• 대한소아치과학회지
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• 제23권2호
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• pp.357-364
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• 1996

소아치과 임상에서 자주 사용되는 3 종의 광중합형 GIC의 아말감에 대한 접착능을 평가 할 목적으로 60 개의 아말감 부착시편을 이용하여 중간결합제인 Scotchbond 의 사용여부에 따른 경화된 아말감에 대한 광중합 GIC의 전단결합강도를 측정하고 경계부의 파절양상을 관찰한 결과, 다음과 같은 결론을 얻었다. 1. 아말감에 대한 광중합형 GIC의 전단강도는 Fuji II LC, Vitremer, Vitrebond의 순으로 높게 나타났다 (p<0.05). 2. 중간결합제인 Scotchbond를 사용하지 않은 경우에서 Scotchbond 를 사용한 경우에 비해 전단결합강도가 높게 나타났다(p<0.05). 3. 결합파절면은 Scotchbond를 사용한 경우의 대부분에서 Scotchbond와 아말감의 경계부에서 시편의 탈락이 나타났다. 아말감과 광중합 GIC의 결합을 시도할 경우에는 Scotchbond는 사용하지 않는 것이 바람직할 것으로 사료되었다.

• Corrosion Science and Technology
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• 제13권5호
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• pp.186-194
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• 2014

Establishment of adhesion strength measurement procedure for marine epoxy coatings was conducted in order to ensure reliability of the test results. It was found that (1) the increase in thickness of the substrates would induce increase of pull-off strength. Especially, the increase in adhesion strength with the substrate thickness increment was attributed to the transition of stress mode to the pure tensile mode excluding bending effect. (2) The longer curing time, the higher pull-off strength. It may be due to higher cross-linking density of the coating (3) The pull-off strength increases as coating thickness increases due to the diminishment of bending effect (4) The longer drying time after water immersion, the higher pull-off strength. It may be due to the evaporation of water molecule at the coating-substrate interface.

• 콘크리트학회논문집
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• 제15권5호
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• pp.739-746
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• 2003

Various researches on the application of polymer dispersions to the cement mortar and concrete have been carried out in many countries like America, Japan and Germany and so on due to their high performance and good modification effect. PAE of polymer dispersion widely used in situ was employed that the high flowability may be induced in the cement mortar. In order to investigate the modification of cement mortar with high flowability by PAE and fracture mode of adhesive strength properties in tension of that, experimental parameters were set as PAE solid-cement ratio(P/C) and cement: fine aggregate(C:F) and the experiments such as unit weight, flow, consistency change, crack resistance and segregation that inform on the general properties have been done. Adhesion in tension is measured with a view to comprehending the properties and fracture mode in tensile load. Consistency change of cement mortar modified by PAE did grow better as the ratio of PAE solid-cement increased and was much superior to that of resin based flooring such as polyurethane and epoxy which recorded the loss of consistency in 90 min. after mixing. Adhesive strength in tension increased with continuity during curing period and showed the maximum in case of C:F=1:1 and P/C=20%.

• 한국안전학회지
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• 제27권6호
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• pp.20-25
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• 2012

Currently, the most important purpose in designing automobile is environment-friendly and safety performance aspect. CFRP(Carbon Fiber Reinforced Plastics) of the advanced composite materials as structure materials for vehicles, has a wide application in lightweight structural materials of air planes, ships and automobiles because of high strength and stiffness. In this study, experimental investigations are carried out for CFRP single and double hat shaped section member in order to study the effect of various stacking condition. They were cured by heating to the appropriate curing temperature($130^{\circ}C$) by means of a heater at the vacuum bag of the autoclave. The stacking conditions were selected to investigate the effect of the interface numbers. The CFRP single and double hat shaped section members which manufactured from unidirectional prepreg sheets were made of 8ply. The static collapse tests performed and the collapse mode and energy absorption capability were analyzed according to interface number.

