• The korean journal of orthodontics
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• v.34 no.4 s.105
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• pp.333-342
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• 2004

The purpose of this study was to evaluate the clinical effectiveness of a plasma arc light and light emitting diode (LED), compared with shear bond strength and the failure pattern of brackets bonded with visible light in direct bonding. Brackets were bonded with Transbond XT to 60 human premolars embedded in the resin blocks according to different light-curing methods. Then, the shear bond strength of each group was measured using a universal testing machine (Instron) and the adhesive failure pattern after debonding was visually examined by light microscope. The results were as follows: 1. The shear bond strength showed no significant difference between the visible light and light emitting diode, but the plasma arc light exhibited a significantly lower shear bond strength compared with the visible light and light emitting diode. 2. In the visible light and light emitting diode, adhesive failure patterns were similar. Bond failure occurred more frequently at the enamel-adhesive interface. 3. The bonding failure of brackets bonded with plasma arc light occurred more frequently at the bracket-adhesive interface. The results of this study suggest that plasma arc light, light emitting diode and visible light are all clinically useful in the direct bonding of orthodontic brackets.

• Journal of Conservation Science
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• v.27 no.2
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• pp.135-144
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• 2011

When metal artifacts have to undergo conservation treatment, the person in charge of the treatment selects and uses various coating mixtures based on his judgment regarding their condition, material, or environment. Since the kinds of coating mixtures or solvents make a difference in the set time of cyanoacrylate adhesives, they have something to do with the efficiency of the conservation treatment. This study examines the effects and causes that affect the set time of cyanoacrylate adhesives according to the kinds of coating mixtures and solvents and suggests ways to increase the set time. As a result, it is thought that as the surface roughness gets flatter, the wettability of adhesive is improved further, which increases the set time. Moreover, the C-F binding of V-Flon, C-O-C absorption peak, molecular weight of the coating mixtures, and glass transition temperature (Tg) were the factors that significantly affected the set time. According to the result of measuring the set time based on the result of superficial and chemical analysis, relative difference was shown according to the kind and viscosity of adhesive, but all the adhesives indicated the following order of the set time: V-Flon > Paraloid B-72 (in xylene) > Paraloid NAD-10 > Paraloid B-72 (in acetone).

• Restorative Dentistry and Endodontics
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• v.33 no.2
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• pp.90-97
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• 2008

The purpose of this study was to evaluate the effect of passive or active application of primer and coat times of bond on the shear bond strength when a self-etching primer adhesive (Clearfil SE Bond) was applied to enamel surface. Crowns of sixteen human molars were selected. Buccal and lingual enamels of crowns were partially exposed and slabs of 1.2 mm thick were made. They were divided into one of four equal groups (n = 8). Group 1: passive application of Primer and 1 coat of Bond, Group 2: active application of Primer and 1 coat of Bond, Group 3: passive application of Primer and 2 coats of Bond, Group 4: active application of Primer and 2 coats of Bond. Clearfil AP-X was bonded to enamel suface of each group using Tygon tubes. The bonded specimens were subjected to microshear bond strength (uSBS) testing with a crosshead speed of 1 mm/min. The results of this study were as follows; 1. The uSBS of Group 1 was the lowest among groups and the uSBS of Group 4 was the highest. 2. There was not statistically significant interaction between enamel uSBS by application method of Primer and coat time of Bond (p > 0.05). 3. There was not statistically significant difference between enamel uSBS by passive and active application of Primer (p > 0.05). 4. There was statistically significant difference between enamel uSBS by one- and two-coat of Bond (p < 0.05).

• The korean journal of orthodontics
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• v.26 no.3
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• pp.301-307
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• 1996

The purpose of this study was to evaluate the effect of surface treatment of porcelain on tensile bond strength. To accomplish this purpose, this study was carried out with 120 samples which were divided into 12 groups with each 10 samples, and the first group was not surface treated, groups 2 through 5 underwent single surface treatment, and groups 6 through 12 underwent compound surface treatment. The results were as follows : 1. In statistic, all the single surface-treated groups showed higher tensile bond strength than the non surface-treated group and the sandblasted group showed the highest tensile bond strength as $10.34{\pm}2.50MPa$. 2. All the compound surface-treated groups showed no noticeable difference in the tensile bond strength(9-11.5MPa). 3. In statistic, no significant difference was found between the sandblasted group and the compound surface-treated groups. 4. There was no fracture of porcelain while testing in this study. Above study demonstrated that compound surface treatment or sandblasing, if used single surface treatment, should be employed to guarantee successful clinical application.

• Korean Journal of Materials Research
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• v.9 no.7
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• pp.724-734
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• 1999

The adhesion characteristics of the thermoplastic resins such as PE, PP PVC, PET and PS were investigated on the surfaces of conventional steel (SS41), steel (SS41P) treated with ultrasonic waves and the SS41P coated with several ceramic powders (SS41PC) by the plasma spray. Alumina (Al$_2$O$_3$), alumina titania (Al$_2$O$_3$95%, TiO$_2$ 5%) and zirconia yttria (ZrO$_2$ 95%, $Y_2$O$_3$5% ) were used for the materials plasma spray The morphologies, surface hardness, surface roughness, and contact angles on SS41, SS41P, and SS41PC were examined. The tensile shear strength and peel strength of the polymers which were attached to the surfaces of ceramics coated on SS41P also were measured. The tensile shear strength and peel strength of polymers adhered to ceramic surface coated on steel were found to be stronger than those of conventional steel. The tensile shear strength and peel strength of the polymers adhered on the surfaces of ceramics coated steel increased in the following order PE > PET > PP > PS > PVC. The high adhesion strength of PE may be attributed to the surface roughness and its anchor effect on the ceramic surface.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.106-113
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• 2011

