• 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.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.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.624-632
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• 2006

In recent years, xenon plasma arc lamp was introduced for high-intensity curing of composite filling materials in direct resin restorations. In this study, two types of restorative materials, namely composites point $4^{(R)}$ and $Z250^{(R)}$ were selected and curing was conducted using a conventional halogen light and two plama curing lights. Two different resin composites were cured using the different units($Flipo^{(R)}$, Ultra-lite 180A, and $TriLight^{(R)}$) and tested for microhardness. The purpose of this study was to test the hypothesis that exposure to a plasma curing lamp for 3, 6. 9 seconds is equivalent to 20 or 40 seconds of irradiation using a conventional halogen curing unit. 1. $Flipo^{(R)}$ and Ultra-lite 180A were able to polymerize point $4^{(R)}$ at 6 seconds to a degree equal to that of the $TriLight^{(R)}$(control) at 40 seconds. 2. $Flipo^{(R)}$ was able to polymerize $Z250^{(R)}$ at 9 seconds to a degree equal to that of the $TriLight^{(R)}$(control) on the bottom surface at 20 seconds. whereas Ultra-lite 180A could not do. 3. Two plasma curing units were able to cure the test-composites with bottom/top ratios approximately 61% to 96% at 3 to 9 seconds. There were some differences between the two composite brands, with $Z250^{(R)}$ displaying less difference between top and bottom hardness values. For point $4^{(R)}$ and $Z250^{(R)}$, at least 6 or 9 seconds were necessary to produce microhardness equivalent to that of the $TriLight^{(R)}$ curing at 20 or 40 seconds.

• Journal of Periodontal and Implant Science
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• v.43 no.2
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• pp.72-78
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• 2013

Purpose: The purpose of this study was to compare the phototoxic effects of blue light exposure on periodontal pathogens in both planktonic and biofilm cultures. Methods: Strains of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis, in planktonic or biofilm states, were exposed to visible light at wavelengths of 400.520 nm. A quartz-tungsten-halogen lamp at a power density of $500mW/cm^2$ was used for the light source. Each sample was exposed to 15, 30, 60, 90, or 120 seconds of each bacterial strain in the planktonic or biofilm state. Confocal scanning laser microscopy (CSLM) was used to observe the distribution of live/dead bacterial cells in biofilms. After light exposure, the bacterial killing rates were calculated from colony forming unit (CFU) counts. Results: CLSM images that were obtained from biofilms showed a mixture of dead and live bacterial cells extending to a depth of $30-45{\mu}m$. Obvious differences in the live-to-dead bacterial cell ratio were found in P. gingivalis biofilm according to light exposure time. In the planktonic state, almost all bacteria were killed with 60 seconds of light exposure to F. nucleatum (99.1%) and with 15 seconds to P. gingivalis (100%). In the biofilm state, however, only the CFU of P. gingivalis demonstrated a decreasing tendency with increasing light exposure time, and there was a lower efficacy of phototoxicity to P. gingivalis as biofilm than in the planktonic state. Conclusions: Blue light exposure using a dental halogen curing unit is effective in reducing periodontal pathogens in the planktonic state. It is recommended that an adjunctive exogenous photosensitizer be used and that pathogens be exposed to visible light for clinical antimicrobial periodontal therapy.