• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.312-315
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• 2018

Although the reversibility of 10,12-pentacosadiynoic amino meta-acid(PCDA-mBzA) against temperature and pH was reported, the modulation of reversibility by ion adsorption at terminal functional group has not been investigated. In this work, we developed a simple method for modulating the reversibility of PCDA-mBzA films upon a thermal stimulus by cadmium ion adsorption inducing the breakage of the outer hydrogen bonding of two hydrogen bonds, which are responsible for the reversible properties of PCDA-mBzA. External reflection-Fourier transform infrared (ER-FTIR) analyses revealed that the hydrogen bonding between the carboxylic acid groups was broken through ion adsorption and only a single hydrogen bond between the amide groups remained in the PCDA-mBzA polymer. In addition, PCDA-mBzA films could recover their original property through cadmium ion desorption. These results present that the transition between reversibility and irreversibility can be modulated artificially simply through the adsorption and desorption of metal ions.

• 대한소아치과학회지
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• 제25권2호
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• pp.400-420
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• 1998

We already know that it is very difficult to obtain an "isolated field" for direct bonding during the surgical exposure of unerupted teeth. The aim of this in-vitro study is to simulate the clinical situation of forced eruption and to evaluate the tensile strengths of preligatured button with several types of contamination which can happen during the surgical exposure of unerupted teeth. Four orthodontic direct bonding systems were used. ($Ortho-One^{TM}$, $Rely-a-Bond^{(R)}$, $Ortho-Two^{TM}$, Phase $II^{(R)}$) Each material was divided into four groups(n=20) : Group 1. (Control, no contamination), Group 2. (Rinse etching agent with saline instead of water), Group 3. (Blood contamination of etched surface for 30 seconds), Group 4. (Blood contamination of primed surface for 30 seconds) 320 bovine anterior permanent teeth were divided into the above mentioned 16 groups. Enamel surface was flattened and ground under water coolant. Pre-ligatured buttons were prepared to the same form. (Cut 0.25 ligature wire 10 cm in length. Twist the ligature wire 30 times clockwise. Mark the wire 15mm and 35mm points from button. Make a loop sticking two points together and twist the loop 6 times counterclockwise.) The bonded specimens were stored at $37^{\circ}C$ saline solution for 3 days. Then the tensile strength of each sample was measured with Instron universal testing machine, crosshead speed of 0.5mm/min. The following results were obtained: 1. As compared to control groups (Group 1) of each material, Rely-a-Bond had a significantly lower mean tensile strengths than other material. (p<0.01) 2. In Group 2. of Ortho-One and Rely-a-Bond, the mean tensile strengths decreased about 7.7% and 11.1%, respectively with statistical significances. (p<0.05) 3. In Group 2. of Ortho-Two and Phase II, the mean tensile strengths did not decrease. 4. In Group 3. of Ortho-One, Rely-a-Bond, Ortho-Two, and Phase II, the mean tensile strengths decreased about 60.8%, 56.1%, 60.2%, and 46.0%, respectively with statistical significances. (p<0.01) 5. In Group 4. of Ortho-One and Rely-a-Bond, the mean tensile strengths did not decrease. 6. In Group 4. of Ortho-Two and Phase II, the mean tensile strengths were decreased about 20.95% and 22.28%, respectively with statistical significances. (p<0.01) There were formations of a hump shaped mass from bonding resin under blood contamination which disturbed direct bonding procedure. According to Reynolds, the proper bond strength for clinical manipulation should be at least 45N or about 4.5Kg.F. According to these results, it can be concluded that Ortho-One could be used during surgical exposure of unerupted teeth. In any case, blood contamination of the etched surface should be avoided, but the blood contamination of primed surface of Ortho-One may not decrease bond strength. Just 'blowing-out' is enough to remove blood from primed surface of Ortho-One. You can verify the clean surface of the primer of Ortho-One after blowing out the blood contamination.

