• The Journal of the Korean dental association
• /
• v.51 no.1
• /
• pp.12-17
• /
• 2013

Curing methods for denial resin-based materials are limited because of the need to polymerize quickly in the oral cavity at an ambient temperature. At present, most dental restorative composites use a camphorquinone-amine complex initiation, visible light-cure, one-component systems. Clinically, it is important to try to optimize the degree of conversion of res in composites using proper manipulation and adequate light-curing techniques to ensure the best outcome.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.29 no.3
• /
• pp.328-336
• /
• 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 Korea Convergence Society
• /
• v.12 no.7
• /
• pp.125-131
• /
• 2021

Blue light with strong energy is required for light-curing resin treatment, which is being used more frequently in dentistry. To reduce the risk of exposure to scattered light, we tried to use colored lenses. The tips for light curing machine and a commercially available yellow-type blue-light blocking lens and a yellow lens colored with yellow dye, which are expected to be effective in blocking blue light, were placed in a UV-Vis spectrometer device, and transmission and blocking of blue light were tested respectively. As a result, the average blue light blocking rate of the light curing machine tips was 99.49%, and the C lens with the highest color density among commercially available lenses showed a high blue light blocking rate of 99.54%. In the case of lenses tinted with yellow, the yellow tinted C lens with the highest tint concentration showed 87.57% of blue light blocking rate. It is judged that the side effects related to the eyes caused by blue light can be reduced if a yellow-type commercially available or colored lens is worn along with a light curing machine tip during resin treatment.

• Restorative Dentistry and Endodontics
• /
• v.35 no.4
• /
• pp.235-237
• /
• 2010

When curing the composite restorations with light curing units, the light guides are often in direct contact with oral tissues, therefore contamination of light guides is inevitable. Curing light guides fall into the "semicritical" instrument category according to the Centers for Disease Control and Prevention (CDC) and must be heat or vapor-sterilized or at a minimum, these semicritical instruments must be sterilized in a liquid chemical agent. Currently, most common methods of maintaining sterility of the light guides are wiping the guide with a disinfectant, such as glutaraldehyde, after each patient use; using autoclavable guides; using presterilized, single-use plastic guides; and using translucent disposable barriers to cover the guide.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2004.11a
• /
• pp.350-354
• /
• 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 of 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 > Surefil > Compoglass > Z100 > Fuji II LC. On the morphological observations by SEM, the large crack formation on the sliding track of Fuji ?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.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2003.05a
• /
• pp.35-38
• /
• 2003

The purpose of this study is to investigate the manufacture of light weight concrete panel using the artificial light-weight aggregate as a part of the substitution of foamed styrene and polyurethane because of narrow allocable temperature Bone in use. The experimental parameter of this study is 40, 60 and 8$0^{\circ}C$ of curing temperature at 100% relative humidity and the type of admixture such as cement, 6mm glass fiber and St/BA emulsion. Testing item is compressive and flexural strength and strength of specimen cured at standard condition is compared to that of specimen cured at 40, 60 and 8$0^{\circ}C$ of curing temperature at 100% relative humidity. As a result or this, it was revealed that the maximum or strength is developed in 6$0^{\circ}C$ or cure temperature at 100% relative humidity in case of the most of the specimen. Specimens modified by St/BA emulsion show the highest development of strength dependent on the curing tmeperature. So, it seems to be effective that evaporation curing method shoud be considered to curing the specimen as the panel core.

• Restorative Dentistry and Endodontics
• /
• v.26 no.5
• /
• pp.387-392
• /
• 2001

When cavity floor is near the pulp, polymerization of light-activated restorations results in temperature increase. This temperature increase cause by both the exothermic reaction process and the energy absorbed during irradiation. Therefore instating base is required. Most frequently used insulating base is glass ionmer. The purpose of this study was to evaluate intrapulpal temperature changes of glass ionomer according to various curing intensity and curing time. Caries and restoration-free mandibular molars extracted within three months were prepared Class I cavity of 3$\times$6mm with high speed handpiece. 1mm depth of dentin was evaluated with micrometer in mesial and distal pulp horns. Pulp chambers were filled with 37.0$\pm$0.1$^{\circ}C$ water to CEJ. Chromium-alumina thermocouple was placed in pulp horn for evaluating of temperature changes. glass ionomer material was placed in 2mm. total curing time was 40s: continuous 40s, intermittent 20s, intermittent 10s. Glass ionomer material was cured with 300mW/$\textrm{cm}^2$, 550mW/$\textrm{cm}^2$ light curing unit. The results were as follows : 1. Temperature in pulp increased as curing unit power is increased. 2. Temperature in pulp more increased continuous emission than intermittent emission.

• Journal of Technologic Dentistry
• /
• v.40 no.2
• /
• pp.57-62
• /
• 2018

Purpose: The aim of this study is to evaluate composite resins of indirect restorations for testing of flexural strength according to various polymerization methods. Methods: Specimen was produced a total of 40 to 10 per each group with a length 25 mm, width 2 mm, thickness 2 mm using a Teflon zig. The polymerization groups were classified into four groups. The first group proceeded with light curing only(LC group). The second group proceeded with light and heat curing(LHC group). The third group proceeded with air press and light curing(ALC group). The fourth group proceeded with air press, light and heat curing(ALHC group). Each prepared group was evaluated by flexural strength test. Statistical analysis was performed by one-way ANOVA. Post-test was performed with Tukey test. Results: The lowest in the ALC group was 119.18 MPa and the highest in the ALHC group was 168.15 MPa. There were statistically significant differences. Conclusion : The composite resin of the indirect restoration is recommended to heat curing along with the air press.

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

• Restorative Dentistry and Endodontics
• /
• v.18 no.1
• /
• pp.215-226
• /
• 1993

Color stability of tooth colored restorative resins is an important factor, particularly in anterior teeth restoration. The purpose of this study was to evaluate the color stability and opacity change of several light curing composite resins. Specimens of eight composite resins(Prisma AP. H., Brilliant Enamel, Charisma, Durafil, Helio Progress, Herculite XR, P-50 and Silux Plus) were divided into two groups : In Group 1, the specimens were polymerized by visible light curing unit for 60 seconds on both sides and in Group 2, the post-cured specimens were heat tempered by light/heat curing unit for 45 units(about 18 min.). All specimens were stored in distilled water at $60^{\circ}C$ for 30 days. The color characteristics($L^*,a^*,b^*$) and opacity of the specimens before and after immersion were measured by spectrocolorimetry and the total color difference(${\Delta}E^*$) and opacity change (${\Delta}Y%$) were computed. The results obtained were as follows : 1. SP and APH in both groups, DF, HP and HXR in Group 1 showed ${\Delta}E^*$-value above 2.0. 2. DF, HP, SP and HXR in Group 1 showed higher ${\Delta}E^*$-value than in Group 2, but the others had no significant difference. 3. The opacity of CH and HXR in Group 1, and of CH and BE in Group 2 decreased after immersion, while that of the others increased. 4. Opacity change of BE, P50 and HXR was significantly different between Group 1 and 2. These results suggest that color change in the post-cure heat tempered specimens by light/heat curing unit was smaller than that of the specimens polymerized by visible light curing unit. No clinically detectable opacity changes were noted for any materials in either goup.