Effect of Light-Curing Exposure Time, Shade, and Thickness on the Depth of Cure of Bulk Fill Composites

2017 ◽  
Vol 42 (5) ◽  
pp. 505-513 ◽  
Author(s):  
A Rodriguez ◽  
P Yaman ◽  
J Dennison ◽  
D Garcia
Keyword(s):  
Statistical Analysis ◽  
Exposure Time ◽  
Light Exposure ◽  
Testing Machine ◽  
Knoop Hardness ◽  
Bonferroni Correction ◽  
Depth Of Cure ◽  
Light Curing ◽  
Hardness Values ◽  
Effect Of Light

SUMMARY Purpose: To investigate the effect of different light exposure times, shades, and thicknesses on the depth of cure (DOC) of bulk fill composites. Methods and Materials: Two bulk fill composites, Tetric EvoCeram Bulk Fill (TBF) and Sonic Fill (SF), and a conventional composite, Filtek Supreme Ultra (FSU), were evaluated. Samples (n=10) were made using two different shades (light and dark), thicknesses (2 and 4 mm) and exposure times (20 and 40 seconds). A Tukon 2100B-testing machine was used to obtain three Knoop hardness numbers (KHNs) measured at the top and bottom of each sample, and DOC was calculated as the bottom/top ratio. Statistical analysis was done using a Student t-test for comparisons between groups with a Bonferroni correction of p < 0.004. Results: Top hardness values ranged from 79.79 to 85.07 for FSU, 69.49 to 91.65 for SF, and 51.01 to 57.82 for TBF. Bottom KHNs ranged from 23.54 to 73.25 for FSU, 45.74 to 77.12 for SF, and 36.95 to 52.51 for TBF. TBF had the lowest overall KHNs. Light-curing exposure time, shade, and material thickness influenced the DOC in most groups, especially at 4-mm depths. A higher bottom/top ratio was achieved when a 40-second cure was compared to a 20-second cure, when light shades were compared to dark shades, and when 2-mm increments were compared to 4-mm increments.

scholarly journals Evaluation of depth of cure and Knoop hardness in a dental composite photo-activated using different methods

2004 ◽  
Vol 15 (3) ◽  
pp. 199-203 ◽  
Author(s):  
Andresa Carla Obici ◽  
Mário Alexandre Coelho Sinhoreti ◽  
Lourenço Correr Sobrinho ◽  
Mario Fernando de Goes ◽  
Simonides Consani
Keyword(s):  
Composite Resin ◽  
Continuous Light ◽  
Acrylic Resin ◽  
Knoop Hardness ◽  
Dental Composite ◽  
Intermittent Light ◽  
Light Emitting ◽  
Depth Of Cure ◽  
The Matrix ◽  
Hardness Values

The aim of this study was to evaluate the depth of cure and Knoop hardness in the P60 composite resin photo-activated using different methods. A bipartite brass matrix (3 mm in diameter X 11 mm in height) was filled with the composite and photo-activation was performed using continuous light, exponential light, intermittent light, plasma arc curing (PAC) or light-emitting diodes (LED). After opening the matrix, the uncured material was removed with a steel spatula and the polymerized composite was measured using a pachymeter. The specimens were then included in self-curing acrylic resin and worn longitudinally and the hardness was measured on the surface and at depths of 1, 2, 3, 4 and 5 mm. The data were analyzed by ANOVA and Tukey's test (5%). The results showed that the depth of cure was higher with the intermittent light, followed by continuous light, exponential light, PAC and LED methods. Up to a depth of 2 mm, all methods revealed similar hardness values, but there were differences between them at other depths, at which LED demonstrated the lowest values followed by PAC.

Effect of Light-Curing Method and Cement Activation Mode on Resin Cement Knoop Hardness

2007 ◽  
Vol 16 (6) ◽  
pp. 480-484 ◽  
Author(s):  
Rubens Nisie Tango ◽  
Mário Alexandre Coelho Sinhoreti ◽  
Américo Bortolazzo Correr ◽  
Lourenço Correr-Sobrinho ◽  
Guilherme Elias Peçanha Henriques
Keyword(s):  
Knoop Hardness ◽  
Resin Cement ◽  
Light Curing ◽  
Curing Method ◽  
Effect Of Light

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.

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.

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.

Photoinitiator dependent composite depth of cure and Knoop hardness with halogen and LED light curing units

Biomaterials ◽  
2003 ◽  
Vol 24 (10) ◽  
pp. 1787-1795 ◽  
Author(s):  
Alexander Uhl ◽  
Robin W. Mills ◽  
Klaus D. Jandt
Keyword(s):  
Knoop Hardness ◽  
Led Light ◽  
Depth Of Cure ◽  
Light Curing

scholarly journals Effect of light-curing method and indirect veneering materials on the Knoop hardness of a resin cement

2009 ◽  
Vol 23 (2) ◽  
pp. 108-112 ◽  
Author(s):  
Nelson Tetsu Iriyama ◽  
Rubens Nisie Tango ◽  
Izabella Paola Manetta ◽  
Mário Alexandre Coelho Sinhoreti ◽  
Lourenço Correr Sobrinho ◽  
...  
Keyword(s):  
Knoop Hardness ◽  
Resin Cement ◽  
Light Curing ◽  
Curing Method ◽  
Effect Of Light

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.

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.

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