scholarly journals Effects of thermocycling and light source on the bond strength of metallic brackets to bovine teeth

2011 ◽  
Vol 22 (6) ◽  
pp. 486-489 ◽  
Author(s):  
Ana Rosa Costa ◽  
Américo Bortolazzo Correr ◽  
Regina Maria Puppin-Rontani ◽  
Silvia Amélia Scudeler Vedovello ◽  
Heloísa Cristina Valdrighi ◽  
...  
Keyword(s):  
Bond Strength ◽  
Light Source ◽  
Tooth Enamel ◽  
Argon Laser ◽  
Light Sources ◽  
Distilled Water ◽  
Experimental Conditions ◽  
Halogen Light ◽  
Acid Gel ◽  
Bovine Enamel

This study evaluated the effects of thermocycling and different light sources on the bond strength of metallic brackets to bovine tooth enamel using an adhesive resin. Bovine teeth were etched with 35% phosphoric acid gel for 20 s. After application of primer, metallic brackets were bonded to the buccal surface using Transbond XT, forming 8 groups (n=20), depending on the light source used for photoactivation (AccuCure 3000 argon laser - 20 s, Apollo 95E plasma arc - 12 s, UltraLume 5 LED - 40 s and XL2500 halogen light - 40 s) and experimental conditions without (Groups 1 to 4) or with thermocycling (Groups 5 to 8). Shear bond testing was carried out after 24 h of distilled water storage (Groups 1 to 4) or storage and thermocycling in distilled water (groups 5 to 8; 1,500 cycles - 5o/55oC). Data were subjected to two-way ANOVA and Tukey’s test (α=0.05). The Adhesive Remnant Index (ARI) was evaluated at ×8 magnification. No significant differences (p>0.05) in bond strength were found when the conditions without and with thermocycling were compared for any of the light sources. No significant differences (p>0.05) in bond strength were found among the light sources, irrespective of performing or not thermocycling. There was a predominance of ARI scores 1 in all groups. In conclusion, light sources and thermocycling had no influence on the bond strength of brackets to bovine enamel.

scholarly journals Effect of etching time and light source on the bond strength of metallic brackets to ceramic

2011 ◽  
Vol 22 (3) ◽  
pp. 245-248 ◽  
Author(s):  
Paulo Roberto Amaral Gonçalves ◽  
Rafael Ratto de Moraes ◽  
Ana Rosa Costa ◽  
Américo Bortolazzo Correr ◽  
Paulo Roberto Aranha Nouer ◽  
...  
Keyword(s):  
Bond Strength ◽  
Light Source ◽  
Argon Laser ◽  
Etching Time ◽  
Strength Testing ◽  
Light Sources ◽  
Ceramic Surface ◽  
Light Activation ◽  
Adhesive Remnant Index ◽  
Halogen Light

This study evaluated the bond strength of brackets to ceramic testing different etching times and light sources for photo-activation of the bonding agent. Cylinders of feldspathic ceramic were etched with 10% hydrofluoric acid for 20 or 60 s. After application of silane on the ceramic surface, metallic brackets were bonded to the cylinders using Transbond XT (3M Unitek). The specimens for each etching time were assigned to 4 groups (n=15), according to the light source: XL2500 halogen light, UltraLume 5 LED, AccuCure 3000 argon laser, and Apollo 95E plasma arc. Light-activation was carried out with total exposure times of 40, 40, 20 and 12 s, respectively. Shear strength testing was carried out after 24 h. The adhesive remnant index (ARI) was evaluated under magnification. Data were subjected to two-way ANOVA and Tukey's test (α=0.05). Specimens etched for 20 s presented significantly lower bond strength (p<0.05) compared with those etched for 60 s. No significant differences (p>0.05) were detected among the light sources. The ARI showed a predominance of scores 0 in all groups, with an increase in scores 1, 2 and 3 for the 60 s time. In conclusion, only the etching time had significant influence on the bond strength of brackets to ceramic.

scholarly journals Influence of Light Source, Thermocycling and Silane on the Shear Bond Strength of Metallic Brackets to Ceramic

