scholarly journals Effect of high-irradiance light curing on exposure times and pulpal temperature of adequately polymerized composite

2020 ◽  
Vol 39 (6) ◽  
pp. 976-983
Author(s):  
William E. SLACK ◽  
Erin M. YANCEY ◽  
Wen LIEN ◽  
Ryan SHERIDAN ◽  
Rodney PHOENIX ◽  
...  
Keyword(s):  
High Irradiance ◽  
Light Curing ◽  
Pulpal Temperature

The Effect of Energy Application Sequence on the Microtensile Bond Strength of Different C-factor Cavity Preparations

10.2341/06-30 ◽  
2007 ◽  
Vol 32 (2) ◽  
pp. 124-132 ◽  
Author(s):  
G. Maghaireh ◽  
M. R. Bouschlicher ◽  
F. Qian ◽  
S. R. Armstrong
Keyword(s):  
Bond Strength ◽  
Clinical Relevance ◽  
High Irradiance ◽  
Resin Composites ◽  
Microtensile Bond Strength ◽  
Light Curing ◽  
Bond Strengths ◽  
Energy Application

Clinical Relevance Light curing of resin composites in high C-factor cavity preparations using a high irradiance energy application sequence may lead to decreased bond strength. However, the high irradiance energy application sequence did not result in lower bond strengths in lower C-factor cavity preparations.

scholarly journals Impact of the light-curing source and curing time on the degree of conversion and hardness of a composite

2013 ◽  
Vol 1 (1) ◽  
pp. 91
Author(s):  
Anderson Catelan ◽  
Caetano Tamires ◽  
Boniek Castillo Dutra Borges ◽  
Giulliana Panfiglio Soares ◽  
Bruno de Castro Ferreira Barreto ◽  
...  
Keyword(s):  
Physical Properties ◽  
Light Emitting Diode ◽  
Knoop Hardness ◽  
High Irradiance ◽  
Degree Of Conversion ◽  
Curing Time ◽  
Light Emitting ◽  
Light Curing ◽  
Ft Ir ◽  
The Impact

Adequate physical properties of the resinous materials are related to clinical longevity of adhesive restorations. The aim of this investigation was to assess the impact of light-curing source and curing time on the degree of conversion (DC) and Knoop hardness number (KHN) of a composite resin. Circular specimens (5 x 2 mm) were carried out (n = 7) of the Filtek Z250 (3M ESPE) composite. The specimens were light-cured by quartz-halogen-tungsten (QTH) XL 3000 (3M ESPE, 450 mW/cm2) or light-emitting diode (LED) Bluephase 16i (Vivadent, 1390 mW/cm2) for 20, 40, or 60 s. After 24 h, absorption spectra of composite were obtained using Spectrum 100 Optica (Perkin Elmer) FT-IR spectrometer in order to calculate the DC and, KHN was performed in the HMV-2T (Shimadzu) microhardness tester under 50-g load for 15 s dwell time. DC and KHN data were subjected to 2-way ANOVA and Tukey’s test at a pre-set alpha of 0.05. The LED showed highest DC and KHN values than QTH (p < 0.05). The increase of curing time improved the DC and KHN, all curing times with statistical difference (p < 0.05). The use of light-curing units with high irradiance and/or the time of cure increased may improve the physical properties of resin-based materials.

Influence of Emission Spectrum and Irradiance on Light Curing of Resin-Based Composites

2017 ◽  
Vol 42 (5) ◽  
pp. 537-547 ◽  
Author(s):  
CAK Shimokawa ◽  
B Sullivan ◽  
ML Turbino ◽  
CJ Soares ◽  
RB Price
Keyword(s):  
Emission Spectrum ◽  
Broad Spectrum ◽  
Light Transmission ◽  
High Irradiance ◽  
Degree Of Conversion ◽  
Single Peak ◽  
Bottom Surface ◽  
Light Conditions ◽  
Violet Light ◽  
Light Curing

