• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.293-299
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• 2005

It is important to reduce chair time and procedure in restorative treatment for children. Composite resin is not only used in esthetic restoration of anterior teeth but also posterior teeth by its improved physical property. The 7th generation dentin bonding system was recently developed in order to simplify three steps which is needed to bond composite resin to tooth surface-etchant, primer, adhesive. We compared shear bond strengths of 4, 5, 6, 7th generations dentin bonding systems. The primary dentin was pretreated with 4, 5, 6, 7th generation dentin bonding systems. Then composite resin was cured to the specimen using molds 2.5mm in diameter and 2mm in height. Thermocycling was performed and shear bond strength was finally measured. The results were as follow; 1. The mean values of shear bond strengths in 5th generation dentin bonding system(group 2) were greater than those of 4, 6, 7th generation dentin bonding system(group 1, 3, 4). The differences were statistically significant. 2. The mean values of shear bond strengths in 4th generation dentin bonding system(group 2) were greater than those of 6, 7th generation dentin bonding system(group 1, 3, 4). But, the differences were not statistically significant. 3. Between the mean values of shear bond strengths in 6, 7th generation dentin bonding system(group 3, 4) were similar.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5745-5751
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• 2013

The purpose of this study was to evaluate the effect of the surface treatment of MMA and TEGDMA concentration, silane coupling agent on the shear bond strength of denture base resin and denture reliners. Denture base resin surface was treated with MMA and TEGDMA concentration, silane coupling agent. After denture reliners were injected bond strength was measured. The results of MMA and TEGDMA concentration on the shear bond strength of Vertex self curing resin showed that the value of MMA 95% and TEGDMA 5%, MMA 90% and TEGDMA 10%, MMA 80% and TEGDMA 20% groups were higher than that of other group(P<0.05). MMA and TEGDMA concentration on the shear bond strength of Kooliner resin showed that the value of MMA 95% and TEGDMA 5%, MMA 90% and TEGDMA 10% were higher than that of other group(P<0.05). Silane coupling agent on the shear bond strength of Vertex self curing resin and Kooliner showed that the value of MMA 95% and silane coupling agent 5% groups was higher than that of other group(P<0.05). Therefore, we could conclude that appropriate chemical surface treatments are supposed to affect the bond of denture base resin and denture reliners.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.289-289
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• 2013

CRFP (carbon fiber reinforced plastics)는 탄소섬유 직물에 수지를 함침시켜 만들어지며, 고강도, 고탄성을 지니면서도 가볍고 밀도가 낮기 때문에 항공우주, 스포츠 용품 등 다양한 분야에서 활용되고 있다. 탄소섬유와 수지의 결합력을 증가시키기 위해 사이징, $HNO_3$ 산화, 전기화학적 산화, 플라즈마 처리 등의 다양한 탄소섬유 표면처리 방법이 개발되고 있다. 본 연구에서는 복합재의 강도향상을 위해 탄소섬유 직물을 마이크로웨이브 알곤 플라즈마로 처리하여 강도변화를 관찰하였다. 플라즈마 처리된 직물은 열가소성수지인 CBT와 함침시켜 탄소섬유 복합재로 제조하였다. 그 결과 플라즈마 처리한 복합재의 강도 향상을 확인할 수 있었고, SEM(scanning electron microscope)을 통해 복합재의 표면이 거칠어진 것을 관찰할 수 있었다. 플라즈마로 인해 직물의 표면적이 증가하여 직물의 표면과 수지의 결합력이 증가한 것으로 판단된다.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.232-239
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• 2009

Statements of the problem: Many denture wearers occasionally use denture adhesives to improve denture retention, stability and chewing efficiency. An ideal denture adhesive is nontoxic, non-irritating, and provides comfort to the oral mucosa. Purpose: The purpose of this study was to evaluate the cytotoxicity and adhesive properties of a selected denture adhesive. Material and methods: To test cytotoxicity of the selected denture adhesive, mouse fibroblast cells were used in MTT testing. Cytotoxicity was examined according to the concentration of the denture adhesive and incubated for 1 to 4 days. To examine adhesive property, a denture base was fabricated on an edentulous dentiform. The adhesive was applied to the denture base, then tensile bond strength was measured, to evaluate the change in retention during 3 days. Results and Conclusion: 1. 1% and 2% concentration denture adhesive cream had no cytotoxicity. 2. The tensile bond strength of the group with both denture adhesive and artificial saliva was significantly higher than that of the group with only denture adhesive(P<.05). The tensile bond strength of the group with denture adhesive was significantly higher than that of with only artificial saliva(P<.05). 3. The tensile bond strength had no significant change during 1 hour, and then gradually decreased. After 1 day, it decrease to half. Within the limitation of this study, the tested denture adhesive had no cytotoxicilty and was effective in improving denture retention. The adhesive strength began to continuously decrease after 1 hour and it decreased to half at 1 day after application.

