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Polymerization of a dual-cured cement through ceramic: LED curing light vs halogen lamp
Lopes, Lawrence Gonzaga;Franco, Eduardo Batista;Name Neto, Abr?o;Herrera, Francyle S.;Kurachi, Cristina;Casta?eda-Espinosa, Juan C.;Lauris, José Roberto Pereira;
Journal of Applied Oral Science , 2004, DOI: 10.1590/S1678-77572004000400011
Abstract: the aim of this study was to investigate the influence of light source, led unit and halogen lamp (hl), on the effectiveness of enforce dual-cured cement cured under a ceramic disc. three exposure times (60, 80 and 120 s) were also evaluated. two experimental groups, in which the polymerization of the dual-cured cement was performed through a ceramic disc, and two control groups, in which the polymerization of the dual-cured cement was performed directly without presence of ceramic disc were subdivided into three subgroups (three different exposure times), with five specimens each: g1a- hl 60s; g1b- hl 80s; g1c- hl 120s; g2a- led 60s; g2b- led 80s; g2c- led 120s; and control groups: g3a- hl 60s; g3b- hl 80s; g3c- hl 120s; g4a- led 60s; g4b- led 80s and g4c- led 120s. cement was applied in a steel matrix (4mm diameter, 1.2mm thickness). in the experimental groups, a ceramic disc was placed on top. the cement was light-cured through the ceramic by a hl and led, however, the control groups were cured without the ceramic disc. the specimens were stored in a light-proof container at 37oc for 24 hours, then vickers hardness was determined. a four-way anova and tukey test (p£ 0.05) were performed. all specimens cured by led for 60s showed inferior values compared with the halogen groups. in general, light-curing by led for 80s and 120s was comparable to halogen groups (60s and 80s) and their control groups. led technology can be viable for light-curing through conventional ceramic indirect restorations, when curing time is increased in relation to hl curing time.
Analysis of the microtensile bond strength to enamel of two adhesive systems polymerized by halogen light or LED
Carvalho, Ana Paula Morales Cobra;Turbino, Míriam Lacalle;
Brazilian Oral Research , 2005, DOI: 10.1590/S1806-83242005000400013
Abstract: with the development of composite resin polymerization techniques, leds were introduced to the market place. based on the studied literature, the aim of this study was to evaluate, through microtensile testing, the bond strength to enamel of a composite resin associated to a conventional (multi-bottle) adhesive system or to a self etching primer adhesive system, polymerized by halogen light or led (light emitting diode). bovine teeth were divided into 4 groups with 10 teeth each (n = 10). then the adhesives scotchbond multipurpose plus (3m-espe) and clearfil se bond (kuraray) were applied following the manufacturers? instructions. both systems were polymerized for 10 s by halogen light (degulux soft start - degussa hulls) set at 550 mw/cm2 or by led (kerr demetron) set at 600 mw/cm2. the composite resin filtek z-250 was applied in four 1 mm increments with the aid of a square, condensation silicon, 5 mm x 5 mm matrix, and polymerized by either of light sources for 40 s. scotchbond multipurpose plus polymerized by halogen light presented the highest bond strength values (39.69 ± 7.07 mpa), and the other groups did not present statistically significant differences: scotchbond multipurpose plus polymerized by led (22.28 ± 2.63 mpa), clearfil se bond polymerized by halogen light (27.82 ± 2.65 mpa) and by led (22.89 ± 5.09 mpa).
Abrasion resistance of composites polymerized by light-emitting diodes (LED) and halogen light-curing units
Martinelli, Janisse;Pires-de-Souza, Fernanda de Carvalho Panzeri;Casemiro, Luciana Assirati;Tirapelli, Camila;Panzer, Heitor;
Brazilian Dental Journal , 2006, DOI: 10.1590/S0103-64402006000100007
Abstract: this study compared the abrasion resistance of direct composite resins cured by light-emitting diodes (led) and halogen light-curing units. twenty specimens (12 mm in diameter; 1.0 mm thick) of each composite resin [tph (dentsply); definite (degussa); charisma (heraus kulzer)] were prepared using a polytetrafluoroethylene matrix. ten specimens per material were cured with the led source and 10 with the halogen lamp for 40 s. the resin discs were polished, submitted to initial surface roughness reading (ra initial - mm) in a roughness tester and stored in water at 37°c for 15 days. the specimens were weighed (m1) and submitted to simulated toothbrushing using slurry of water and dentifrice with high abrasiveness. after 100 minutes in the toothbrushing simulator, the specimens were cleaned, submitted to a new surface roughness reading (ra final - mm) and reweighed (m2). mass loss was determined as the difference between m1 and m2. data were recorded and analyzed statistically by one-way anova and tukey test at 5% significance level. the composite resin with greater size of inorganic fillers (tph) showed the lowest mass loss and surface roughness means, indicating a higher resistance to toothbrush abrasion (p<0.05). definite cured with led presented the least resistance to toothbrush abrasion, showing the highest means of surface roughness and mass loss (p<0.05). the led source did not show the same effectiveness as the halogen lamp for polymerizing this specific composite resin. when the composite resins were cured a halogen lcu, no statistically significant difference was observed among the materials (p>0.05). it may be concluded that the type of light-curing unit and the resin composition seemed to interfere with the materials' resistance to abrasion.
