• 대한치과보철학회:학술대회논문집
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• 2001.11a
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• pp.41-41
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• 2001

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.1
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• pp.42-52
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• 2002

The purpose of this study was to evaluate the bond strength of reline resin to pressure injection type thermoplastic denture base resin. The denture base resins used in this study were $Hi-polycarbonate^{(R)}$(High Dental Co., Japan), Acetal $dental^{(R)}$(Pressingdental s.r.1., Repubblica di San Marine) of thermoplastic resin and Acron $MC^{(R)}$(GC Dental Industrial Co., Japan) of heat cured resin. The reline resins used were Lucitone $199^{(R)}$(Dentsply international Inc., USA), Tokuso $rebase^{(R)}$(Tokuyama Corp., Japan), and $Lightdon-U^{(R)}$(Dreve-Dentamid-Gmbh, Germany). The reline resins are representative of heat-cured, self-cured, and light-cured resin respectively Bond strength was examined by use of a three-point transverse flexural strength test. The results were as follows 1. The bond strength of Lucitone 199 to Acron MC was the highest. 2. The bond strengths of Lucitone 199 and Tokuso rebase to Hi-polycarbonate resulted in a value of approximately one half that of Lucitone 199 to Acron MC and there were no significant differences between these and the bond strength of Tokuso rebase to Acron MC(p<0.05) 3. The bond strengths of reline resins to Acetal dental were lower than those of reline resins to Hi-polycarbonate. 4. For all base resins Lightdon-U showed lower bond strength than the other reline resins.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.1
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• pp.38-49
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• 2000

The purpose of this study was to evaluate the effects of thermocycling on the shear bond strength of Co-Cr alloy to denture base resin. PMMA denture base resin such as heat-cured $Vertex-RS^{(R)}$, self-cured $Vertex-SC^{(R)}$ and 4-META denture base resin such as heat-cured $Meta-Dent^{(R)}$, self-cured $Meta-Fast^{(R)}$ was bonded to Co-Cr alloy. Samples were divided into 3 groups : no thermocycling group as control, thermocycling between $5^{\circ}C\;and\;55^{\circ}C$ with 15 second dwell time as group 1, thermocycling with 1 minute dwell time as group 2. The shear bond strength was measured and the interface between metal and resin was observed by SEM. The results were as follows. 1. The shear bond strength decreased significantly according to thermocycling and dwell time(P<0.001). 2. The bond strength of Co-Cr alloy and 4-META denture base resin was significantly higher than that of Co-Cr alloy and PMMA denture base resin(P<0.001) 3. In SEM, there was no gap in control group, but there was much and large gap in group 1, 2. The longer dwell times, the lower bond strength. PMMA denture base resin had more gap than 4-META denture base resin in the interface. These results revealed that thermocycling decreased the bond strength between Co-Cr alloy and denture base resin and dwell time of thermocycling changed the effect of thermocycling. The results suggested that oral temperature change affect the bond strength of prosthesis.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.241-247
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• 2013

PURPOSE. To evaluate the effect of various metal oxides on impact strength (IS), fracture toughness (FT), water sorption (WSP) and solubility (WSL) of heat-cured acrylic resin. MATERIALS AND METHODS. Fifty acrylic resin specimens were fabricated for each test and divided into five groups. Group 1 was the control group and Group 2, 3, 4 and 5 (test groups) included a mixture of 1% $TiO_2$ and 1% $ZrO_2$, 2% $Al_2O_3$, 2% $TiO_2$, and 2% $ZrO_2$ by volume, respectively. Rectangular unnotched specimens ($50mm{\times}6.0mm{\times}4.0mm$) were fabricated and drop-tower impact testing machine was used to determine IS. For FT, compact test specimens were fabricated and tests were done with a universal testing machine with a cross-head speed of 5 mm/min. For WSP and WSL, disc-shaped specimens were fabricated and tests were performed in accordance to ISO 1567. ANOVA and Kruskal-Wallis tests were used for statistical analyses. RESULTS. IS and FT values were significantly higher and WSP and WSL values were significantly lower in test groups than in control group (P<.05). Group 5 had significantly higher IS and FT values and significantly lower WSP values than other groups (P<.05) and provided 40% and 30% increase in IS and FT, respectively, compared to control group. Significantly lower WSL values were detected for Group 2 and 5 (P<.05). CONCLUSION. Modification of heat-cured acrylic resin with metal oxides, especially with $ZrO_2$, may be useful in preventing denture fractures and undesirable physical changes resulting from oral fluids clinically.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.3
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• pp.211-220
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• 2000