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.647-656
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• 1999

The purpose of this study was to investigate the shear bond strength and marginal microleakage of composite to enamel and dentin according to different treatment methods when the applied bonding agent was contaminated by artificial saliva. For the shear bond strength test, the buccal and occlusal surfaces of one hundred twenty molar teeth were ground to expose enamel(n=60) and dentin surfaces(n=60). The specimens were randomly assigned into control and 5 experimental groups with 10 samples in each group. In control group, a bonding system(Scotchbond$^{TM}$ Multi-Purpose plus) and a composite resin(Z-100$^{TM}$) was bonded on the specimens according to manufacture's directions. Experimental groups were subdivided into 5 groups. After polymerization of an adhesive, they were contaminated with at artificial saliva on enamel and dentin surfaces: Experimental group 1 ; artificial saliva was dried with compressed air. Experimental group 2 ; artificial saliva was rinsed with air-water spray and dried. Experimental group 3 ; artificial saliva was rinsed, dried and applied an adhesive. Experimental group 4 ; artificial saliva was rinsed, dried, and then etched using phosphoric acid followed by an adhesive. Experimental group 5, artificial saliva was rinsed, dried, and then etched with phosphoric acid followed by consecutive application of both a primer and an adhesive. Composite resin(Z-100$^{TM}$) was bonded on saliva-treated enamel and dentin surfaces. The shear bond strengths were measured by universal testing machine(AGS-1000 4D, Shimaduzu Co. Japan) with a crosshead speed of 5mm/minute under 50kg load cell. Failure modes of fracture sites were examined under stereomicroscope. The data were analyzed by one-way ANOVA and Tukey's test. For the marginal microleakage test, Class V cavities were prepared on the buccal surfaces of sixty molars. The specimens were divided into control and experimental groups. Cavities in experimental group were contaminated with artificial saliva and those surfaces in each experimental groups received the same treatments as for the shear test. Cavities were filled with Z-100. Specimens were immersed in 0.5% basic fuchsin dye for 24 hours and embedded in transparent acrylic resin and sectioned buccolingually with diamond wheel saw. Four sections were obtained from the one specimen. Marginal microleakages of enamel and dentin were scored under streomicroscope and averaged from four sections. The data were analyzed by Kruskal-Wallis test and Fisher's LSD. The results of this study were as follows. 1. The shear bond strength to enamel showed lower value in experimental group 1(13.20${\pm}$2.94MPa) and experimental group 2(13.20${\pm}$2.94MPa) than in control(20.03${\pm}$4.47MPa), experimental group 4(20.96${\pm}$4.25MPa) and experimental group 5(21.25${\pm}$4.48MPa) (p<0.05). 2. The shear bond strength to dentin showed lower value in experimental group 1(9.35${\pm}$4.11MPa) and experimental group 2(9.83${\pm}$4.11MPa) than in control group(17.86${\pm}$4.03MPa), experimental group 4(15.04${\pm}$3.22MPa) and experimental group 5(14.33${\pm}$3.00MPa) (p<0.05). 3. Both on enamel and dentin surfaces, experimental group 1 and 2 showed many adhesive failures, but control and experimental group 3, 4 and 5 showed mixed and cohesive failures. 4. Enamel marginal microleakage was the highest in experimental group 1 and there was a significant difference in comparison with other groups (p<0.05). 5. Dentin marginal microleakages of experimental group 1 and 2 were higher than those of other groups (p<0.05). This result suggests that treatment methods, re-etching with 35% phosphoric acid followed by re-application of adhesive or repeating all adhesive procedures, will produce good effect on both shear bond strength and microleakage of composite to enamel and dentin if the polymerized bonding agent was contaminated by saliva.

