The Effect of Light Curing Source on the Residual Yellowing of Resin Composites

2007 ◽  
Vol 32 (5) ◽  
pp. 443-450 ◽  
Author(s):  
M. G. Brackett ◽  
W. W. Brackett ◽  
W. D. Browning ◽  
F. A. Rueggeberg
Keyword(s):  
Blue Light ◽  
Clinical Relevance ◽  
Light Emitting Diode ◽  
Color Difference ◽  
Resin Composites ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Light Curing ◽  
Selection Of ◽  
Effect Of Light

Clinical Relevance The selection of light curing unit (quartz-tungsten-halogen or blue light-emitting diode), composite classification and shade have an influence on the amount of residual yellow after photocuring and, in some combinations, the color difference may be visually detectable.

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 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 The Effect of Irradiation Distance on Microhardness of Resin Composites Cured with Different Light Curing Units

2010 ◽  
Vol 04 (04) ◽  
pp. 440-446 ◽  
Author(s):  
Isil Cekic-Nagas ◽  
Ferhan Egilmez ◽  
Gulfem Ergun
Keyword(s):  
Light Emitting Diode ◽  
Resin Composite ◽  
Composite Layer ◽  
Hardness Test ◽  
Resin Composites ◽  
Plasma Arc ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Halogen Light ◽  
Light Curing

Objectives: The aim of this study was to compare the microhardness of five different resin composites at different irradiation distances (2 mm and 9 mm) by using three light curing units (quartz tungsten halogen, light emitting diodes and plasma arc).Methods: A total of 210 disc-shaped samples (2 mm height and 6 mm diameter) were prepared from different resin composites (Simile, Aelite Aesthetic Enamel, Clearfil AP-X, Grandio caps and Filtek Z250). Photoactivation was performed by using quartz tungsten halogen, light emitting diode and plasma arc curing units at two irradiation distances (2 mm and 9 mm). Then the samples (n=7/ per group) were stored dry in dark at 37°C for 24 h. The Vickers hardness test was performed on the resin composite layer with a microhardness tester (Shimadzu HMV). Data were statistically analyzed using nonparametric Kruskal Wallis and Mann-Whitney U tests.Results: Statistical analysis revealed that the resin composite groups, the type of the light curing units and the irradiation distances have significant effects on the microhardness values (P<.05).Conclusions: Light curing unit and irradiation distance are important factors to be considered for obtaining adequate microhardness of different resin composite groups. (Eur J Dent 2010;4:440-446)

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 Sorption, solubility and residual monomers of a dental adhesive cured by different light-curing units

2010 ◽  
Vol 21 (5) ◽  
pp. 432-438 ◽  
Author(s):  
Francine do Couto Lima Moreira ◽  
Nelson Roberto Antoniosi Filho ◽  
João Batista de Souza ◽  
Lawrence Gonzaga Lopes
Keyword(s):  
Light Source ◽  
High Performance ◽  
Light Emitting Diode ◽  
Single Bond ◽  
Light Emitting ◽  
Dental Adhesive ◽  
Quartz Tungsten Halogen ◽  
Light Curing ◽  
Storage Times ◽  
Curing Regimes

The aim of this study was to assess polymerization ability of three light-curing units by evaluating the influence of the light source, curing regimen and permeant (water or ethanol) on sorption, solubility and amount of residual monomers of a dental adhesive. Specimens of Adper Single Bond 2 were fabricated using a stainless steel circular matrix (8 mm x 1 mm). One quartz-tungsten-halogen (QTH) lamp and two light-emitting diode (LED) device at three different curing regimes (L1 = 12 J; L2 = 24 J; L3 = 24 J) were used to cure the specimens. Specimens were stored in two types of permeants - deionized water or 75% ethanol - for two storage times (G1 =7 days; G2 = 30 days). The specimens underwent water sorption and solubility tests, according to ISO 4049:2000 standard. After storage, residual monomers were identified and quantified by high performance liquid chromatography (HPLC). For sorption, L1 showed the highest values and QTH, the lowest. For solubility, in ethanol-stored groups, L1 had also the highest values, and QTH, the lowest, and findings were significantly different from the other curing regimens. L1 leached significantly more monomers than the others, and QTH had the lowest results. In conclusion, the type of light source, the curing regimen and the permeant affected sorption, solubility and amount of residual monomers of the adhesive under study.