• Composites Research
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• v.31 no.6
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• pp.299-303
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• 2018

In order to improve the interfacial bonding force and reaction polymerization degree of the carbon fiber reinforced nylon 6 composite material, the surface of the existing epoxy-sizing carbon fiber was desized to remove the epoxy and treated with urethane, nylon and phenoxy sizing agent, was observed. The interfacial bond strength of the resized carbon fiber was confirmed by IFSS (Interfacial Shear Strength) and the fracture surface was observed by scanning electron microscope. The results showed that the interfacial bonding strength of the carbon fiber treated with nylon and phenoxy sizing agents was higher than that of urethane - based sizing. It has been found that the urethane - type resizing carbon fiber has lower interfacial bonding strength than the conventional epoxy - sizing carbon fiber. This result shows that the interfacial bonding between carbon fiber and nylon 6 is improved by removing low activity and smoothness of existing carbon fiber.

• The korean journal of orthodontics
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• v.39 no.5
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• pp.320-329
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• 2009

Objective: The aim of this study was to evaluate the effect of metal primers and thermocycling on shear bond strength between the orthodontic bracket and gold alloy. Methods: For this study, 80 specimens made of dental gold alloy were divided into 8 groups based on the combination of metal primers (none, Alloy primer, Metaltite, V-primer) and thermocycling (with and without thermocycling). Shear bond strength testing was performed with a universal testing machine. Bond failure sites were classified by a modified ARI (Adhesive Remnant Index) score. Results: All metal primer treated groups showed a significantly higher shear bond strength than the only sandblasting treated group without thermocycling (p < 0.05). There were no significant differences on shear bond strength in the groups with thermocycling (p > 0.05). Bond failure sites of the metal primer treated group without thermocycling occurred at gold alloy/adhesive interface, whereas there were no differences on bonding failure sites in the groups with thermocycling. Conclusions: These findings suggest that using metal primer on gold alloy enhances the initial bracket bond strength. But, this effect was not shown with thermocycling.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.433-442
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• 2021

In this study, the properties of no-fines polymer concrete with different polymer binder contents were evaluated. The polymer concrete was formulated using a polymeric binder (unsaturated polyester resin), fly ash, and recycled coarse aggregate (60%) and crushed coarse aggregate (40%). The polymeric binder content (4.0-6.0wt.%) was used as an experimental variable because it dramatically affects both the cost-effectiveness and material properties. The results showed that the density, compressive strength, flexural strength both before and after exposure to freezing and thawing increased as the polymer binder content increased, while the absorption, void ratio, permeable voids, coefficient of permeability, and acid resistance (mass loss by acid attack) decreased as the polymeric binder content increased. In particular, even though the void ratio was 18.4% and the water permeability coefficient was 7.3mm/sec, the compressive strength and flexural strength were as high as 38.0MPa and 10.0MPa, respectively, much more significant than those of previous studies. Other properties such as absorption and acid resistance were also found to be excellent. The results appear to be rooted in the increased adhesion of the binder by adding a cross-linking agent and the surface hydrophobicity of the polymer.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.107-114
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• 2002

The purpose of this study was to determine and compare the shear bond strength of two self-etching primer systems to primary teeth contaminated with saliva and blood. Clearfil SE Bond and AQ Bond were evaluated. One hundred specimens were made by seventy-five deciduous teeth(fifty anterior and twenty-five posterior teeth) and divided randomly into ten groups. Small flat dentinal surfaces were prepared by grinding the buccal, lingual and labial areas. Specific surface treatments were applied to each group: (1) a self-etching primer application(control group), (2) saliva contamination followed by primer(Group I), (3) primer curing followed by saliva contamination (Group II), (4) blood contamination followed by primer(Group III), (5) primer curing followed by blood contamination(Group IV). After bonding of composite resin(Z100, 3M, USA) to contaminated sample surfaces and thermocycling(1,000 cycles), shear bond strengths were measured using Universal Testing Machine(Zwick Z020, Zwick Co., Germany). The results were as follows; 1. Group I showed lower shear bond strength than control group but no statistically significant difference was found(P>0.05). 2. Group II and blood contamination group(Group III & IV) showed significantly lower shear bond strength than control group(P<0.01). 3. The shear bond strength of Clearfil SE Bond was significantly higher than that of AQ Bond(P<0.05).

