptable as a pretreatment method for resin infiltration in early caries lesions for primary anterior teeth. It was notable that surface conditioning with dental pumice or metal strip before etching was effective in increasing the penetration. This procedural modification might be much more correspondent with minimally invasive concept and hopefully contribute to increased safety and utility in pediatric dentistry.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.839-852
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• 1997

It has been submitted that different ion solutions containing sulfate induce crystal growth and might substitute conventional acid etching for pretreatment of enamel in orthodontic bonding(${\AA}rtun$ et al., Am. J. Orthod. 85, 333, 1984). This investigation was designed to evaluate the relevance of crystal growth on the enamel surface as an alternative to conventional acid etching in direct bonding of orthodontic brackets. Annexing Li2SO4, MgSO4, K2SO4 respectively in the solution with $25\%$ polyacrylic md 0.3M sulfuric acids were employed to enhance the crystal growth. Human bicuspids were treated with various parameters as combinations of crystal growth and glass ionomer cement, crystal growth and orthodontic resin, acid etching and orthodontic resin for an investigative purpose. Crystal growth solution containing MgSO4 showed the highest shear bond strength(15.6MPa) within the groups of bonding brackets with glass ionomer cement(p<0.01). Bonding with glass ionomer cement on the surface of crystal growth demonstrated higher shear bond strength than with orthodontic resin(p<0.001). Bonding with glass ionomer cement on the surface treated with crystal growth solution containing MgSO4 or K2SO4 was not different shear bond strength statistically from bonding with orthodontic resin on the acid-etched surface. It suggests that bonding brackets with glass ionomer cement on the surface treated with crystal growth solution containing MgSO4 or K2SO4 is a potential alternative to bonding with resin on the acid etched sufrace.

• Restorative Dentistry and Endodontics
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• v.27 no.6
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• pp.569-576
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• 2002

This study was peformed to evaluate the interfacial shear bond strength of base (direct and indirect) and repair composites with aging and surface treatment methods. Direct composite resin specimens ($Charisma^{\circledR}$, Heraeus Kulzer, Germany) were aged for 5 min, 1 hour, 24 hours, and 1 week in $37^{\circ}C$ distilled water before surface treatment, and then divided into five groups Group 1, grinding; Group 2, grinding and application of bonding agent, Group 3, grinding, etching with 37% phosphoric acid for 30sec, and application of bonding agent, Group 4, grinding, etching with 37% phosphoric acid for 30sec, silane treatment, and application of bonding agent ; Group 5, grinding, etching with 4% hydrofluoric acid for 30sec. silane treatment, and application of bonding agent. Indirect composite resin specimens ($Artglass^{\circledR}$, Heraeus Kulzer, Germany) were aged for 1 week in $37^{\circ}C$ distilled water and divided into seven groups Group 1 - Group 5, equal to Charisma specimens; Group 6, grinding, etching with 37% phosphoric acid for 60sec, silane treatment, and application of bonding agent; Group7, grinding, etching with 4% hydrofluoric acid for 60 sec, silane treatment, and application of bond-ing agent. The repair material($Charisma^{\circledR}$) was then added on the center of the surface (5 mm in diameter. 5 mm in height). The shear bond strength was tested and the data was analyzed using one-way ANOVA and the Student- Newman-Keuls test. The following conclusions were drawn. 1 The shear bond strength of $Charisma^{\circledR}$ specimens aged for 1 hour was significantly higher in Group 2 and Group 5 than in Group 1 (p<0.05), and that of $Charisma^{\circledR}$ specimens aged for 1 week was signifi-cantly higher in Group 3 and Group 5 than in Group 1 (p<0.05). No significant difference was found in the bond strength of specimens aged for 5 min and 24 hours. 2. In Group 2 of the $Charisma^{\circledR}$ specimens, there was significant difference between the bond strength of 24 hours and that of 1 week (p<0.05). 3. In Group 4 of the $Charisma^{\circledR}$ specimens, the shear bond strength of specimens aged for 24 hours was significantly higher than the others(p<0.05) 4. There was no significant difference between the shear bond strength of the $Artglass^{\circledR}$ specimens, 5. Most of the $Charisma^{\circledR}$ specimens showed cohesive fractures. Artglass^{\circledR}$ specimens that were etched with acid (phosphoric or hydrofluoric) for 30 sec showed more cohesive fractures.

• The korean journal of orthodontics
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• v.43 no.3
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• pp.120-126
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• 2013

Objective: To gain basic information regarding the biologic stability of plasma ion-implanted miniscrews and their potential clinical applications. Methods: Sixteen plasma ion-implanted and 16 sandblasted and acid-etched (SLA) miniscrews were bilaterally inserted in the mandibles of 4 beagles (2 miniscrews of each type per quadrant). Then, 250 - 300 gm of force from Ni-Ti coil springs was applied for 2 different periods: 12 weeks on one side and 3 weeks contralaterally. Thereafter, the animals were sacrificed and mandibular specimens including the miniscrews were collected. The insertion torque and mobility were compared between the groups. The bone-implant contact and bone volume ratio were calculated within 800 mm of the miniscrews and compared between the loading periods. The number of osteoblasts was also quantified. The measurements were expressed as percentages and analyzed by independent t-tests (p < 0.05). Results: No significant differences in any of the analyzed parameters were noted between the groups. Conclusions: The preliminary findings indicate that plasma ion-implanted miniscrews have similar biologic characteristics to SLA miniscrews in terms of insertion torque, mobility, bone-implant contact rate, and bone volume rate.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.410-414
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• 2013

