• Journal of Technologic Dentistry
• /
• v.42 no.2
• /
• pp.65-71
• /
• 2020

Purpose: To know the transmittance of light when wearing shading goggles and to protect eyes from blue light emitted from dental scanner when using CAD/CAM works or inducing polymerization reactions of dental resin with curing unit and infrared light occurred when melting Dental precious metal and non-precious metal alloys. Methods: By measuring and comparing the average transmittances of blue light, visible light and infrared ight by using UV-Vis Spectrophotometer analysis measuring instrument, I compared 3 GREEN Color Goggles worn when casting Dental precious metal and non-precious metal alloys, and compared each of YELLOW, ORANGE Color Goggles worn when using Dental CAD/CAM scanners and Light Curing(LED) the Dental resin. Results: In blue light range, YELLOW Color Goggles are more effective than ORANGE Color Goggles. In infrared light range, No.12 Goggles are more effective than No.10 and No.11 Goggles. Conclusion: When wearing blue light shading goggles to avoid harmful blue light occurred in using dental scanner and curing light, and when wearing infrared light shading goggles to avoid harmful infrared light during casting, to avoid the Side Effects like transmittance rate of blue light and infrared light goggles becomes too high to block appropriate amount of harmful light or too low that causing lower image clarity.

• The Journal of Korean Academy of Prosthodontics
• /
• v.28 no.1
• /
• pp.193-202
• /
• 1990

The purpose of this study was to compare the fithness, hardness and bending strength of the conventional reliners and visible light curing reliner. Nine regions were selected in the upper transverse section which were thought to be of interest from a clinical standpoint and the discrepancies between the dentures and the master cast in these regions were determined by the coordinated measuring machine(UMM-500, Zeiss, W. Germany). The results were as follows ; 1. The experimental denture bases showed the lowest fittness at the central portion of the posterior palatal border and the intimate contact in the buccal flanges regardless of relining materials and relining methods. 2. The fittness of relined denture base was the best in autopolymerizing group and in the order of long processing, short processing and visible light curing group. 3. The fittness after 24 hour-storage in water was improved in long processing and autopolymerizing groups, but there was no significant difference. 4. The hardness was the highest in long processing group and decreased in the order of short processing, visible light curing and autopolymerizing group. 5. The bending strength was the highest in long processing group and decreased short processing, visible light curing, and aotopolymerzing group in order.

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

• The Journal of Advanced Prosthodontics
• /
• v.3 no.3
• /
• pp.126-131
• /
• 2011

PURPOSE. The aim of this in vitro study was to examine the curing efficiency of various resin-based materials polymerized through ceramic restorations with 3 different thicknesses. Curing efficiency was evaluated by determining the surface microhardness (VHN) of the resin specimens. MATERIALS AND METHODS. Four kinds of resin materials were used. Z350 (3M ESPE $Filtek^{TM}$ Z350: A2 Shade), Z250 (3M ESPE $Filtek^{TM}$ Z250: A2 Shade) and $Variolink^{(R)}$ II (VL: Ivoclar vivadent, base: transparent) either with or without a self-curing catalyst (VLC: Ivoclar vivadent, catalyst: low viscosity/transparent) were filled into the silicone mold (10 mm diameter, 1 mm thick). They were cured through ceramic discs (IPS e.max Press MO-0 ingot ivoclar vivadent, 10 mm diameter, 0.5, 1 and 2 mm thicknesses) by LED light-curing units for 20 and 40 seconds. Vicker's microhardness numbers (VHNs) were measured on the bottom surfaces by a microhardness tester. Data were analyzed using a 3-way analysis of variance (ANOVA) at a significance level of 0.05. RESULTS. The thickness of ceramic disc increased, the VHNs of all four resin types were decreased (P<.05). The mean VHN values of the resins light cured for 40 seconds were significantly higher than that of LED for 20 seconds in all four resin materials (P<.05). VLC showed significantly higher VHN values than VL regardless of other conditions (P<.05). Z350 and Z250 showed higher values than VL or VLC (P<.01). CONCLUSION. Thinner ceramic disc with increased curing time resulted higher VHN values of all resin materials. The use of a catalyst produced a greater hardness with all polymerization methods. Restorative resin materials (Z350, Z250) showed higher VHN values than resin cement materials (VL, VLC).

• Journal of the korean academy of Pediatric Dentistry
• /
• v.25 no.4
• /
• pp.731-748
• /
• 1998

The purpose of this study was to test the hypothesis that the more thorough cure of lightactivated composite resin could be obtained if a new way of delivering the light source deep through the resin body is developed when compared to the conventional bulk cure or incremental cure. Using cylindrical resin blocks and natural teeth, various curing conditions were tested for their effects on the degree of microleakage and microhardness. Data were analyzed statistically using One-Way ANOVA and Scheff's Multiple Range test. The results of the present study were as follows: 1. The increment of reduction in microhardness with depth was shown to be higher in group I and II than in group II and V. 2. At the level of lower inner surface and the bottom surface, significantly lower microhardness values were obtained in group I and II when compared to group III, IV and V. Group IV showed the lowest value among three groups(III, IV, V) representing the only statistically significant difference from group V(p<05). 3. Differences between groups in the degree of microleakage detected were shown to be statistically significant (p<05) with the exception of group IV and V at both occlusal and gingival margins. 4. Based upon the above-mentioned results, commonly cited recommendation of incremental curing is strongly supported and the light-transmitting wedge insertion method can be considered as a effective and feasible clinical procedure for the better curing of composite resin. However, more studies under a variety of conditions should be completed before this method is applied actually to the clinical setting.