Evaluation of wear rate of dental composites polymerized by halogen or LED light curing units
Alaghehmand H.,Safarcherati H.,Ghasemzadeh Azar F.
Journal of Dental Medicine , 2006,
Abstract: Background and Aim: Sufficient polymerization is a critical factor to obtain optimum physical properties and clinical efficacy of resin restorations. The aim of this study was to evaluate wear rates of composite resins polymerized by two different systems Light Emitting Diodes (LED) to and Halogen lamps. Materials and Methods: In this laboratory study, 20 specimens of A3 Tetric Ceram composite were placed in brass molds of 2*10*10 mm dimensions and cured for 40 seconds with 1 mm distance from surface. 10 specimens were cured with LED and the other 10 were cured with Halogen unit. A device with the ability to apply force was developed in order to test the wear of composites. After storage in distilled water for 10 days, the specimens were placed in the wear testing machine. A chrome cobalt stylus with 1.12 mm diameter was applied against the specimens surfaces with a load of 2 kg. The weight of each samples before and after 5000, 10000, 20000, 40000, 80000 and 120000 cycles was measured using an electronic balance with precision of 10-4 grams. Data were analyzed using t test and paired t test. P0.05). Conclusion: Based on the results of this study, LED and halogen light curing units resulted in a similar wear rate in composite resin restorations.
Halogen light versus LED for bracket bonding: shear bond strength  [cached]
Paulo Eduardo Guedes Carvalho,Valdemir Muzulon dos Santos,Hassan Isber,Flávio Augusto Cotrim-Ferreira
Dental Press Journal of Orthodontics , 2013,
Abstract: INTRODUCTION: LED light-curing devices seek to provide a cold light activator which allows protocols of material polymerization with shorter duration. OBJECTIVE: The present study aimed to evaluate the shear bond strength of bracket bonding using three types of light-curing devices: One with halogen light (Optilight Plus - Gnatus) and two with LEDs (Optilight CL - Gnatus and Elipar Freelight - 3M/ESPE). RESULTS: Comparing the results by analysis of variance, the Gnatus LED device showed an inferior statistical behavior in relation to other light sources, when activated by a short time. But, when it was used for 40 seconds, the polymerization results were consistent with the other evaluated sources. The device with the best average performance was the halogen light, followed by the 3M/ESPE LED. CONCLUSION: It was concluded that the LEDs may be indicated in orthodontic practice, as long as a protocol is used for the application of light with the activation time of 40 seconds. INTRODU O: os aparelhos de fotopolimeriza o por LED buscam proporcionar uma luz ativadora fria, que possibilite protocolos de polimeriza o do material com menor tempo de dura o. OBJETIVO: avaliar a resistência à tra o da colagem de braquetes, utilizando três tipos de aparelhos fotoativadores: um de luz halógena (Optilight Plus - Gnatus) e outros dois de LED (Optilight CL - Gnatus; e Elipar Freelight - 3M/Espe). RESULTADOS: comparando os resultados por meio da análise de variancia, o aparelho de LED Gnatus apresentou comportamento estatístico inferior em rela o às outras fontes de luz, quando ativado por tempo reduzido. Já quando foi utilizado o tempo de 40 segundos, os resultados de polimeriza o foram compatíveis com as demais fontes avaliadas. O aparelho que apresentou melhor desempenho médio foi o de luz halógena, seguido pelo LED 3M/Espe. CONCLUS O: concluiu-se que os LEDs podem ser indicados na prática ortod ntica, uma vez que seja utilizado um protocolo de aplica o da luz com tempo de ativa o de 40 segundos.
