scholarly journals Effect of ceramic thicknesses and opacities on water sorption and solubility of a light-curing resin cement by different units

2021 ◽  
Vol 20 ◽  
pp. e211656
Author(s):  
Gabriela Alves de Cerqueira ◽  
Lais Sampaio Souza ◽  
Rafael Soares Gomes ◽  
Giselle Maria Marchi ◽  
Paula Mathias
Keyword(s):  
Water Sorption ◽  
Light Emitting Diode ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
The Other ◽  
Experimental Conditions ◽  
Light Emitting ◽  
Light Curing

Aim: This study evaluated the water sorption and solubility of a light-cured resin cement, under four thicknesses and four opacities of a lithium disilicate ceramic, also considering three light-emitting diode (LED) units. Methods: A total of 288 specimens of a resin cement (AllCem Veneer Trans – FGM) were prepared, 96 samples were light-cured by each of the three light curing units (Valo – Ultradent / Radii-Cal – SDI / Bluephase II – Ivoclar Vivadent), divided into 16 experimental conditions, according to the opacities of the ceramic: High Opacity (HO), Medium Opacity (MO), Low Translucency (LT), High Translucency (HT), and thicknesses (0.3, 0.8, 1.5, and 2.0 mm) (n = 6). The specimens were weighed at three different times: Mass M1 (after making the specimens), M2 (after 7 days of storage in water), and M3 (after dissection cycle), for calculating water sorption and solubility. Results: The higher thickness of the ceramic (2.0 mm) significantly increased the values of water sorption (44.0± 4.0) and solubility (7.8±0.6), compared to lower thicknesses. Also, the ceramic of higher opacity (HO) generated the highest values of sorption and solubility when compared to the other opacities, regardless of the thickness tested (ANOVA-3 factors / Tukey’s test, α = 0.05). There was no influence of light curing units. Conclusion: Higher thicknesses and opacities of the ceramic increased the water sorption and solubility of the tested light-cured resin cement.

scholarly journals Effect of light-curing units, post-cured time and shade of resin cement on knoop hardness

2009 ◽  
Vol 20 (5) ◽  
pp. 410-413 ◽  
Author(s):  
Rogério Vieira Reges ◽  
Ana Rosa Costa ◽  
Américo Bortolazzo Correr ◽  
Evandro Piva ◽  
Regina Maria Puppin-Rontani ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Knoop Hardness ◽  
Resin Cement ◽  
Light Emitting ◽  
Ceramic Disc ◽  
Quartz Tungsten Halogen ◽  
Cure Time ◽  
Light Curing ◽  
Effect Of Light ◽  
Made In

The aim of this study was to evaluate the Knoop hardness after 15 min and 24 h of different shades of a dual-cured resin-based cement after indirect photoactivation (ceramic restoration) with 2 light-curing units (LCUs). The resin cement Variolink II (Ivoclar Vivadent) shade XL, A2, A3 and opaque were mixed with the catalyst paste and inserted into a black Teflon mold (5 mm diameter x 1 mm high). A transparent strip was placed over the mold and a ceramic disc (Duceram Plus, shade A3) was positioned over the resin cement. Light-activation was performed through the ceramic for 40 s using quartz-tungsten-halogen (QTH) (XL 2500; 3M ESPE) or light-emitting diode (LED) (Ultrablue Is, DMC) LCUs with power density of 615 and 610 mW/cm2, respectively. The Koop hardness was measured using a microhardness tester HMV 2 (Shimadzu) after 15 min or 24 h. Four indentations were made in each specimen. Data were subjected to ANOVA and Tukey's test (a=0.05). The QTH LCU provided significantly higher (p<0.05) KHN values than the LED LCU. When the post-cure times were compared for the same shade, QTH and LED at 24 h provided significantly higher (p<0.05) KHN values than at 15 min. It may be concluded that the Knoop hardness was generally dependent on the LCU and post-cure time. The opaque shade of the resin cement showed lower Knoop hardness than the other shades for both LCUs and post-cure times.

