scholarly journals Polymerization quality testing of composite resins cured by led light source

2003 ◽  
Vol 50 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Larisa Blazic ◽  
Slavoljub Zivkovic ◽  
Dejan Pantelic ◽  
Vladimir Pipic
Keyword(s):  
Light Source ◽  
Light Exposure ◽  
Light Emitting Diode ◽  
Composite Resins ◽  
Curing Time ◽  
Light Emitting ◽  
Led Light ◽  
Depth Of Cure ◽  
Dental Tissues ◽  
Hard Dental Tissues

The quality of interface between composite resin materials and hard dental tissues is highly dependent on the polymerization light source. Newly developed blue light- emitting diode units for light polymerization of dental restorative materials are the most innovative light source technology in dentistry nowadays. The aim of this work was to estimate the depth of cure of five different light-activating composite resins exposed to different irradiation times (5s, 10s, 20s and 40s) when the experimental LED light source was used. The tested materials were: Tetric Ceram (Vivadent), Point 4 (Kerr), Admira (VOCO), Filtek Z250 (3M) and Diamond Lite (DRM Lab., Inc). The depth of cure testing was determined using a penetrometer. Results after 40s curing time were as following: the deepest depth of cure was achieved after application of Filtek Z 250, Diamond Lite Point 4 and Tetric Ceram. For the restorative material Admira was found the lowest depth of cure for the light exposure of 40s. An experimental LED light source achieved a sufficient depth of cure (over 2 mm) for all tested materials after curing time of 10s. The polymerization light source spectral distribution should be considered in addition to irradiance as a depth of cure indicator.

Effect of Distance from Curing Light Tip to Restoration Surface on Depth of Cure of Composite Resin

2008 ◽  
Vol os15 (4) ◽  
pp. 147-152 ◽  
Author(s):  
Stephen M Dunne ◽  
Brian J Millar
Keyword(s):  
Light Exposure ◽  
Light Emitting Diode ◽  
Light Output ◽  
Separation Distance ◽  
Composite Resins ◽  
Human Tooth ◽  
Light Emitting ◽  
Depth Of Cure ◽  
Halogen Light ◽  
Light Curing

Aims While light-activating composite resins, the light tip may not always be close to the surface of the restoration. This may be intentional in an attempt to create a ramp cure. The aim of this study was to determine the effect of a range of separation distances between the light tip and the restoration surface on the depth of composite cure for different types of light-curing units with a broad range of outputs. Methods Three halogen light units, one plasma arc-curing (PAC) light unit and two light-emitting diode (LED) curing lights in clinical use were tested, and a total of 570 restorations cured in a two-part human tooth model at separations ranging from 0 to 15 mm. The tooth was disassembled and depth of cure determined using the scrape test ISO 4049. Light intensity was also measured at each separation distance for each light. Results The depth of cure was generally found to decrease as the separation distance increased for all lights at the various cure times. However, the effect of increasing the separation distance was less than anticipated. The depth of cure was also related to the light output. Conclusions Depth of composite cure was directly related to intensity and duration of light exposure and inversely related to distance of the light source from the surface for halogen and plasma lights. However, the effect of increasing the separation distance up to 15 mm was less than expected. Altering the separation distance in order to modify the polymerisation characteristics is unlikely to be effective.

1.331μm Narrow-Bandwidth Light Source Based on Polymer Micro-Blazed Grating

2008 ◽  
Author(s):  
Hairong Wang ◽  
Xianni Gao ◽  
Guoliang Sun ◽  
Yulong Zhao ◽  
Zhuangde Jiang
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Diffraction Order ◽  
Blazed Grating ◽  
Light Emitting ◽  
Led Light ◽  
Narrow Bandwidth ◽  
Narrow Width ◽  
The Cost

In order to detect methane (CH4) accurately and reliably, this paper presents a sensor which consists of infrared diode, fixtures, blazed grating, to realize the extremely narrow-bandwidth light at wavelength of 1.331μm. Based on factors such as compatibility with the transmission characteristics of silica fiber and the cost, a LED (light-emitting diode) with center wavelength of 1.3μm is selected. The LED light is modulated as the parallel light beam. As the light is incident in a micro-blazed grating with certain angle, by diffraction and interference, the light will output the maximum light intensity of its diffraction order at 1.331 μm, which just is an absorption peak of CH4. Micro-blazed grating applied here is low cost and easy replication by various ways, which makes extreme narrow width wavelength possible. Simulation and analysis indicate the designed prototype can output 1.331μm with bandwidth from 1.32907μm to 1.332495μm. With the light source basing on light dividing system, more reliable and higher sensitive measurement of the dangerous gases such as methane and carbon monoxide (CO) can be realized.

