• The Journal of Advanced Prosthodontics
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• 제5권3호
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• pp.226-233
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• 2013

PURPOSE. This study evaluated the adhesion of 10-MDP containing self-etch and self-adhesive resin cements to dentin with and without the use of etch-and-rinse technique. MATERIALS AND METHODS. Human third molars (N=180) were randomly divided into 6 groups (n=30 per group). Conventional (Panavia F2.0, Kuraray-PAN) and self-adhesive resin cements (Clearfil SA, Kuraray-CSA) were bonded to dentin surfaces either after application of 3-step etch-and-rinse (35% $H_3PO_4$ + ED Primer) or two-step self-etch adhesive resin (Clearfil SE Bond). Specimens were subjected to shear bond strength test using the universal testing machine (0.5 mm/min). The failure types were analyzed using a stereomicroscope and quality of hybrid layer was observed under a scanning electron microscope. The data (MPa) were analyzed using two-way ANOVA and Tukey's tests (${\alpha}$=.05). RESULTS. Overall, PAN adhesive cement showed significantly higher mean bond strength ($12.5{\pm}2.3-14.1{\pm}2.4$ MPa) than CSA cement ($9.3{\pm}1.4-13.9{\pm}1.9$ MPa) (P<.001). Adhesive failures were more frequent in CSA cement groups when used in conjunction with two-step self-adhesive (68%) or no adhesive at all (66%). Hybrid layer quality was inferior in CSA compared to PAN cement in all conditions. CONCLUSION. In clinical situations where bonding to dentin substrate is crucial, both conventional and self-adhesive resin cements based on 10-MDP can benefit from etch-and-rinse technique to achieve better quality of adhesion in the early clinical period.

• 구강회복응용과학지
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• 제36권1호
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• pp.1-11
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• 2020

목적: 본 연구의 목적은 polyetherketoneketone (PEKK)의 표면 처리 방식에 따른 세가지 종류의 임시 보철물 제작용 레진과의 전단결합강도를 비교하는 것이다. 연구 재료 및 방법: 60개의 PEKK 시편을 110 ㎛의 산화알루미늄 입자(Cobra, Renfert GmbH, Hilzinge, Germany)로 분사 처리하고 시편에 Visio.link (Bredent, Senden, Germany)를 도포하지 않은 군(U)과 도포한 군(P)으로 30개씩 나누었다. 이후 한 변이 3.2 mm인 정사각형의 모양으로 polymethylmethacrylate (PMMA), polyethylmethacrylate (PEMA), bis-acryl composite resin을 PEKK에 각각 20개씩 접착하여 총 6개의 군(UM, UE, UC, PM, PE, PC)으로 분류하였다. 완성된 시편은 37℃의 증류수에 24시간 보관하였다. 만능재료시험기의 크로스헤드의 속도를 2 mm/min로 설정하고 전단결합강도를 측정하였다. 각 군간의 전단결합강도 값의 유의차를 확인하기 위하여 일원배치분산분석(one-way ANOVA)과 Tukey HSD test를 시행하였다. 결과:UM, UE군은 UC군과 유의한 전단결합강도의 차이를 나타내었다(P < 0.05). PC군이 UC군보다 높은 전단결합강도를 나타내었다(P < 0.05). 결론: 임상적으로 PEKK에 PMMA와 PEMA를 접착하는 경우에 Visio.link의 적용이 필요하지 않으나, bis-acryl composite resin을 접착하는 경우에는 Visio.link의 적용이 추천된다.

• 한국강구조학회 논문집
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• 제16권2호통권69호
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• pp.235-245
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• 2004

