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.

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 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 Monomer Release from Resin Based Dental Materials Cured With LED and Halogen Lights

2010 ◽  
Vol 04 (01) ◽  
pp. 034-040 ◽  
Author(s):  
Asli Topaloglu Ak ◽  
A. Riza Alpoz ◽  
Oguz Bayraktar ◽  
Fahinur Ertugrul
Keyword(s):  
High Performance ◽  
Light Emitting Diode ◽  
Dental Materials ◽  
Composite Resins ◽  
Time Intervals ◽  
Significance Level ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Bonferroni Test ◽  
One Way Anova

ABSTRACTObjectives: To measure the release of TEGDMA and BisGMA from two commercially available composite resins; Filtek Z 250 (3M ESPE, Germany), Leaddent (Leaddent, Germany) and two fissure sealants; Helioseal F (3M ESPE, Germany) Enamel Loc (Premiere Rev, USA) over 1, 3 and 7 days after polymerization with standard quartz-tungsten halogen Coltolux II (QHL) (Coltene Switzerland) and a standard blue light emitting diode Elipar Freelight 2 (3M ESPE, Germany).Methods: 9 samples of each material were placed in disc shaped specimens in 1 mm of thickness and 10 mm in diameter (n=36). Each material was polymerized using LED for 20 s (n=12), 40 s (n=12) and halogen for 40 s (n=12), respectively. High Performance Liquid Chromatography (HPLC) was used to measure the amount of monomers released over 1, 3 and 7 days. Data was analyzed using one way ANOVA and Bonferroni test for multiple comparisons with a significance level of .05.Results: LED 20 sec group showed the highest release of monomers at 1, 3 and 7 days in sealant groups. Halogen 40 sec group resulted highest release of monomers for Leaddent at all time intervals (P<.05)Conclusions: Efficiency of the curing unit and applying the recommended curing time of the light activated resin based dental materials is very important to protect the patient from potential hazards of residual monomers. (Eur J Dent 2010;4:34-40)

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.

scholarly journals Evaluation of Different Light-Curing Units—Light-Emitting Diodes and Quartz–Tungsten–Halogen-Based Light-Curing Units in Polymerization of Posterior Composite: An In Vitro Study

2018 ◽  
Vol 6 (02/03) ◽  
pp. 060-064
Author(s):  
R. Bansal ◽  
M. Bansal ◽  
S. Walia ◽  
C. Gupta ◽  
L. Bansal ◽  
...  
Keyword(s):  
Composite Resin ◽  
Light Emitting Diode ◽  
In Vitro Study ◽  
Hardness Test ◽  
Acrylic Resin ◽  
Halogen Lamp ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Light Curing

Abstract Objective To assess the adequacy of various light-curing units to polymerize the posterior composite resin. Materials and Methods Specimens were prepared by placing a single increment of posterior composite resin in split cylindrical metallic mold of dimension (6.0 mm in diameter and 5 mm in depth). Polymerization was done by utilizing one quartz-tungsten-halogen and three light-emitting diode light-curing units of different powers. The specimens of composite resin were then mounted on metallic molds utilizing autopolymerizing acrylic resin. After polishing, the complete setting of composite resin material was analyzed using Vickers hardness test. Results Showed in each group, hardness reduced as we moved from upper to lower surface of composite resin. Furthermore, hardness increased as intensity of light was increased. The maximum hardness was detected when light-emitting diode light-curing unit having intensity of 1,250 mW/cm2 was utilized and least hardness was detected when halogen lamp having intensity 418 mW/cm2 was utilized and results were found to be highly significant (p < 0.01). Conclusion It was concluded that increased top and bottom hardness can be accomplished by utilizing the light-curing unit of high intensity.

