• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1057-1060
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• 2004

In this study, the wear characteristics of five different dental composite resins cured by conventional halogen light and LED light sources were investigated. Five different dental composite resins of Surefil, Z100, Dyract AP, Fuji II LC and Compoglass were worn against a zirconia ceramic ball using a pin-on-disk type wear tester with 15 N contact force in a reciprocal sliding motion with sliding distance of 10 mm/cycle at 1Hz under the room temperature dry condition. The wear variations of dental composite resins were linearly increased as the number of cycles increased. It was observed that the wear resistances of these specimens were in the order of Dyract AP ＆gt; Surefil ＆gt; Compoglass ＆gt; Z100 ＆gt; Fuji II LC. On the morphological observations by SEM, the large crack formation on the sliding track of Fuji II LC specimen was the greatest among all resin composites. Dyract AP showed the least wear with few surface damage. There is no significant difference in wear performance between conventional halogen light curing and light emitting diodes curing sources. It indicates that a light emitting diodes (LED) source can replace a halogen light source as a curing unit for composite resin restorations.

• 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.

• Tribology and Lubricants
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• v.21 no.6
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• pp.268-271
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• 2005

In this study, the wear characteristics of five different dental composite resins cured by conventional halogen light and LED light sources were investigated. Five different dental composite resins of Surefil, Z100, Dyract AP, Fuji II LC and Compoglass were worn against a zirconia ceramic ball using a pin-on-disk type wear tester with 15N contact force in a reciprocal sliding motion of sliding distance of 10mm/cycle at 1Hz under the room temperature dry condition. The wear variations of dental composite resins were linearly increased as the number of cycles increased. It was observed that the wear resistances of these specimens were in the order of Dyract AP > Surefil > Compoglass > Z100 > Fuji II LC. On the morphological observations by SEM, the large crack formation on the sliding track of Fuji II LC specimen was the greatest among all resin composites. Dyract AP showed less wear with few surface damage. There is no significant difference in wear performance between conventional halogen light curing and light emitting diodes curing sources. It indicates that a light emitting diodes (LED) source can replace a halogen light source as curing unit for composite resin restorations.

• 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.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 Korea Convergence Society
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• v.10 no.12
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• pp.177-181
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• 2019

The purpose of this study was to investigate the degree of blocking of blue light of the tips and goggles of the curing light during the dental treatment using the blue light of the light curing. The light curing tips and goggles were placed on a UV-Vis spectrometer and the results of light transmission were analyzed. Comparative analysis. As a result, all four types of light curing tips used in the analysis showed excellent blue light blocking effect. In the case of safety goggles, red-type goggles showed blue light transmittance similar to those of light curing than yellow-type goggles. As a result, it is recommended that the attachment of the light curing with high degree of blue light blocking and the wearing of safety glasses are necessary to protect the eyes. This behavior is thought to reduce persistent irritation and fatigue in the eyes.

• 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.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.652-663
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• 1996

The purpose of this study was to evaluate the tensile bond strength to tooth structure of composite resin and glass ionomer cement according to filling methods and light curing units. In this study, two class V cavities were prepared on the buccal surface of each tooth of 140 extracted human molars, and they were randomly assigned into 3 experimental groups with 40 teeth and control group with 20 teeth. And then, each experimental groups subdivided into 2 groups(A,B) according to light curing units. The cavities of each group were filled with the CLEARFIL FII self curing resin(Control Group), Z-100 light curing resin(Group 1), Vitremer$^{TM}$ light curing glass ionomer cement(Group 2) and Z-100 light curing resin over the Vitrebond$^{TM}$ liner(Group 3). And subdivided A Group used Argon Laser(SPECTRUM$^{TM}$, U.S.A.), B Group used XL 1,000 curing light (3M, U.S.A.). The specimens underwent temperature changed from $5^{\circ}C$ to $55^{\circ}C$ five hundred times. After thermocycling, specimens were stored in 100% relative humidity at $37^{\circ}C$ for 24 hours. And then, the tensile bond strength of specimens were calculated with Universal Testing Machine(AGS-100A, Japan). The results were as follows : 1. Among the experimental groups, the group 2-B showed the highest tensile bond strength ($18.89{\pm}7.80$) and the group 1-A showed the lowest tensile bond strength ($11.68{\pm}2.28$). There was significant difference between group 2-B and group 1-A(p<0.01). 2. Between the light curing units, the XL 1,000 unit showed higher tensile bond strength ($16.63{\pm}3.20$) than that of the Argon Laser unit ($13.73{\pm}2.30$). There was significant difference between XL 1,000 and Argon Laser(p<0.01). 3. About filling methods and materials, the group 2 showed the highest tensile bond strength ($17.56{\pm}1.89$) and the group 1 showed the lowest tensile bond strength($13.03{\pm}1.90$). There was significant difference between group 2 and group 1,3(p<0.01). In conclusion, the results showed that the glass-ionomer cement that cured by XL 1,000 light curing unit demonstrated significantly higher tensile bond strength than other curing unit and filling methods.

• The korean journal of orthodontics
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• v.46 no.6
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• pp.364-371
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• 2016

Objective: With the introduction of third-generation light-emitting diodes (LEDs) in dental practice, it is necessary to compare their bracket-bonding effects, safety, and efficacy with those of the second-generation units. Methods: In this study, 80 extracted human premolars were randomly divided into eight groups of 10 samples each. Metal or polycrystalline ceramic brackets were bonded on the teeth using second- or third-generation LED light-curing units (LCUs), according to the manufacturers' instructions. The shear bond strengths were measured using the universal testing machine, and the adhesive remnant index (ARI) was scored by assessing the residual resin on the surfaces of debonded teeth using a scanning electron microscope. In addition, curing times were also measured. Results: The shear bond strengths in all experimental groups were higher than the acceptable clinical shear bond strengths, regardless of the curing unit used. In both LED LCU groups, all ceramic bracket groups showed significantly higher shear bond strengths than did the metal bracket groups except the plasma emulation group which showed no significant difference. When comparing units within the same bracket type, no differences in shear bond strength were observed between the second- and third-generation unit groups. Additionally, no significant differences were observed among the groups for the ARI. Conclusions: The bracket-bonding effects and ARIs of second- and third-generation LED LCUs showed few differences, and most were without statistical significance; however, the curing time was shorter for the second-generation unit.