• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.80-87
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• 2004

This study was carried out to improve the properties of powdered tannin adhesive(PT) by adding liquid tannin resin(LT) to PT in the manufacture of particleboard. Mixing the LT to PT from 50% to 100% by weight did not show any difference in particleboard properties, but the higher the powdered tannin resin ratio, the lower the properties of the board. The proper ratio of PT to LT was 30:70 for the improvement of PT-particleboard, unless LT lower than 70%. Internal bonding strength was in proportional to the amount of LT. Mixing amino adhesives and PT did not show any improvements in mechanical and physical properties of the board but they only acted as scavenger for the free formaldehyde.Manufacturing particle board with the adhesive of 30:70 (PT:LT) and by using double blender resulted in high-performance products of E₀ level of formaldehyde emission with high water resistance (U type; below 12%, M type; below 25%), as well as saving chip drying energy.

• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.9-19
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• 2008

The purpose of this study was: (1) to compare nanoleakage patterns of a conventional 3-step etch and rinse adhesive system and two experimental hydrophobic adhesive systems and (2) to investigate the change of the nanoleakage patterns after load cycling. Two kinds of hydrophobic experimental adhesives, ethanol containing adhesive (EA) and methanol containing adhesive (MA), were prepared. Thirty extracted human molars were embedded in resin blocks and occlusal thirds of the crowns were removed. The polished dentin surfaces were etched with a 35 % phosphoric acid etching gel and rinsed with water. Scotchbond Multi-Purpose (MP), EA and MA were used for bonding procedure. Z-250 composite resin was built-up on the adhesive-treated surfaces. Five teeth of each dentin adhesive group were subjected to mechanical load cycling. The teeth were sectioned into 2 mm thick slabs and then stained with 50 % ammoniacal silver nitrate. Ten specimens for each group were examined under scanning electron microscope in backscattering electron mode. All photographs were analyzed using image analysis software. Three regions of each specimen were used for evaluation of the silver uptake within the hybrid layer. The area of silver deposition was calculated and expressed in gray value. Data were statistically analyzed by two-way ANOVA and post-hoc testing of multiple comparisons was done with the Scheffe's test. Silver particles were observed in all the groups. However, silver particles were more sparsely distributed in the EA group and the MA group than in the MP group (p < .0001). There were no changes in nanoleakage patterns after load cycling.

• Restorative Dentistry and Endodontics
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• v.36 no.3
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• pp.203-210
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• 2011

Objectives: The purpose of this study was to evaluate the effect of various application methods of one-step self-etch adhesives to microtensile resin-dentin bond strength. Materials and Methods: Thirty-six extracted human molars were used. The teeth were assigned randomly to twelve groups (n = 15), according to the three different adhesive systems (Clearfil Tri-S Bond, Adper Prompt L-Pop, G-Bond) and application methods. The adhesive systems were applied on the dentin as follows: 1) The single coating, 2) The double coating, 3) Manual agitation, 4) Ultrasonic agitation. Following the adhesive application, light-cure composite resin was constructed. The restored teeth were stored in distilled water at room temperature for 24 hours, and prepared 15 specimens per groups. Then microtensile bond strength was measured and the failure mode was examined. Results: Manual agitation and ultrasonic agitation of adhesive significantly increased the microtensile bond strength than single coating and double coating did. Double coating of adhesive significantly increased the microtensile bond strength than single coating did and there was no significant difference between the manual agitation and ultrasonic agitation group. There was significant difference in microtensile bonding strength among all adhesives and Clearfil Tri-S Bond showed the highest bond strength. Conclusions: In one-step self-etching adhesives, there was significant difference according to application methods and type of adhesives. No matter of the material, the manual or ultrasonic agitation of the adhesive showed significantly higher microtensile bond strength.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.661-672
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• 2006

