• 구강회복응용과학지
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• 제29권1호
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• pp.37-44
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• 2013

근관치료 후 적절한 치관부 밀폐를 위해 레진을 이용한 코어수복방법이 현재 많이 사용되고 있다. 하지만, 근관치료 과정에서 사용되는 NaOCl이나 EDTA같은 근관세척제는 레진 접착에 영향을 주는 것으로 알려져 있으며, 이에 관한 많은 연구들이 이루어져 왔다. 본 연구에서는 ethanol wet bonding을 치수강 상아질에 적용 시에 NaOCl과 EDTA가 결합강도에 미치는 영향에 대해 조사하였다. 30개의 인간 대구치로부터 총 60개의 시편을 얻었고, 이를 무작위로 4개의 군으로 분류했다. G1: 증류수로 세척후 증류수로 마무리 세척, G2: NaOCl로 세척 후 NaOCl로 마무리세척, G3: NaOCl로 세척 후 EDTA로 마무리세척, G4: NaOCl로 세척 후 EDTA로 마무리세척하고 접착과정에서 산부식과정 생략. 접착과정은 인산부식 후 에탄올의 농도를 50%, 70%, 80%, 95% 그리고 100%로 순차적으로 증가시켜가면서 상아질을 탈수시키고 에탄올에 적셔지도록 하였다. 프라이머는 HEMA가 포함되지 않은 상용화된 접착제인 ALL-BOND 3 RESIN과 에탄올을 반반씩 섞어 만들었다. 프라이머 적용 후 ALL-BOND 3 RESIN을 접착제로 사용하였다. 저점도 복합레진을 이용하여 6mm 두께로 적층충전한 후 빔 형태로 잘라 미세인장결합강도 실험을 하였다. NaOCl 처리한 그룹은 미세인장결합강도에 통계적으로 유의한 차이를 보여주지는 않았지만 낮은 평균값을 보여주었다(p=0.052). NaOCl 처리 후 1분간 EDTA로 처리한 그룹은 다른 그룹보다 유의하게 높은 결합강도를 보여주었다(p<0.05). EDTA 처리가 결합강도를 향상 시켰지만, 산부식 과정을 생략할 경우 유의하게 낮은 결합 강도를 보여주었으며, 이는 EDTA처리가 산부식 과정을 대신할 수는 없다는 것을 보여준다.

• 대한치과보철학회지
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• 제45권4호
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• pp.419-430
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• 2007

Purpose: This in vitro study evaluated shear bond strengths of surface treatment porcelains with four porcelain repair systems simulating intraoral bonding of composite resin to feldspathic porcelain or pressable porcelain. Material and methods: Eighty Porcelain disks were prepared. Group A: forty disk specimens were fabricated with Feldspathic Porcelain($Omega^{(R)}900$, Vident, Menlo Park, CA, USA). Group B: forty disk specimens were fabricated with Pressable Porcelain(IPS Empress 2 ingot, Ivoclar-Vivadent, Schaan, Liechtenstein, Germany). Each groups was divided into 4 subgroups and composite resin cylinders were bonded to specimen with one of the following four systems: Clearfil Porcelain Bond(L. Morita, Tustin, CA, USA), Ulradent Porcelain Etch. (Ultradent, Salt Lake City UT, USA), Porcelain Liner-M(Sun Medical Co., Kyoto, Japan), Cimara Kit(Voco, Germany). After surface conditioning with one of the four porcelain repair systems substrate surfaces of the specimen were examined microscopically(SEM). Shear bond strengths of specimens for each subgroup were determined with a universal testing machine (5mm/min crosshead speed) after storing them in distilled water at $37{\pm}1^{\circ}C$ for 24 hours. Stress at failure was measured in $MP_a$, and mode of failure was recorded. Differences among four repair systems were analyzed with two way ANOVA and Duncan test at the 95% significance level. Results: In the scanning electron photomicrograph of the treated porcelain surface, hydrofluoric acid etched group appeared the highest roughness. The shear bond strength of the phosphoric acid etched group was not significantly(p>0.05) different between feldspathic porcelain and pressable porcelain. But in no treatment and roughened with a bur group, the shear bond strength of the feldspathic porcelain was significantly higher than that of the pressable porcelain. In hydrofluoric acid etched group, the shear bond strength of the pressable porcelain was significantly higher(p<0.05). Conclusion: 1. Treatment groups showed significantly greater shear bond strengths than no treatment group(p<0.05). 2. Group with more roughened porcelain surface did not always show higher shear bond strengths. 3. In phosphoric acid etched group, there was no significant difference in shear bond strength between feldspathic porcelain and pressable porcelain(p>0.05). However in the other groups, there were significant differences in shear bond strengths between feldspathic porcelain and pressable porcelain(p<0.05).

