• The korean journal of orthodontics
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• v.35 no.6 s.113
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• pp.433-442
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• 2005

The purpose of this study was to evaluate and compare the shear bond strength of orthodontic brackets depending on the variety of adhesives and whether saliva exists, by using self-etching primer (SEP). Groups were divided according to the type of adhesive into resin adhesive (Trans bond XT) and resin-modified glass ionomer cement (Fuji Ortho LC). One group of resin adhesive used XT primer after etching with 37% phosphoric acid, and the other group used self-etching primer. One group of resin-modified glass ionomer cement only used etching for bonding, and the other group used SEP. Each of the groups were also classified by whether saliva was contaminated or not. and then the shear bond strength was measured. The results showed that when using resin adhesive, the shear bond strength of SEP was lower than the XT primer. In the resin-modified glass ionomer cement groups, the shear bond strength which depends on the priming method, did not have a meaningful difference statistically When saliva was contaminated, the group which used SEP, regardless of the adhesive variety, had a greater shear bond strength than the normal priming group. From these results, SEP showed a shear bond strength that is possible to be used clinically, regardless of the adhesive variety. It can especially be clinically useful to use SEP to bond brackets even on tooth surfaces contaminated with saliva, because it offers the appropriate bonding strength as well as shorter treatment time and easy application.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.386-396
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• 2004

Statement of problem: It is not clear how to make a stable bonding between zirconia ceramic and resin cement. And the study about surface treatment of zirconia ceramic or bonding resin cement are not enough. Purpose: To measure and compare the shear bond strength of some resin cements on zirconia ceramic after different surface treatments. Material and method: 48 ceramic discs were made of 3 ceramic materials, zirconia ceramics (Zi-Ceram), heat-pressed ceramics (IPS Empress 2) and slip cast alumina ceramics (In-Ceram). According to the surface treatments of ceramic specimens and resin cements, specimens were classified into 6 groups and each group was composed of 8 specimens. For the surface treatment of Zi-Ceram group (test group), sandblasting and diamond bur preparation were applied and Superbond C&B and Panavia F were bonded respectively. For IPS Empress 2 group (control group), Variolink II was bonded after sandblasting, acid etching, silanization and for In-Ceram ALUMINA group (control group), Panavia F was bonded after sandblasting. After storing specimens in distilled water for 24 hours, the shear bond strength was measured by the universal testing machine. Results and conclusion: 1. Zi-Ceram group with Superbond C&B cement showed higher bond strength than with Panavia F cement regardless to the surface treatments (p<0.05). 2. In Zi-Ceram group with Superbond C&B cement, sandblasting treatment group (12.1MPa) showed higher bond strength than diamond bur treatment group (7.7MPa) (p<0.05). In Zi-Ceram group with Panavia F cement, there were no significant differences in the bond strength according to the surface treatments (p>0.05). 3. Zi-Ceram group with sandblasting and Superbond C&B cement (12.1MPa) showed the highest bond strength. The bond strength of this group was not significantly different from In-Ceram ALUMINA group (10.4MPa) (p>0.05) and lower than IPS Empress 2 group (15.9MPa) (p<0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.426-437
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• 2005

