• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.164-167
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• 2004

The purpose of this study is to investigate the properties of composite systems using polymer cement and epoxy resins for waterproofing and anti-corrosion to concrete structures such as water supply facilities and sewage-works. In this study these engineering properties of composite systems using polymer-modified mortar and epoxy resins were examined and could be confirmed to satisfy the guidelines of KS. Especially, it was turn out that the adhesion properties was excellent and high crack-resistance up to 1.49mm will be perform.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.55-58
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• 2004

Phenolin resin, prepared form phenol and formaldehyde, is one of the oldest thermosetting resins available. Phenolic resins are cured via condensation polymerization with evolution of water, which in molding process is a big problem. The use of phenolic resins in glass fiber composites is growing, primarily due to their low flame spread, low smoke generation and low smoke toxicity properties. SMC of phenolics has been rearched since the 1986. The technology challenge was to match resin viscosity, handling and cure with those for the polyester SMC to avoid any special processing for fabricators and end users. Phenolic SMC was chosen because of the ease of molding to the required shape with light- weight, thin wall structure and with excellent fire protection.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.64-67
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• 1990

Bending strength, bending elastic modulus ,and fracture toughness of different types of dental composite resins were deter mined. The relationship between bending strength, fracture toughness and filler volume fraction of dental composite resin was understood. In Acoustic Emission(AE) behavior during fracture toughness test, characteristic generation patterns of each type were understood. The fracture toughness values, AE generation patterns, and the nature of fracture surface were analyzed to understand fracture behavior of dental composite resin.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.167-172
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• 1982

The purpose of this study was to evaluate the marginal sealing ability of "Silar". Using freshly extracted human teeth and 2% acquous methylene blue, the marginal leakage of dye in restorative materials such as Silar, Silar with acid etching technique, Hi-Pol, Hi-Pol Enamel Bond system, Adaptic and Amalgam were investigated at $37^{\circ}C$ and under temperature cycling in range of $4^{\circ}C-60^{\circ}C$. The results as follows; 1. All filling materials showed some degree of marginal penetration by 2% methylene blue dye. 2. Silar with acid etching technique revealed effective marginal sealing ability, but under temperature cycling it showed increased marginal leakage. 3. All composite resins showed greater marginal leakage than amalgam restoration. 4. Silar had the most effective marginal sealing ability in experimented composite resins.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.7 no.1
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• pp.18-26
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• 1998

The improvement of esthetic dentistry has been accelerated from the development of composite resin and dentin-enamel adhesive since 1980's. The indirect composite resin restorations have more accurate proximal contact point and occlusal form than direct restoration. And the side effect of resin shrinkage is minimal because the amount of composite used in oral cavity is limited in cement space. As a results, marginal leakage, hypersensitivity, secondary caries, and discoloration are significantly diminished. The first generation laboratory composite resin used in indirect resin restoration had been widespread in 1980's and the second generation laboratory composite resins were developed in 1990's. The second generation laboratory composite resins are called Ceramic Polymer. The physical properties of Ceramic Polymer are improved because of high content of inorganic filler, and the esthetics and biocompatibility are better than that of the first generation resin. So the application range using composite resin have been broadened. The purpose of this paper is to introduce Targis & Vectris system that is classified to second generation laboratory composite and to report several cases in which the system was utilized for restoration.

• Restorative Dentistry and Endodontics
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• v.32 no.6
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• pp.542-549
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• 2007

The purpose of this study was to evaluate the difference in the surface roughness after polishing and to evaluate the difference in color stability after immersion in a dye solution among four types of composite resin materials. Four light-polymerized composite resins(Shade A2) with different sized filler content(a nanofilled, a hybrid, a microfilled, a flowble) were used. Average surface roughness (Ra) was measured with a surface roughness tester (Surftest Formtracer) before and after polishing with aluminum oxide abrasive discs(Super-Snap). Color of specimens before and after staining with 2% methylene blue solution were measured using spectrophotometer(CM-3700d) with SCI geometries. The results of Ra and ${\Delta}E$ were analyzed by one-way analysis of variance(ANOVA), a Scheffe multiple comparison test and Student t-test(p=0.05). After polishing, Ra values were decreased regardless of type of composite resins. In surface roughness after polishing and color stability after staining, nanofilled composite resin was not different with other composite resins except flowable resins.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.1
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• pp.13-22
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• 2009

