• 대한치과교정학회지
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• 제22권2호
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• pp.289-296
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• 1992

The purpose of this study was to evaluate and compare the shear bond strengths and failure sites of metal brackets bonded with chemically cured adhesive and light-cured adhesive. 10 brackets were bonded on prepared enamel surfaces with $Transbond^{circledR}$ (Unitek/3M; U.S.A.) light-cured orthodontic adhesive and another 10 brackets were bonded with $Ortho-one^{\circledR}$ (Bisco:U.S.A.) chemically cured orthodontic adhesive. 24 hours after bonding, the Instron universal testing machine was used to measure the shear bond strengths. The failure sites were examined under streoscopic microscope. The results were as follows: 1 . The mean shear bond strength of metal brackets bonded with light-cured adhesive was lower than that of metal brackets bonded with chemically cured adhesive, but the difference was not statistically significant (p < 0.05). 2. Regardless of the type of adhesives, the brackets were failed primarily at the bracket base-adhesive interface. 3. Bonding of metal brackets with light-cured adhesive is considered to be clinically acceptable.

• Structural Engineering and Mechanics
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• 제84권6호
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• pp.799-811
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• 2022

Adhesive bonding has seen rapid development in recent years, with emphasis to composite patch repairing processes of geometric defects in aeronautical structures. However, its use is still limited given its low resistance to climatic conditions and requirement of specialized labor to avoid fabrication induced defects, such as air bubbles, cracks, and cavities. This work aims to numerically analyze, by the finite element method, the failure behavior of a damaged plate, in the form of a bonding defect, and repaired by an adhesively bonded composite patch. The position and size of the defect were studied. The results of the numerical analysis clearly showed that the position of the defect in the adhesive layer has a large effect on the value of J-Integral. The reduction in the value of J-Integral is also related to the composite stacking sequence which, according to the mechanical properties of the ply, provides better load transfer from the plate to the repair piece through the adhesive. In addition, the increase in the applied load significantly affects the value of the J-Integral at the crack tip in the presence of a bonding defect, even for small dimensions, by reducing the load transfer.

• Restorative Dentistry and Endodontics
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• 제40권3호
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• pp.202-208
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• 2015

Objectives: This study determined the effect of the air-stream application time and the bonding technique on the dentin bond strength of adhesives with different solvents. Furthermore, the content and volatilization rate of the solvents contained in the adhesives were also evaluated. Materials and Methods:Three adhesive systems with different solvents (Stae, SDI, acetone; XP Bond, Dentsply De Trey, butanol; Ambar, FGM, ethanol) were evaluated. The concentrations and evaporation rates of each adhesive were measured using an analytical balance. After acid-etching and rinsing, medium occlusal dentin surfaces of human molars were kept moist (conventional) or were treated with 10% sodium hypochlorite for deproteinization. After applying adhesives over the dentin, slight air-stream was applied for 10, 30 or 60 sec. Composite cylinders were built up and submitted to shear testing. The data were submitted to ANOVA and Tukey's test (${\alpha}=0.05$). Results: Stae showed the highest solvent content and Ambar the lowest. Acetone presented the highest evaporation rate, followed by butanol. Shear bond strengths were significantly affected only by the factors of 'adhesive' and 'bonding technique' (p < 0.05), while the factor 'duration of air-stream' was not significant. Deproteinization of dentin increased the bond strength (p < 0.05). Stae showed the lowest bond strength values (p < 0.05), while no significant difference was observed between XP Bond and Ambar. Conclusions: Despite the differences in content and evaporation rate of the solvents, the duration of air-stream application did not affect the bond strength to dentin irrespective of the bonding technique.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1997년도 한국재료학회 추계학술발표회
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• pp.25-25
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• 1997

• 펄프종이기술
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• 제44권2호
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• pp.35-41
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• 2012

In this study, wheat starch adhesive was investigated the shape and structure of starch, the difference in characteristics such as chemical composition according to the fermenting period of 2 years or less. The fermenting period of wheat starch adhesive is 1 month, 2months, 4 months,6 months, 1 year, 2years old. The wheat starch adhesives were investigated total sugar contents, protein contents, properties of gelatinization, pH, the bonding strength and also observed the surface of starch,. As a result, the longer the fermenting period, the increasing in total sugar contents and decreasing in protein contents. The particle shape and surface were similar regardless of the period. In addition, properties of gelatinization according to the fermenting period also could not see the difference. In pH of the adhesive, the longer the fermenting period, the near to neutral. The adhesive was high bonding strength in 4 months, but appeared a tendency to decrease from 6 months. The damage assessment through the UV degradation in regard to the papers applied the adhesive was accomplished. Color difference was no change except 1 month. The 4 months and 6 months' pH was each 5.0, 5.2. But it was near to neutral that the 12 months and 24 months' pH was each 5.7, 5.9.