• Restorative Dentistry and Endodontics
• /
• v.19 no.2
• /
• pp.409-428
• /
• 1994

Endodontic surgery is performed when conventional endodontic therapy fails or is contraindicated. In such cases, retrograde filling materials including amalgam, composite resin, and various cements have been used. Biocompatibilty and margin sealing ability of retrograde filling materials are important for the long term success of endodontic surgery. In vitro cell culture is frequently used as the method of measuring the biocompatibilty of dental materials. The purpose of this study was to evaluate the cytotoxicity of six kinds of retrograde filling materials including newly developed light curing glass ionomer cements. Each material was mixed according to. the manufacture's instruction and evaluated as : freshly mixed, 24-hour after mixing, and 168-hour after mixing respectively. The elution solution was extracted after 24-hour contact with materials using media. Cytotoxicity was evaluated by direct contact, or elution contact. Test results of radiochromium($^{51}Cr$) release, cell viability using tetrazolium dye (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl dimethyltetrazolium bromide(MTT) test and lactate dehydrogenase(LD) of damaged L929 cells were analyzed. In the $^{51}Cr$ release of direct contact, all experimental retrograde filling materials except amalgam and glass ionomer cement showed increased cytotoxicity compared to control. In the $^{51}Cr$ release of elution solution, the released $^{51}Cr$ was so minimal that it was impossible. to evlauate the cytotoxicity exactly. The elution solutions of glass ionomer cement and IRM showed marked cytotoxicity in MTT test. LD enzyme activity was highest in tests of direct contact with composite, light curing composite, and light curing glass ionomer cement and IRM. Amalgam revealed least cytotoxicity while IRM showed cytotoxicity using all three methods. Composite, light curing composite and light curing glass iomomer cement were cytotoxic in the tests of $^{51}Cr$ release and LD activity. Glass ionomer cement showed cytotoxic effect only in the MTT method. From these results it is suggested that the standardization and optimization of cytotoxicity testing, especially using elution solutions, should be strongly advised.

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

• Applied Chemistry
• /
• v.15 no.1
• /
• pp.17-20
• /
• 2011

A disposable light exposure detector kit has been developed by UV curing of a hydrogel material. The devised light exposure detector kit consisted of light sensitive structures, bottom plate, character sheet and sticky back plate. A light exposure detector kit has a serial light sensitive structures that contain various light sensitive dyes such as rhodamine and fluorescein. The light sensitive structure composed of UV curable hydrogel polymer material as a supporing material and photosensitive dye in a certain concentration. The fabrication procedure of the ligh exposure detector kit is very simple and fast due to UV curing procedure of a photopolymerizable hydrogel material such as poly(ethylene glycol) methyl ether acrylate (PEGMEA) and poly(ethylene glycol) diacrylate (PEGDA) with a photosensitive dye. By the proposed fabrication method, various size and shape of a light exposure detector kit could be fabricated using a flexible elastomer mold. Due to a fast and inexpensive fabrication method, the light exposure detector kit could be use a single use for various industrial applications. According to light irradation, the light sensitive structure on a light exposure detector kit could be lose its color by decomposition of a photosensitive dye chemical in the structure. Thus the amount of the exposed light on a substrate could easily be recognised by changing color or transparency of the structure.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.05a
• /
• pp.332-333
• /
• 2013

This research utilizes the modified sulfur having the low melting point which 65℃ is tries to study the strength property of the mortar according to the cure method of the modified sulfur mortar. And we try to use as basic data for investigating the curing condition of the light panel optimum utilizing the modified sulfur. We experimented by five kinds; 20℃ water curing method and 20, 40, 60, 80(℃) air dry curing method. In 3 day curing, the compressive strength was improved caused by high curing temperature. But the compressive strength was degraded caused by enhanced temperature in 7day curing and 28day curing. Therefore, the curing temperature of the modified sulfur mortar is determined that it comes 20 time case curing and the water curing is the most recommendable.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.41 no.2
• /
• pp.152-156
• /
• 2014

The purpose of this study is to compare efficiency of broad spectrum LEDs ($VALO^{(R)}$, Ultradent, USA) with conventional LED curing lights ($Elipar^{TM}$ Freelight 2, 3M ESPE, USA) using a microhardness test. The light curing units used were $VALO^{(R)}$ in three different modes and $Elipar^{TM}$ Freelight 2. The exposure time was used according to the manufacturer's instructions. After cured resin specimens were stored in physiological saline at $37^{\circ}C$ for 24 hours, microhardness was measured using Vickers microhardness tester. The microhardness of upper and lower sides of the specimens were analyzed separately by the ANOVA method (Analysis of Variance) with a significance level set at 5%. At upper side of resin specimens, an increased microhardness was observed in the broad spectrum LED curing light unit with a high power mode for 4 seconds and plasma emulation mode for 20 seconds (p < 0.05). However, at the lower side of resin specimens, there were no significant differences in microhardness between broad spectrum LED curing light unit and conventional LED curing light unit.