We report the wet etching of titanium nickel (TiNi) films for the production of nano-electro-mechanical (NEM) device. $SiO_2$ and $Si_3N_4$ have been selected as sacrificial layers of TiNi metal and etched with polyethylene glycol and hydrofluoric acid (HF) mixed solution. Volume percentage of HF are varied from 10% to 35% and the etch rate of the $SiO_2$, $Si_3N_4$ and TiNi are reported here. Within the various experiment results, 15% HF mixed polyethylene glycol solution show highest etch ratio between sacrificial layer and TiNi metal. Especially $Si_3N_4$ films shows high etch ratio with TiNi films. Wet etching results are measured with SEM inspection. Therefore, this experiment provides a novel method for TiNi in the nano-electro-mechanical device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.1
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• pp.58-61
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• 2012

In our report a relatively simple process for fast nano-texturing of p-type(100) CZ- silicon surface using silver catalyzed wet chemical etching in aqueous hydrofluoric acid (HF) and hydrogen peroxide solution($H_2O_2$) at room temperature. The wafers were saw-damaged by NaOH(6 wt%) at $60^{\circ}C$ for 150s. To obtain a nano-structured black surface, a thin layer of silver with thickness of 1 - 10 nm was deposited on the surfaces by evaporation system. After this process the samples were etched in HF : $H_2O_2$ : $H_2O$ = 1:5:10 at room temperature for 80s - 220s. Due to the local catalytic of the Ag clusters, this treatment results in the nano-scale texturing on the surface. This resulted in average reflectance values less than 9% after the silver on the surface of the wafers were removed.

• Fashion & Textile Research Journal
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• v.15 no.2
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• pp.302-308
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• 2013

This study is a preliminary investigation of the influence of surface characteristics of substrates on detergency of particulate soil. The surface of PET film was modified with NaOH and NaOH+ethylene diamine on different times. The surface morphology of the film was scanned by AFM and surface energies were calculated from measured contact angles between several solutions and film based on the geometric mean and a Lewis acid base method. The surface morphology of PET film treated with NaOH and NaOH+ethylene diamine became more etched, and the surface area, surface roughness and the coefficient of friction of film increased with treatment of NaOH and NaOH+ethylene diamine. The contact angle of film treated with NaOH and NaOH+ethylene diamine decreased in water and surfactant solution; in addition, the surface energy increased was largely attributed to the increased portion on the polar surface energy of film. However, the effect of the diamine addition to the NaOH treatment solution on surface characteristics of PET film was insignificant.

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.871-875
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• 1998

High aspect ratio microstructures were fabricated by photolithography. The material for the microstructure was photosensitive glass which has good mechanical and electrical insulation properties. The photosensitive glass was exposed to ultraviolet light at 312nm through a chromium mask in which the structures are drawn. After heat treatment process over $500^{\circ}C$, the photosensitive glass was etched in a 10% hydrofluoric acid solution with ultrasonic conditions. Final dimension of the micro-framework was greatly dependent on the thickness of photosensitive glass, mask pattern, ultraviolet light exposure and etching conditions. The maximum aspect ratio of the micro-framework obtained from this work was over 30.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.2
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• pp.365-372
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• 1997

This study was executed to measure the shear bond strength of Panavia EX and Panavia 21 when the Ni-Cr-Be alloy castings were cemented to the enamel surfaces with these cements. The cast metal plates of Ni-Cr-Be alloy were sandblasted and cemented to acid etched enamel surface with Panavia EX or Panavia 21. Their shear bond strength were measured with Instron Universal Testing machine. Within the limits of this study, following conclusions were withdrawn. 1. The mean shear bond strength were 26.85.7MPa, in Panavia EX and 28.35.2MPa, in Panavia 21. 2. t-Test revealed no statistical significance between two groups(.05 level) 3. Macroscopically, bond failures were revealed compound fracture at metal and enamel interfaces, in cases of both cements, as the cement attached partly on both metal and enamel surface.

• Journal of the Korean institute of surface engineering
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• v.53 no.3
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• pp.109-115
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• 2020

In this study, polycrystalline diamond was synthesized by chemical vapor deposition (CVD). Diamond films were deposited on a-plane sapphire substrates while changing the concentration of methane for hydrogen (CH₄/H₂), and the concentrations of methane were 0.25, 0.5, 1, 2, 3 and 4 vol%, respectively. Crystallinity and nucleation density according to changes in methane concentration were investigated. At this time, the discharge power, vacuum pressure, and deposition time were kept constant. In order to deposit polycrystalline diamond, the sapphire substrate was etched with sulfuric acid and hydrogen peroxide (ratio 3:7), and the sapphire surface was polished for 30 minutes with 100 nm-sized nanodiamond particles. The deposited diamond thin film was analyzed by a scanning electron microscope (SEM), a Raman spectra, Atomic force microscope (AFM) and an X-ray diffractometer (XRD). By controlling the ratio of methane to hydrogen and performing appropriate pre-treatment conditions, a polycrystalline diamond thin film having excellent crystallinity and nucleation density was obtained.