• 대한소아치과학회지
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• 제26권3호
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• pp.554-563
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• 1999

심미적 수복재료인 복합 레진과 글래스 아이오노머 시멘트는 중합방식에 따라 화학중합형, 광중합형, 그리고 이 두 가지 중합방식을 겸비한 이중중합형으로 분류할 수 있다. 화학중합형과 광중합형에 대해서는 지금까지 다수의 보고가 있었으나, 충전용 복합 레진의 경우 이들과 이중중합형을 비교한 예는 아직 찾기 힘든 실정이었으므로, 이러한 관점에서의 연구가 필요할 것으로 사료되었다. 이 연구에서는 이중중합 수복재가 단일중합방식에 비해 어떠한 특성을 보이는지를 탐구하고자 하였다. 사용된 재료는 광중합형 복합 레진인 Veridonfil-Photo와 이중중합형인 Bis-core, 이중중합형의 글래스 아이오노머 시멘트인 Fuji II LC와 화학중합형인 Ketac-fil을 사용하였다. 가로 30mm, 세로 30mm, 높이 1mm와 3mm인 두 종류의 아크릴릭 몰드 중앙에 직경 7mm의 hole을 형성하여 여기에 4종의 수복재를 충전하였다. 충전 직후부터 시작하여 24시간 경과시까지 일정 시간의 간격으로 표면, 1mm, 3mm 깊이에서의 경도를 미세경도계(Shimadzu Micro Hardness Tester HMV-2000, Shimadzu Co. Japan)로 측정하였다. 측정치를 통계처리하여 얻은 결과는 다음과 같다. 1. 4 종의 수복재 모두에서, 중합직후에 비해 24시간 경과후의 미세경도가 증가되었다. 2. 중합 직후부터 24시간 경과시점까지의 미세경도를 측정한 결과, Ketac-fil을 제외한 나머지 수복재에서는 각 깊이간 경도의 차이가 있었다. 3. 각 수복제의 최종중합에 도달하는 시간을 조사한 결과, 이중중합형이 3min의 깊이에서 광중합형이나 화학중합형에 비해 중합이 더 오래 지속된 것으로 나타났다. 이상의 결과에서 조사광이 충분히 도달하지 못하여 중합이 현저히 떨어지는 수복재의 심부에도 이중중합방식을 사용할 경우에는 지속적인 중합반응이 일어나 중합도가 증가하는 것으로 나타났다.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.479-484
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• 2013

PURPOSE. The aim of this study was to evaluate the effects of additional acid etching and curing mechanism (light-curing or self-curing) of a composite resin on the dentin bond strength and compatibility of one-step self-etching adhesives. MATERIALS AND METHODS. Sixteen human permanent molars were randomly divided into eight groups according to the adhesives used (All-Bond Universal: ABU, Clearfil S3 Bond: CS3), additional acid etching (additional acid etching performed: EO, no additional acid etching performed: EX), and composite resins (Filtek Z-250: Z250, Clearfil FII New Bond: CFNB). Group 1: ABU-EO-Z250, Group 2: ABU-EO-CFNB, Group 3: ABU-EX-Z250, Group 4: ABU-EX-CFNB, Group 5: CS3-EO-Z250, Group 6: CS3-EO-CFNB, Group 7: CS3-EX-Z250, Group 8: CS3-EX-CFNB. After bonding procedures, composite resins were built up on dentin surfaces. After 24-hour water storage, the teeth were sectioned to make 10 specimens for each group. The microtensile bond strength test was performed using a microtensile testing machine. The failure mode of the fractured specimens was examined by means of an optical microscope at ${\times}20$ magnification. The data was analyzed using a one-way ANOVA and Scheffe's post-hoc test (${\alpha}$=.05). RESULTS. Additional etching groups showed significantly higher values than the no additional etching group when using All-Bond Universal. The light-cured composite resin groups showed significantly higher values than the self-cured composite resin groups in the Clearfil S3 Bond. CONCLUSION. The additional acid etching is beneficial for the dentin bond strength when using low acidic one-step self-etch adhesives, and low acidic one-step self-etch adhesives are compatible with self-cured composite resin. The acidity of the one-step self-etch adhesives is an influencing factor in terms of the dentin bonding strength and incompatibility with a self-cured composite resin.

