• 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.28 no.4
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• pp.638-642
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• 2001

Recently, plasma arc curing system for curing resin composites has been introduced. This is characterized by a high output of light energy, which has the advantage of reducing the chair time and thereby making the treatment more comportable for the patients as well as for the dentist. The purpose of this study was to compare the shear bond strengths of light-cured orthodontic adhesive polymerized with conventional halogen light and plasma arc light. The 2 curing devices used were the XL3000 (3M, USA) conventional curing light and the Flipo (LOKKI, France) plasma arc light. The results from the present study can be summarized as fellows; 1. The mean shear bond strength for three groups were quite similar for 50 second conventional light group, 2 second plasma arc curing light group, 5 second plasma arc curing light group. 2. There was no statistically significant difference for three groups(p>0.05).

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.127-135
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• 2010

A study on that LED in 36[W] class replaces broadcast illuminator to save energy and improve the quality of film because tungsten halogen illuminators are too hot and spending lots of electrical capacity at the time of camera shooting. And the following result was obtained .36[w] LED lighting fixture's illuminance is lower than 1[kw] halogen Light but object's illuminance became higher, and at the image be showed very bright and softly.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.9
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• pp.738-742
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• 2012

This paper conducted a study on how the heat radiation of light emitting diode(LED) luminaires affects the indoor temperature increase. The effect was compared with that of a 20 W compact fluorescent lamp(CFL) and a 50 W MR16 halogen lamp which are most widely used inside of cruises, a LED downlight and a 4W MR16 LED replacing each of them. We installed a luminarie inside a thermally shielded chamber, measuring the temperature changes under the same volume every 5 minutes and compared the result with theoretically calculated heat radiation. The temperature changes in the chamber was measured four times, on seven hours' period in order to keep sufficient time once the temperature reaches the thermal equilibrium state. The results showed that the temperature of the 20 W E26 CFL and the 10 W LED downlight increased by $21.1^{\circ}C$ and $10.4^{\circ}C$ respectively, while that of the 50 W halogen MR16 and the 4 W LED MR16 increased by $33.9^{\circ}C$ and $4.8^{\circ}C$ respectively. The experimental heat radiation were calculated from the results and the experimental heat radiation of the CFL and the LED downlight were 171.5 cal and 86.5 cal, and those of the halogen MR16 and the LED MR16 were 275.3 cal and 36.5 cal. Therefore, the heat radiation was reduced by 49.5% and 86.7%, respectively, by replacing conventional light source with LED. In conclusion, we can expect a reduction of power consumption in air condition system and the effect on indoor temperature increase by application of LED luminaires.

• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.368-373
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• 2010

Objectives: This study investigated the effect of infection control barrier thickness on power density, wavelength, and light diffusion of light curing units. Materials and Methods: Infection control barrier (Cleanwrap) in one-fold, two-fold, four-fold, and eightfold, and a halogen light curing unit (Optilux 360) and a light emitting diode (LED) light curing unit (Elipar FreeLight 2) were used in this study. Power density of light curing units with infection control barriers covering the fiberoptic bundle was measured with a hand held dental radiometer (Cure Rite). Wavelength of light curing units fixed on a custom made optical breadboard was measured with a portable spectroradiometer (CS-1000). Light diffusion of light curing units was photographed with DSLR (Nikon D70s) as above. Results: Power density decreased significantly as the layer thickness of the infection control barrier increased, except the one-fold and two-fold in halogen light curing unit. Especially, when the barrier was four-fold and more in the halogen light curing unit, the decrease of power density was more prominent. The wavelength of light curing units was not affected by the barriers and almost no change was detected in the peak wavelength. Light diffusion of LED light curing unit was not affected by barriers, however, halogen light curing unit showed decrease in light diffusion angle when the barrier was four-fold and statistically different decrease when the barrier was eight-fold (p < 0.05). Conclusions: It could be assumed that the infection control barriers should be used as two-fold rather than one-fold to prevent tearing of the barriers and subsequent cross contamination between the patients.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.471-479
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• 2001

The purpose of this study was to compare the effect of the high intensity halogen light $(850\sim1000mW/cm^2)$ with that of the conventional halogen light $(400mW/cm^2)$ on the hardness of composite resin. Three resin composites (Z-100, 3M, U.S.A. : Tetric Ceram, Vivadent, Liechtenstein; SureFil, Dentsply, U.S.A.) were filed in the stainless steel moulds which were 4mm in diameter and 2, 3, 4, and 5mm in depth, respectively. They were cured under the four different modes : (1) conventional mode, 40 seconds at $400mW/cm^2$; (2) 'ramp' mode, 10 seconds at 100 to $1000mW/cm^2$ plus 10 seconds at $1000mW/cm^2$; (3) 'boost' mode, 10 seconds at $1000mW/cm^2$; and (4) 'standard' mode, 20 seconds at $850mW/cm^2$. The surface hardnesses of the top and the bottom of the resin samples were measured with a microhardness tester (MXT70, Matsuzawa, Japan). The top surface hardness was not significantly different among the curing modes. The bottom surface hardness was generally the highest in the conventional mode and the lowest in the high intensity boost mode. There was no significant difference in the bottom surface hardness between the conventional mode and the high intensity standard mode in 2mm depth. The results suggest that the curing time of the high intensity halogen light $(850mW/cm^2)$ should be at least 20 seconds to produce the equal level of the bottom surface hardness of 2mm resin composite as compared to the hardness produced by the conventional halogen light $(400mW/cm^2)$.