• 대한소아치과학회지
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• 제35권4호
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• pp.692-699
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• 2008

본 연구의 목적은 표면처리가 기존의 레진과 새로운 레진 사이의 전단결합강도에 미치는 영향을 평가하는 것이다. 준비된 레진 시편을 6군으로 임의로 배분하여 각각의 표면처리를 한 후 수리용 레진을 축조하였다. 일주일간 보관 후 전단결합강도 를 측정하였고 일원분산 분석법으로 통계처리하여 다음과 같은 결과를 얻었다. 1. 3군과 4군(air abrasion)은 1군(산부식)에 비해 전단결합강도가 유의하게 높게 나타났다(p<0.05). 5군과 6군(diamond bur)은 1군(산부식)에 비해 높은 전단결합강도를 나타냈으나 통계적으로 유의하지 않았다(p>0.05). 2. 2군(자가부식 접착제)은 1군(산부식)에 비해 전단결합강도가 낮게 나타났으나 유의한 차이는 없었다(p>0.05). 3. 3군(air abrasion)과 4군(air abrasion+산부식)에서 전단결합강도의 차이는 유의하지 않았다(p>0.05). 4. 5군(diamond bur)과 6군(diamond bur+산부식)에서 전단결합강도의 차이는 유의하지 않았다(p>0.05). 결론적으로, 복합레진의 수리 시 air abrasion으로 표면처리를 했을 때의 결합강도가 가장 높았고, 산부식 방법과 처리여 부는 수리강도에 유의한 영향을 미치지 않았다.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2173-2179
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• 2017

The intracytoplasmic membrane of Rhodobacter sphaeroides readily vesiculates when cells are lysed. The resulting chromatophore membrane vesicle (CMV) contains the photosynthetic machineries to synthesize ATP by ATPase. The light-dependent ATPase activity of CMV was lowered in the presence of $O_2$, but the activity increased to the level observed under anaerobic condition when the reaction mixture was supplemented with ascorbic acid (${\geq}0.5mM$). Cell lysis in the presence of biotinyl cap phospholipid (bcp) resulted in the incorporation of bcp into the membrane to form biotinylated CMV (bCMV), which binds to streptavidin resin at a ratio of approximately $24{\mu}g$ bacteriochlorophyll a/ml resin. The ATPase activity of CMV was not affected by biotinylation, but approximately 30% of the activity was lost by immobilization to resin. Interestingly, the remaining 70% of ATPase activity stayed constant during 7-day storage at $4^{\circ}C$. On the contrary, the ATPase activity of bCMV without immobilization gradually decreased to approximately 40% of the initial level in the same comparison. Thus, the ATPase activity of CMV is sustainable after immobilization, and the immobilized bCMV can be used repeatedly as an ATP generator.

• Macromolecular Research
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• 제17권5호
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• pp.289-295
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• 2009

Low viscosity aromatic hyperbranched polyester epoxy resin (HTBE) was synthesized by the reaction between epichlorohydrin (ECH) and carboxyl-end hyperbranched polyester (HTB) which was prepared from inexpensive materials $A_2$ (1,4-butanediol glycol, BEG) and $B_3$ (trimellitic anhydride, TMA) by pseudo one-step method. The molar mass of the HTB was calculated from its acid value by "Recursive Probability Approach". The degree of branching (DB) of the HTB was characterized by model compounds and $^1H$ NMR-minus spectrum technology, and the DB of the HTB was about $0.47{\sim}0.63$. The viscosity and epoxy equivalent weight of the HTBE were $3,600{\sim}5,000\;cp$ and lower than 540 g/mol respectively. The reaction mechanism and structure of the $AB_2$ monomer, HTB and HTBE were investigated by MS, $^1H$ NMR and FTIR spectra technology. The molecular size of HTBE is under 8.65 nm and its shape is ellipsoid-like as determined by molecular simulation.

• 한국염색가공학회지
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• 제29권1호
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• pp.25-36
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• 2017

This study worked on the synthesis of waterborne polyurethane/epoxy hybrid resins containing aminosilane compound to replace conventional phenol resins used for a coating material for loudspeaker dampers, which are not harmful to human being. Waterborne polyurethane resins were synthesized from two diisocyanate of 4,4'-diphenylethane diisocyanate and toluene diisocyanate, two polyols of polyester polyols(PEP), polycarbonatediol(PCD), including and anionic center of dimethylol butanoic acid, a chain extenders of ethylenediamine(EDA), and a neutral agent of triethylamine. Synthesized polyurethane resins and commercially available bisphenol A type waterborne epoxy resin were blended in weight ratios of 80:20 to prepare polyurethane/epoxy hybrid resins. The synthesized waterborne polyurethane/epoxy hybrid resins were reacted with aminosilane compound to improve mechanical properties. Aminosilane-treated polyurethane /epoxy hybrid resins showed better mechanical properties.