• Journal of Oral Medicine and Pain
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• v.31 no.3
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• pp.211-221
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• 2006

Purpose The aims of this study were to evaluate micro-tensile bond strength of composite resin bonded to dentin following high-speed rotary handpiece preparation or Er:YAG laser preparation with two different adhesive systems and to assess the influence of different Er:YAG laser energies on the micro-tensile bond strength. Materials and Methods In this study, 40 third morlars were used. Flat dentin specimans were obtained and randomly assigned to eight groups. Dentin surfaces were prepared with one of four cutting types: carbide bur, Er:YAG laser (2 W, 3 W and 4 W) and conditioned with two bonding systems, Scotchbond Multipurpose Plus (SM), Clearfil SE bond (SE) and composite resin-build ups were created. After storage for 24 hours, each specimen was serially sectioned perpendicular to the bonded surface to produce more than thirty slabs in each group. Micro-tensile bond strength test was performed at a crosshead speed of 1.0 mm/min. Micro-tensile bond strengths (${\mu}TBS$) were expressed as means$\pm$SD. Data were submitted to statistical analysis using two-way ANOVA, one-way ANOVA, Student-Newman-Keuls' multiple comparison test and t-test. Results and Conclusion 1. Regardless of bonding systems, the ${\mu}TBS$ according to cutting types were from highest to lowest : 3 W, 2 W, Bur, and 4 W. In addition, there was no significant difference between Bur and 4 W (p<0.001). 2. Regardless of cutting types, SM showed significantly higher ${\mu}TBS$ than SE (p<0.001). 3. Bonding to dentin conditioned with SM resulted in higher ${\mu}TBS$ for 3 W compared to Bur, 2 W, and 4 W. There was no significant difference between 2 W and Bur (p<0.001). 4. Bonding to dentin conditioned with SE resulted in higher ${\mu}TBS$ for 3 W compared to 2 W, 4 W, and Bur. Bur exhibited significant lower ${\mu}TBS$ than all other cutting types. There were no significant differences between 3 W, 2 W and between 4 W and Bur (p<0.001). 5. The ${\mu}TBS$ of laser cutting groups were shown in order from highest to lowest: 3 W, 2 W and 4 W in two bonding systems. There was no significant difference between 2 W and 3 W in SE (p<0.001). : The ${\mu}TBS$ of composite resin bonded dentin was significantly affected by interaction between the cutting type and bonding system. In the range of 2 W-3 W, cavity preparation of the Er:YAG laser seems to supply good adhesion of composite resin restoration no less than bur preparation. In particular, if you want to use the self-etching system, including Clearfil SE bond for the purpose of a simplification of the bonding procedures and prevention of adverse effects by excessive etching, an Er:YAG laser may offer better adhesion than a bur.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.158-164
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• 2019

The purpose of this study was to compare the bond strength of resin-modified glass ionomer (RMGI) to dentin with saliva contamination at different stages and using different decontamination procedures. Extracted human permanent molars were embedded onto acrylic resin with the dentin surface exposed. Group I was a control group that was conditioned with polyacrylic acid (PAA). Groups II and III were contaminated with saliva before PAA conditioning and Groups IV, V, and VI were contaminated with saliva after PAA conditioning. After saliva contamination, Groups II and IV were dried, Groups III and V were rinsed and dried, and Group VI was additionally conditioned with PAA. After surface treatment, the dentin specimens were filled with RMGI. Group I showed significantly higher bond strength than the other groups. Group VI showed a significantly higher bond strength than the other saliva contaminated groups. However, there were no significant differences in the failure mode between the different groups. Saliva contamination impaired the bond strength of RMGI to dentin, regardless of when the saliva contamination occurred. Decontamination with washing and drying could not improve the shear bond strength of RMGIC. When saliva contamination occurred after PAA conditioning, additional PAA conditioning improved the shear bond strength.