scholarly journals Effect of the increase of energy density on knoop hardness of dental composites light-cured by conventional QTH, LED and xenon plasma arc

2005 ◽  
Vol 16 (3) ◽  
pp. 218-224 ◽  
Author(s):  
Américo Bortolazzo Correr ◽  
Mário Alexandre Coelho Sinhoreti ◽  
Lourenço Correr Sobrinho ◽  
Rubens Nisie Tango ◽  
Luis Felipe Jochims Schneider ◽  
...  
Keyword(s):  
Energy Density ◽  
Light Emitting Diode ◽  
Knoop Hardness ◽  
Composite Resins ◽  
Plasma Arc ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Light Curing ◽  
Cylindrical Cavities ◽  
Hardness Values

The aim of this study was to evaluate the effect of the increase of energy density on Knoop hardness of Z250 and Esthet-X composite resins. Cylindrical cavities (3 mm in diameter X 3 mm in depth) were prepared on the buccal surface of 144 bovine incisors. The composite resins were bulk-inserted and polymerized using different light-curing units and times: conventional QTH (quartz-tungsten-halogen; 700 mW/cm²; 20 s, 30 s and 40 s); LED (light-emitting diode; 440 mW/cm²; 20 s, 30 s and 40 s); PAC (xenon plasma arc; 1700 mW/cm²; 3 s, 4.5 s and 6 s). The specimens were stored at 37°C for 24 h prior to sectioning for Knoop hardness assessment. Three measurements were obtained for each depth: top surface, 1 mm and 2 mm. Data were analyzed statistically by ANOVA and Tukey's test (p<0.05). Regardless of the light source or energy density, Knoop hardness of Z250 was statistically significant higher than that of Esthet-X (p<0.05). Specimens cured with PAC had lower hardness than those cured with QTH and LED (p<0.05). Higher Knoop hardness was obtained when the energy density was increased for LED and PAC (p<0.05). No statistically significant differences (p>0.05) were found for QTH. Knoop hardness values decreased with the increase of depth. The increase of energy density produced composites with higher Knoop hardness means using LED and PAC.

Comparative Effectiveness of Two Light Curing Units on the Properties of Dental Resin Composites

2020 ◽  
Keyword(s):  
Light Emitting Diodes ◽  
Polymerization Reaction ◽  
Resin Composites ◽  
Micro Hardness ◽  
Dental Resin ◽  
Light Emitting ◽  
Dental Resin Composites ◽  
Light Intensities ◽  
Quartz Tungsten Halogen ◽  
Light Curing

Background: Setting of conventional glass ionomers cement and dental resin composites as filling materials is predominantly through polymerization reaction, which is usually induced by light. The objective of this study was to assess the temperature changes, light intensities, sorption and solubility capability and comparative micro hardness in Dental Resin Composites (DRC) by using two different light curing units that is Quartz Tungsten Halogen (QTH) and Light Emitting Diodes (LED). Methods: This analytical, experimental, in-vitro study was spanned over one month, conducted in the laboratory of Dental Materials, Dr. Ishrat-ul-Ibad Khan Institute of Oral Health Sciences. Through non-probability, convenient sampling, 60 samples of DRCs was prepared as 10mm in diameter and 2mm in thickness in the steel moulds by a single trained operator. Effect of heat generation, light intensities, sorption and solubility and micro hardness during polymerization of DRCs were all measured. Statistical analysis was done using SPSS with descriptive statistics and two sample independent t-tests. The p-value of <0.05 was considered significant at 95 % confidence level. Results: Mean surface micro hardness of DRC was found to be 15.48±0.46 and 18.26±0.53 when QTH and LED lamps were employed respectively. Whereas, mean light intensity of QTH and LED lamps were found to be 434 and 925mW/cm2. No significant difference in temperature change during polymerization reaction (p=0.128) and in sorption and solubility capability (p=0.001) of DRC was observed. Conclusion: Light-emitting diodes were evaluated to be more effective than Quartz Tungsten Halogen Light in achieving increased surface micro hardness of DRC. Keywords: Light; Glass Ionomer Cements; Tungsten; Hardness.

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