scholarly journals Effect of light-curing methods on resin cement knoop hardness at different depths

2007 ◽  
Vol 18 (4) ◽  
pp. 305-308 ◽  
Author(s):  
Mário Alexandre Coelho Sinhoreti ◽  
Izabella Paola Manetta ◽  
Rubens Nisie Tango ◽  
Nelson Tetsu Iriyama ◽  
Rafael Leonardo Xediek Consani ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Light Emitting Diode ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Resin Cement ◽  
Control Group ◽  
Light Emitting ◽  
Halogen Light ◽  
Curing Methods ◽  
Light Curing

This study evaluated, using Knoop hardness test, the polymerization depth of Rely-X dual-cured resin cement activated by chemical reaction alone (control group) or by chemical/physical mode with light curing through a 1.5-mm-thick ceramic layer (HeraCeram). Bovine incisors had their buccal surface flattened and hybridized. On this surface, a rubber mould (5 mm diameter; 1 mm high) was bulk filled with cement. Either a polyester strip or a 1.5-mm-thick disc of the veneering material was seated over this set. Light curing was performed with either conventional halogen light (QTH; XL2500) for 40 s, light-emitting diode (LED; Ultrablue Is) for 40 s or xenon plasma arc (PAC; Apollo 95E) for 3 s. In a control group, cement setting occurred by chemical reaction alone. After storage dry in dark (24 h/37ºC), the specimens (n=5) were sectioned for hardness (KHN) measurements at three depths in a microhardness tester (50 gf load/15 s). Data were submitted to ANOVA and Tukey's test (a = 0.05). Rely-X cement presented higher Knoop hardness values when the QTH and LED LCUs were used, compared to the control group and PAC. Light curing with PAC resulted in lower hardness compared to the control group. Cement hardness was significantly lower in deeper regions.

Sorption and Solubility of Composites Cured with Quartz-tungsten Halogen and Light Emitting Diode Light-curing Units

2008 ◽  
Vol 9 (2) ◽  
pp. 73-80 ◽  
Author(s):  
Luci Regina P. Archegas ◽  
Danilo B. M. Caldas ◽  
Rodrigo N. Rached ◽  
Sergio Vieira ◽  
Evelise M. Souza
Keyword(s):  
Water Sorption ◽  
Hybrid Composites ◽  
Light Emitting Diode ◽  
Composite Resins ◽  
Light Sources ◽  
Constant Mass ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Light Curing ◽  
Storage Times

Abstract Aim The objective of this study was to evaluate the effect of light polymerization on water sorption and solubility of hybrid composites. Methods and Materials Three composite resins were used to make discs cured with either quartz-tungsten halogen (QTH) or light emitting diode (LED) curing units. The specimens were stored in a desiccator at 37°C and weighted to a constant mass, then immersed in deionized water for different periods of time, and reconditioned until achieving a constant mass. Sorption and solubility were calculated and subjected to analysis of variance (ANOVA) and Tukey tests (p<0.01). Results There were no statistically significant differences between the light sources. Water sorption increased with storage time for all the composites. The lowest sorption was observed for Herculite XRV™, followed by Tetric Ceram™, and Filtek Z250™. Increased storage times reduced the solubility of Filtek Z250™ but did not affect the solubility of Herculite XRV™ and Tetric Ceram™. Conclusion Water sorption and solubility of composites are not affected by the type of polymerization when the same intensity and exposure times are used. Thus, the differences found are probably related to the composition of the materials. Clinical Significance Water sorption and solubility of composites can lead to a shortened service life. However, these properties are not correlated to the type of polymerization. Citation Archegas LRP, Caldas DBM, Rached RN, Vieira S, Souza EM. Sorption and Solubility of Composites Cured with Quartz-tungsten Halogen and Light Emitting Diode Light-curing Units. J Contemp Dent Pract 2008 February;(9)2:073-080.

scholarly journals Influence of photoinitiators and light sources on the degree of conversion of experimental resin cements.