The composite resin, due to its esthetic quality, is considered the material of choice for restoration of anterior teeth. To get a satisfactory result in the composite resin restorations, it is necessary to choose right shade. At present, most of the commercial composite resins are based on the Vita Lumin shade guides or shade guides that are provided by their company, but color differences among them might be expected even using the same shade in various materials. This study is to measure color differences between various light-cured composite resins and shade guides and to provide the clinicians with information which may aid in improved color match of esthetic restoration. Four kinds of light-cured composite resins (Gradia Direct (GD), Z250 (Z250), Clearfil AP-X (AP-X), Esthet X (E X)) and shade guides with A2 and A3 shade were used. Three specimens of each material and one specimen of each shade guide were made. Each composite resin was filled into the Teflon mold (1.35 mm depth, 8 mm diameter), followed by compression, polymerization and polishing with wet sandpaper. Shade guides were grinded with polishing stones and rubber points to a thickness of approximately 1.35 mm. Color characteristics were performed with a spectrophotometer(color i5, GretagMacbeth, USA). A computer-controlled spectrophotometer was used to determine CIELAB coordinates ($L^*$, $a^*$, $b^*$) of each specimen and shade guide. The CIELAB measurements made it possible to evaluate the amount of the color difference values (${\Delta}E^*ab$) between composite resins and shade guides. CIE standard D65 was used as the light source. The results were as follows : 1. Among the $L^*$, $a^*$, $b^*$ values of most of 4 kinds of composite resin specimens which are produced by same shade, there were significant differences(p<0.05). 2. Among all 4 kinds of composite resin specimens which are produced by same shade, there were color differences that is perceptible to human eye(${\Delta}E^*>3.3$). 3. Between most of composite resin specimens investigated and their corresponding shade guides, there were color differences that is perceptible to human eye(${\Delta}E^*>3.3$). 4. In the clinical environment, it is recommended that custom shade guides be made from resin material itself for better color matching. Shade guides supplied by manufacturers or Vita Lumin shade guide may not provide clinicians a accurate standard in matching color of composite resins, and there are perceptible color differences in most of products. Therefore, it is recommended that custom shade guides be made from resin material itself and used for better color matching.

• Restorative Dentistry and Endodontics
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• v.4 no.1
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• pp.35-38
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• 1978

The purpose of this study was to measure micro-knoop hardness and coefficient of thermal expansion on composite resins (Epolite, Adaptic, Hipol and Compo T.) Four different type of composite resins were measured at the varying depth of 30, 60, 90, 150, 200, 400, 700 and 1000 micron from the surface to deep portion. The specimens were stored both in the air room temperature for 2 days, 30 days and in water at $37^{\circ}C$ for 30 days. Thermal expansions of specimens(4mm in diameter and 50mm in height) were measured in quartz tube dilatometer from $20^{\circ}$ to $70^{\circ}C$ The following results were obtained. 1. The hardness of superficial portion were lower than inner portion of resin. 2. The value of hardness obtained from the specimen stored in room temperature in the water at $37^{\circ}C$ for 30 days were lower than above described Cases. 3. The coefficient of thermal expansion of Adaptic had $29.75{\times}10^{-6}/^{\circ}C$, Hipol had $30{\times}10^{-6}/^{\circ}C$, Epolite had $39.85{\times}10^{-6}/^{\circ}C$ and Compo T had $36.95{\times}10^{-6}/^{\circ}C$.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.67-80
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• 1990

This study was performed for elucidating the effects on surface polishing of composite resins. In this study, Silux(microfilled), Graft(hybrid), Bisfil- I (hybrid posterior) and Hi-pol(conventional) were used. Sixty specimens were made with 4 brands of composite resins and Optilux system in $2.0{\times}1.3{\times}1.0cm$ resin block which has a cavity with 0.5cm diameter and 0.5cm depth. Polishing was done with #600 sand paper and Soflex, Super-snap, Micron finishing system, or Composite polishing kit. Final polished surfaces were measured by roughness tester(Kasaka Lab. Ltd., Japan) and image analyser(Omnimet Image Analyser, Buehler, USA). The results were as follows, 1. The celluloid strip produced the smoothest surfaces. 2. Light curing microfilled composite resin, Silux, had smoother surface than any others. 3. The surfaces polished by Soflex were smoothest. 4. Aluminum oxide disk, Soflex and Super-Snap, made smoother surface than diamond bur, M.F.S., or silicon point, Composite polishing kit. 5. The roughness values of surface polished by M.F.S. composed of diamond burs, were less than those of Composite polishing kit made from silicone points.

• Journal of Industrial Technology
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• v.35
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• pp.35-39
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• 2015

One of the purposes of the study was to investigate and compare the physical properties(depth of light cure, degree of conversion, water absorption) of 4 kinds of composit resins prepared in this lab; Bis-GMA based, Bis-EMA based, Bis-GMA/UDMA based, and Bis-EMA/UDMA based composit. Another aim was to compare the physical properties of the composit resins with those of the commercialized products(Charmfil flow(Denkist), Quadrant flow(CAVEX)) in market. All of the composit resins and the commercialized products showed almost same values of the physical properties. It was found that all of the composit resins prepared in this lab satisfied the physical properties specified in ISO 4049.