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 Influence of Photoinitiator and Light-Curing Source on Bond Strength of Experimental Resin Cements to Dentin

2016 ◽  
Vol 27 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Dario Raimundo Segreto ◽  
Fabiana Scarparo Naufel ◽  
William Cunha Brandt ◽  
Ricardo Danil Guiraldo ◽  
Lourenço Correr-Sobrinho ◽  
...  
Keyword(s):  
Bond Strength ◽  
Ceramic Material ◽  
Light Emitting Diode ◽  
Viable Alternative ◽  
Microtensile Bond Strength ◽  
Resin Cements ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Light Curing

Abstract This study evaluated the bond strength (BS) of experimental resin cements formulated with different photoinitiators when activated by two kinds of light-curing units (LCUs) through a ceramic material. Seven resin blends with different camphorquinone (CQ) and/or phenylpropanedione (PPD) concentrations (weight) were prepared: C5: 0.5% CQ; C8: 0.8% CQ; P5: 0.5% PPD; P8: 0.8% PPD; C1P4: 0.1% CQ and 0.4% PPD; C4P1: 0.4% CQ and 0.1% PPD; C4P4: 0.4% CQ and 0.4% PPD. Two LCUs were used: one quartz-tungsten-halogen (QTH - 850 mW/cm²) and one light-emitting diode (LED - 1300 mW/cm²). The microtensile bond strength of each blend was assessed. Data were submitted to two-way ANOVA and Tukey's test (α=0.05). The BS values did not exhibit significant differences for LCUs, regardless of the photoinitiator type. Three cements showed significant differences: P5 and C5 had higher BS with QTH, and C4P1 with LED. For QTH, P5 showed the highest and C1P4 the lowest BS. For the LED, C4P1 showed the highest BS of all the cements. The results indicated that PPD was a viable alternative in the formulation of photocured resin cements, reducing or eliminating CQ that is yellowish without impairing the bond strength. Furthermore, both LED and QTH were effective in curing resin cements that contain PPD or CQ.

scholarly journals Temperature Increase at the Light Guide Tip of 15 Contemporary LED Units and Thermal Variation at the Pulpal Floor of Cavities: An Infrared Thermographic Analysis

2013 ◽  
Vol 38 (3) ◽  
pp. 324-333 ◽  
Author(s):  
M Gomes ◽  
A DeVito-Moraes ◽  
C Francci ◽  
R Moraes ◽  
T Pereira ◽  
...  
Keyword(s):  
Temperature Increase ◽  
Light Guide ◽  
Light Emitting Diode ◽  
Thermal Variation ◽  
Linear Temperature ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Light Curing ◽  
Thermographic Analysis ◽  
Dental Cavities

SUMMARY In this study, a comprehensive investigation on the temperature increase at the light guide tip of several commercial light-emitting diode (LED) light-curing units (LCUs) and the associated thermal variation (ΔT) at the pulpal floor of dental cavities was carried out. In total, 15 LEDs from all generations were investigated, testing a quartz-tungsten-halogen (QTH) unit as a reference. The irradiance level was measured with a power meter, and spectral distribution was analyzed using a spectrometer. Temperature increase at the tip was measured with a type-K thermocouple connected to a thermometer, while ΔT at the pulpal floor was measured by an infrared photodetector in class V cavities, with a 1-mm-thick dentin pulpal floor. The relationship among measured irradiance, ΔT at the tip, and ΔT at the pulpal floor was investigated using regression analyses. Large discrepancies between the expected and measured irradiances were detected for some LCUs. Most of the LCUs showed an emission spectrum narrower than the QTH unit, with emission peaks usually between 450 and 470 nm. The temperature increase at the tip followed a logarithmic growth for LCUs with irradiance ≥1000 mW/cm2, with ΔT at the tip following the measured irradiance linearly (R2=0.67). Linear temperature increase at the pulpal floor over the 40-second exposure time was observed for several LCUs, with linear association between ΔT at the pulpal floor and measured irradiance (R2=0.39) or ΔT at the tip (R2=0.28). In conclusion, contemporary LED units show varied irradiance levels that affect the temperature increase at the light guide tip and, as a consequence, the thermal variation at the pulpal floor of dental cavities.

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