SUMMARY Purpose: This study examined the influence of different emission spectra (single-peak and broad-spectrum) light-curing units (LCUs) delivering the same radiant exposures at irradiance values of 1200 or 3600 mW/cm2 on the polymerization and light transmission of four resin-based composites (RBCs). Methods and Materials: Two prototype LCUs that used the same light tip, but were either a single-peak blue or a broad-spectrum LED, were used to deliver the same radiant exposures to the top surfaces of the RBCs using either standard (1200 mW/cm2) or high irradiance (3600 mW/cm2) settings. The emission spectrum and radiant power from the LCUs were measured with a laboratory-grade integrating sphere coupled to a spectrometer, and the light beam was assessed with a beam profiler camera. Four RBCs (Filtek Supreme Ultra A2, Tetric EvoCeram A2, Tetric EvoCeram T, and TPH Spectra High Viscosity A2) were photoactivated using four different light conditions: single-peak blue/standard irradiance, single-peak blue/high irradiance, broad-spectrum/standard irradiance, and broad-spectrum/high irradiance. The degree of conversion (N=5) and microhardness at the top and bottom of 2.3-mm-diameter by 2.5-mm-thick specimens (N=5) were analyzed with analysis of variance and Tukey tests. The real-time light transmission through the RBCs was also measured. Results: For all light conditions, the 2.3-mm-diameter specimens received a homogeneous irradiance and spectral distribution. Although similar radiant exposures were delivered to the top surfaces of the RBCs, the amount of light energy emitted from the bottom surfaces was different among the four RBCs, and was also greater for the single-peak lights. Very little violet light (wavelengths below 420 nm) reached the bottom of the 2.5-mm-thick specimens. The degree of conversion and microhardness results varied according to the RBC (p&lt;0.05). The RBCs that included alternative photoinitiators had greater microhardness values at the top when cured with broad-spectrum lights, while at the bottom, where little violet light was observed, the results were equal or higher when they were photoactivated with single-peak blue lights. With the exception of the microhardness at the top of TPH, equivalent or higher microhardness and degree-of-conversion values were achieved at the bottom surface when the standard (1200 mW/cm2) irradiance levels were used compared to when high irradiance levels were used. Conclusions: Considering the different behaviors of the tested RBCs, the emission spectrum and irradiance level influenced the polymerization of some RBCs. The RBCs that included alternative photoinitiators produced greater values at the top when cured with broad-spectrum lights, while at the bottom, results were equal or higher for the RBCs photoactivated with single-peak blue lights.

scholarly journals Effectiveness of high irradiance for short-time exposures on polymerization of composite under metal brackets

2017 ◽  
Vol 87 (6) ◽  
pp. 834-840 ◽  
Author(s):  
André L. Faria-e-Silva ◽  
David A. Covell ◽  
Jack L. Ferracane ◽  
Carmem S. Pfeifer
Keyword(s):  
Total Energy ◽  
Repeated Measures ◽  
Near Infrared ◽  
High Irradiance ◽  
Small Magnitude ◽  
Orthodontic Bracket ◽  
Mapping Tool ◽  
Infrared Spectrometer ◽  
Light Curing ◽  
Short Time

ABSTRACT Objective: To evaluate the effect of different curing modes available in a dental light-curing unit on degree of conversion (DC) of a composite photoactivated under a metal orthodontic bracket. Materials and Methods: The average irradiance and total energy delivered by three curing modes (standard, high, and extra power) of a multiwave LED unit (Valo Cordless, Ultradent Products, South Jordan, Utah) were measured using the longest time available for each mode (20, 4, and 3 seconds, respectively). Brackets (n = 3/group) were bonded to molar epoxy resin replicas using each curing mode. Mesiodistal sections, 0.5 mm thick, were assessed using an infrared spectrometer microscope. Spectra of composite beneath the brackets were sequentially collected using the mapping tool in near-infrared (NIR)-transmittance mode. Composite conversion was mapped between the mesial and distal edges of the bracket base using 400-μm steps for a total of 10 measurements per specimen. Data from irradiance and total energy were analyzed by one-way ANOVA, while data of DC were analyzed with two-way repeated measures ANOVA (α = 0.05). Results: The highest DC values were observed for standard power (mean 56%, P &lt; .05), while no difference was observed between high (50%) and extra power (49%) modes. Regarding the site of measurement, higher DC was observed close to the bracket edges (52%, P &lt; .05). Conclusions: The use of high irradiance for a short time slightly reduced the DC. The small magnitude of reduction suggests that use of a high irradiance protocol is a clinically valid approach when bonding metal brackets.

scholarly journals Evaluation of Eye Protection Filters Used with Broad-Spectrum and Conventional LED Curing Lights

2017 ◽  
Vol 28 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Carlos José Soares ◽  
Monise de Paula Rodrigues ◽  
Andomar Bruno Fernandes Vilela ◽  
Erick René Cerda Rizo ◽  
Lorraine Braga Ferreira ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Emission Spectra ◽  
High Irradiance ◽  
Patient Simulator ◽  
Mean Values ◽  
Eye Protection ◽  
Tukey Test ◽  
Light Curing ◽  
The Mean

