Thermal analysis of dental resins cured with blue light-emitting diodes (LEDs)

Nomura, Yutaka; Teshima, Wataru; Tanaka, N.; Yoshida, Yugo; Nahara, Yukinori; Okazaki, Mitsuko

doi:10.1002/jbm.10126.abs

Cited by 11 publications

(9 citation statements)

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“…25,31 Dental resins cured with blue LEDs show a larger depth of cure, a higher DC and more stable three-dimensional structures than those cured using halogen lamps. 32 In this experiment the values of conversion of the EndoREZ + Accelerator system were the highest of all materials tested, both with UltraLume LED 5 and Mini LED lamp. In addition, among the materials tested with the same lamp, EndoREZ + Accelerator showed the highest values of enthalpy after the first irradiation time (20 s).…”

Section: Discussionmentioning

confidence: 66%

Comparison of the Degree of Conversion of Resin Based Endodontic Sealers Using the DSC Technique

et al. 2011

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Objectives:The aim of this study was to determine the degree of conversion (DC) of three resin based endodontic sealers using the DSC technique.Methods:The sealers tested were: EndoREZ (ER) (Ultradent, South Jordan, UT); EndoREZ with Accelerator (ER+A) (Ultradent, South Jordan, UT); RealSeal (RS) (SybronEndo, Orange, CA). Two LED units were used to activate the sealers: UltraLume LED 5 (Ultradent, South Jordan, UT, USA); Mini LED Satelec (Satelec Acteon Group, Mérignac Cedex, France). Samples of 4.0 mg were analyzed with a DSC 7 calorimeter (Perkin Elmer Inc., Wellesley, MA, US). Each specimen was irradiated by each lamp four times for 20 seconds at an interval of 2 mins, while the DSC 7 recorded the heat flow developed during the treatment. The degree of conversion and the kinetic curves were calculated from the values of heat developed during each polymerization. The data were statistically analysed with a Kruskal-Wallis one-way ANOVA multiple range and Student-Newman-Keuls (SNK) tests at a P value of .05.Results:Statistically significant differences were found in the degree of conversion among the sealers: ER+A showed the highest values with both lamps.Conclusions:The higher polymerization rate in resin sealers is obtained with the addition of a catalyst.

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Section: Discussionmentioning

confidence: 66%

Comparison of the Degree of Conversion of Resin Based Endodontic Sealers Using the DSC Technique

et al. 2011

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“…In contrast to previous generations of LED lights, which used an array of LEDs with low light intensity (3,7), newer LED devices, such as the LEDemetron and Coltolux LED, usually use a highintensity blue LED containing a larger semi-conductor crystal, which increases both the illuminated area and the light intensity. The higher light intensity of the newer LED devices along with their narrow spectral output makes them similar or even more efficient than conventional QTH light-curing units (16)(17)(18)(19).…”

Section: Discussionmentioning

confidence: 99%

Effect of exposure time on curing efficiency of polymerizing units equipped with light-emitting diodes

et al. 2007

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A study was conducted to evaluate the top and bottom hardness of two composites cured using polymerizing units equipped with light-emitting diodes [LED] (LEDemetron; Elipar FreeLight, Coltolux LED) and one quartz-tungsten halogen device [QTH] (Optilux 501) under different exposure times (20, 40 and 60 sec). A matrix mold 5 mm in diameter and 2 mm in depth was made to obtain five disc-shaped specimens for each experimental group. The specimens were cured by one of the light-curing units (LCUs) for 20, 40 or 60 sec, and the hardness was measured with a Vickers hardness-measuring instrument (50 g/30 sec). Data were subjected to three-way ANOVA and Tukey's test (alpha = 0.05). LED LCUs were as effective as the QTH device for curing both composites. A significant increase in the microhardness values were observed for all light LCUs when the exposure time was changed from 20 sec to 40 sec. The Z250 composite showed hardness values that were usually higher than those of the Charisma composite under similar experimental conditions. LED LCUs are as efficient for curing composites as the QTH device as long as an exposure time of 40 sec or higher is employed. An exposure time of 40 sec is required to provide composites with a uniform and high Knoop hardness when LED light-curing units are employed.

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“…Some related reports showed that the temperature rise from the LED was not as high as that from the plasma arc and QTH curing lights 10,11) . However, it must be highlighted that the irradiance of LEDs then was lower than the current LEDs [12][13][14] . Some reports have already shown that secondgeneration LEDs have the potential to exceed QTH LCUs in terms of effectiveness if the composites are selected carefully [15][16][17] .…”

Section: Introductionmentioning

confidence: 91%

Reducing, by Pulse Width Modulation, the Curing Temperature of a Prototype High-power LED Light Curing Unit

2006

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Third-generation LEDs have high irradiance and efficiency, but the associated temperature rise is potentially hazardous to the pulp of teeth. We evaluated, during composite polymerization, the irradiance and temperature rise of a prototype highpower LED light curing unit（LCU）with optimal pulse width modulation（PWM） , and then compared the results with four off-the-shelf high-power LCUs. A cavity was prepared in a tooth, and a composite resin layer was applied and cured. For each LCU, the irradiance and temperature changes at the pulp-dentin junction were measured. Microhardness（Vickers hardness）of cured composite samples was measured for each LCU. Our prototype had a final temperature of 36.4±1.3℃ and irradiance of 1,182±1 mW/cm 2 . The unit with the highest temperature had a temperature of 48.7±1.2℃ and an irradiance of 1,194±1 mW/cm 2 . Based on the results of the present study, it was shown that PWM technology reduced the curing temperature while retaining the polymerization effectiveness of a high-power LED LCU.

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Thermal analysis of dental resins cured with blue light-emitting diodes (LEDs)

Cited by 11 publications

References 0 publications

Comparison of the Degree of Conversion of Resin Based Endodontic Sealers Using the DSC Technique

Comparison of the Degree of Conversion of Resin Based Endodontic Sealers Using the DSC Technique

Effect of exposure time on curing efficiency of polymerizing units equipped with light-emitting diodes

Reducing, by Pulse Width Modulation, the Curing Temperature of a Prototype High-power LED Light Curing Unit

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