2015 ◽  
Vol 18 (2) ◽  
pp. 65 ◽  
Author(s):  
Dario Raimundo Segreto ◽  
Fabiana Scarparo Naufel ◽  
William Cunha Brandt ◽  
Ricardo Danil Guiraldo ◽  
Lourenço Correr-Sobrinho ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Degree Of Conversion ◽  
The Other ◽  
Light Sources ◽  
Spectroscopy Data ◽  
Resin Cements ◽  
Light Emitting ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Quartz Tungsten Halogen ◽  
Light Curing

<p><strong>Objective: </strong>The aim of this study was to evaluate the degree of conversion (DC) of seven experimental resin cements formulated with different photoinitiators when activated by two light-curing units (LCUs) through ceramic material. <strong>Material and Methods: </strong>Seven resin blends with different camphorquinone (CQ) and/or phenyl propanedione (PPD) rates were prepared: C5: 0.5% wt CQ; C8: 0.8% wt CQ; P5: 0.5% wt PPD; P8: 0.8% wt PPD; C1P4: 0.1% wt CQ and 0.4% wt PPD; C4P1: 0.4% wt CQ and 0.1% wt PPD; and C4P4: 0.4% wt CQ and 0.4% wt PPD. Each mixture was loaded with 65% wt of silanized filler particles. For photoactivation procedures, two LCUs were used: a quartz-tungsten-halogen (QTH) and a light emitting diode (LED). <strong>Results: </strong>Irradiance (mW/cm²) was calculated by the ratio of the output power by the area of the tip. DC was assessed by Fourier transformed infrared spectroscopy. Data were submitted to a two-way ANOVA and Tukey’s test (5%). DC values do not show significant differences for LCUs regardless of the photoinitiator type. The highest DC was found for experimental cement P8 and the lowest for C5. <strong>Conclusion:</strong> Intermediate DC values were found for the other cements. However, when QTH was used, P8 exhibited differences among C1P4, C4P1 and C5; whereas when LED was employed, P8 differed only for C4P1 and C5. Thus, PPD is a viable alternative for the manufacture of photoactivated cements, and the PPD/CQ association may also be viable since C4P4 was similar to P8.</p>

Optimization and evaluation of a blue light photoinitiating system for textile inkjet printing

2018 ◽  
Vol 89 (10) ◽  
pp. 1964-1974
Author(s):  
Yi Huang ◽  
Guangdong Sun ◽  
Yating Ji ◽  
Dapeng Li ◽  
Qinguo Fan ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emitting Diode ◽  
Absorption Efficiency ◽  
Polymerization Rate ◽  
Nozzle Clogging ◽  
Light Emitting ◽  
Custom Made ◽  
Light Curing ◽  
Set Up ◽  
Pigment Ink

A blue light curing process was developed to solve the nozzle clogging challenge commonly encountered in conventional textile pigment printing, by using camphorquinone (CQ) and ethyl-4-dimethylaminobenzoate (EDMAB) as a photoinitiator combination and substituting oligomers and monomers for a polymeric binder. High light absorption efficiency was insured by closely matching the spectrum of the photoinitiator with a custom-made blue light light-emitting diode set-up. Kinetic analyses of such a CQ/EDMAB system indicated that the maximum polymerization rate of the monomer was proportional to [PI]0.5 and [I0]0.5, while excessive high photoinitiator concentration (>1 wt%) will decrease the polymerization rate because of the “filter effect.” With optimized blue light curable pigment ink formula and irradiation conditions, the photocurable pigment printed fabrics exhibited uniform and vibrant colors, clear outlines, and excellent wet and dry rubbing fastness of grades 4 and 4–5, respectively.