Effectiveness of Second-generation Light-emitting Diode (LED) Light Curing Units

2007 ◽  
Vol 8 (2) ◽  
pp. 35-42 ◽  
Author(s):  
Fabrício Aulo Ogliari ◽  
Ulisses Bastos Campregher ◽  
Susana Maria Werner Samuel ◽  
Carmen Beatriz Borges Fortes ◽  
Alberth David Correa Medina ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Second Generation ◽  
Light Emitting Diode ◽  
Strength Properties ◽  
Knoop Hardness ◽  
Curing Time ◽  
Light Emitting ◽  
Led Light ◽  
Three Samples ◽  
Light Curing

Abstract Aim The purpose of this study was to evaluate the effectiveness of three commercially available light emitting diode (LED) light curing units (LCU) (Elipar FreeLight - 3M ESPE; UltraLume LED2 - Ultradent; and Single V - BioArt) for polymerizing Z250-A3 composite (3M ESPE) using Knoop hardness, polymerization depth, and flexural strength properties. Methods and Materials The XL 2500 (3M ESPE) LCU, which is a conventional halogen unit, was used as a control. In all cases the curing time was 20 seconds. Hardness was determined 24 hours after composite cure for 10 samples of 8 mm diameter and 2 mm height for each LCU tested. Samples were stored dry in a lightproof container prior to testing. The depth of cure of the composite was measured immediately after composite polymerization for each LCU using three samples 4 mm in diameter and 6 mm in height. Flexural strength was determined for five samples 24 hours after immersion in distilled water at 37°C. Each sample measured 25 mm in length, 2 mm in width, and 2 mm in height for each LCU tested. Conclusion The results were treated statistically for comparison of the LCUs. In all cases the results obtained by LED LCUs were not different or were higher than a conventional halogen LCU. Clinical Significance Second generation LED LCUs were as effective as/or more effective than a halogen LCU for polymerization of the used composite. The present study shows second generation LEDs have the potential to replace halogen LCUs. Citation Campregher UB, Samuel SMW, Fortes CBB, Medina ADC, Collares FMC, Ogliari FA. Effectiveness of Second-generation Light-emitting Diode (LED) Light Curing Units. J Contemp Dent Pract 2007 February;(8)2:035-042.

scholarly journals The effects of halogen and light-emitting diode light curing on the depth of cure and surface microhardness of composite resins

2011 ◽  
Vol 14 (2) ◽  
pp. 136 ◽  
Author(s):  
BatuCan Yaman ◽  
Can Dörter ◽  
Dina Erdilek ◽  
BegümGüray Efes ◽  
Yavuz Gömeç ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Composite Resins ◽  
Surface Microhardness ◽  
Light Emitting ◽  
Depth Of Cure ◽  
Light Curing

Composite Resin Microhardness: The Influence of Light Curing Method, Composite Shade, and Depth of Cure

2008 ◽  
Vol 9 (4) ◽  
pp. 43-50 ◽  
Author(s):  
Cesar Henrique Zanchi ◽  
Flávio Fernando Demarco ◽  
Camila Silveira de Araújo ◽  
Marcelo Thomé Schein ◽  
Sinval Adalberto Rodrigues
Keyword(s):  
Composite Resin ◽  
Light Emitting Diode ◽  
Curing Time ◽  
Light Emitting ◽  
Depth Of Cure ◽  
Quartz Tungsten Halogen ◽  
Light Curing ◽  
Curing Method ◽  
Hardness Values ◽  
Knoop Indenter

Abstract Aim The aim of this study was to investigate the influence of light curing method, composite shade, and depth of cure on composite microhardness. Methods and Materials Forty-eight specimens with 4 mm of depth were prepared with a hybrid composite (Filtek Z-100, 3M ESPE); 24 with shade A1 and the remaining with shade C2. For each shade, two light curing units (LCUs) were used: a quartz-tungsten-halogen (QTH) LCU (Optilight Plus - Gnatus) and a light emitting diode (LED) LCU (LEC 470 II - MM Optics). The LED LCU was tested using two exposure times (LED 40 seconds and LED 60 seconds). After 24-hour storage, three indentations were made at mm depth intervals using a Knoop indenter. Data were submitted to three-way analysis of variance (ANOVA) and Tukey's test (p<0.05). Results The three factors tested (light curing method, shade, and depth) had a significant influence on the composite microhardness (p<0.05). All groups presented similar hardness values in the first mm, except for composite shade C2 cured with LED for 40 seconds. The hardness decreased with depth, especially for shade C2 for 40 seconds. Increasing light-curing time with LED produced hardness values similar to the QTH. Conclusions The light curing method including variations of time, the depth of cure, and the composite shade influence the composite microhardness. Clinical Significance Clinicians should avoid thicker increments when working with composite restorations. Extended light-curing time might be indicated depending on the composite shade and on the light-curing device. Citation de Araújo CS, Schein MT, Zanchi CH, Rodrigues SA Jr, Demarco FF. Composite Resin Microhardness: The Influence of Light Curing Method, Composite Shade, and Depth of Cure. J Contemp Dent Pract 2008 May; (9)4:043-050.