The use of autopolymerizing-cured resin and light-cured resin for direct relining of complete and partial dentures has been popular. This investigation compared the adhesion of autopolymerizing-cured reline resin(Tokuso Rebase, Mild Rebaron) or light-cured reline resin(Mild Rebaron LC, Lighton-U) to metal base or resin base. Cylindrical samples were made from metal($Biosil^{(R)}$) or heat-cured resin(QC-20) and were prepared to produce a flat bonding surface. Cylindrical metal samples were roughened by scratch or by scratch and sandblast and were treated with primer(MR Bond) after scratch and sandblast. And then, liners were prossesed to the cylindrical metal or resin samples according to the manufacturer's recommendations so as to bond metal base or resin base. The specimens were tested in pure tension by using an Instron Univesal testing machine for the four direct reline resins. The results were as follows ; 1. In comparison with tensile bond strength of material relined on resin base or metal base, the case of resin base produced significantly higher tensile bond strength than the case of metal base. 2. Metal surface pretreatment or primer improved the tensile bond strength between the reline resin and the metal($Biosil^{(R)}$) base. 3. The tensile bond strength of Mild Rebaron LC relined on resin base or metal base were similar to those of the other reline resins.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.2
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• pp.161-170
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• 2000

The use of autopolymerizing-cured resin and light-cured resin for direct relining of complete and partial dentures has been popular. This investigation compared the adhesion of autopolymerizing-cured reline resin(Tokuso Rebase, Mild Rebaron) or light-cured reline resin(Mild Rebaron LC, Lighton-U) to metal base or resin base. Cylindrical samples were made from metal($Biosil^{(R)}$) or heat-cured resin(QC-20) and were prepared to produce a flat bonding surface. Cylindrical metal samples were roughened by scratch or by scratch and sandblast and were treated with primer(MR Bond) after scratch and sandblast. And then, liners were prossesed to the cylindrical metal or resin samples according to the manufacturer's recomendations so as to bond metal base or resin base. The specimens were tested in pure tension by using an Instron Univasal testing machine for the four direct reline resins. The results were as follows ; 1. In comparison with tensile bond strength of material relined on resin base or metal base, the case of resin base produced significantly higher tensile bond strengths than the case of metal base. 2. Metal surface pretreatment or primer improved the tensile bond strength between the reline resin and the metal($Biosil^{(R)}$) base. 3. The tensile bond strengths of Mild Rebaron LC relined on resin base or metal base were similar to those of the other reline resins.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.254-266
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• 1997

This study was to know the usefulness of argon laser for composite resin, to prove the polymerized effect of heat treatment of composite resin inlay and to get the curing method for optimal physical properties of composite resin inlay. In this study we used four light curing units and one heat curing unit: Visilux $II^{TM}$, a visible light gun: $SPECTRUM^{TM}$, an argon laser: Unilux AC$^{(R)}$ and Astorn XL$^{(R)}$, visible light curing unit: CRC-$100^{TM}$ for heat treatment. Compared to a control group, we divided the experemental groups into five as follows: Control group: Light curing(Visilux $II^{TM}$) Experimental group 1 : Light curing(Visilux $II^{TM}$) + Light curing(Unilux AC$^{(R)}$) Experimental group 2: Light curing(Visilux $II^{TM}$) + Light curing(Astron XL$^{(R)}$) + Heat treatment(CRC-$100^{TM}$) Experimental group 3 : Laser curing($SPECTRUM^{TM}$) Experimental group 4 : Laser curing($SPECTRUM^{TM}$) + Light curing(Unilux AC$^{(R)}$) Experimental group 5 : Laser curing($SPECTRUM^{TM}$) + Light curing(Astron XL$^{(R)}$) + Heat treatment (CRC-$100^{TM}$) According to the above classification, we made samples through the curing of Clearfil CR Inlay$^{(R)}$, which is a composite resin for inlay, in a separable cylindrical metal mold and polycarbonate plate. And then, we measured and compared the value of compressive strength, diametral tensile strength and the surface micro hardness of each sample. The results were as follows : 1. Among the experimental groups, group 5 showed the highest value of compressive strength, $157.50{\pm}10.24$ kgf and control group showed the lowest value of compressive strength, $103.93{\pm}21.93$ kgf. Control group showed significant difference with the experimental groups(p<0.001). Group 2 which was treated by the heat showed higher compressive strength than that of group 1 which was not, and there was significant difference between group 1 and group 2(p<0.001). Group 5 which was treated by heat showed higher compressive strength than group 4 which was not, and there was significant difference group 4 and group 5(p<0.001). 2. Among the experimental groups, group 5 showed the highest value of diametral tensile strength, $95.84{\pm}1.97$ kgf and control group showed the lowest value of diametral tensile strength, $81.80{\pm}2.17$ kgf. Control group which was cured by visible light showed higher diametral tensile strength than group 3 which was cured Argon Laser. Group 2 which was treated by heat showed higher compressive strength than that of group 1 which was not, and there was significant difference between group 1 and group 2(p<0.001). Group 5 which was treated by heat showed higher compressive strength than group 4 which was not, and there was a significant difference group 4 and group 5(p<0.001). 3. Among the experimental groups, group 5 showed the highest value of microhardness of top surface, $148.42{\pm}9.57$ kgf and control group showed the lowest value of microhardness, $111.43{\pm}7.63$ kgf. In the case of bottom surface, group 5 showed the highest value of $146.19{\pm}7.62$ kgf, and control group showed the lowest, $104.03{\pm}11.05$ kgf. Group 3 which was cured by Argon Laser showed higher diametral tensile strength than control group which was cured only with a visible light gun. Group 2 which was treated by heat showed higher compressive strength than that of group 1 which was not, and there was a significant difference between group 1 and group 2(p<0.001). Group 5 which was treated by heat showed higher compressive strength than group 4 which was not, and there was a significant difference group 4 and group 5(p<0.001). 4. According to the above results, we took a conclusion that argon laser can be used as a useful unit for curing the composite resin and heat treatment can improve the physical properties of the composite resin inlay.

• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.191-205
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• 1992

The purpose of this study was to evaluate the microleakage of class II composite resin inlays and compare them with the conventional light-cured resin filling restorations. Class II cavities were prepared in 60 extracted human molars with which cervical margins were located below 1.0mm at the cemento-enamel junction using No. 701 tapered fissure carbide bur. All of the prepared cavities were restored as follows and divided into 6 groups. Group I and 2 were restored using direct filling technique and group 3,4,5 and 6 were restored using direct inlay technique that was cemented with dual-cured resin cements. group I: Cavities were restored with light-curing composite resin, Brilliant Lux. group 2. Cavities were restored with light-curing composite resin, Clearfil PhotoPosterior. group 3: Cavities were restored with Clearfil CR Inlay and heat treated at $125^{\circ}C$ for 7 minutes. group 4: Cavities were restored with same material as group 3 and heat treated at $100^{\circ}C$ for 15 minutes. group 5: Cavities were restored with Brilliant (Indirect esthetic system) and heat treated at $125^{\circ}C$ for 7 minutes. group 6: Cavities were restored with same material as group 5 and heat treated at $100^{\circ}C$ for 15 minutes. All specimens were polished with same method and thermocycled between $6^{\circ}C$ and $60^{\circ}C$, then immersed in a bath of 2.0% aqueous solution of basic fuchsin dye for 24 hours. Dyed specimens were sectioned longitudinally and dye penetration degree was read on a scale of 0 to 4 by Tani and Buonocore's method 45). The results were as follows: 1. Microleakage was observed rather at the cervical margins than at the occlusal margins in all groups. 2. Composite resin inlay groups showed significantly less leakage than direct filling groups at the cervical margins (p < 0.001). 3. In composite resin inlay groups, there was no significant difference in microleakage between specimens by heat treating temperature and time (p > 0.05). 4. There was no significant difference in leakage between each groups at the occlusal margins (p > 0.05).

• Journal of Advanced Marine Engineering and Technology
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• v.8 no.2
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• pp.81-87
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• 1984

The effect of heat treatment and mechanical stress on the dielectic strength of epoxy resin film is studied. The film with 30-210 .mu.m thickness are casted at room temperature for 8 hours and post cured at the range of temperature 60-180 .deg. C, and the heat setting time are two kind, ie, 2 and 10 hours. The samples are made with Stycast 1266 that the primary compound is diglycidyl ether of bisphenol A, and the hardner is denaturated polyamines. Under no mechanical stresses, the maximum dielectric strength of the sample is obtained for the sample heat treated for 2 hours at 150 .deg. C. However, the best dielectric strength characteristics under compressive stress is obtained for the sample heat treated at 90 .deg. C and 120 .deg. C. The dielectric strength of the sample are also affected significantly by the cooling velocity of the sample after post heat setting at given temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.766-771
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• 2016

This study examined the long-term durability of PC boxes, which was manufactured by low-carbon eco-friendly concrete using an alternative binder to cement and alternative fine aggregate to sand and microwave heat curing system to reduce the construction cost of a near-surface transit system. Based on the test results, the initial compressive strength of microwave heat cured concrete was higher than that of the steam cured concrete, but those were similar in the long-term age. In addition, there was no significant difference between the two curing conditions in the chemical resistance and the freeze-thawing resistance, and the chloride ion penetration level of the concrete cured by two methods was very low. Therefore, low-carbon eco-friendly concrete and microwave heat curing technology are expected to contribute to the economic construction of a near-surface transit system, and reduce carbon dioxide emissions and environmental impact.