2015 ◽  
Vol 26 (6) ◽  
pp. 685-688 ◽  
Author(s):  
Hugo Franco de Abreu Neto ◽  
Ana Rosa Costa ◽  
Américo Bortolazzo Correr ◽  
Silvia Amélia Vedovello ◽  
Heloísa Cristina Valdrighi ◽  
...  
Keyword(s):  
Bond Strength ◽  
Light Source ◽  
Shear Bond Strength ◽  
Water Storage ◽  
Deionized Water ◽  
Light Sources ◽  
Experimental Conditions ◽  
Halogen Light ◽  
Significant Difference ◽  
Post Hoc

The objective of this study was to evaluate the effects of different light sources, thermocycling and silane on the bond strength of metallic brackets to ceramic. Cylinders of feldspathic ceramic were etched with 10% hydrofluoric acid for 60 s. Half of the cylinders (Groups 1 to 4) received two layers of silane. Metallic brackets were bonded to the cylinders using Transbond XT and divided into 8 groups (n=20), according to light source (Radii Plus LED - 40 s; Groups 1, 2, 5 and 6 and XL 2500 halogen light - 40 s; Groups 3, 4, 7 and 8) and experimental conditions with (Groups 2, 4, 6 and 8) without thermocycling (Groups 1, 3, 5 and 7). Shear bond testing was carried out after 24 h of deionized water storage (Groups 1, 3, 5 and 7) and thermocycling (Groups 2, 4, 6 and 8; 7,000 cycles - 5°/55 °C). Date were submitted to three-way ANOVA and Tukey's post hoc test (α=0.05). The Adhesive Remnamt Index (ARI) was evaluated at 8× magnification. The application of silane was effective in increasing the shear bond strength of the brackets to ceramic (p<0.05). Significant difference (p<0.05) on the bond strength was observed between light sources with or without thermocycling. The ARI showed a predominance of scores 0 for all groups, with an increase in scores 1, 2 and 3 for the silane groups. In conclusion, silane improved significantly the shear bond strength of the brackets to ceramic. The thermocycling and light sources influence on the bond strength.

scholarly journals Dentine bond strength of a composite resin polymerized with conventional light and argon laser

2004 ◽  
Vol 18 (3) ◽  
pp. 271-275 ◽  
Author(s):  
Patricia Ramos Lloret ◽  
Kátia Martins Rode ◽  
Míriam Lacalle Turbino
Keyword(s):  
Bond Strength ◽  
Composite Resin ◽  
Testing Machine ◽  
Argon Laser ◽  
Acrylic Resin ◽  
Tensile Tests ◽  
Distilled Water ◽  
Universal Testing ◽  
Halogen Light ◽  
Adhesive Materials

The use of argon laser (488 nm) has been suggested as a new alternative for polymerizing adhesive materials. This study aimed to evaluate the tensile bond strength of a microfilled composite (A110, 3M) inserted by incremental technique (3 increments of 1 mm) and by single increment (3 mm) polymerized by argon laser for 10, 20 and 30 seconds and halogen light for 40 seconds. Eighty (8 groups of 10 teeth) freshly extracted bovine teeth were stored in a freezer in distilled water for one week. The crowns were cross-sectioned from the roots. Pulpectomy was performed and the pulp chambers were sealed with wax. The buccal surfaces of the teeth were ground with wet sandpaper (grains: 120, 400, and 600) to expose the surface dentin, and the teeth were then included in acrylic resin. A metal device was used to fix each sample and a black propylene matrix25 (3 mm high with an internal millimetric delimitation) was used to insert the material according to the groups studied. The polymerization intervals were of 10, 20 and 30 seconds for the laser polymerization and 40 seconds for the conventional polymerization. Tensile tests were performed by a Universal Testing Machine 4442 (Instron) at a speed of 0.5 mm/min and 500 N load. According to the methodology used, the incremental technique increased bond strength values. There was no difference between the studied polymerization techniques when resin was filled in 3 increments.

scholarly journals Effect of White Light Devoid of “Cyan” Spectrum Radiation on Nighttime Melatonin Suppression Over a 1-h Exposure Duration