• Restorative Dentistry and Endodontics
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• 제27권1호
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• pp.44-53
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• 2002

목적 : 최근 개발된 bonding agent 중 일부는 다양한 함량의 filler를 포함하고 있으며 filler의 첨가는 bonding agent의 기계적인 물성을 향상시킴으로써 접착력의 향상에 기여한다는 주장이 있다. 본 연구에서는 다양한 함량의 filler를 포함한 adhesive를 실험적으로 만들어, filler의 함량이 전단접착강도에 미치는 영향을 살펴보고 임상적으로 가장 적절한 filler의 함량을 알아보고자 하였다. 또 adhesive의 간접인장강도를 측정하여 adhesive의 기계적인 물성과 접착력과의 상관관계를 알아보았다. 방법 : 발거된 건전한 70개의 대구치를 투명 레진에 매몰하고 상아질면을 노출시켰다. 3M사의 Scotchbond Multipurpose의 etchant와 primer를 제조사의 지시대로 적용하고 1$\mu\textrm{m}$크기의 barium glass filler를 0, 5, 10, 15, 20, 30, 45wt% 포함하도록 실험적으로 제작한 adhesive를 도포한 후 레진을 충전하여 시편을 완성하였다. Instron으로 0.5mm/min의 속도에서 전단접착강도를 측정하고 그 단면을 입체현미경으로 관찰하여 파절의 양상을 확인하였다. Filler함량에 따른 adhesive의 후경을 측정하기 위해 상기한 방법으로 시편을 제작하여 주사 전자현미경으로 관찰한 후 Sigmascan을 이용하여 그 후경을 측정하였다. 또, 지름 4mm 높이 6mm의 원통형 시편을 제작하여 Instron로 간접인장강도의 측정을 시행하였다. 얻어진 결과는 Kruskal-Wallis test와 Mann-Whitney test를 시행하여 분석하였으며, 상관관계를 분석을 위해 Pearson Product Moment Correlation Coefficient를 구하였다. 결과 : 1) Filler함유량에 따라 전단접착강도는 유의할 만한 차이를 보였다(p<0.05). 2) Filler함량의 증가에 따라 전단접착강도는 유의하게 증가하여 15% 수준에서 가장 높은 갈(19.9$\pm$1.38Mpa)을 보였으며 20% 이상의 수준에서는 유의하게 감소하였다(p<0.05). 3) Adhesive의 간접인장강도는 20% 수준까지는 증가하는 양상을 보였으나 통계적 유의성은 없었으며(p>0.05), 30% 이상에서는 유의할 만한 감소를 보였다(p<0.05). 4) Adhesive의 후경은 0% 수준에서 5.97$\pm$1.23$\mu\textrm{m}$부터 45%수준에서 73.37$\pm$11.7$\mu\textrm{m}$까지 유의하게 증가하였다(p<0.05). 5) Filler함량에 따른 Adhesive의 간접인장강도와 전단접착강도는 상관관계가 없었다.

• 대한치과교정학회지
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• 제48권4호
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• pp.245-252
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• 2018

Objective: We aimed to perform in-vitro evaluation to compare 1) shear bond strength (SBS), adhesive remnant index (ARI), and color change between self-etched and acid-etched primers; 2) the SBS, ARI and color change between direct and indirect bonding; and 3) the enamel roughness (ER) between 12-blade bur and aluminum oxide polisher debonding methods. Methods: Seventy bovine incisors were distributed in seven groups: control (no bonding), direct (DTBX), and 5 indirect bonding (ITBX, IZ350, ISONDHI, ISEP, and ITBXp). Transbond XT Primer was used in the DTBX, ITBX, and ITBXp groups, flow resin Z350 in the IZ350 group, Sondhi in the ISONDHI group, and SEP primer in the ISEP group. SBS, ARI, and ER were evaluated. The adhesive remnant was removed using a low-speed tungsten bur in all groups except the ITBXp, in which an aluminum oxide polisher was used. After coffee staining, color evaluations were performed using a spectrophotometer immediately after staining and prior to bonding. Results: ISONDHI and ISEP showed significantly lower SBS (p < 0.01). DTBX had a greater number of teeth with all the adhesive on the enamel (70%), compared with the indirect bonding groups (0-30%). The ER in the ITBX and ITBXp groups was found to be greater because of both clean-up techniques used. Conclusions: Direct and indirect bonding have similar results and all the primers used show satisfactory adhesion strength. Use of burs and polishers increases the ER, but polishers ensure greater integrity of the initial roughness. Resin tags do not change the color of the teeth.