The object of this clinical study was to evaluate the short-term outcome of modified resin-bonded fixed partial dentures which utilizes the original tooth undercuts and different path of insertion of components. Materials and methods: 71 units of modified RBFPDs that were used in 21 patients at the Department of Prosthodontics, College of Dentistry, Yonsei University were evaluated. The follow-up period was up to 25 months, the mean being 7 months. Survival rate, mobility, percussion, probing depth, bleeding on probing, plaque index was recorded and radiographs were taken to monitor alveolar bone loss. Results & Conclusion: Within the limits of this short term retrospective study, it was concluded that: 1. No mechanical failure such as debonding or fracture of the framework was found during the follow-up period. 2. The periodontal apparatus was stable and no clinical change was observed after prosthetic treatment. 3. No significant marginal bone loss was found in the radiographic evaluation.

• Restorative Dentistry and Endodontics
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• v.34 no.3
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• pp.184-191
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• 2009

The purpose of this study was to evaluate the physical properties of different self-adhesive resin cements and their shear bond strength on dentin and lithium disilicate ceramic and compare these result with that of conventional resin cement. For this study, four self-adhesive resin cements (Rely-X Unicem, Embrace Wetbond, Mexcem, BisCem), one conventional resin cement (Rely-X ARC) and one restorative resin composite (Z-350) were used. In order to evaluate the physical properties, compressive strength, diametral tensile strength and flexural strength were measured. To evaluate the shear bond strength on dentin, each cement was adhered to buccal dentinal surface of extracted human lower molars. Dentin bonding agent was applied after acid etching for groups of Rely-X ARC and Z-350. In order to evaluate the shear bond strength on ceramic, lithium disilicate glass ceramic (IPS Empress 2) disks were prepared. Only Rely-X ARC and Z-350 groups were pretreated with hydrofluoric acid and silane. And then each resin cement was adhered to ceramic surface in 2 mm diameter. Physical properties and shear bond strengths were measured using a universal testing machine. Results were as follows 1. BisCem showed the lowest compressive strength, diametral tensile strength and flexural strength. (P<0.05) 2. Self-adhesive resin cements showed significantly lower shear bond strength on the dentin and lithium disilicate ceramic than Rely-X ARC and Z-350 (P<0.05) In conclusion, self-adhesive resin cements represent the lower physical properties and shear bond strength than a conventional resin cement.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.213-220
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• 2018

In order to use Pitch pine (Pinus rigida Miller) as the material of the structural glued laminated timber, the effect of the amount of resin exudation due to storage time after the planning and the knot of the lamina were evaluated on the bonding properties of the glued board with resorcinol resin. For Pitch pine that was dried at high temperature ($120{\sim}95^{\circ}C$) and low temperature ($65{\sim}50^{\circ}C$), the flat sawn(tangential section) showed higher amount of resin exudation than the quarter sawn(radial section). And the low temperature drying wood showed higher resin exudation than the high temperature drying wood. The low and high temperature drying wood showed the highest amount of resin exudation on the 3rd day and 7th day, respectively and they were gradually decreased. However, there were no significant differences from 15 to 90 days. Adhesion performances were low until 2~3 days with high exudation of resin, but there were no significant differences after 15 days. Both high temperature and low temperature drying woods satisfied the Korean standard regardless of the storage time. The adhesive strengths of the laminating parts including knots were higher than those of KS criteria, but the wood failures were not satisfied the KS standard. Adhesive performances according to the laminating combinations (quarter sawn + quarter sawn, flat sawn + flat sawn, quarter sawn + flat sawn) were better than those of KS criteria in all laminating combinations in both high temperature and low temperature drying woods.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.5
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• pp.35-42
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• 2014

Thermal analysis properties and adhesive properties of self-healing agents were evaluated through differential scanning calorimetry, reaction heat measurement, and adhesive shear test. D1E0, D3E1, D1E1, D1E3, and D0E1, depending on the mixing ratio of DCPD and ENB, were considered as self-healing agents. The amount of Grubbs' catalyst, depending on the type of self-healing agents, was varied from 0.1 wt% to 1.5 wt%. In the case of DCPD, the polymerization reaction occurred faster and the stabilized adhesive strength increased as the amount of catalyst increased; however, a large amount of catalyst was required. ENB had excellent reactivity with a small amount of the catalyst; however, high reaction heat was observed at the early stage of polymerization. Thermal analysis properties and adhesive properties of self-healing agents can be controlled by varying a mixing ratio of DCPD and ENB. Among the self-healing agents used for this study, the D3E1 would be one of the most preferable candidates with regard to maximum adhesive strength, reaching time to maximum adhesive strength, stabilized adhesive strength, and reaction heat.

• Journal of Adhesion and Interface
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• v.23 no.3
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• pp.87-93
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• 2022

To analyze the interfacial property between the fiber and the matrix, work of adhesion was used generally that was calculated by surface energies. In this paper, it was determined what types of contact angle measurement methods were more accurate between static and dynamic contact angle measurements. 4 types of glass fiber and epoxy resin were used each other to measure the contact angle. The contact angle was measured using two types, static and dynamic contact angle methods, and work of adhesion, W_a was calculated to compare interfacial properties. The interfacial property was evaluated using microdroplet pull-out test. Generally, the interfacial property was proportional to work of adhesion. In the case of static contact angle, however, work of adhesion was not consistent with interfacial property. It is because that dynamic contact angle measurement comparing to static contact angle could delete the error due to microdroplet size to minimize the surface area as well as the meniscus measuring error.