• Restorative Dentistry and Endodontics
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• 제29권4호
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• pp.386-398
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• 2004

Objectives: The purpose of this study was to observe the reaction kinetics and the degree of polymerization of composite resins when cured by different light sources and to evaluate the effectiveness of the blue Light Emitting Diode Light Curing Units (LED LCUs) compared with conventional halogen LCUs. Materials and Methods: First, thermal analysis was performed by a differential scanning calorimeter (DSC). The LED LCU (Elipar Freelight, $320{\;}mW/\textrm{cm}^2$) and the conventional halogen LCU (XL3000, $400{\;}mV/\textrm{cm}^2$) were used in this study for curing three composite resins (SureFil, Z-250 and AEliteFLO). Second. the degree of conversion was obtained in the composite resins cured according to the above curing mode with a FTIR. Third, the measurements of depth of cure were carried out in accordance with ISO 4049 standards. Statistical analysis was performed by two-way ANOVA test at 95% levels of confidence and Duncan's procedure for multiple comparisons. Results: The heat of cure was not statistically different among the LCUs (p > 0.05). The composites cured by the LED (Exp) LCUs were statistically more slowly polymerized than by the halogen LCU and the LED (Std) LCU (p < 0.05). The composite resin groups cured by the LED (Exp) LCUs had significantly greater degree of conversion value than by the halogen LCU and the LED (Std) LCU (p =0.0002). The composite resin groups cured by the LED (Std) LCUs showed significantly greater depth of cure value than by the halogen LCU and the LED (Exp) LCU (p < 0.05).

• 대한소아치과학회지
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• 제31권2호
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• pp.280-289
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• 2004

치과용 수복재료가 요구하는 심미성과 치아의 보존 및 편의성 등의 여러 조건들을 만족시키기 위해서 치과용 복합레진은 적절한 중합이 이루어져 물리적 기계적 성질을 충족하고, 색조의 안전성, 중합시의 수축과 이에 따른 변연 적합도 문제를 해결할 수 있어야 한다. 본 연구에서는 광중합 복합레진 Z250의 색상과 두께를 달리 하여 광투과도와 중함도를 각각 적외선 분광분석법과 미세경도 측정을 통해 비교하여 다음과 같은 결과를 얻었다. 1. 플라즈마 아크 중합기의 사용 시 3초 중합과 6초 중합의 경우로 나누어 실험하였으며 6초 중합에 있어서 할로겐 중합 20초와 유사한 광투과도 및 미세경도를 나타내었다. 2. 광중합 복합레진의 색상을 A1, A2, A3, A3.5로 나누어 실험한 결과 레진의 표면에서는 색상별로 광투과도나 경도의 차이가 나타나지 않았으나, 2, 3, 4mm로 깊이가 증가함에 따라 색상에 따른 광투과도나 경도의 차이가 확연하게 나타났고 특히 색상이 어두워질수록 4mm의 깊이에서 중합도가 더욱 낮았다. 3. 중합깊이의 비교를 위하여 0, 2, 3 4mm깊이로 나누어 실험한 결과, 2mm이상의 깊이에 있어서는 미반응 단량체의 양이 유의하게 많은 것으로 나타났다. 4. 광중합 복합레진의 광투과도를 알아보는 FTIR을 통한 단량체 전환도와 미세경도 측정사이에는 유의한 상관관계를 보였다.

• Restorative Dentistry and Endodontics
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• 제29권6호
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• pp.504-514
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• 2004

LED 광중합기(Elipar FreeLight, 3M-ESPE)와 할로겐 광중합기(VIP Bisco)로 광조사한 수종의 상아질 접착제에 대해서 상아질 전단접착강도를 비교하였다 또한 이번 연구의 광학적 근거를 얻기 위해 두 광중합기의 파장에 따른 광강도와 스펙트럼을 비교하였다. 이번 연구에서 사용된 상아질 접착제는 Scotchbond Multipurpose (3M ESPE), Single Bond (3M ESPE). One-Step (Bisco), Clearfil SE Bond (Kuraray), Adper Prompt (3M ESPE) 이다. VIP는 487 nm에서 최대정점을 가지는 넓은 스펙트럼의 분포를 보이는 반면에, Elipar FreeLight는 465 nm에서의 최대정점을 중심으로 좁은 스펙트럼의 분포를 보였다. Clearfil SE bond를 제외하고 할로겐과 LED로 광조사 한 각 상아질 접착제에서 상아질 전단접착강도값의 유의성 있는 차이는 보이지 않았다 (P > 0.05). 이러한 결과는 camphoroquinone의 흡수스펙트럼과 LED의 좁은 영역의 스펙트럼사이에 강한 연관성으로 설명할 수 있다.

