• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.328-336
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• 2002

Recently, new light curing unit utilizing the plasma xenon arc lamp is introduced. This curing unit is operated at relatively high intensity, so shortening the curing time significantly. The aim of this experiment was to estimate curing capability of plasma xenon arc lamp curing unit compared to traditional halogen lamp curing unit. Degree of conversion was evaluated by Raman spectroscopy after irradiation of specimens with halogen lamp curing unit(Optilux 150, Demetron, USA) for 20s, 40s, 60s and plasma xenon arc lamp curing unit(flipo, Lokki, France) for 2s, 3s, 6s. The results showed that strong light intensity of plasma xenon arc lamp curing unit did not compensate for short exposure time completely. So, Multi-layered curing within 2mm thickness and additional exposure time is recommanded when light-cured composite resin is polymerized with plasma xenon arc lamp curing unit.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.19-29
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• 2002

The purpose of this study was to compare the polymerization shrinkage and the compressive strength of composite and compomer cured with two different light sources ; conventional halogen-light curing unit and recently-developed plasma arc curing unit. The 'strain gauge method' was used for determination of polymerization shrinkage and the compressive strength was measured by universal testing machine. The results of the present study can be summarized as follows: 1. Filling materials in polyethylene molds showed the initial expansion in the early phase of polymerization. This was followed by the rapid contraction in volume during the first 60 seconds and gradually diminished as curing process continued. 2. The polymerization shrinkage in tooth samples was generally lower than in the mold samples. 3. The generally lower amount of linear polymerization shrinkage was observed in compomer and plasma arc curing unit group when compared to composite and conventional curing unit. 4. The higher compressive strength values was found in composite groups regardless curing methods. The results of this study strongly support the application of plasma arc system and fluoride-containing compomer in the field of clinical pediatric dentistry claiming its effectiveness in curing the esthetic dental materials and the anticariogenic capacity.

• The Journal of Advanced Prosthodontics
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• v.4 no.2
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• pp.93-96
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• 2012

PURPOSE. The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units. MATERIALS AND METHODS. A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (${\alpha}$=.05). RESULTS. ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance ($P$ <.001). CONCLUSION. Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.284-292
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• 2005

The aim of this study was to identify and quantify the major or detectable monomers released from any of five commercially-available, light-cured pit and fissure sealants with three different light sources : conventional halogen light curing unit, plasma arc light curing unit and LED curing unit. After curing, specimens were immediately immersed in distilled water for different time intervals. The time related release of monomers were analyzed by high performance liquid chromatography(HPLC). Identification and quantitative analysis of monomers were performed by the comparison of the elution time and the absorption peak height of the eluates with those of the authentic sample. The result of this study can be summarized as follows. 1. Standard solution peaks with retention times of 2.3, 3.2, 5.6, 6.5, 10.4 minutes were identified as BPA, TEGDMA, UDMA, Bis-GMA, Bis-DMA, respectively. 2. None of the chromatograms of the tested sealants displayed peaks with the same retention time as that of the standard solution, except for TEGDMA. 3. The highest release rate of TEGDMA was observed during the 12hr period for all samples and declined thereafter. 4. The elution of TEGDMA from curing with Halogen curing unit for 20 second and LED for 10 second was less than that resulting from curing with Plasma arc for 3 second. 5. TEGDMA was detected at much lower levels in eluates from the Pit & Fissure $Sealant^{TM}$ than other sealants. The elution of TEGDMA from the $Helioseal^{(R)}$ F cured with Halogen light curing unit, the $Concise^{TM}$ cured with Plasma arc curing unit and the $Teethmate^{(R)}$ F-1 cured with LED curing unit were higher than other sealants.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.180-188
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• 2002