• Restorative Dentistry and Endodontics
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• 제24권2호
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• pp.310-321
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• 1999

In this in vitro study, confocal laser scanning microscopic morphology of dentin-resin interface and its relationship to shear bond strength were investigated after the exposed dentin surfaces were treated with 3 different kinds of dentin adhesive systems[three-step; Scotchbond Multi-Purpose Plus(SMPP), self-priming bonding resin; Single Bond(SB), self-etching primer; Clearfil Liner Bond 2(LB2)]. 52 extracted human molar teeth without caries and/or restorations. The experimental teeth were randomly divided into three groups of seventeen teeth each. In five teeth of each group, class V cavities(depth: 1.5mm) with 900 cavosurface angles were prepared at the cementoenamel junction on buccal and lingual surfaces. Bonding resins of each dentin adhesive system were mixed with rhodamine B. Primer of SMPP was mixed with fluorescein. In group 1. the exposed dentin was conditioned with etchant, applied with above primer and bonding resin of SMPP. In group 2, with etchant and self-priming bonding agent of SB. In group 3, with self-etching primer and bonding agent of LB2. After treatment with dentin adhesive systems, composite resin were applied and photocured. The experimental teeth were cut longitudinally through the center line of restoration and grounded so that about $90{\mu}m$-thick wafers of buccolingually orientated dentin were obtained. And, $70{\sim}80{\mu}m$-thick wafers sectioned horizontally, thus presenting a dentinal tubules at 900 to the cut surface of a remaining tooth, were obtained. Primer of SMPP mixed with rhodamine B was applied to these wafers. Confocal laser scanning microscopic investigations of these wafers were done within of 24 hours after treatment. To measure shear bond strength, the remaining twelve teeth of each group were grounded horizontally below the dentinoenamel junction, so that no enamel remained. After applying dentin adhesive systems on the dentin surface, composite was applied in the shape of cylinder. The cylinder was 5mm in diameter, and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. It was concluded as follows ; 1. Hybrid layer of SMPP(mean: $4.56{\mu}m$) was thicker than that of any other groups. This value was not statistically significant thicker than that of SB(mean: $3.41{\mu}m$, p>0.05), and significant thicker than that of LB2(mean: $1.56{\mu}m$, p<0.05). There was a statistical difference between SB and LB2(p<0.05). 2. Although there were variations in the length of resin tag even in a sample, and in a group, most samples in SMPP and SB showed resin tags extending above $20{\mu}m$. But samples in LB2 showed resin tags of $10{\mu}m$ at best. 3. Besides primer's infiltration into demineralized peritubular dentin and dentinal tubules, fluorophore of primer was detected in the lateral branches of dentinal tubules. 4. All groups demonstrated statistically significant differences from one another(p<0.05), with shear bond strengths given in descending order as follows: SMPP(18.3MPa), SB(16.0MPa) and LB2(12.4MPa). 5. LB2 having thinnest hybrid layer($1.56{\mu}m$) showed the lowest shear bond strength(12.4MPa).

• 분석과학
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• 제5권4호
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• pp.477-484
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• 1992

형질 전환된 사철느타리버섯으로부터 초원심분리 및 설탕밀도 기울기법으로 44% 층에서 미토콘드리아를 분리정제하였다. ATPase와 ATP synthase의 최적 활성조건은 각각 pH 7.4, $60^{\circ}C$ 및 pH 7.5, $57^{\circ}C$였고, km값은 11.6mM과 8.4mM였다. ATPase는 기질농도 5~6mM의 ATP에서, ATP synthase는 5~10mM ADP 농도에서 활성이 높으며, 그 이상의 농도에서는 기질 저해를 받았다. ATPase/ATP synthase 모두 $Mg^{2+}$ 의존성 효소로 $G_{418}$으로 비경쟁적인 저해를 받았다. 효소의 아미노산 분석결과 hydrophobic 아미노산 잔기는 50.5%, small 아미노산 잔기는 56.1%, hydrogen bonding 아미노산 잔기는 43.7%, helix breaking 아미노산 잔기는 55.2%였다. 인지질을 분석한 결과 phosphatidyl glycerol, phosphatidyl choline 및 phosphatidyl ethanolamine으로 구성되었고 phosphatidyl serine과 phosphatidyl inositol은 전혀 없었다. 포화 지방산은 palmitate(51.31%)와 stearate(18.32%)의 함량이 많았고, 불포화 지방산($C_{18:1}$, $C_{18:2}$ 및 $C_{16:1}$)의 함량도 많았다.