This study was performed to compare the shear bond strength of AQ Bond $Plus^{TM}$ with AQ $Bond^{TM}$ and Single $Bond^{TM}$. Also by observing the fractured interface under scanning electro-microscope, the fracture pattern and the quality of hybrid layer were analyzed. The possibility of clinical application of all-in-one system which has an advantage to reduce chair time for children with difficult behavior pattern was evaluated, The results obtained are as follows ; 1. There was no significant difference between AQ $Bond^{TM}$ and AQ Bond $Plus^{TM}$ in shear bond strength and Single Bond showed the highest bond strength with statistical significant difference (p<0.05). 2. Adhesive fracture pattern was mainly observed in both enamel/dentin in AQ $Bond^{TM}$ and AQ Bond $Plus^{TM}$ group while Single Bond group showed equal numbers for cohesive and adhesive pattern. 3. Under scanning electro-microscope, resin tags observed in AQ $Bond^{TM}$ and AQ Bond $Plus^{TM}$ were very weak and tangled while strong and thick tags were shown with many lateral branches in Single Bond. Careful case selection and accurate clinical application is recommended when using AQ $Bond^{TM}$ and AQ Bond $Plus^{TM}$considering the result showing its weaker strength than Single $Bond^{TM}$.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.2
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• pp.335-348
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• 1996

Retention is one of the major factors deciding the success and longevity of resin bonded restorations. The purpose of this study was to find a better resin cement and metal surface treatment method that would enhance the bonding strength. The bonding surfaces of Verabond, one of Ni-Cr-Be alloys, were treated with sandblasting(Group 1), sandblasting and EZ-Oxisor(Group 2), sandblasting and silicoating(Group 3), and than thay were bonded with All-Bond C & B, Panavia 21, Superbond C & B. The specimens were thermocycled, and the tensile bond strength was measured using the unive-rsal testing machine. Also the mode of bond failure was observed. The results were as folows. 1. The Superbond C & B showed the highest bond strength among the three resin cements and decreased in the order of Panavia 21, All-Bond C & B. There was significant differe-nce among them(p<0.05). 2. Group 3 showed the highest bond strength among the three metal surface treatment methods, and there was significant difference compared with Group 1 and Group 2(p<0.05). But there was no significant difference between Group 1 and Group 2. 3. Observing the mode of bond failure, Superbond C & B and Panavia 21 showed mostly cohesive failure in all groups. All-Bond C & B showed all types of bond failure in Group 3, but Group 1 and Group 2 showed only adhesive failure. 4. According to the results of this study, the silicoating method and 4-META containing resin cement were considered to be more acceptable for resin bonded restoration.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.2
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• pp.184-196
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• 2001

The objective of this study was to investigate the influence of resin cements and ceramic etching on shear bond strength of Empress 2 ceramic and observe the change of microstructure of ceramic according to etching time. Sixty-six square ceramic specimens($6{\times}6{\times}1.5mm$) were prepared. 6 specimens were etched with different etching times(0, 10, 20, 30, 40 and 60 seconds) and observed by means of a scanning electron microscope(SEM). Other sixty specimens were divided into 6 groups with 10 specimens in each group. 3 groups were etched with 4% hydrofluoric acid and each groups was bonded with 3 resin cements(Variolink II, Super-Bond C&B, Panavia F). Each specimen was subjected to a shear load in an Instron at a cross-head speed of 0.5mm/min and was observed with SEM after mechanical testing to establish modes of failure. The results were as follows : 1. Within etched groups, Variolink II and Super-Bond C&B exhibited significantly greater bonding strengths than Panavia F(p<0.05) 2. Bond strength of etching groups had three to five times greater than that of no-etching groups. 3. All of no-etching groups showed adhesive failure and etching groups mostly showed mixed failure. And, 20-second etching specimen showed the most distinct lithium disilicate crystal. so it is considered that 20-second etching is optimal time for bonding.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1511_1512
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• 2009