Statement of problem : Although zirconium oxide ceramics are more and more commonly used in restorative dentistry, for many clinical applications only limited data can be found in the literature. However it is quite clear that hydrofluoric acid etching is impossible with zirconia ceramics. Therefore, other bonding techniques are required in order to lute these materials adhesively. Purpose : The purpose or this study was to evaluate the effects of surface treatments on shear bond strengths between two resin cements and a zirconia ceramic. Materials and methods : Experimental industrially manufactured yttrium-oxide-partially-stabilized zirconia ceramic discs (Adens, Korea) were used for this study. The ceramic specimens divided into five experimental groups and a control group (as received). Five surface treatments were studied 1) sandblasting with 110$\mu$m $Al_2O_3$ at 3 bars pressure 13 seconds at a distance of 10 mm, 2) flame-treated with the Silano-Pen for 5 $s/cm^3$, 3) grinding with a diamond bur. 4) sandblasting + Silano-Pen treatment, 5) diamond bur preparation + Silano-Pen treatment. Acrylic plastic tube (5 mm in height and 3 mm in diameter) were filled with composite to fabricate composite cylinders The composite cylinders were bonded to the ceramic specimens with either Superbond C&B or Panavia F resin luting agents. All cemented specimens were tested under shear loading until fracture on universal testing machine at a crosshead speed 1mm/min; the maximum load at fracture was recorded. Sheat bond strength data were analyzed with oneway analysis of variance and Tukey HSD tests (P<.05). Treated ceramic surfaces and fracture surfaces after shear testing were examined morphologically using scanning electron microscope. Results: Ceramic surface treatment with Silano-Pen after sandblasting improved the bond strength of Superbond C&B resin cement. Supevbond C& B resin cement at Silano-Pen aiker sandblasting($27.4{\pm}3.8MPa$) showed statistically higher shear bond strength than the others. Conclusion: Within the limitation of this study, Superbond C& &B resin cement are suitable for cementation of zirconia ceramics and flame-treated with the Silano-Pen after sandblasting is required to enhance the bond strength.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.449-457
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• 2016

At this study, we select five colorful and high-acid fruits: grape, lemon, orange, grapefruit and kiwi, and we made a composite resin specimen and dipped into fruit juice in order to figure out influence that affects on surface corrosion and coloring. We dipped resin specimen into fruit juice by three-day and seven-day interval at $37^{\circ}C$. Control group used the resin that was not dipped into fruit juice. For surface change according to the time, it was observed by using scanning electron microscopy, and it was measured by using spectrophotometer for change of coloring degree. As a result of surface change of resin by using scanning electron microscopy, furrow size between surface particles increased, and rectangular rod-shape structure was emerged, and small prominent particles on bumps disappeared. As a result of coloring degree of resin by measuring spectrophotometer, a difference between experimental group appears with the darkest brightness in the case where it is dipped into grape extracts.

• Journal of the Korean Chemical Society
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• v.27 no.5
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• pp.353-360
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• 1983

The adsorption behavior of 8-hydroxyquinoline (8HQ) on Amberlite XAD-4 and-7 resins was investigated by measuring its distribution coefficients under various experimental conditions, such as shaking time, pH and concentration of methanol in the medium. The application of 8HQ-impregnated-XAD resins for the absorption and separation of metal ions was studied. The maximum adsorption of 8HQ on XAD resins was observed in the 30% methanol solution having pH range from 6.0 to 9.0. The impregnation capacities of XAD resins for 8HQ were 3.81${\times}$10-2mmol, 8HQ/g, XAD-4 resins and 2.60${\times}$10-2mmol, 8HQ/g, XAD-7 resin, respectively. The 8HQ-impregnated-XAD resins were stable in pH range from 6.0 to 10.0 and the amount of 8HQ leached from XAD-4 resin by eluting with hydrochloric acid(above 5M) was negligible. The optimum pH range for the adsorption of metal ions on 8HQ-impregnated XAD resin was also 6.0 to 10.0, and the adsorption mole ratio of metal ion to 8HQ were 1 : 2 for Cu(II), Cd(II) and Ni(II), and 1 : 3 for Fe(III) at the above pH range. It was found that the absorbed metal ions on 8HQ-impregnated-XAD resins were recovered quantitatively with 5M HCl and 8HQ-impregnated-XAD-4 resin could be reusable over 5 times without decrease in its impregnation capacity.

