• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.641-644
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• 2005

The study on the interaction forces of some biological materials is important to understanding biological phenomena and their application to practical purpose. This paper introduces a measuring technique for biological adhesive forces using the AFM(Atomic Force Microscope). Since no standardized thesis on adhesive forces exist, the adhesive forces is defined as adhesive forces against a hardened surface of biological materials. To grant the results are meaningful, which is based on the understanding the surface characteristics of biological materials using the AFM, a nominal value of average adhesive force per unit area should be measured. Therefore the modified AFM probe with small micro glass bead was proposed so that it can guarantee the required contact area for measuring the average adhesive forces. A pyrex glass substrate with circular patterns, which was fabricated by micromachining technique, is introduced in order to controll the contact area. The two types of mussel adhesive proteins, Celltak and recombinant-MGFP5, were tested by the proposed measuring method. The test results show that the adhesive force of the mussel adhesive proteins can be reliably measured by use of this method.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.575-586
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• 2000

In this study, adaptation of compomer to saliva contaminated dentin was evaluated with scanning electron microscope(SEM) and confocal laser scanning microscope(CLSM). For the SEM study, the occulusal surfaces of thirty two molar teeth were grounded to exposure dentin surfaces. The specimen were randomly assigned to control and three experimental groups with four samples in each group. In control group, Dyract and F-2000 compomer were bonded on the specimens according to the manufactures direction. Experimental groups were subdivided into three groups. They were contaminated with saliva on dentin surfaces ; Experimental group 1 : Saliva was dried with compressed air. Experimental group 2 : Saliva was rinsed with air-water spray and dried. Experimental group 3 : After polymerization of an adhesive, they were contaminated with saliva, and then saliva was rinsed with air-water spray and dried. Dyract and F-2000 compomer were bonded on saliva-treated dentin surfaces. The interfaces between dentin and compomer were observed with SEM. For the CLSM study, Class V cavities were prepared in buccal and ligual surfacess of thirty two molars. The specimens were divided into control and experimental groups. Class V cavities in experimental group were contaminated with saliva and those surfaces in each experimental groups received the same treatments as for the SEM study. Cavities were applied Prime & Bond 2.1 and F-2000 compomer primer/adhesive that were mixed with fluorescein, and then were filled with Dyract and F-2000 compomer. Specimens were embedded in transparent acrylic resin and sectioned buccolingual1y with diamond wheel saw, and then mounted on cover slide for CLSM study. The interface between cavity and compomer was observed by fluoresence imaging with a CLSM. The results were as follows : 1. In SEM exammination of Dyract group, control group, experimental group 2, 3 showed close adaptation to dentin and hybrid layer of $3{\sim}4{\mu}m$ diameter. Interfacial gap between compomer and dentin in experimental group 1 was wider than in control group. 2. In SEM examination of F-2000 group, adaptation to dentin of control group was closer than Dytact control group, but hybrid-like layer was not observed. Interfacial gap between compomer and dentin in experimental group 1 was wider than in Dyract experimental group 1. 3. In dissolution specimens of Dyract and F-2000 group, resin tags penetrated through dentinal tubules in control group and experimental group 1 and 3, but the penetration of resin tag was irregular and partial in experimental group 1. 4. In CLSM exammination of Dyract and F-2000 group, adhesive patterns of control and experimental groups showed same as in SEM. This result suggests the treatment methods, rinsing & drying, repeating all adhesive procedures, will produce good effect on adaptation of compomer to dentin if the dentin surface or polymerized adhesive is contaminated by saliva.

• The korean journal of orthodontics
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• v.34 no.4 s.105
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• pp.325-332
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• 2004