A Comparison of the Shear Bond Strength of Orthodontic Brackets Bonded With Light-Emitting Diode and Halogen Light-Curing Units  [PDF]
SM. Abtahi,Z. Khamverdy
Journal of Dentistry of Tehran University of Medical Sciences , 2006,
Abstract: Statement of the problem: Various methods such as light emitting diode (LED) have been used to enhance the polymerization of resin-based orthodontic adhesives. There is a lack of information on the advantages and disadvantages of different light curing systems.Purpose: The aim of this study was to compare the effect of LED and halogen light curing systems on the shear bond strength of orthodontic brackets.Materials and Methods: Forty extracted human premolars were etched with 37% phosphoric acid and cleansed with water spray and air dried. The sealant was applied on the tooth surface and the brackets were bonded using Transbond adhesive (3M Unitek,Monrovia, Calif). Adhesives were cured for 40 and 20 seconds with halogen (Blue Light, APOZA, Taiwan) and LED (Blue dent, Smart, Yugoslavia) light-curing systems,respectively. Specimens were thermocycled 2500 times (from 5 to 55 °C) and the shear bond strength of the adhesive system was evaluated with an Universal testing machine (Zwick GmbH, Ulm, Germany) at a crosshead speed of 1 mm/min until the bracketswere detached from the tooth. Adhesive remnant index (ARI) scores were determined after bracket failure. The data were submitted to statistical analysis, using Mann-Whitney analysis and t-test.Results: No significant difference was found in bond strength between the LED and halogen groups (P=0.12). A significant difference was not observed in the adhesive remnant index scores between the two groups (P=0.97).Conclusion: Within the limitations of this in vitro study, the shear bond strength of resin-based orthodontic adhesives cured with a LED was statistically equivalent to those cured with a conventional halogen-based unit. LED light-curing units can be suggested for the polymerization of orthodontic bonding adhesives.
Monomer conversion of composite dental resins photoactivated by a halogen lamp and a LED: a FT-Raman spectroscopy study
Soares, Luís Eduardo Silva;Rocha, Rick;Martin, Airton Abrah?o;Pinheiro, Antonio L. B.;Zampieri, Marcelo;
Química Nova , 2005, DOI: 10.1590/S0100-40422005000200012
Abstract: eighteen circular blocks of resins cured either by a led or a halogen lamp (20, 40 and 60 s), had their top (t) and bottom (b) surfaces studied using a ft-raman spectrometer. systematic changes in the intensity of the methacrylate c=c stretching mode at 1638 cm-1 as a function of exposure duration were observed. the calculated degree of conversion (dc) ranged from 45.0% (b) to 52.0% (t) and from 49.0% (b) to 55.0% (t) for the led and halogen lamp, respectively. led and halogen light produced similar dc values with 40 and 60 s of irradiation.
Polymerization quality testing of composite resins cured by led light source  [PDF]
Bla?i? Larisa,?ivkovi? Slavoljub,Panteli? Dejan V.,Pipi? Vladimir
Stomatolo?ki Glasnik Srbije , 2003, DOI: 10.2298/sgs0301007b
Abstract: 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.
Sorption, solubility and residual monomers of a dental adhesive cured by different light-curing units
Moreira, Francine do Couto Lima;Antoniosi Filho, Nelson Roberto;Souza, Jo?o Batista de;Lopes, Lawrence Gonzaga;
Brazilian Dental Journal , 2010, DOI: 10.1590/S0103-64402010000500010
Abstract: 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.
Compressive strength of esthetic restorative materials polymerized with quartz-tungsten-halogen light and blue LED
Silva, Cecy Martins;Dias, Katia Regina Hostilio Cervantes;
Brazilian Dental Journal , 2009, DOI: 10.1590/S0103-64402009000100009
Abstract: this study compared the compressive strength of a composite resin and compomer photoactivated with a conventional quartz-tungsten halogen-light (xl 3000, 3m/spe) and a blue light-emitting diode (led) (smartlite ps; dentsply/de trey). forty disc-shaped specimens were prepared using a split polytetrafluoroethylene matrix (4.0 mm diameter x 8.0 mm hight) in which the materials were inserted incrementally. the curing time of each increment was of 40 s with the qth and 10 s with the led. the specimens were randomly assigned to 4 groups (n=10), according to the light source and the restorative material. after storage in distilled water at 37oc ± 2oc for 24 h, the specimens was tested in compressive strength in a universal testing machine with load cell of 500 kgf running at a crosshead speed of 0.5 mm/min. data (in mpa) were analyzed statistically by anova and student-newman-keuls test (p<0.05). for the composite resin, light curing with the qth source did not produce statistically significant difference (p>0.05) in the compressive strength when compared to light curing with the led source. however, light curing of the compomer with the qth source resulted in significantly higher compressive strength than the use of the led unit (p>0.05). the composite resin presented significantly higher (p>0.05) compressive strength than the compomer, regardless of the light source. in conclusion, the compressive strength of the tested materials photoactivated with a qth and a led light source was influenced by the energy density employed and the chemical composition of the esthetic restorative materials.
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