Abstract The high irradiance and the different emission spectra from contemporary light curing units (LCU) may cause ocular damage. This study evaluated the ability of 15 eye protection filters: 2 glasses, 1 paddle design, and 12 dedicated filters to block out harmful light from a monowave (HP-3M ESPE) and a broad-spectrum (Valo, Ultradent) LED LCU. Using the anterior sensor in the MARC-Patient Simulator (BlueLight Analytics) the irradiance that was delivered through different eye protection filters was measured three times. The LCUs delivered a similar irradiance to the top of the filter. The mean values of the light that passed through the filters as percent of the original irradiance were analyzed using two-way ANOVA followed by Tukey test (a= 0.05). The emission spectra from the LCUs and through the filters were also obtained. Two-way ANOVA showed that the interaction between protective filters and LCUs significantly influenced the amount of light transmitted (p< 0.001). Tukey test showed that the amount of light transmitted through the protective filters when using the HP-3M-ESPE was significantly greater compared to when using the Valo, irrespective of the protective filter tested. When using the HP-3M-ESPE, the Glasses filter allowed significantly more light through, followed by XL 3000, ORTUS, Google Professional, Gnatus filters. The Valo filter was the most effective at blocking out the harmful light. Some protective filters were less effective at blocking the lower wavelengths of light (<420 nm). However, even in the worst scenario, the filters were able to block at least 97% of the irradiance.

scholarly journals Effect of High-Irradiance Light-Curing on Micromechanical Properties of Resin Cements

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Anne Peutzfeldt ◽  
Adrian Lussi ◽  
Simon Flury
Keyword(s):  
Exposure Duration ◽  
Resin Composite ◽  
High Irradiance ◽  
Resin Cement ◽  
Indentation Modulus ◽  
Resin Cements ◽  
Radiant Exposure ◽  
Micromechanical Properties ◽  
Light Curing ◽  
Power Mode

This study investigated the influence of light-curing at high irradiances on micromechanical properties of resin cements. Three dual-curing resin cements and a light-curing flowable resin composite were light-cured with an LED curing unit in Standard mode (SM), High Power mode (HPM), or Xtra Power mode (XPM). Maximum irradiances were determined using a MARC PS radiometer, and exposure duration was varied to obtain two or three levels of radiant exposure (SM: 13.2 and 27.2 J/cm2; HPM: 15.0 and 30.4 J/cm2; XPM: 9.5, 19.3, and 29.7 J/cm2) (n=17). Vickers hardness (HV) and indentation modulus (EIT) were measured at 15 min and 1 week. Data were analyzed with nonparametric ANOVA, Wilcoxon-Mann-Whitney tests, and Spearman correlation analyses (α=0.05). Irradiation protocol, resin-based material, and storage time and all interactions influenced HV and EIT significantly (p≤0.0001). Statistically significant correlations between radiant exposure and HV or EIT were found, indicating that high-irradiance light-curing has no detrimental effect on the polymerization of resin-based materials (p≤0.0021). However, one resin cement was sensitive to the combination of irradiance and exposure duration, with high-irradiance light-curing resulting in a 20% drop in micromechanical properties. The results highlight the importance of manufacturers issuing specific recommendations for the light-curing procedure of each resin cement.

Effect of LED Light-Curing Spectral Emission Profile on Light-Cured Resin Cement Degree of Conversion

2020 ◽  
Author(s):  
RQ Ramos ◽  
RR Moraes ◽  
GC Lopes
Keyword(s):  
Clinical Relevance ◽  
Degree Of Conversion ◽  
Resin Cement ◽  
Light Activation ◽  
Spectral Emission ◽  
Led Light ◽  
Emission Profile ◽  
Light Curing

Clinical Relevance The use of multipeak LED light-curing guarantees efficiency on light activation of Ivocerin-containing light-cured resin cement.

Kinetic energy and spatial distribution of ions in high irradiance laser ionization source

2011 ◽  
Vol 26 (6) ◽  
pp. 1183 ◽  
Author(s):  
Yiming Lin ◽  
Ruibin Xu ◽  
Lingfeng Li ◽  
Wei Hang ◽  
Jian He ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Kinetic Energy ◽  
High Irradiance ◽  
Laser Ionization ◽  
Ionization Source

High-Irradiance Degradation Studies of Metamorphic 1eV GaInAs Solar Cells

2012 ◽  
Vol 1432 ◽  
Author(s):  
Ryan M. France ◽  
Myles A. Steiner
Keyword(s):  
Solar Cells ◽  
Active Region ◽  
Dislocation Density ◽  
Dark Current ◽  
Degradation Mechanism ◽  
Control Cell ◽  
High Irradiance ◽  
Threading Dislocation ◽  
Threading Dislocation Density ◽  
Degradation Studies

ABSTRACTInitial tests are performed regarding the degradation of lattice-mismatched GaInAs solar cells. 1eV metamorphic GaInAs solar cells with 1-2×106 cm-2 threading dislocation density in the active region are irradiated with an 808 nm laser for 2 weeks time under a variety of temperature and illumination conditions. All devices show a small degradation in Voc that is logarithmic with time. The absolute loss in performance after 2 weeks illuminated at 1300 suns equivalent and 125°C is 7 mV Voc and 0.2% efficiency, showing these devices to be relatively stable. The dark current increases with time and is analyzed with a two-diode model. A GaAs control cell degrades at the same rate, suggesting that the observed degradation mechanism is not related to the additional dislocations in the GaInAs devices.

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