A self-etching primer that combines the etchant and primer in one chemical compound saves time and should be mote cost-effective to the clinician and patient. The purpose of this study was to evaluate the clinical effectiveness of a self-etching primer by measuring shear bond strengths according to various conditions and observing adhesive failure patterns. For this Investigation, 120 upper and lower premolars extracted for orthodontic purposes were used and randomly divided into six groups of twenty teeth each. Human premolars were embedded in a metal cylinder with orthodontic resin. Metal brackets and ceramic brackets were bonded with XT primer and self-etching primer by means of XT adhesive. Upon curing, plasma arc light and visible light were used. After bonding, the shear bond strength was tested by Instron universal testing machine, and the amount of residual adhesive that remained on the tooth after debonding was measured by stereoscope and assessed with an adhesive remnant index. The results were as fellows: 1. When brackets were bonded, if other conditions remained the same, there was no significant difference in shear bond strength due to the type of primer - either self-etching primer or XT primer. 2. When metal brackets were bonded, there was no significant difference in shear bond strength according to the source of light - plasma arc light or visible light - and type of primer. 3. There was a very significant difference in shear bond strength according to the type of brackets - metal or ceramic brackets. The shear bond strength of ceramic brackets was stronger than metal brackets. 4. When the adhesive failure patterns of metal brackets bonded with self-etching primer were observed by using the adhesive remnant index, the bond failure of the metal bracket occurred more frequently at the bracket-adhesive. The failure of the ceramic bracket, however, occurred more frequently at the enamel-adhesive interface. The adhesive failure patterns of metal brackets bonded with XT primer observed the same patterns. The above results suggest that self-etching primer can be clinically useful for bonding the brackets without fear of a decrease in shear bond strength.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.835-845
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• 1994

In this paper, the effects of the adhesive thickness and adherend roughness on the static and fatigue strengths of the adhesively bonded circular single lap joints has been investigated by an experimental method. The stacking sequence effect of the composite adherend on the static and fatigue strength and the fracture patterns of the adhesive failure were also observed. Since the circular single lap joint fails catastrophically beyond the static strength of fatigue limit, the tubular polygonal adhesively bonded joints such as triangular, tetragonal, pentagonal, hexagonal as well as elliptical joints were manufactured in order to give partial mechanical characteristics to the adhesively bonded tubular joints. These joints were tested both in static and fatigue modes. From the experimental investigations, it was found that the fatigue strength of the circular adhesively bonded joints was much dependent on the arithmetical average surface roughness of the adherends and the polygonal adhesively bonded joints had better fatigue strength characteristics than the circular adhesively bonded joints.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.6
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• pp.732-746
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• 2003

Statement of problem. Soft lining materials, also referred to as tissue conditioning materials, tissue heating materials, relining materials, soft liners or tissue conditioners, were first introduced to dentistry by a plastic manufacturer in 1959. Since the introduction of the materials to the dental field, their material properties have been continually improved through the effort of many researchers. Soft lining materials have become widely accepted, particularly by prosthodontists, because of their numerous clinical advantages and ease of manipulation. Unfortunately, few reports have been issued upon the topic of increasing the bond strength between the base metal alloy used in cast denture bases and PMMA soft liner modified with 4-META, nor upon the pattern of debonding and material change in wet environment like a intra oral situation. Purpose. The purposes of this study were comparing the bond strength between base metal alloy used for the cast denture bases and PMMA soft liner modified with 4-META, and describing the pattern of debonding and material property change in wet environment like the intraoral situation. Material and Methods. This study consisted of four experiments: 1. The in vitro measurement of shear bond strength of the adhesive soft liner. 2. The in vitro measurement of shear bond strength of the adhesive soft liner after 2 weeks of aging. 3. A comparison of debonding patterns. 4. An evaluation the Relation time of modified soft liner. The soft liner used in this study was commercially available as Coe-soft (GC America.IL.,USA), which is provided in forms of powder and liquid. This is a PMMA soft liner commonly used in dental clinics. The metal primer used in this study was 4-META containing primer packed in Meta fast denture base resin (Sun Medical Co., Osaka, Japan). The specimens were formed in a single lap joint desist which is useful for evaluating the apparent shear bond strength of adhesively bonded metal plate by tensile loading. Using the $20{\times}20mm$ transparent grid, percent area of adhesive soft liner remaining on the shear area was calculated to classify the debonding patterns. To evaluate the change of the initial flow of the modified adhesive soft liner, the gelation time was measured with an oscillating rheometer (Haake RS150W/ TC50, Haake Co., Germany). It was a stress control and parallel plate type with the diameter of 35mm. Conclusion. Within the conditions and limitations of this study, the following conclusions were drawn as follows. 1. There was significant increase of bond strength in the 5% 4-META, 10% 4-META containing groups and in the primer coated groups versus the control group(P<0.05). 2. After 2 weeks of aging, no significant increase in bond strength was found except for the group containing 10% 4-META (P<0.05). 3. The gelation times of the modified soft liner were 9.3 minutes for the 5% 4-META containing liner and 11.5 minutes for the 10% 4-META liner. 4. The debonding patterns of the 4-META containing group after 2 weeks of aging were similar to those of immediaely after preparation, but the debonding pattern of the primer group showed more adhesive failure after 2 weeks of aging.