2019 ◽  
Vol 34 (2) ◽  
pp. 195-204 ◽  
Author(s):  
Rohan Nagare ◽  
Mark S. Rea ◽  
Barbara Plitnick ◽  
Mariana G. Figueiro
Keyword(s):  
Light Source ◽  
White Light ◽  
Exposure Duration ◽  
Ganglion Cells ◽  
Phase 1 ◽  
Biological Clock ◽  
Light Level ◽  
Light Signal ◽  
Light Sources ◽  
Experimental Conditions

The intrinsically photosensitive retinal ganglion cells are the main conduit of the light signal emanating from the retina to the biological clock located in the suprachiasmatic nuclei of the hypothalamus. Lighting manufacturers are developing white light sources that are devoid of wavelengths around 480 nm (“cyan gap”) to reduce their impact on the circadian system. The present study was designed to investigate whether exposure to a “cyan-gap,” 3000 K white light source, spectrally tuned to reduce radiant power between 475 and 495 nm (reducing stimulation of the melanopsin-containing photoreceptor), would suppress melatonin less than a conventional 3000 K light source. The study’s 2 phases employed a within-subjects experimental design involving the same 16 adult participants. In Phase 1, participants were exposed for 1 h to 3 experimental conditions over the course of 3 consecutive weeks: 1) dim light control (<5 lux at the eyes); 2) 800 lux at the eyes of a 3000 K light source; and 3) 800 lux at the eyes of a 3000 K, “cyan-gap” modified (3000 K mod) light source. The same protocol was repeated in Phase 2, but light levels were reduced to 400 lux at the eyes. As hypothesized, there were significant main effects of light level ( F1,12 = 9.1, p < 0.05, ηp² = 0.43) and exposure duration ( F1,12 = 47.7, p < 0.05, ηp² = 0.80) but there was no significant main effect of spectrum ( F1,12 = 0.16, p > 0.05, ηp² = 0.01). There were no significant interactions with spectrum. Contrary to our model predictions, our results showed that short-term exposures (≤ 1 h) to “cyan-gap” light sources suppressed melatonin similarly to conventional light sources of the same CCT and photopic illuminance at the eyes.

Visibility of the phantom array effect according to luminance, chromaticity and geometry

2019 ◽  
Vol 52 (3) ◽  
pp. 377-388
Author(s):  
SW Park ◽  
C-S Lee ◽  
HR Kang ◽  
HS Pak ◽  
A Wilkins
Keyword(s):  
Light Source ◽  
Pulse Width Modulation ◽  
Light Emitting Diode ◽  
Field Of View ◽  
Light Sources ◽  
Experimental Conditions ◽  
Threshold Frequency ◽  
Automotive Lighting ◽  
Lighting Systems ◽  
Angular Field Of View

Light-emitting diode-based lighting systems are now applied in both general lighting and automotive lighting. Time-modulated control methods such as pulse width modulation are frequently applied as a dimming method. This paper presents the characteristics of the visibility of the phantom array effect according to luminance, chromaticity and angular field of view. The threshold frequency of the visibility of the phantom array increases in proportion to the logarithm of the luminance of the light source. As the angular field of view of the light source increases, the threshold frequency of the visibility of the array decreases exponentially over a range from 0.125° to 4° in our experimental conditions. The threshold frequency at which the array is visible depends on chromaticity at high light source modulation frequencies. When designing time-modulated light sources, our findings can be applied so as to minimize the phantom array effect.

scholarly journals Halogen light versus LED for bracket bonding: shear bond strength

2013 ◽  
Vol 18 (1) ◽  
pp. 31e1-31e6 ◽  
Author(s):  
Paulo Eduardo Guedes Carvalho ◽  
Valdemir Muzulon dos Santos ◽  
Hassan Isber ◽  
Flávio Augusto Cotrim-Ferreira
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
The Other ◽  
Light Sources ◽  
Activation Time ◽  
Average Performance ◽  
Halogen Light ◽  
Statistical Behavior ◽  
Light Curing ◽  
Short Time