Newly developed curing units(plasma arc curing units) operate at relatively high intensity and are claimed to result in optimum properties of composite resin in a short curing time. The purpose of this study was to evaluate the microhardness and microleakage at the resin-tooth interface of two types of composite resins polymerized with visible light and plasma arc curing units. The results from the present study can be summarized as follows 1. Microhardness in each depth was shown to be higher in group AHL than AP3 & AP6. Group ZHL was lower than AP6 at surface(p<0.05) and had no statistically significant difference at 1mm and 2mm(p>0.05). In other depths, group ZHL was higher than ZP3 and ZP6(p<0.05). 2. The incremental reduction in microhardness with depth was shown to be in all group except in surface-1mm of group AHL and $1{\sim}2mm$ of group ZHL(p<0.05). 3. Degree of microleakage in all oops were shown to be higher in gingival margin than occlusal margin but no statistically significant difference(p>0.05). 4. Differences between curing methods in microleakage were shown to be no statistically significant difference(p>0.05). 5. Differences between composite resins in microleakage were shown to be no statistically significant differ once(p>0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.707-714
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• 2003

Plasma Arc Curing(PAC) units operate at relatively high intensity and claimed to result in optimum properties of composite resin in a short curing time, so the interest of pediatric dentists about PAC units have been increased recently. But PAC units used for polymerizing restorative resins produce heat during operation. The purpose of this study was to evaluate temperature transmission through dentin of various depths using two types of PAC units(Flipo, Q-Lux plasma 100). The results from the present study can be summarized as follows : 1. When PAC be used continuously, temperature on tip was increased as curing times, and Q-Lux showed greater temperature rising(p<0.001). 2. Compared temperature transmission as dentin depth, temperature rising rate was decreased as dentin thickened(0.5, 1.0, 1.5, 2.0mm)(p<0.05). 3. Compared temperature transmission as resin depth, temperature rising rate was also decreased as resin thickened(1.0, 2.0mm)(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.273-279
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• 2004

Recently, newly developed single high-intensity LED curing lights for composite resins are claimed to have a higher intensity than previous LED curing lights and to results in optimal properties and short curing time. The purpose of this study was to determine the curing effectiveness of the curing units and to evaluate the relationship between the degree of polymerization and distance from curing light tip end to resin surface. One composite resin was tested(Filtek Z250). Thin film specimens were cured with a LED curing unit(Elipar Freelight 2, 10s), Plasma Arc curing unit(Flipo, 6s), Halogen curing light(XL3000, 20s) at four curing light tip to the resin surface(0mm, 2mm, 4mm, 6mm). Degree of conversion of composite resins were determined by a Fourier Transform Infrared Spectrometer(FTIR). From the present study, the following results were obtained. 1. In all curing units, relative light intensity was significantly decreased according to the increase of distance of light tip to the resin surface(p<0.05). LED curing units showed a higher percentile decrease in intensity than other curing units. 2. In all curing units, degree of conversion was decreased as increase of the distance but no statistically significant difference(p>0.05) except between 4mm and 6mm(p<0.05). 3. When comparing degree of conversion of light curing units at each distance(0mm, 2mm, 4mm, 6mm), LED curing light had a higher degree of conversion than plasma arc and halogen curing lights at 0, 2, 4mm(p<0.05). At 6mm, there was a no significant difference among the curing units(p>0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.245-253
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• 2003

The degree of conversion of cross-linked polymer has great importance in determining the physical and mechanical properties, and biocompatibility. Therefore, this study examined the comparison of light-cured composite resin polymerization of various light-curing systems composed of plasma arc, halogen, LED curing units and pluse-delay curing with FTIR. From this experiment, The following results were obtained : 1. From FTIR, the degree of conversion(DC) of composite resin was 34.52-49.31%, DC of composite resin used in Flipo was $39.36{\pm}1.22%$, CrediII $45.64{\pm}1.34%$, XL3000 $43.48{\pm}1.34%$, VIP(mode 4) $44.31{\pm}0.72%$, LUXOMAX $49.31{\pm}2.37%$, Elipar Freelight $44.51{\pm}0.62%$ and $34.52{\pm}0.85%$ in pulse-delay curing. 2. The degree of conversion of composite resin in each light-curing unit was highest DC of the LUXOMAX system, lowest DC of the pulse-delay curing. 3. Compared with other curing system, Flipo, LUXOMAX, and pulse-delay curing were significant difference(p<0.05). 4. In same curing method group, the differences of each light-curing unit were no significace in halogen(conventional) curing method(p>0.05), but significance in plasma arc curing and LED curing method(p<0.05).

