• 대한소아치과학회지
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• 제31권2호
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• pp.273-279
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• 2004

최근에 소개된 single high-intensity LED 중합기는 이전의 LED 중합기에 비해 높은 광도를 가지며 짧은 중합시간에 적절한 물성을 가질 수 있다고 한다. 본 연구는 single high-intensity LED 중합기의 중합성능을 평가하기 위하여 거리에 따른 중합도를 조사하였다. Mylar strip사이에 복합레진(Filtek Z250)을 넣고 압접시켜 만든 얇은 필름형 시편을 LED 중합기(Elipar Freelight 2, 10초), 플라스마 중합기(Flipo, 6초)와 할로겐 중합기 (XL3000, 20초)를 사용해 0mm, 2mm, 4mm, 6mm에서 광도를 측정하고 중합시켰다. 중합된 시편을 Fourier Transform Infrared Spectrometer(FTIR)를 이용해 중합도를 측정한 후 다음과 같은 결론을 얻었다. 1. 모든 중합기에서 거리가 증가할수록 유의하게 광도가 감소하였으며 LED중합기의 경우 6mm에서 다른 중합기에 비해 가장 많은 광도 감소율을 보였다(p<0.05). 2. 모든 중합기에서 거리가 증가함에 따라 4mm까지는 중합도가 감소하였지만 유의한 차이는 보이지 않았다(p>0.05). 하지만 4mm와 6mm사이에서는 모든 중합기에서 유의하게 감소하였다(p<0.05). 3. 각 거리에 따른 중합기간의 중합도 차이는 0mm, 2mm, 4 mm에서 LED중합기가 다른 중합기보다 유의하게 높은 중합도를 보였으며 (p<0.05) 플라스마 중합기와 할로겐 중합기 사이에서는 유의한 차이가 없었다. 하지만 6 mm에서는 모든 중합기 사이에 유의한 차이를 보이지 않았다(p>0.05).

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.35-60
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• 1997

Physical properties of composite resins such as strength, resistance to wear, discoloration, etc, depend on the degree of conversion of the resin components. The clinical behavior of restorative resins varies brand to brand. Part of this variation is associated with the filler and differences in the polymer matrix. The polymer matrix of resins may differ because the involved monomers are dissimilar and because of variation in the catalyst system. The purpose of this study was to evaluate the degree of conversion of the composite resins according to the depth of cure and light curing time. 7mm diameter cylindrical aluminum molds were filled with each of five different hybrid light curing composite resins(Z-100, Charisma, Herculite XRV, Prisma TPH, Veridonfil) on the thin resin films. The molds were 1mm, 2mm, 3mm, 4mm, and 5mm in depth to produce resin films of various heights. Each sample was given 20sec, 40sec, and 60sec illumination with a light source. The degree of conversion of carbon double bonds to single bonds in the resin films was examined by means of Fourier Transform Infrared Spectrometer. The results were obtained as follows; 1. There was difference in the degree of conversion among five light curing composite resins according to the depth of cure for 20sec, 40sec, and 60sec illumination with light source with statistical significance(P<0.05). 2. Five light curing composite resins show lower degree of conversion at surface of the resin than depth of 1mm. 3. The degree of conversion of five light curing composite resins was siginificantly reduced from the maximum for the resin film when the light passed through as little as 1mm of each composite. 4. The degree of conversion of five light curing composite resins decrease significantly at the depth of 4mm, and polymerization was not occured at the depth of 5mm except for Prisma TPH. 5. The degree of conversion of five light curing composite resins was increased with increased light curing time, and there was no significant differences in the degree of conversion above 4mm in Z-100, 3mm in Charisma, and at depth of 5mm in Herculite XRV and Veridonfil(P>0.05).

• Restorative Dentistry and Endodontics
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• 제20권1호
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• pp.33-54
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• 1995

The degree of conversion of composite resin was known to have influence on the mechanical properties of composite materials such as hardness, strength, wear resisitance, dimensional and color stability. Also unreacted monomer was reported to be harmful to the pulp. So the degree of conversion was a very important factor in the success of composite resin restorations. In recent, the dual cure resin cement was developed with the advocations that it could increase the curing rates in the sites where the curing ligt could not reach. Moreover many manufactors added some adhesive components in the resin cement. This study was undertaken to observe the effects of curing depth and light curing times on the degree of conversion of dual cure resin cements. CR INLAY CEMENT, DUAL CEMENT and OPTEC BOND, by the Fourier transform Infrared analysis, changing the curing depth 1mm, 2mm and 3mm, and varying the light curing time 20 seconds, 40 seconds and 80 seconds at each depth. The cytotoxicity of dual cure resin cements was tested by the in vitro MTT method using L929 cell. The results was evaluated and compared statistically. The results were obtained as follows : 1. The dual cure resin cements reavealed various degree of conversion, CR INLAY CEMENT and DUAL CEMENT had a tendency to be more reactive to the light cure and OPTEC BOND was a more chemical one. 2. CR INLAY CEMENT and DUAL CEMENT showed the lowest degree of conversion in 2 mm depth, and in 3mm depth the degree of conversion increased, which were due to the chemical cure of dual cures, but OPTEC BOND showed decreasing degree of conversion with increasing curing dept h and all experimental groups showed lower degree of conversion than CHEMICAL group which cured in dark room with no light, so the weak light-curing of dual cure resin cement prevented the chemical cure. (P<0.05) 3. CR INLAY CEMENT and DUAL CEMENT showed increasing degree of conversion in 1 mm and 3 mm, according to the increasing cure times, but in 2 mm depth the degree of conversion decreased with increasing light-curing times and OPTEC BOND showed contrary tendency, but there was no ststistical importance in the differences among the experimental group.(P>0.05) 4. The optical density by MTT assay of extractions of CR INLAY CEMENT, DUAL CEMENT and OPTEC BOND revealed no statitically important differences comparing with optical density of negative control.(P>0.05) 5. CR INLAY CEMENT showed a tendency of increaing cytotoxicity with days and DUAL CEMENT and OPTEC BOND showed higher cytotoxicity in 2 days than in 4 days, but there was no statistical importance in the differences.(P>0.05).