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.

scholarly journals Conventional and High Intensity Halogen Light Effects on Water Sorption and Microhardness of Orthodontic Adhesives

2008 ◽  
Vol 78 (1) ◽  
pp. 134-139 ◽  
Author(s):  
Tancan Uysal ◽  
Faruk Ayhan Basciftci ◽  
Yagmur Sener ◽  
Murat Selim Botsali ◽  
Abdullah Demir
Keyword(s):  
Light Source ◽  
High Intensity ◽  
Water Sorption ◽  
Null Hypothesis ◽  
Light Energy ◽  
Light Sources ◽  
Orthodontic Adhesives ◽  
Quartz Tungsten Halogen ◽  
Halogen Light ◽  
Total Light

Abstract Objective: To test the null hypothesis that when the equivalent total light energy is irradiated to three orthodontic adhesive resins, there is no difference between the microhardness and water sorption values regardless of the curing light sources. Materials and Methods: Samples were divided into six groups according to the combination of three orthodontic adhesives (Kurasper F, Light-Bond, Transbond XT) and two light intensities (quartz tungsten halogen [QTH] and high intensity quartz tungsten halogen [HQTH]). One half of each of the 40 samples of three adhesive pastes was polymerized for 20 seconds by a QTH light source, and the other half was polymerized for 10 seconds by a HQTH light source. Water sorption was determined and Vickers hardness was established with three measurements per sample at the top, center, and bottom. Statistical analysis was performed using two-way analysis of variance (ANOVA) with multiple comparisons (Tukey-HSD). Results: Statistically significant differences were found among all adhesives for water sorption and hardness values cured with QTH and HQTH. The HQTH curing unit resulted in higher values than did the QTH. The highest water sorption values were observed for Kurasper F cured with HQTH and the lowest value was observed for Transbond XT cured with QTH. For microhardness Light-Bond cured with HQTH produced the highest values, and Transbond XT cured with QTH produced the lowest. Conclusions: When the equivalent total light energy is irradiated to three orthodontic adhesive resins, there are significant differences between the microhardness and water sorption values cured with the QTH and HQTH light source. The null hypothesis is rejected.

scholarly journals Effect of Light Sources on the Bond Strength of Resin Material to Thin-walled Roots

2014 ◽  
Vol 25 (3) ◽  
pp. 225-231 ◽  
Author(s):  
Rosângela Paniago Machado ◽  
Carolina de Andrade Lima Chaves ◽  
Fuad Jacob Abi Rached-Junior ◽  
Cassio José de Souza ◽  
Danielle Cristine Messias ◽  
...  
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Testing Machine ◽  
Control Group ◽  
Light Sources ◽  
Root Reinforcement ◽  
Halogen Light ◽  
Different Sources ◽  
Push Out ◽  
Effect Of Light

The aim of this study was to evaluate the bond strength to the dentin of an adhesive material used for root reinforcement light activated with different sources. Roots were divided into 4 groups (n=15) according to the light source used to activate the resin reinforcement: GI, non-weakened roots (control); GII, halogen light (H) 600 mW/cm2; GIII, LED 800 mW/cm2 and GIV, LED 1500 mW/cm2. The reinforcement was done with adhesive, composite resin and fiberglass posts. After 24 h, the specimens were sectioned and the first slice of each post region was used in the push out test in a universal testing machine with a crosshead speed of 0.5 mm/min. Failure modes of the debonded specimens were examined. Data (MPa) were analyzed by ANOVA and Holm-Sidak test (=0.05). The second slice from each region was analyzed by scanning electron microscopy (SEM). LED-1500 (4.69 ± 1.74) provided bond strength similar to the control group (5.05 ± 2.63) and statistically different from H-600 (1.96 ± 0.94) and LED-800 (2.75 ± 1.90), which were similar to each other (p<0.05). Cervical (4.16 ± 2.32) and middle (4.43 ± 2.32) regions showed higher bond strength than the apical (2.25 ± 1.50) (p<0.05). There was a prevalence of adhesive failures in H-600 and LED-800 and cohesive failures in LED-1500. SEM showed the formation of long, numerous and fine tags. It was concluded that LED-1500 provided higher bond strength of resin reinforcement to the dentin.