현재 합성 구조가 사용성 측면에서 경제적이고 작업성이 좋으며, 시공상의 편의성 등의 장점이 있다는 것은 일반화된 사실이지만, 자체의 춤이 깊기 때문에 철골조 건물에 적용하기에 여러 가지 비효율적 측면이 있다. 따라서 본 연구에서는 합성보의 전체 춤을 절감할 수 있도록 철골보의 춤내에 콘크리트를 삽입하여 일체화함으로써 철골조 고층건물에서 층고를 최소화 할 수 있는 이른바 "슬림플로어" 공법에 대한 연구를 수행하였다. 본 연구는 콘크리트에 매입된 비대칭 철골보를 가지는 부분 합성 슬림플로어 시스템의 휨거동에 관한 것이다. 총 8개의 실대형 실험체를 철골보 춤, 전단연결 유무, 슬래브 유효폭, 및 콘크리트 토핑두께 별로 제작하여 실험을 수행하였다. 실험결과, 별도의 전단연결재를 설치하지 않은 실험체는 자체가 가지고 있는 기계적 화학적 부착응력으로 인해 완전합성보에 비해서 $0.53{\sim}0.95$의 전단합성비를 나타내었다.

• The Journal of Advanced Prosthodontics
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• 제13권5호
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• pp.292-303
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• 2021

PURPOSE. The aim of this in vitro study was to evaluate the effect of silane and universal adhesive applications on the micro-shear bond strength (µSBS) of different resin-matrix ceramics (RMCs). MATERIALS AND METHODS. A total of 120 slides (14 × 12 × 1 mm) were produced from 5 different RMC materials (GC Cerasmart [GC]; Brilliant Crios [BC]; Grandio blocs [GB]; Katana Avencia [KA]; and KZR-CAD HR 2 [KZR]) and sandblasted using 50 ㎛ Al₂O₃ particles. Each RMC material was divided into six groups according to the surface conditioning (SC) method as follows: control (G1), silane primer (G2), silane-free universal adhesive (G3), silane-containing universal adhesive (G4), silane primer and silane-free universal adhesive (G5), and silane primer and silane-containing universal adhesive (G6). Three cylindric specimens made from resin cement (Bifix QM) were polymerized over the treated surface of each slide (n = 12). After thermal cycling (10000 cycles, 5 - 55℃), µSBS test was performed and failure types were evaluated using a stereomicroscope. Data were analyzed using 2-way ANOVA and Tukey tests (α = .05). RESULTS. µSBS values of specimens were significantly affected by the RMC type and SC protocols (P < .001) except the interaction (P = .119). Except for G2, all SC protocols showed a significant increase in µSBS values (P < .05). For all RMCs, the highest µSBS values were obtained in G4 and G6 groups. CONCLUSION. Only silane application did not affect the µSBS values regardless of the RMC type. Moreover, the application of a separate silane in addition to the universal adhesives did not improve the µSBS values. Silane-containing universal adhesive was found to be the best conditioning method for RMCs.

• Smart Structures and Systems
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• 제29권3호
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• pp.445-455
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• 2022

Steel anchor bolts are installed in concrete using a variety of methods. One of the most common methods of anchor bolt installation is using epoxy resin as an infill material injected into the drilled hole to act as a bonding material between the steel bolt and the surrounding concrete. Typical design standards assume uniform stress distribution along the length of the anchor bolt accompanied with single crack leading to pull-out failure. Experimental evidence has shown that the steel anchor bolts fail owing to the multiple failure patterns, hence these design assumptions are not realistic. In this regard, the presented research work details the analytical model that takes into consideration multiple micro cracks in the infill material induced via impact loading. The impact loading from the Schmidt hammer is used to evaluate the bond condition bond condition of anchor bolt and the epoxy material. The added advantage of the presented analytical model is that it is able to take into account the various type of end conditions of the anchor bolts such as bent or U-shaped anchors. Through sensitivity analysis the optimum stiffness and shear strength properties of the epoxy infill material is achieved, which have shown to achieve lower displacement coupled with reduced damage to the surrounding concrete. The accuracy of the presented model is confirmed by comparing the simulated deformational responses with the experimental evidence. From the comparison it was found that the model was successful in simulating the experimental results. The proposed model can be adopted by professionals interested in predicting and controlling the deformational response of anchor bolts.