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3787-3789
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• 2013

In this study, the silicone thermal curing degree of the silicone-encapsulated quantum dot light emission diode was measured using the various types of chemical ligands around quantum dot. It was confirmed that the trioctyl phosphin oxide (TOPO) ligand around the quantum dot was responsible for dispersion of the quantum dot in silicone encapsulant and decline of the thermal curing degree of the silicone encapsulant. Also, it was confirmed that the thermal curing degree of silicone encapsulants containing the steric acid (SA) and the dodecanoic acid (DA) ligands were higher than the one of TOPO ligand.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.27-28
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• 2019

In this study, the characteristics of compressive strength of ultra high strength concrete supplied with moisture from outside by vacuum water absorbing curing method were investigated. Specimens were prepared by replacing the binder(Silifa fume and GGBS) by 25 wt% with respect to the weight of cement at W/B 0.16. Each specimen was subjected to water Vacuum absorbing curing time 0 min, 30 min, 60 min, 90 min and 120 minutes immediately after the demolding. Curing was performed at $20^{\circ}C$ Air-dry curing, $90^{\circ}C$ steam curing, $90^{\circ}C$ steam curing and $180^{\circ}C$ autoclave curing. Experimental results showed that water absorbing degree increased with increasing water absorbing curing time, and BS25 sample had higher water absorbing degree than SF25 sample at same time. Compressive strength tended to increase up to about 40% in water absorbing degree, but compressive strength decreased again in water absorbing more than 40%.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.827-831
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• 1995

This study was designed to etermine the changes in the degree of conversion for composite resins after heat curing following the methods proposed by Lee & Park(1995). 8-mm diameter hole was made in 1mm teflon plate and one of three types of composites (Charisma, Brilllant, Z100) was placed and light cured for 60seconds. The samples were devided into 3 groups according to the placing composites. After light curing, the samples were separated from the moulds. Using this method, 10 samples were prepared in each group; 5 samples from each group were heat cured according to the methods proposed by manutfactures, These samples were then thinned to 50-$70{\mu}m$ and analysed with a Fourier Transform Infrared Spectrometer. Standard baseline technique was used to calculate the degree of conversion. When the samples were light cured, the degrees of conversion in each groups were 47.1 % (charisma), 53.3% (Z100), and 70.1 % (Brilliant). The degree of conversion after heat curing were; 60.1 % (Charisma), 71.1 % (Z100), and 73.3 % (Brillant). Once the samples were heat cured, there were significant increases in degree of conversion.

• 대한치과보철학회지
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• 제43권1호
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• pp.1-14
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• 2005

Statement of problem. Among the physical properties of adhesion luting cement, the aspect that requires the most important factor is the degree of solubility and water sorption. Dissolution or an inadequate due to excessive water sorption inside the oral cavity compromises the while concurrently increasing the susceptibility to secondary dental caries. Susceptibility to dissolution and difficulty of removing remnant cement from the gingival sulcus have hindered the use of dental resin cement in the clinical practice, but the improved characteristics of newer generation resin cements have interest in and enabled resin cements to be widely used in adhesion of fixed prosthesis, such as laminate veneers and all-ceramic crowns. Purpose. The purpose of this study is to compare and analyze the degrees of solubility and water sorption of a variety of resin cements widely used for clinical purposes with different curing methods. Material and methods. Self-curing resin cements, $Avanto^{(R)}$, $C&B^{TM}$ CEMENT and Superbond C&B cements comprised group 1, 2 and 3. The dual-curing resin cements $Panavian^{TM}$ F, $Calibra^{(R)}$ and $Variolink^{(R)}$ II were divided into groups 4, 5, and 6, respectively. The investigation was carried out using disc-shaped specimens as specified by ANSI/ADA Specification No. 27. The degree of water sorption, water solubility and lactic acid solubility of each test group was analyzed statistically leading to the following conclusion. Results. The degree of water sorption was shown to increase in the following order : group 6, 5, 4, 2, 1 and 3. There were significant differences between the water sorption of each group. Results of the degree of water solubility were shown to increase in the following order : group 6, 5, 4, 2, 1 and 3. Statistically significant differences were found between each group, with the exception of groups 1 and 3. Finally, the degree of lactic acid solubility was found to increase in the following order : group 6,5,4,2,3 and 1. Significant differences were found between each group. In general dual-curing resin cements displayed substantially lower values than self-curing resin cements with regard to water sorption, water solubility, and lactic acid solubility. Conclusions. From the results of this study, dual-curing resin cements show a significantly lower degree of water sorption and solubility than their self-curing counterparts. Clinically, when selecting resin cements, the product with a lower degree of water sorption and solubility are preferred. The results of this study indicate that the use-of dual-curing resin cements is preferable to self-curing cements.