• Restorative Dentistry and Endodontics
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• 제14권1호
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• pp.41-56
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• 1989

The purpose of this study was to examine the effect of temperature dependence of the behavior on the physical properties of posterior composite resins. Three light cure posterior composite resins (Heliomolar, Litefil-P, and P-50) and one chemical cure posterior composite resin (Bisfil-II) were used as experimental materials. Composite resin was placed in a cylindrical brass mold (2.5 mm high and 6.5 mm inside diameter) that was rested on a glass plate. Another flat glass was placed on top of the mold, and the plate was tightly clamped together. After the mold had been filled with the light cure composite material, the top surface was cured for 30 seconds with a light source. Chemical cure resin specimens were made in the same manner as above. Three hundreds and twenty composite resin specimens were constructed from the four composite materials. One hundred and sixty specimens of them were placed in a heater at $50^{\circ}C$, $75^{\circ}C$, $100^{\circ}C$, $125^{\circ}C$, $150^{\circ}C$, $175^{\circ}C$ and $200^{\circ}C$ for 5 minutes or 10 minutes respectively before compressive strengths were measured. Another one hundred and sixty specimens were tested for the diametral tensile strengths in the same way as above. They were randomly divided into eight groups according to the mode of heating methods as follows and stored in distilled water at $37^{\circ}C$ for 24 hours. Group $37^{\circ}C$ - specimens were stored at $37^{\circ}C$ in distilled water for 24 hours. Group $50^{\circ}C$ - specimens were heated at $50^{\circ}C$ after curing. Group $75^{\circ}C$ - specimens were heated at $75^{\circ}C$ after curing. Group $100^{\circ}C$ - specimens were heated at $100^{\circ}C$ after curing. Group $125^{\circ}C$ - specimens were heated at $125^{\circ}C$ after curing. Group $150^{\circ}C$ - specimens were heated at $150^{\circ}C$ after curing. Group $175^{\circ}C$ - specimens were heated at $175^{\circ}C$ after curing. Group $200^{\circ}C$ - specimens were heated at $200^{\circ}C$ after curing. Twenty specimens of each of four composite resins were respectively made by insertion of materials into same mold for examining the dimensional changes between before and after heating. The final eighty specimens were stored in distilled water at $37^{\circ}C$ for 24 hours before testing the dimensional changes. Compressive and diametral tensile strengths were measured crosshead speed 1mm/minute and 500Kg in full scale with a mechanical testing machine (DLC 500 Type, Shimadzu Co., Japan). Dimensional changes were determined by measuring the diametral changes of eighty specimens with micrometer (Mitutoyo Co., Japan). Results were as follows: 1. Diametral tensile strengths of specimens in all groups were increased with time heated compared with control group except for that in group $50^{\circ}C$ and the maximum diametral tensile strength was appeared in the specimen of Litefil-P heated for 10 minutes at $100^{\circ}C$. In heliomolar and P-50, it could be seen in the specimen heated for 10 minutes at $150^{\circ}C$, but in Bisfil-II, it could be found in the specimen heated for 5 minutes at $150^{\circ}C$. 2. Compressive strengths of specimens in all groups was tended to be also increased with time heated but that in group $50^{\circ}C$ and the maximum compressive strengths were showed in the same specimens conditioned as the diametral tensile strengths of four composite materials tested. 3. In Heliomolar, Litefil-P, and Bisfil-II, it was decreased in diameters of resin specimens between before heating and increased in diameters of resin specimens after storing in distilled water, but it was not in P-50. 4. There is little difference in diametral tensile strengths, compressive strengths, and dimensional changes followed by heating the resin specimens for 5 minutes and 10 minutes, but there is no statistical significances.