• 한국도로학회논문집
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• 제15권4호
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• pp.85-94
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• 2013

PURPOSES: The performance of tack coat, commonly used for layer interface bonding, is affected by application rate and curing time. In this study, bonding strength tests were performed according to the application rate and curing time of asphalt emulsion. Based on finding from this study, optimum application rates and curing times are proposed. METHODS: In order to investigate bonding characteristic of asphalt emulsion, tests were performed on both asphalt concrete pavement and portland concrete pavement. Also, asphalt emulsions were tested at the application rate of 0, 0.2, 0.4, 0.6, and $0.8{\ell}/m^2$ and at the curing time of 0, 0.5, 1, 2, and 24 hours. Pull-off test and shear bonding strength test, which commonly used for bonding strength measurement of asphalt emulsion, were adopted for this study. To assess field performance under different testing condition, asphalt emulsions were applied to in-service pavement. Throughout coefficient of determination analysis between material index properties from asphalt emulsion and mechanical response from bonding strength tests, performance correlativity was analyzed. RESULTS: Test results show that optimum application rate for asphalt overlay on asphalt concrete pavement (AOA) and asphalt overlay on concrete pavement (AOC) was $0.4{\sim}0.5{\ell}/m^2$ and $0.3{\sim}0.5{\ell}/m^2$, respectively. According to the curing time increment, tensile strength and shear strength of AOC were increased to 22~44% and 20~39%, respectively. AOA case also show strength increment in tensile strength (42%) and shear strength (9%). We tested the applicability of tack coat materials at the field sites, and our findings demonstrated that the bonding (for D and E) and rapid curing (for B, C, and D, E) performances were superior than others. Among material index properties, there was a high correlation between penetration ratio and bonding strength test result. CONCLUSIONS : Result show that interlayer bonding strength was affected by asphalt emulsion type, application rate and curing time. AOC required slightly higher application ($0.1{\ell}/m^2$) than AOA. Both AOA and AOC cases show higher strength at longer curing time. Up to 2hours of curing, rapid strength increments were observed, but strength increment ratio was decreased after 2hours of curing. From the observed correlation between penetration ratio and bonding strength, it is expected that penetration ratio can be used as one of important factors affecting bonding strength analysis.

• Restorative Dentistry and Endodontics
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• 제29권2호
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• pp.177-184
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• 2004

본 연구는 광중합형 상아질 접착제에서 광조사 시간의 증가가 접착제 표면의 미중합층에 대한 영향과 그에 따른 전단접착강도에 대해 연구하고자 120개의 치아를 아크릴 몰드에 식립한 후 상아질이 노출되도록 연마하였다. 3종류의 접착제 〔All Bond2 (AB2), One-Step (OS) and Adper Prompt (AP)〕를 40개 치아에 제조사의 지시대로 도포한 후 각각 다른 광조사 시간 (10, 20, 30 and 60sec)동안 광조사 하고 복합레진을 접착한 24시간 후 전단접 착강도를 측정하였다. 미중합층의 두께와 중합률은 슬라이드 글라스와 FT-NIR을 이용하여 FT-NIR spectrum에서의 peak height를 비교 측정하여 다음과 같은 결론을 얻었다. 1. 전단접착강도에서 AB2는 20초 이후 감소하고, AP는 30초까지 증가하였으며,OS는 차이를 보이지 않았다. 2. 미중합층 두께는 3가지 접착제 모두 유의성 있는 차이를 보이지 않았다. 3. 중합률에서 OS는 10초와 나머지군 사이에 유의성 있는 차이를, AP는 60초에서 유의성 있게 증가되고, AB2의 경우 차이를 나타내지 않았다.

• The Journal of Advanced Prosthodontics
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• 제7권3호
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• pp.214-223
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• 2015