• Journal of Advanced Marine Engineering and Technology
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• 제33권3호
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• pp.387-394
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• 2009

It has been observed that coated steel structures are rapidly deteriorated than designed lifetime due to acid rain caused by air pollution etc.. Therefore improvement of corrosion resistance of anti-corrosive paint is very important in terms of safety and economic point of view. In this study corrosion resistance for five kinds of anti-corrosive paints including acryl, fluorine and epoxy resin series were investigated with electrochemical methods such as corrosion potential, polarization curves, impedance and cyclic voltammogram measurements etc.. There were somewhat good relationships between values measured by electrochemical methods such as corrosion current density obtained by cathodic and anodic polarization curves, value of impedance estimated with AC impedance, and polarization resistance on the cyclic voltammogram, for example, corrosion current density was decreased with increasing of values of impedance and polarization resistance on the cyclic voltammogram. However their relationships between corrosion current density and corrosion potential were not well coincided each other. Consequently it is considered that although a corrosion potential of F101 of fuoric resin series shifted to negative direction than other anti-corrosive paints, its corrosion resistance, indicating on the cathodic and anodic polarization curves, AC impedance curves and cyclic voltammogram, was the most superior to other paints, whereas A100 containing arcylic resin showed a relatively poor corrosion resistance compared to other paints.

• 한국물환경학회지
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• 제29권5호
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• pp.691-702
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• 2013

This review paper summarizes the theory, application, and potential drawbacks of diffusive gradient in thin film (DGT) probe which is a widely used in-situ passive sampling technique for monitoring inorganic contaminants in aquatic environments. The DGT probe employs a series of layers including a filter membrane, a diffusive hydrogel, and an ionic exchange resin gel in a plastic unit. The filter side is exposed to an aquatic environment after which dissolved inorganic contaminants, such as heavy metals and nuclides, diffuse through the hydrogel and are accumulated in the resin gel. After retrieval, the contaminants in the resin gel are extracted by strong acid or base and the concentrations are determined by analytical instruments. Then aqueous concentrations of the inorganic contaminants can be estimated from a mathematical equation. The DGT has also been used to monitor nutrients, such as ${PO_4}^{3-}$, in lakes, streams, and estuaries, which might be helpful in assessing eutrophic potential in aquatic environments. DGT is a robust in-situ passive sampling techniques for investigating bioavailability, toxicity, and speciation of inorganic contaminants in aquatic environments, and can be an effective monitoring tool for risk assessment.

• 대한의용생체공학회:의공학회지
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• 제16권4호
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• pp.533-542
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• 1995

The present study investigated the effectiveness of pretreatment on dentin bonding. The adhesive resin was 5% 4-methacryloyloxyethyl trimellitate anhydride (4-META) in methyl methacrylate (MMA) combined with poly-MMA powder. Polymerization of this resin was initiated by tri-n-butyl borage (TBB). Ground bovine dentin samples were etched with either an aqueous solution of 10% citric (10-0 solution) (Group I) or aqueous solution of 10% citric acid and 3% ferric chloride(10-3 solution) (Group ll ). After etching, the primer (an aqueous solution of 35% hydroxyethyl methacrylate (HEM- A) and 5% glutaraldehyde was applied on the differently etched surfaces (Group III , Group IV). The 10-0 treatment showed the lowest tensile bond strength, followed by the 10-3 treatment, primer application after the 10-0 treatment and primer application after the 10-3 treatment. The relationship among the surface morphology after pretreatment, fractured surface morphology and tensile bond strength was examined. It revealed that the surface morphology change by different pretreatment influenced the bond strength and the resulting fractured surface morphology. The correlation of tensile bond strength with the fracture morphology was explained.

• 대한치과교정학회지
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• 제15권2호
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• pp.271-277
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• 1985

With modification of the acid etch technique and improvements of the physical and mechanical properties of the acrylic resin, the removal of directly bonded attachments and the finishing of the underlying enamel have become an acute clinical problem. This study was to evaluation the efficacy of recently introduced instrumentation and techniques to remove bonded brackets and residual resin, and restore the affected enamel surface to an acceptable clinical condition. Fortyeight premolar which were scheduled for extraction for orthodontic purposes were bonded with brackets using super-C ortho. Four additional premolars with untreated surfaces were used as controls. After one weak the brackets were removed and the residual resin removed by hand scaler, green stone, green rubber wheel, sandpaper disc, tungsten carbide bur, Sof-lex disc. Half the experimental teeth were given a final pumicing and then all were extracted and stored in 50 percent ethanol. The scanning electron microscopy was used to evaluated the enamel surface. Following results were obtained; 1. A satisfactory result was obtained by means of the Sof-lex disc. 2. The order of the scratch formation was the procedure using hand scaler, green atone, tungsten carbide bur, sandpaper disc, green rubber wheel, and Sof-lex disc. 3. The procedures using green stone and tungsten carbide bur showed many groove formations and the other procedures showed none. 4. final pumicing serves effectively to remove residual adhesive and restore the enamel surface.