• 한국세라믹학회지
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• 제31권12호
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• pp.1577-1587
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• 1994

TiO2 thin films with the substitution of oxygen with nitrogen were deposited on silicon substrate by metalorganic chemical vapor deposition (MOCVD) using Ti(OCH(CH3)2)4 (titanium tetraisopropoxide, TTIP) and N2O as source materials. X-ray diffraction (XRD) results indicated that the crystal structure of the deposited thin films was anatase TiO2 with only (101) plane observed at the deposition temperatures of 36$0^{\circ}C$ and 38$0^{\circ}C$, and with (101) and (200) plane at above 40$0^{\circ}C$. Raman spectroscopic results indicated that the crystal structure was anatase TiO2 in accordance with the XRD results without any rutile, fcc TiN, or hcp TiN structure. No fundamental difference was observed with temperature increase, but the peak intensity at 194.5 cm-1 increased with strong intensity at 143.0 cm-1 for all samples. The crystalline size of the films varied from 49.2 nm to 63.9 nm with increasing temperature as determined by slow-scan XRD experiments. The refractive index of the films increased from 2.40 to 2.55 as temperature increased. X-ray photoelectron spectroscopy (XPS) study showed only Ti 2s, Ti 2p, C 1s, O 1s and O 2s peaks at the surface of the film. The composition of the surface was estimated to be TiO1.98 from the quatitative analysis. In the bulk of the film Ti 2s, Ti 2p, O 1s, O 2s, N 1s and N 2s were detected, and Ti-N bonding was observed due to the substitution of oxygen with nitrogen. A satellite structure was observed in the Ti 2p due to the Ti-N bonding, and the composition of titanium nitride was determined to be about TiN1.0 from the position of the binding energy of Ti-N 2p3/2 and the quatitative analysis. The spectrum of Ti 2p energy level could be the sum of a 4, 5, or 6 Gaussian curve reconstruction, and the case of the sum of the 6 Gaussian curve reconstruction was physically most meaningful. From the results of Auger electron spectroscopy (AES), it was known that the composition was not varied significantly throughout the whole thickness of the film, and silicon oxide was not observed at the interface between the film and the substrate. The composition of the film was possible (TiO2)1-x.(TiN)x or TiO2-2xNx and in this experimental condition x was found to be about 0.21-0.16.

• 대한치과보철학회지
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• 제42권4호
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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).

• 대한치과보철학회지
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• 제30권1호
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• pp.55-64
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• 1992

This study investigated the effect of porcelain primer on bonding of coomposite resin to porcelain surface. In order to test the bond strength between porcelain and composite resin, porcelain cylinders were embedded in acrylic resin, and polished with 240grit silicone caqrbide paper. The specimens were divided into twelve groups. All specimens were treated with three porcelain primers and bonded with five composite resins. All test groups were stored in $37^{\circ}C$ distilled water for 48hours. Shear bond strengths were measured with Instron(Model 4201) at a cross-head speed of 1mm/min. The obtained results were as follows : 1. Scotchprime/Silux II group and BISCO Porcelain Primer/Bisfill group showed significant higher bond strengths than Clearfil Porcelain Primer/photo Clearfil Bright group(p<0.05). And there was no significant differences in bond strengths between Scotchprime/Silux II group and BISCO Porcelain Primer/Bisfill group(p>0.05). 2. When composite resins were used with Scotchprime, the bond strengths were decresed Silux II$(16.68{\pm}3.35MPa)$, Bisfil$(16.23{\pm}4.54MPa)$, Poly-Fill$(14.74{\pm}4.08MPa)$, Photo Clearfil Bright$(13.75{\pm}2.89MPa)$ and Pekalux$(14.74{\pm}4.08MPa)$ in order, but there was no statistical significance(p>0.05). 3. When composite resins were used with BISCO Porcelain Primer, the bond strength were decreased Bisfil$(16.17{\pm}1.60MPa)$, Silux II$(12.13{\pm}2.37MPa)$, Poly-Fill$(10.78{\pm}1.99MPa)$, Photo Cleafil Bright $(9.91{\pm}4.59MPa)$ and Pekalux$(7.36{\pm}2.16MPa)$ in order, but there was no statistical significance(p>0.05). 4. Silux II, Photo Clearfil Bright and Poly-Fill used with Scotchprime showed significant higher bond strengths than BISCO Porcelain Primer(p>0.05).