scholarly journals Microleakage under Orthodontic Brackets Using High-Intensity Curing Lights

2009 ◽  
Vol 79 (1) ◽  
pp. 144-149 ◽  
Author(s):  
Mustafa Ulker ◽  
Tancan Uysal ◽  
Sabri Ilhan Ramoglu ◽  
Huseyin Ertas
Keyword(s):  
High Intensity ◽  
Light Emitting Diode ◽  
Bonferroni Correction ◽  
Light Emitting ◽  
Halogen Light ◽  
Halogen Light Source ◽  
Light Curing ◽  
Curing Light ◽  
High Intensity Light ◽  
Nail Varnish

Abstract Objective: To compare the microleakage of the enamel-adhesive-bracket complex at the occlusal and gingival margins of brackets bonded with high-intensity light curing lights and conventional halogen lights. Materials and Methods: Forty-five freshly extracted human maxillary premolar teeth were randomly separated into three groups of 15 teeth each. Stainless steel brackets were bonded in all groups according to the manufacturer's recommendations. Specimens (15 per group) were cured for 40 seconds with a conventional halogen light, 20 seconds with light-emitting diode (LED), and 6 seconds with plasma arc curing light (PAC). After curing, the specimens were further sealed with nail varnish, stained with 0.5% basic-fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage for the enamel-adhesive and bracket-adhesive interfaces from both the occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U-tests with a Bonferroni correction. Results: The type of light curing unit did not significantly affect the amount of microleakage at the gingival or occlusal margins of investigated interfaces (P &gt;.05). The gingival sides in the LED and PAC groups exhibited higher microleakage scores compared with those observed on occlusal sides for the enamel-adhesive and adhesive-bracket interfaces. The halogen light source showed similar microleakage at the gingival and occlusal sides between both adhesive interfaces. Conclusions: High-intensity curing units did not cause more microleakage than conventional halogen lights. This supports the use of all these curing units in routine orthodontic practice.

scholarly journals Determination of 3,4,5-Trihydroxybenzoic Acid Exploiting a Visible-Light-Driven Photoelectrochemical Platform: Application in Wine and Tea Samples

2022 ◽  
Author(s):  
Kayni Lima ◽  
Ridvan Fernandes ◽  
Clenilton dos Santos ◽  
Flavio Damos ◽  
Rita de Cássia Luz
Keyword(s):  
Light Emitting Diode ◽  
Glass Slide ◽  
Experimental Conditions ◽  
Amperometric Determination ◽  
Light Emitting ◽  
Promising Tool ◽  
Visible Light Driven ◽  
Photoelectrochemical Method ◽  
Acid Determination

The present work is based on the development and application of a photoelectrochemical method for the amperometric determination of 3,4,5-trihydroxybenzoic acid in different samples. The method is based on the use of a photoelectrochemical platform based on a glass slide coated with fluorine-doped tin oxide, which has been modified with cadmium sulfide and poly(D-glucosamine) and subjected to a light-emitting diode (LED) lamp. The photoelectrochemical platform was sensitive to the increase of the concentration of the antioxidant 3,4,5-trihydroxybenzoic acid in the solution. Under the optimized experimental conditions, the photoelectrochemical method presented a linear response for a 3,4,5-trihydroxybenzoic acid concentration ranging from 0.2 up to 500 μmol L-1. The method was applied to 3,4,5-trihydroxybenzoic acid determination in samples of wines and teas with recoveries between 95.88 and 101.72%. The results obtained suggest that the developed platform is a promising tool for quantifying the 3,4,5-trihydroxybenzoic acid.

scholarly journals Surface Hardness of Nanohybrid and Microhybrid Resin Composites Cured by Light Emitting Diode and Quartz Tungsten Halogen Light Curing Systems: An Invitro Study