PURPOSE. To measure the surface loss of dental restorative zirconia and the short-term bond strength between an indirect composite resin (ICR) and zirconia ceramic after various sandblasting processes. MATERIALS AND METHODS. Three hundred zirconia bars were randomly divided into 25 groups according to the type of sandblasting performed with pressures of 0.1, 0.2, 0.4 and 0.6 MPa, sandblasting times of 7, 14 and 21 seconds, and alumina powder sizes of 50 and $110{\mu}m$. The control group did not receive sandblasting. The volume loss and height loss on zirconia surface after sandblasting and the shear bond strength (SBS) between the sandblasted zirconia and ICR after 24-h immersion were measured for each group using multivariate analysis of variance (ANOVA) and Least Significance Difference (LSD) test (${\alpha}$=.05). After sandblasting, the failure modes of the ICR/zirconia surfaces were observed using scanning electron microscopy. RESULTS. The volume loss and height loss were increased with higher sandblasting pressure and longer sandblasting treatment, but they decreased with larger powder size. SBS was significantly increased by increasing the sandblasting time from 7 seconds to 14 seconds and from 14 seconds to 21 seconds, as well as increasing the size of alumina powder from $50{\mu}m$ to $110{\mu}m$. SBS was significantly increased from 0.1 MPa to 0.2 MPa according to the size of alumina powder. However, the SBSs were not significantly different with the sandblasting pressure of 0.2, 0.4 and 0.6 MPa. The possibilities of the combination of both adhesive failure and cohesive failure within the ICR were higher with the increases in bonding strength. CONCLUSION. Based on the findings of this study, sandblasting with alumina particles at 0.2 MPa, 21 seconds and the powder size of $110{\mu}m$ is recommended for dental applications to improve the bonding between zirconia core and ICR.

• 대한치과보철학회지
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• 제47권2호
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• pp.174-181
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• 2009

연구목적: 본 연구에서는 35% 과산화수소를 사용하는 전문가 미백 술식에서 레진 접착제의 접착력 회복을 위한 유예 기간을 비교하고자 한다. 연구 재료 및 방법:3M사의 Single Bond와 Z350을 이용하여 미백 직 후, 1일후, 2일후, 일주일 후의 시간 차이를 두고 상아질에 접착된 복합 레진의 전단 결합 강도를 측정하여 다음과 같은 결과를 얻었다. 결과: 미백 처리 직 후의 상아질 전단 결합 강도는 다른 군에 비해 유의하게 낮았으며(P<.05), 미백 처리 전에 비해 약 78%의 결합력 감소를 보였다. 미백 처리 1일 후의 상아질 결합 강도는 미백 직 후 감소된 결합력의 51%에 이르는 회복을 보였으며, 2일 경과한 시편에서는 감소된 결합력의 63%가 회복되었다. 두 군은 미백 직 후에 비해 유의하게 큰 회복력을 보였으나, 두 군 간에는 유의한 차이가 없었다(P>.05). 미백 처리 후 결합력의 회복은 초기 24시간 이내에 급격히 일어나며 그 이후에는 서서히 일어나는 것으로 사료된다. 미백 일주일 후의 시편은 미백 처리 전에 비해97%에 이르는 결합력을 보이며 두 군 간에는 유의한 차이가 없었다(P>.05). 결론: 그러므로35% 과산화수소를 적용하는 전문가 미백 술식에서는 1주일간의 유예기간을 두고 복합 레진 접착술을 시행하는 것이 적절할 것으로 사료된다.

• 한국철도학회논문집
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• 제19권2호
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• pp.224-233
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• 2016

무가선 트램 궤도구조는 도심지 가로망 내에 구축되는 관계로, 포장면 레벨 및 평탄성 확보를 위하여 기존 도로포장면과 동일하게 아스팔트 포장 덧씌우기 형태로 콘크리트 슬래브 상에 포설하게 된다. 그러나, 이들의 거동특성이 분명하게 파악된 바 없다. 본 연구에서는 무가선 트램용 매립형궤도 기초구조를 구성하는 아스팔트 포장층의 복합포장단면 내 거동특성을 분석하기 위하여 이들 이질 궤도 구성층재료 사이의 인장부착강도와 전단부착강도 파악을 위한 실내시험을 실시하였다. 이러한 실내부착강도 시험을 위하여 콘크리트 슬래브와 상단 아스팔트 포장층 사이에 사용할 부착재료를 선정하고 이에 따른 부착방식을 결정하였다. 트램용 매립형궤도 구성층 사이의 인장부착강도와 전단저항 실내시험결과로부터 공용성 및 내구성 확보를 위한 가장 핵심적인 설계 파라미터를 추출할 수 있었다. 또한 복합단면에 대한 유한요소해석으로부터 층간경계부에서의 인장변형률 특성을 분석하였다.