scholarly journals Effect of etching time and light sources on the shear bond strength of metal brackets to ceramic cylinders

2014 ◽  
Vol 62 (2) ◽  
pp. 117-122
Author(s):  
Magda Regina PIAIA ◽  
Ana Rosa COSTA ◽  
Américo Bortolazzo CORRER ◽  
Lourenço CORRER-SOBRINHO ◽  
Ivana Uglik GARBUI ◽  
...  
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Etching Time ◽  
Strength Testing ◽  
Light Sources ◽  
Plasma Arc ◽  
Light Activation ◽  
Time Intervals ◽  
Tukey Test ◽  
Halogen Light

OBJECTIVE: To evaluate the shear bond strength of brackets bonded to ceramic with Transbond XT resin, etching time intervals (1 and 2 minutes) and three Light sources (Xenon Plasma Arc, LED and Halogen Light ), with and without silane. METHODS: In total, 12 feldspathic ceramic cylinders (15 mm x 20 mm), etched with 10% hydrofluoric acid were used. For light activation, the brackets were divided according to the light source to be used (n-15): LED UltraLume 5 (L); Apollo 95E plasma arc (AP) and Halogen light XL 2500 (H). After 24 h the samples were submitted to shear bond strength testing at crosshead speed of 0.5 mm/minute. RESULTS: The data were submitted to the analysis of variance (ANOVA) and the Tukey test (5%). Bond Strength: UltraLume 5 (11.4 ± 3.56 MPa) was superior to XL 2500 (9.12 ± 2.83 MPa) and Plasma Arc (5.11 ± 2.93 MPa) (p<0.05). No difference was found between ceramic with silane (8.31 ± 4.17 MPa) and without silane (8.68 ± 3.86 MPa). Etching time of 2 minutes (9.13 ± 3.98 MPa) was superior to time of 1 minute (7.86 ± 3.96 MPa). CONCLUSION: The results showed that LED was shown to be more efficient for polymerizing the material for Transbond XT bonding. The use of silane did not influence the bond strength values. The acid etching time of 2 minutes was more effective than that of 1 minute.

scholarly journals Absorption spectar of six composite resins analyzed by using a spectrophotometer

2002 ◽  
Vol 49 (1-2) ◽  
pp. 24-28
Author(s):  
Larisa Blazic ◽  
Dejan Pantelic ◽  
Tatjana Brkanic
Keyword(s):  
Light Source ◽  
Composite Resins ◽  
Polymerization Process ◽  
High Tech ◽  
Light Sources ◽  
Spectra Analysis ◽  
Halogen Light ◽  
Absorption Of Light ◽  
Dental Profession ◽  
High Degree

The dental profession increase utilization of light-curable restorative materials nowadays. Conventional halogen light sources with newly developed, high-tech light activating units are simultaneously present in modern dentistry. The present study was conducted in order to characterize the degree of light irradiation absorption, and according to absorbed energy spectral distribution estimate the opportunity for application of the most compatible polymerization light source. As a material in this work six composite resins were tested: Admira (VOCO), Admira Flow (VOCO), Filtek P60 (3M), Helio Progress (Vivadent), Tetric Ceram (Vivadent) and Tetric Flow (Vivadent). Absorption spectra analysis pointed out the absorbance values of all tested composite resin materials were very close to absolution peak of Camphorquinone (468 nm). The most similar absorbance values (%) in relationsliip to wavelenght (nm) in comparasion to Camphorquinone absorption maximum were as follows: 99,47 % for Admira; 98,02 % for Filtec P60; 97,72 % for Tetric Ceram; 97,51 % for Helio Progress, and a bit smaller values were found for Admira Flow (96,21 %) and for Tetric Flow (94,21 %). The results in this analysis which was done by using a spectrophometer pointed out high degree absorption of light for tested materials could have significant influence on polymerization process, and also on proper choice of polymerization light source.

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