• Restorative Dentistry and Endodontics
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• 제24권4호
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• pp.546-553
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• 1999

In Older to evaluate the effectiveness of 'One-bottle dentin adhesive system', the shear bond strengths of two fourth generation dentin adhesive systems and two One-bottle systems to the occlusal dentin of the freshly extracted third molars were measured by the regulation of the ISO TR 11405. The fourth generation dentin adhesive systems used in this study were Scotchbond Multi-Purpose Plus and All-Bond 2, and the One-bottle systems were Single Bond and One-Step. The effects of the thickness of hybrid layer and adhesive layer, the diameter of resin tag and the ratio between the diameter of resin tag and that of dentinal tubule were analyzed as the contributing factors of the shear bond strength of dentin bonding systems from the Scanning Electron Microscopic images. The results were as follows: 1. The shear bond strengths of Scotchbond Multi-Purpose, All-Bond 2, and Single Bond were 16.98${\pm}$3.40 MPa, 15.10${\pm}$2.77 MPa and 15.05${\pm}$3.18 MPa, respectively. There were no statistical differences(p>0.05). 2. But, the shear bond strength of One-Step were significantly lower than those of the other groups (11.81${\pm}$1.95 MPa, p<0.05). 3. The thicknesses of hybrid layer and adhesive layer of One-Step were significantly thinner than those of the other groups(p<0.05). The differences of the diameter of resin tag(p=0.0685) and the ratio between the diameter of resin tag and that of dentinal tubule(p=0.2401) were not significant among all the material groups. 4. The thickness of hybrid layer and adhesive layer might be considered as contributing factors of the she at bond strengths of dentin bonding systems, but the diameter of resin tag and the ratio between the diameter of resin tag and that of dentinal tubule might not.

• 한국세라믹학회지
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• 제35권6호
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• pp.594-602
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• 1998

유기용메인 이소옥탄(isooctane)에 계면활성제를 이용하여 물을 역마이셀 형태로 생성시킨 후, 이소프로필 알코올(isopropyle alcohol)에 묽힌 티타늄알코옥사이드(tetraisopropyl orthotitanate)를 가하여 가수분해 반응를 거쳐 TiO(OH)2 분말을 제조하였다. 역마이셀에 의한 TiO(OH)2 분말 제조에 미치는 공정변수들인 계면활성제의 종류, 농도, 보조계면활성제, 가수분해 반응온도, pH등이 생성된 입자의 크기, 모양, 입도분포에 미치는 영향을 규명하였다. 비이온계활성제인 Span 80을 사용하였을 경우에는 Span 80의 농도변화, 가수분해 반응온도 변화, pH변화에 무관하게 입도분포가 uninodal형태였으나, 음이온계면활성제인 Aerosol-OT(AOT)를 사용하였을 경우, binodal형태를 나타내었다. 에타올(ethanol)을 cosurfactant로 첨가한 계(AOT, 1.0CMC, isooctane+ethanol, pH2.5, 30$^{\circ}C$)로 부터 생성된 입자는 평균입경이 0.12${\mu}{\textrm}{m}$ 으로서 미세할 뿐아니라 입도분포도 매우 좁은 것을 알 수 있다. 따라서, cosurfactant의 유무가 생성 입자의 입도분포에 큰 영향을 미치는 것을 알 수 있다. FT-IR 분석으로 T1-O 결합과 Ti-OH 결합에 의한 흡수피크를 확인하였고, TGA-DTA 분석결과에 의하면 41$0^{\circ}C$ 부근의 발열피크로 부터 비정질 구조에서 anatase 구조로 결정화가 시작됨을 알 수 있었으며, 온도 상승과 더불어 결정이 성장하여 약 45$0^{\circ}C$ 정도에서 비정질상이 anatase상의 결정구조로 완전히 전이됨을 확인하였다.