• 대한치과교정학회지
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• 제39권6호
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• pp.393-401
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• 2009

본 연구는 직접 또는 간접 부착법으로 부착한 교정용 브라켓을 열순환 처리 후에 전단 결합 강도(shear bond strength, SBS)와 치아-접착제-브라켓 복합체의 미세 누출을 비교하기 위하여 시행하였다. 50개의 치아우식증이 없는 사람 소구치를 구하여 동등한 2개의 군으로 나누었다. 직접 부착군에서는 광중합 접착제 및 primer (Transbond XT)를 사용하였고 간접 부착군에서는 광중합 접착제와(Transbond XT) 화학중합 primer (Sondhi Rapid Set)를 사용하였다. 중합 후에 치아는 24시간 동안 증류수에 보관하였고 이후 500회 열순환 처리를 하였다. 미세누출의 평가를 위해 각 군에서 10개의 치아에 nail varnish로 추가 봉연을 실시하고 0.5% basic fuchsin에 24시간 동안 염색한 후 입체현미경으로 검경하였다. 만능시험기를 이용하여 각 군의 치아 15개로 SBS를 계측하였고 adhesive remnant index (ARI)를 평가하였다. 결과 자료는 Mann-Whitney U test, Chi-square test, Fisher's exact test로 통계 분석하였다. 직접 부착군과 간접 부착군 사이에 SBS 및 미세누출의 통계적으로 유의한 차이는 보이지 않았으며 간접 부착군에서 통계적으로 유의하게 ARI 점수가 낮았다. 브라켓의 탈락은 법랑질-레진 계면에서 발생하였다. 이상의 결과로 보아 부착법의 차이는 미세누출의 양과 SBS에 유의한 영향을 미치지 않는다.

• Composites Research
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• 제33권6호
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• pp.371-376
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• 2020

접착강도는 표면처리 기술을 통해 향상시킬 수 있다. 가장 일반적인 방법은 기계적인 결합력을 향상시킬 수 있는 접착 표면의 변화이다. 본 연구는 접착면의 레이저 표면 처리가 기계적 결합력에 미치는 영향과 탄소섬유 강화 복합재료(CFRP)의 접착 결합에 대해 설명한다. 1064 nm의 레이저를 활용하여 표면 조도를 패턴화했다. 레이저 샷의 수, 패턴의 방향, 길이가 CFRP/CFRP 단일 조인트의 접착력에 미치는 영향을 인장 시험을 통해 조사했다. ASTM D5868에 따른 시험을 수행하였으며, 파단 후 손상된 표면을 분석하여 결합 메커니즘을 결정했다. 접착 강도의 증가를 위해서는 CFRP 표면에 최적화된 레이저 샷의 수와 조도 깊이가 구성되어야 한다. 인장방향에서의 전단응력을 고려할 때, 접착층의 파단 경로를 길어지게 하는 45°의 방향의 조도가 접착강도의 증가를 야기했다. 그러나 레이저에 의한 조도의 길이는 접착 강도에 크게 영향을 주지 못했다. 레이저를 이용한 접착면의 표면처리는 기계적 결합 메커니즘을 확보하고 CFRP 접착 조인트의 접착 강도를 향상시키는 적합한 방법이라는 결론을 도출할 수 있다. 레이저 처리를 이용한 이점을 완전히 이용하기 위해서는 최적화된 레이저 공정 변수에 대한 연구가 반드시 필요하다.

• Structural Engineering and Mechanics
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• 제83권5호
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• pp.693-707
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• 2022

Bonded joints have proven their performance against conventional joining processes such as welding, riveting and bolting. The single-lap joint is the most widely used to characterize adhesive joints in tensile-shear loadings. However, the high stress concentrations in the adhesive joint due to the non-linearity of the applied loads generate a bending moment in the joint, resulting in high stresses at the adhesive edges. Geometric optimization of the bonded joint to reduce this high stress concentration prompted various researchers to perform geometric modifications of the adhesive and adherends at their free edges. Modifying both edges of the adhesive (spew) and the adherends (bevel) has proven to be an effective solution to reduce stresses at both edges and improve stress transfer at the inner part of the adhesive layer. The majority of research aimed at improving the geometry of the plate and adhesive edges has not considered the effect of temperature and water absorption in evaluating the strength of the joint. The objective of this work is to analyze, by the finite element method, the stress distribution in an adhesive joint between two 2024-T3 aluminum plates. The effects of the adhesive fillet and adherend bevel on the bonded joint stresses were taken into account. On the other hand, degradation of the mechanical properties of the adhesive following its exposure to moisture and temperature was found. The results clearly showed that the modification of the edges of the adhesive and of the bonding agent have an important role in the durability of the bond. Although the modification of the adhesive and bonding edges significantly improves the joint strength, the simultaneous exposure of the joint to temperature and moisture generates high stress concentrations in the adhesive joint that, in most cases, can easily reach the failure point of the material even at low applied stresses.