• Korean Journal of Materials Research
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• v.24 no.6
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• pp.305-309
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• 2014

When sunlight irradiates a boron-doped p-type solar cell, the formation of BsO2i decreases the power-conversion efficiency in a phenomenon named light-induced degradation (LID). In this study, we used boron-doped p-type Cz-Si solar cells to monitor this degradation process in relation to irradiation wavelength, intensity and duration of the light source, and investigated the reliability of the LID effects, as well. When halogen light irradiated a substrate, the LID rate increased more rapidly than for irradiation with xenon light. For different intensities of halogen light (e.g., 1 SUN and 0.1 SUN), a lower-limit value of LID showed a similar trend in each case; however, the rate reached at the intensity of 0.1 SUN was three times slower than that at 1 SUN. Open-circuit voltage increased with increasing duration of irradiation because the defect-formation rate of LID was slow. Therefore, we suppose that sufficient time is needed to increase LID defects. After a recovery process to restore the initial value, the lower-limit open-circuit voltage exhibited during the re-degradation process showed a trend similar to that in the first degradation process. We suggest that the proportion of the LID in boron-doped p-type Cz-Si solar cells has high correlation with the normalized defect concentrations (NDC) of BsO2i. This can be calculated using the extracted minority-carrier diffusion-length with internal quantum efficiency (IQE) analysis.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.1
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• pp.82-89
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• 2018

In a photodynamic therapy, the difference of antibacterial capacity was compared according to the type of source of light when the same quantity of energy is irradiated. After S. mutans is formed in planktonic state and biofilm state, erythrosine diluted to $40{\mu}M$ was treated for 3 minutes, and as the type of light source, Halogen, LED, and Plasma arc were used, which were irradiated for 30 seconds, 15 seconds and 9.5 seconds, respectively. After the completion of the experiment, CFU of each experiment arm was measured to compare the photodynamic therapeutic effects according to each condition. The CFU of each experiment arm had no statistically significant difference. Under the same quantity of energy, the photodynamic therapeutic effect can be said to be the same regardless of types of light source, which is a useful result in the clinical field with various light irradiators.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.421-430
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• 2004

The purpose of this study was to measure and compare the amount of unreacted TEGDMA from pit and fissure sealants cured with three different light sources; conventional halogen light curing unit, plasma arc light curing unit and argon laser. The specimens were eluted in distilled water for different time intervals. The time-related release of TEGDMA were analyzed by reverse-phase high performance liquid chromatography(HPLC). The result of present study can be summarized as follows: 1. The time-related release of TEGDMA decreased with increasing curing time in conventional halogen light, however, that not statistically significant difference(p>0.05). 2. The elution from the specimens cured for 6 and 9 seconds with plasma arc light was similar results corresponding with the time-related TEGBMA release, and was significantly lower than that cured for 3 seconds(p<0.05). 3. The elution of TEGDMA from the specimens cured with argon laser was significantly higher than that cured with halogen and plasma arc light(p<0.05). 4. The elution of TEGDMA from under recommended time of three different light sources were showed to be no statistically significant difference(p>0.05). 5. In time-related release of TEGDMA from recommended time of each light sources, the results correspond to 40 seconds of halogen light and 6 seconds of plasma arc light were similar(p>0.05). 6. The elution of TEGDMA, from over recommended time of three different light sources were showed to be no statistically significant difference(p>0.05). In this study, I suggest that curing time of plasma arc light is 6 and/or 9 seconds in the field of clinical pediatric dentistry claiming its effectiveness in optimal polymerization and reduced chair time.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.122-129
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• 2007

The purpose of this study was to evaluate the effects of a various light curing time on the residual monomers released from light-cured dental sealant, and to examine the effectiveness of surface treatment in reducing the oxygen-inhibited layer of light-cured dental sealant($Helioseal^{(R)}$ F, Vivadent, Liechtenstein). Specimens were cured with a halogen light curing unit(XL 3000, 3M, USA) for 20, 40, 60s. Surface treatment of a light-cured dental sealant included no treatment(control group), a 10-seconds exposure to distilled water(Group I), 10-seconds manual application using a cotton pellet wetted with 75% alcohol(Group II), and 10-seconds application of a water/pumice slurry using a rubber cup on a slow-speed handpiece The specimens were eluted in distilled water for 10 minutes. All elutes were analyzed by HPLC for identification and quantitive analysis of monomers. The results of this study can be summarized as follows. 1. None of the chromatograms of the tested sealant displayed peaks with the same retention time as that of the standard solution, except for TEGDMA. 2. The release of TEGDMA decreased with increasing curing time in conventional halogen light. 3. All surface treatment group had a decrease of monomer release in comparison with no treatment group. 4. Treatment that Group III eliminated the greatest amount of any type of residual monomers. 5. The elution of unreacted monomers from curing with halogen curing unit for 60s and Group III was less than other groups.