scholarly journals Degree of conversion and hardness of an orthodontic resin cured with a light-emitting diode and a quartz-tungsten-halogen light

2009 ◽  
Vol 32 (1) ◽  
pp. 83-86 ◽  
Author(s):  
G. P. Cerveira ◽  
T. B. Berthold ◽  
A. A. Souto ◽  
A. M. Spohr ◽  
E. M. Marchioro
Keyword(s):  
Light Emitting Diode ◽  
Degree Of Conversion ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Halogen Light

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 different light sources on degree of conversion, hardness and plasticization of a composite

2013 ◽  
Vol 1 (2) ◽  
pp. 134
Author(s):  
Bruno de Castro Ferreira Barreto ◽  
Anderson Catelan ◽  
Ricardo Coelho Okida ◽  
Gisele Fernanda Gonçalves ◽  
Gisele Rodrigues da Silva ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Light Emitting Diode ◽  
Knoop Hardness ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Light Sources ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Light Curing ◽  
Ft Ir

Clinical performance of composite resins depends largely on their mechanical properties, and those are influenced by several factors, such as the light-curing mode. The purpose of this study was to evaluate the influence of different light sources on degree of conversion (DC), Knoop hardness (KHN) and plasticization (P) of a composite resin. Disc-shaped specimens (5 x 2 mm) of Esthet-X (Dentsply) methacrylate-based microhybrid composite were light-cured using quartz-tungsten-halogen (QTH) Optilight Plus (Gnatus) or light-emitting diode (LED) Ultraled (Dabi Atlante) curing units at 400 and 340 mW/cm2 of irradiance, respectively. After 24 h, absorption spectra of composite were obtained using Nexus 670 (Nicolet) FT-IR spectrometer in order to calculate the DC. The KHN was measured in the HMV-2000 (Shimadzu) microhardness tester under 50 g loads for 15 s, and P was evaluated by percentage reduction of hardness after 24 h of alcohol storage. Data were subjected to t-Student test (alpha = 0.05). QTH device showed lower P and higher KHN than LED (p < 0.05), and no difference between the light-curing units was found for DC (p > 0.05). The halogen-curing unit with higher irradiance promoted higher KHN and lower softening in alcohol than LED.

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)

The Knoop Hardness of a Composite Resin Polymerized with Different Curing Lights and Different Modes

2007 ◽  
Vol 8 (2) ◽  
pp. 52-59 ◽  
Author(s):  
A. Rüya Yazici ◽  
Gerard Kugel ◽  
Gülsün Gül
Keyword(s):  
High Intensity ◽  
Composite Resin ◽  
Light Emitting Diode ◽  
Surface Hardness ◽  
Knoop Hardness ◽  
Light Emitting ◽  
Soft Start ◽  
Quartz Tungsten Halogen ◽  
Halogen Light ◽  
Mode 3

Abstract Aim The purpose of this study was to compare the surface hardness of a hybrid composite resin polymerized with different curing lights. Methods and Materials Two 3.0 mm thick composite resin discs were polymerized in a prepared natural tooth mold using: (1) a conventional quartz-tungsten halogen light (QTH- Spectrum 800); (2) a high-intensity halogen light, Elipar Trilight (TL) - standard/exponential mode; (3) a high-intensity halogen light, Elipar Highlight (HL) - standard/soft-start mode; (4) a light-emitting diode, Elipar Freelight (LED); and (5) a plasma-arc curing light, Virtuoso (PAC). Exposure times were 40 seconds for the halogen and LED lights, and three and five seconds for the PAC light. Following polymerization, the Knoop hardness was measured at the bottom and the top surfaces of the discs. Results Significant differences were found between top and bottom Knoop Hardness number (KHN) values for all lights. The hardness of the top and bottom surfaces of both specimens cured by the PAC light was significantly lower than the other lights. No significant hardness differences were observed between the remaining curing units at the top of the 2.0 mm specimens. Significant differences were found between the LED and two modes of HL on the bottom surfaces. For the 3.0 mm thick samples, while significant differences were noted between LED and TL standard mode and between the two TL curing modes on the top, significant differences were only observed between QTH and the standard modes of TL and HL at the bottom. Citation Yazici AR, Kugel G, Gül G. The Knoop Hardness of a Composite Resin Polymerized with Different Curing Lights and Different Modes. J Contemp Dent Pract 2007 February;(8)2:052-059.

scholarly journals Degree of conversion of adhesive systems light-cured by LED and halogen light

2007 ◽  
Vol 18 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Cesar Augusto Galvão Arrais ◽  
Fenelon Martinho Pontes ◽  
Luis Presley Serejo dos Santos ◽  
Edson Roberto Leite ◽  
Marcelo Giannini
Keyword(s):  
Light Emitting Diode ◽  
Adhesive System ◽  
Degree Of Conversion ◽  
Infrared Analysis ◽  
Adhesive Systems ◽  
Light Emitting ◽  
Halogen Light ◽  
Etch And Rinse ◽  
Before And After ◽  
Light Curing

This study evaluated the effect of blue light emitting diode (LED) and quartz tungsten halogen (QTH) on the degree of conversion (DC) of an etch-and-rinse Single Bond adhesive system (SB) and a mixture composed of primer solution and resin bond from Clearfil SE Bond self-etching adhesive system (CB) using Fourier transform infrared analysis (FTIR). Adhesives were applied to potassium bromide pellet surfaces and FTIR analyses were performed before and after photo-activation for 10 s with either LED (Freelight 1 - 400 mw/cm²) or QTH (XL 3000 - 630 mw/cm²) light-curing units (n=8). Additional FTIR spectra were obtained from photo-activated samples stored in distilled water for 1 week. The DC was calculated by comparing the spectra obtained from adhesive resins before and after photo-activation. The results were analyzed by two-way split-plot ANOVA and Tukey's test (p<0.05). Both adhesive systems exhibited low DC (%) immediately after photo-activation (SB/QTH: 18.7 ± 3.9; SB/LED: 13.5 ± 3.3; CF/QTH: 13.6 ± 1.9; CF/LED: 6.1 ± 1.0). The DC of samples light-cured with LED was lower than DC of those light-cured with QTH, immediately after light curing and after 1 week (SB/QTH: 51.3 ± 6.6; SB/LED: 50.3 ± 4.8; CF/QTH: 56.5 ± 2.9; CF/LED: 49.2 ± 4.9). The LED curing unit used to photo-activate the adhesive resins promoted lower DC than the QTH curing unit both immediately after light curing and 1 week after storage in water.

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>

Sign in / Sign up

Export Citation Format

Share Document