• 한국작물학회지
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• 제45권2호
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• pp.79-82
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• 2000

Tuberous root of yacon (Polymnia sonchifolia Poeppig ＆ Endlicher) has not starch, and its brix degree changes during the curing. Therefore its chemical composition changes were investigated according to different curing conditions. Tuberous root contained 87.1% moisture at harvesting, that was decreased to 84.1-86.0% at 30 days after curing in different curing conditions. Brix degree was increased from 5.7 to 14.2-15.8% at 30 days after curing in comparison to at harvesting. Free sugars were detected from tuberous root in yacon by HPLC; that were fructose, glucose and sucrose. Fructose contents were increased from 0.09 to 1.04-1.79% during 30 days in five curing conditions. Glucose contents were shown to increase from 0.03 to 1.04-1.37 %. Sucrose contents were shown to increase from 0.04 to 0.13-0.43%. Tuberous root contained fructose, glucose and sucrose in order of amount that were highest in single-polyethylene film covered green house. Sucrose was little as comparison with fructose and glucose. Fructose and glucose were increased to 16.7 and 40.7 times, respectively, but sucrose was increased little about 6.8 times.

• 대한소아치과학회지
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• 제30권2호
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• pp.245-253
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• 2003

치과용 복합레진의 중합률은 레진 기질내의 이중결합의 전환도를 나타내는 것으로 이는 재료의 물리적 성질과 기계적 성질 및 생체 친화성에 영향을 미친다. 레진의 중합도가 증가하면 취성과 수축이 증가하고 중합도가 낮으면 기계적 물리적 성질이 감소한다. 따라서 본 연구에서는 광중합형 복합레진을 사용하여 플라즈마 아크 중합기 2종, 할로겐 중합기 2종, LED 중합기 2종, pulse-delay curing의 서로 다른 중합방법의 경우를 FTIR 분석법으로 복합레진의 물리적 기계적 성질 및 생체친화성에 영향을 미치는 중합률을 분석하여 다음과 같은 결과를 얻었다. 1. 광중합 복합레진의 중합률은 FTIR로 측정하였을 때 34.52-49.31%사이로 나타났으며 플라즈마 아크 중합의 경우 Flipo는 $39.96{\pm}1.22%$, CrediII는 $45.64{\pm}1.34%$로, 할로겐 중합시 XL3000은 $43.48{\pm}1.34%$, VIP의 mode 4 사용시는 $44.31{\pm}0.72%$, LED의 LUXOMAX는 $49.31{\pm}2.37%$, Elipar Freelight는 $44.51{\pm}0.62%$, pulse-delay curing시에는 $34.52{\pm}0.85%$로 나타났다. 2. 각 중합 방법별로 중합률은 LED 중합 방법을 이용한 LUXOMAX가 다른 실험군에 비하여 가장 높은 중합률을 나타냈으며 pulse-delay curing 방법이 가장 낮은 중합률을 보였다. 3. Flipo 중합기, LUXOMAX 중합기, pulse-delay curing 방법이 다른 중합기와 비교하여 통계적으로 유의한 차이를 보였다(p<0.05). 4. 각 중합방법이 동일한 군 내의 중합기기별 차이에서는 할로겐에서는 광중합기 사이에 중합률의 차이를 보이지 않았으나 플라즈마 아크에서는 CrediII가, LED에서는 LUXOMAX가 중합률이 높았다(p<0.05).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.255-257
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• 2012

Epoxy resin without any hardener can harden in the presence of hydroxide ions in cement mortars and concretes at ambient temperature. The purpose of present study is to examine the hardening properties of hardener-free epoxy-modified mortars by curing conditions. The hardener-free epoxy-modified mortars using diglycidyl ether of A epoxy resin are prepared with various polymer-cement ratios, and subjected to initial moist/dry curing, initial steam(90℃) curing, initial steam/heat(80℃, 100℃) curing.As a result, degree of hardening of epoxy resin in initial moist/dry cured, initial steam cured and initial steam/heat(80℃) cured hardener-free epoxy-modified mortars is decreased with increasing polymer-cement ratio. However, it is markedly improved with additional dry-curing periods. On the other hand, regardless of the polymer-cement ratio and dry curing periods, degree of hardening of hardener-free epoxy-modified mortars with initial steam/heat(100℃) cure is over 95%.