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.488-492
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• 2002

The purpose of this study was to evaluate the effectiveness of plasma arc curing (PAC) unit for composite and compomer curing. To compare its effectiveness with conventional quartz tungsten halogen (QTH) light curing unit, the polymerization shrinkage rates and amounts of three composites (Z100, Z250, Synergy Duo Shade) and one compomer, that had been light cured by PAC unit or QTH unit, was compared using a custome made linometer. The measurement of polymerization shrinkage was peformed after polymerization with either QTH unit or PAC unit. In case of curing with the PAC unit, the composite was light cured with Apollo 95E for 6s, the power density of which was recorded as 1350 mW/$\textrm{cm}^2$ by Coltolux Light Meter. For light curing with QTH unit, the composite was light cured for 30s with the XL2500, the power density of which was recorded as 800 mW/$\textrm{cm}^2$ by Coltolux Light Meter. The amount of linear polymerization shrinkage was recorded in the computer every 0.5s for 60s. Ten measurements were made for each material. The amount of linear polymerization shrinkage for each material in 10s and 60s which were cured with PAC or QTH unit were compared with t test. The amount of polymerization shrinkage in the tested materials were compared with 1way ANOVA with Duncan's multiple range test. As for the amounts of polymerization shrinkage in 60s, there was no difference between PAC unit and QTH unit in Z250 and Synergy Duo Shade. In Z100 and Dyract AP, it was lower when it was cured with PAC unit than when it was cured with QTH unit (p<0.05). As for the amounts of polymerization shrinkage in 10s, there was no difference between PAC unit and QTH unit in Z100 and Dyract AP. The amounts of polymerization shrinkage was significantly higher when it was cured with PAC unit in Z250 and Synergy Duo Shade (p<0.05). The amounts of polymerization shrinkage in the tested materials when they were cured with QTH unit were Z250 (6.6um) < Z100 (9.3um), Dyract AP (9.7um) < Synergy Duo Shade (11.2um) (p<0.05). The amount of polymerization shrinkage when the materials were cured with PAC unit were Dyract AP (5.6um) < Z100 (8.1um), Z250(7.0um) < Synergy Duo Shade (11.2um) (p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.199-206
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• 2001

The purpose of study was to compare the plasma arc light with the halogen light in compostie resin curing. Three composite resin materials(Z-100, 3M, USA; Tetric Ceram, Vivadent, Liechtenstein; SureFil, Dentsply, USA) were filled in the teflon molds (4mm in diameter and 2, 3, 4, 5mm in thickness) and cured with either the conventional low-intensity light curing unit with a halogen lamp (Optilux 360, Demetron, U.S.A.) for duration of 40 seconds or with the high-intensity light curing unit with a plasma arc lamp (Flipo, Lokki, France) for duration of 3, 6, and 9 seconds. The intensity of halogen light was about $370mW/cm^2$ and that of plasma light was about $1,900mW/cm^2$. After one week, the surface hardnesses of both the top and the bottom of the resin samples were measured with a microhardness tester(MXT70, Matsuzawa, Japan). There were significant differences in the hardness between the top and the bottom of the resin samples except the 2mm thickness samples cured by halogen light for 40s or by plasma light for 9s. There was no significant difference between the hardness values of the top surfaces of the thickness groups. The hardness values of the bottom surfaces decreased as the curing time decreased and as the thickness of resin samples increased, and the three kinds of resin composites showed similar patterns. The results suggest that the halogen light for 40 seconds might be able to cure greater depth of resin composites than the plasma light for 3, 6, or 9 seconds.