• KSBB Journal
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• v.24 no.6
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• pp.515-520
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• 2009

This study presented facile method of cell patterning using fabricated PDMS patterns on polyelectrolyte coated surface. This basic principle is the fabrication of functional surface presenting two orthogonal surfaces such as cell adhesive and repellent properties. Cell adhesive surface was firstly fabricated with simple coating of polyelectrolyte multilayer. And then, the desired patterns of PDMS for the prevention of nonspecific binding of cells were transferred onto the previously formed thin film of polyelectrolyte multilayer. Thus, we could prepare novel functional surface simultaneously containing PDMS and polyelectrolyte region. As expected, the PDMS regions showed effective prevention of nonspecific binding of cell and the other region, exposed polyelectrolyte area, provided cell adhesive environment. The height of formed PDMS structure was about 100 nm. Based on this method, cell patterning can be successfully obtained with various pattern shapes and sizes. Therefore, we expect that this simple method will be useful platform technology for the development of cell chip, cell based assay system, and biochip.

• Journal of Pharmaceutical Investigation
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• v.15 no.2
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• pp.45-52
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• 1985

For the model tablets using mannitol and Avicel PH 101 as excipients, the patterns of disintegration and dissolution from the differences of physical properties were investigated. It was found that the patterns in the dissolution and binding forces in the interaction of materials by estimates of solid-solid or liquid surface free energy due to cohesive or adhesive properties of materials, and solid surface free energy in binding forces of tablet should be considered as an important factor in dissolution processes.

• Proceedings of the KACD Conference
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• 2002.11a
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• pp.717-717
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• 2002

No Abstract, See Full Text

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.117-123
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• 2009

This paper presents a numerical simulation of guided ultrasonic waves propagating in aluminum-epoxy-aluminum adhesive plates. In particular, this study investigated the effect of the epoxy thickness on the dispersive patterns, such as the phase velocity and group velocity of guided ultrasonic waves. In addition to investigating the dispersive curves, a numerical simulation using the pulse-echo method was carried out. This simulation showed that the degree of sensitivity of the epoxy thickness is dependent on the curvature of the phase and group dispersion curves, the maximum amplitude of the received time signals, and the peak frequency of the real components of the Fourier transform. Then, the linear relations between the epoxy thickness and the received and transformed signals were constructed to estimate the epoxy thickness.

• Journal of Periodontal and Implant Science
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• v.33 no.1
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• pp.91-102
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• 2003

Several effective treatment methods and materials have been developed for the treatment of furcation involvement. Currently, the combination of guided tissue regeneration (GTR) and bone grafts is the most commonly prescribed method of treating furcation involved defects. But because these cases often present with poor accessibility, placement of the membrane may be difficult and consequently, clinically impractical. In this study, the alveolar bone healing patterns of adult beagle dogs presenting with alveolar bone destruction treated by one of two methods - treatment using solely bone allografts (BBP(R)), or treatment using bone allografts (BBP(R)) stabilized by a fibrin adhesive - were comp ared. The effects of the fibrin adhesive on the initial stabilization of the newly formed bone, subsequent regeneration of bone, and the feasibility of the clinical application of the fibrin adhesive were analyzed. The results of the study were as follows: 1. Clinical signs of inflammation at the 4-8 week interval were not observed: but signs of mild inflammation were histologically observed at the 4-week interval. 2. Allografts stabilized by fibrin adhesive showed good bone formation, whereas defects treated with only the allograft material showed incomplete alveolar bone regeneration. 3. Allografts stabilized by fibrin adhesive showed a decrease in the amount old bone with a concurrent increase in the formation of new lamellar bone four weeks post-op, whereas defects treated with only the allograft material showed no new lamellar bone formation at the same interval. 4. In detects treated with only the allograft material, the defective area was filled with connective tissue 8-weeks post-op, whereas fibrin adhesive stabilized allografts showed viable connections between the original bone and the newly formed bone, in addition to neovascularization 8-weeks post-op. The results of this study show that concurrent use of fibrin adhesive materials can stabilize the allograft material and aid in new bone formation Although the stability of fibrin adhesives fall short of the results achievable by GTR membranes, in cases presenting with poor accessibility that contraindicate the use of membranes, fibrin adhesive materials provide a viable and effective alternative to graft stabilization and new bone formation.