2020 ◽  
Author(s):  
Anuradha Vitthal Wankhade ◽  
Sharad Basavraj Kamat ◽  
Santosh Irappa Hugar ◽  
Girish Shankar Nanjannawar ◽  
Sumit Balasaheb Vhate
Keyword(s):  
Light Emitting Diode ◽  
Surface Hardness ◽  
Composite Resins ◽  
Resin Composites ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Halogen Light ◽  
Intergroup Comparison ◽  
Light Curing ◽  
Curing Systems

Introduction: New generation composite resin materials have revolutionized the art of aesthetic dentistry. The clinical success is dependent on effective polymerisation and surface hardness which in turn are dependent on the performance of Light Curing Units (LCU). This study utilises surface hardness as a measure of degree of polymerisation of composite resins achieved by LCUs. Aim: To evaluate the difference in surface hardness of nanohybrid and microhybrid resin composites cured by light curing systems, Light Emitting Diode (LED) and Quartz Tungsten Halogen (QTH). Materials and Methods: In this invitro experimental study, two types of hybrid composites (Nanohybrid and Microhybrid) were tested for surface hardness by using two different light curing systems (LED and QTH). All the Nanohybrid and Microhybrid specimens were cured using LED and QTH LCUs, thus giving four combinations. A total of 60 specimens (6 mm diameter and 2 mm depth) were prepared using Teflon mould with 15 samples for each combination. Surface hardness was measured on upper and lower surface after 24 hours and hardness ratio was calculated. Data was analysed using independent t-test for intergroup comparison. Level of significance was kept at 5%. Results: Surface hardness of resin composites cured by LED LCU was greater than those cured by QTH LCU. Additionally, the hardness value was greater for the upper surface. Nanohybrids showed better surface hardness than Microhybrids for both the LCUs. Conclusion: Nanohybrid composite resins and LED system were found to be more effective in terms of surface hardness as compared to their counterparts.

scholarly journals The Influence of Distance on Radiant Exposure and Degree of Conversion Using Different Light-Emitting-Diode Curing Units

2019 ◽  
Vol 44 (3) ◽  
pp. E133-E144 ◽  
Author(s):  
AO Al-Zain ◽  
GJ Eckert ◽  
JA Platt
Keyword(s):  
Strong Correlation ◽  
Light Emitting Diode ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Degree Of Conversion ◽  
Light Emitting ◽  
Radiant Exposure ◽  
Light Curing ◽  
Irradiance Data ◽  
Resin Curing

SUMMARY Objectives: To investigate the influence of curing distance on the degree of conversion (DC) of a resin-based composite (RBC) when similar radiant exposure was achieved using six different light-curing units (LCUs) and to explore the correlation among irradiance, radiant exposure, and DC. Methods and Materials: A managing accurate resin curing-resin calibrator system was used to collect irradiance data for both top and bottom specimen surfaces with a curing distance of 2 mm and 8 mm while targeting a consistent top surface radiant exposure. Square nanohybrid-dual-photoinitiator RBC specimens (5 × 5 × 2 mm) were cured at each distance (n=6/LCU/distance). Irradiance and DC (micro-Raman spectroscopy) were determined for the top and bottom surfaces. The effect of distance and LCU on irradiance, radiant exposure, and DC as well as their linear associations were analyzed using analysis of variance and Pearson correlation coefficients, respectively (α=0.05). Results: While maintaining a similar radiant exposure, each LCU exhibited distinctive patterns in decreased irradiance and increased curing time. No significant differences in DC values (63.21%-70.28%) were observed between the 2- and 8-mm distances, except for a multiple-emission peak LCU. Significant differences in DC were detected among the LCUs. As expected, irradiance and radiant exposure were significantly lower on the bottom surfaces. However, a strong correlation between irradiance and radiant exposure did not necessarily result in a strong correlation with DC. Conclusions: The RBC exhibited DC values &gt;63% when the top surface radiant exposure was maintained, although the same values were not reached for all lights. A moderate-strong correlation existed among irradiance, radiant exposure, and DC.

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