This paper presents a polarization switching antenna integrated with silicon RF MEMS SPDT switches in the form of a package. A low-loss quartz substrate made of SoQ (silicon-on-quartz) bonding is used as a dielectric material of the patch antenna, as well as a packaging lid substrate of RF MEMS switches. The packaging/antenna substrate is bonded with the bottom substrate including feeding lines and RF MEMS switches by BCB adhesive bonding, and RF energy is transmitted from signal lines to antenna by slot coupling. Through this approach, fabrication complexity and degradation of RF performances of the antenna due to the parasitic effects, which are all caused from the packaging methods, can be reduced. This structure is expected to be used as a platform for reconfigurable antennas with RF MEMS tunable components. A linear polarization switching antenna operating at 19 GHz is manufactured based on the proposed method, and the fabrication process is carefully described. The s-parameters of the fabricated antenna at each state are measured to evaluate the antenna performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.841-850
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• 2008

Strength and failure of composite-to-aluminum rivetted, bonded, and rivet/bonding hybrid single-lap joints were investigated by experiment. A total of 82 joint specimens were tested with 3 different overlap lengths and 2 types of stacking sequence. FM73m adhesive film and NAS9308-4-03 rivet were used for hybrid joints. While failure loads of the bonded and hybrid joints increased as the overlap length increased, failure loads of the rivetted joints were not affected by the overlap length. Effect of the stacking sequence was not remarkable in the simple bonded or rivetted joints. Failure loads of the hybrid joints, however, showed the maximum of 30% difference depending on the stacking sequence. Major failure mode of the bonded and hybrid joints was the delamination of the composite adherend and failure mode of riveted joints was the rivet failure with local bearing.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.361-367
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• 2018

The purpose of this study was to evaluate the influence of hydrofluoric acid etching treatment on the bonding strength of yttria-stabilized tetragonal zirconia polycrystal(Y-TZP). Four groups of zirconia-resin cement specimens were prepared; 1) ZGS group (zirconia, no treatment), 2) ZGSH group (zirconia, hydrofluoric acid etching treatment) 3) H-ZGS group (Hybrid zirconia, no treatment) 4) H-ZGSH group (Hybrid zirconia, hydrofluoric acid etching treatment). The shear bond strength between zirconia and porcelain was measured using a Instron Universal Testing Machine(Model DBBP-500, Instron Corporation, Kyonggi, Korea). Data were statistically analyzed using independent t-test and two-way ANOVA(${\alpha}=0.05$). The ceramic-resin cement bonding strength was affected by hydrofluoric acid etching treatment(p<0.05). Digital microscope examination of the fracture surface showed mixed failures with adhesive and cohesive types in hydrofluoric acid etching treatment with treated zirconia and hybrid zirconia groups.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.2
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• pp.225-233
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• 1994

The restorations of the severely damaged teeth by post core have been increased with the developement of endodontic procedures. But high failure rates of these procedures being reported, various restorative modifications were induced for successful treatments. Cast post-core and prefabricated post with core buildups are choice of treatment. The main causes of failure of the restorations are the fracture of post and core, root fracture, and recurrent caries due to microleakage. Recently, the acid etching technique and the use of dentin bonding agent at tooth surface to reduce the possible microleakage at the tooth-restoration interfaces were introduced. The object of this study was to measure and compare the microleakage by the types and cementation methods of post-core. For this study, forty extracted human anterior teeth were selected for specimen. After cleansing and routine endodontic procedures, anatomic crowns of each specimen were removed at the level of 2mm above the cementoenamel junction. Canals were preparated for post insertion and specimens were divided into four groups randomly. Post-cores were fabricated according to method for each group. Microleakage was measured by length of dye penetration at the tooth-restoration interfaces with measuring microscope at 50 magnification. Oneway ANOVA and t-test were performed for statistical analysis of resulting data. The following results were obtained from this study. 1. There wert significant statistical differences in degree of microleakage between each group (p<0.01). 2. Cast post-core cemented with ZPC (Group I) showed the most severe microleakage pattern$(1.5547{\pm}0.0872mm)$, and cast post-core cemented with adhesive resin cement after tooth surface treatment with dentin bonding agent (Group II) showed the least microleakage $(0.1497{\pm}0.0872mm)$. 3. Group IV revealed less dye penetrations than group III, but no statistical significance was seen between two groups.