• Restorative Dentistry and Endodontics
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• v.24 no.3
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• pp.473-481
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• 1999

This study evaluated the shear bond properties of IPS Empress glass ceramic to enamel and dentin surfaces with three ceramic surface treatments, and three resin cements. The influence of thermocycling was also investigated. The purpose of this study was to investigate the influences of resin cements, ceramic surface treatments, and thermocycling on shear bond properties. Ninety freshly extracted, noncarious human molars were selected for this study. The surface treatments of ceramic were etching <5.0% hydrofluoric acid, application of silane coupling agents(Tokuso Ceramic Primer, Clearfil porcelain bond, Monobond-S), and the combination of the two methods. Empress cylinders were bonded to enamel and dentin surfaces with three kinds of resin cements(Bistite resin cement, Panavia 21, Variolink). The specimens were aged in $37^{\circ}C$ distilled water for 24 hours. Half of the specimens were then thermocycled 500times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 15 seconds. Each specimen was debonded in shear mode and measured shear bond properties by using the universal testing machine(Zwick 020, Germany). The data were analyzed by SPSS/PC+(one-way ANOVA, Scheffe' s test and t-test). The results were as follows : 1. Without thermocyling, there was significant difference of shear bond strength to enamel surface between Bistite Resin Cement and Panavia 21 in case of etched and silane-treatment(p<0.05). 2. Without thermocyling, the shear bond strength of a group treated with silane and etching was significantly higher than that of a group treated with silane or etching with the application of Panavia 21 and Variolink(p<0.05). 3. A group treated with etching with the application of Variolink only showed a decrease of shear bond strength after thermocycling(p<0.05).

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1247-1250
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• 2008

This presentation highlights work from the authors' laboratories on the various kinds of oxide optical materials, mainly luminescence and pigment materials with different forms (powder, core-shell structures, thin film and patterning) prepared by the Pechini-type sol-gel (PSG) process. The PSG process which uses the common metal salts (nitrates, acetates, chlorides etc) as precursors and citric acid (CA) as chelating ligands of metal ions and polyhydroxy alcohol (such as ethylene glycol or poly ethylene glycol) as cross-linking agent to form a polymeric resin on molecular level, allowing the preparation of many forms of luminescent materials.

• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.304-309
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• 1991

Target transformation factor analysis is applied to analyze the components of unresolved fraction in the elution curve of La, Pr and Gd which is obtained using the chelate agent- impregnated resin and 0.7 M hydrochloric acid as an eluent. We determined the number of components contributing to the unresolved fractions and verified the presence of suspected components.

• The korean journal of orthodontics
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• v.20 no.1
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• pp.103-110
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• 1990

Metal brackets were recycled by variable methods for economic reason. Such recycling methods had a great effect on bracket slot width and bonding strength. Therefore, the recycling methods that don't change the properties of original bracket were suggested. In this study, debonded brackets were recycled with 30 kinds of solvents and bracket surfaces were examined by S.E.M. (Super IIIA, ISI International Scientific Instruments, Japan) and Stero Microscope (Sz-Tr, Olympus Tokyo, Japan) methods. The following results were obtained. 1. Thermosetting resin adhesives (eq. $Monolok^{(R)}$, $Concise^{(R)}$) were swelled most in sulfuric acid (assays 95%) and slightly in alcohol groups. 2. The solvent was exchanged every 24 hours during the brackets were recycled with sulfuric acid (assays 95%). As the passage of time, the adhesives were removed more clearly, and after 72 hours adhesives were nearly detached from bracket base. 3. Chemical recycled metal bracket surface showed no irregular structure by S.E.M. method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.7
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• pp.20-26
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• 2003

The ultra-lightweight high strength polymer concrete could be used for the drain structures under severe condition. In this study, materials used were unsaturated polyester resin, heavy calcium carbonate, artificial lightweight coarse aggregate and perlite. In the test results, the unit weight of the ultra-lightweight high strength polymer concrete was 946 kg f/$\textrm{m}^3$ and the compressive strength was appeared in 34.5 MPa. The compressive strength, splitting tensile strength, flexural strength, acid resistance and weather resistance were shown in excellently than that of the normal cement concrete. The draining trench had 1m length, 0.24 m width, 0.02 m thickness and 0.07 m height. The developed trench could be effectively used at the draining structures.