Effects of light source spectrum and background colour on the perception of paintings

2019 ◽  
Vol 52 (1) ◽  
pp. 36-63
Author(s):  
L Bellia ◽  
F Fragliasso ◽  
E Stefanizzi
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Source Spectrum ◽  
Light Emitting ◽  
Colour Temperature ◽  
Test Room ◽  
Led Light ◽  
Lighting Conditions ◽  
Set Up ◽  
Effect Of Light

This paper presents an experiment on the effect of light on the perception of paintings. The experiment was performed in a test-room where a typical museum exhibition set-up was simulated. Two different paintings were shown to 44 participants, under different light scenes obtained by using tuneable LED (Light Emitting Diode) wallwashers. To set the light scenes, the following parameters were modified: correlated colour temperature of the lighting, illuminance on the painting and the colour of the background wall. Participants answered a questionnaire to assess the perception of the paintings’ colours, the lighting conditions and the pleasantness of the exhibition set-up. The results demonstrated that illuminance is the parameter mainly affecting perception, for both paintings. However, correlated colour temperature and wall colour, as well as the combination of the three different considered parameters, can more or less influence perception depending on the chromatic composition of the painting.

scholarly journals Effect of High Irradiance on Depth of Cure of a Conventional and a Bulk Fill Resin-based Composite

2015 ◽  
Vol 40 (6) ◽  
pp. 662-672 ◽  
Author(s):  
MQ AlQahtani ◽  
PL Michaud ◽  
B Sullivan ◽  
D Labrie ◽  
MM AlShaafi ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Light Exposure ◽  
Light Emitting Diode ◽  
Knoop Hardness ◽  
High Irradiance ◽  
Led Light ◽  
Depth Of Cure ◽  
Radiant Exposure ◽  
Anova Model ◽  
Qth Light

SUMMARY Objectives This study evaluated the effect of using three commercial light curing units (LCUs) delivering a range of irradiance values, but delivering similar radiant exposures on the depth of cure of two different resin-based composites (RBCs). Methods A conventional hybrid RBC (Z100 shade A2, 3M ESPE) or a bulk fill RBC (Tetric EvoCeram Bulk Fill shade IVA, Ivoclar Vivadent) was packed into a 10-mm deep semicircular metal mold with a 2-mm internal radius. The RBC was exposed to light from a plasma-arc-curing (PAC) light (Sapphire Plus, DenMat) for five seconds, a quartz-tungsten-halogen (QTH) light (Optilux 501, Kerr) for 40 seconds, or a light-emitting-diode (LED) light (S10, 3M ESPE) for 20 seconds and 40 seconds (control). The Knoop microhardness was then measured as soon as possible at the top surface and at three points every 0.5 mm down from the surface. For each RBC, a repeated measures analysis of variance (ANOVA) model was used to predict the Knoop hardness in a manner analogous to a standard regression model. This predicted value was used to determine at what depth the RBC reached 80% of the mean hardness achieved at the top surface with any light. Results The PAC light delivered an irradiance and radiant exposure of 7328 mW/cm2 and 36.6 J/cm2, respectively, to the RBCs; the QTH light delivered 936 mW/cm2 and 37.4 J/cm2 and in 20 seconds the LED light delivered 1825 mW/cm2 and 36.5 J/cm2. In 40 seconds, the control LED light delivered a radiant exposure of 73.0 J/cm2. For Z100, using 80% of the maximum hardness at the top surface as the criteria for adequate curing, all light exposure conditions achieved the 2.0-mm depth of cure claimed by the manufacturer. The LED light used for 40 seconds achieved the greatest depth of cure (5.0 mm), and the PAC light used for five seconds, the least (2.5 mm). Tetric EvoCeram Bulk Fill achieved a 3.5-mm depth of cure when the broad-spectrum QTH light was used for 40 seconds delivering 37.4 J/cm2. It required a 40-second exposure time with the narrow-spectrum LED, delivering approximately 73 J/cm2 to reach a depth of cure of 4 mm. Conclusions When delivering a similar radiant exposure of 37 J/cm2, the QTH (40 seconds) and LED (20 seconds) units achieved a greater depth of cure than the PAC (five seconds) light. For both resins, the greatest depth of cure was achieved when the LED light was used for 40 seconds delivering 73 J/cm2 (p&lt;0.05).

scholarly journals Influence of Prolonged Light-curing Time on the Shear Bonding Strength of Resin to Bleached Enamel

2010 ◽  
Vol 35 (6) ◽  
pp. 672-681 ◽  
Author(s):  
M. Hussain ◽  
Y. Wang
Keyword(s):  
Exposure Time ◽  
Bonding Strength ◽  
Clinical Relevance ◽  
Light Exposure ◽  
Light Emitting Diode ◽  
Resin Composite ◽  
Curing Time ◽  
Light Emitting ◽  
Light Curing ◽  
Shear Bonding Strength

Clinical Relevance The bonding strength of resin composite to bleached enamel can be enhanced by increasing the light exposure time of light-emitting diode units if bonding is delayed for 24 hours.

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