Track topics on Twitter Track topics that are important to you
This study evaluated the effect of light curing unit (LCU) guide type (regular or homogenizing) on top and bottom microhardness of conventional and bulk-fill resin-based composites (RBCs). A polywave light-emitting-diode (LED) LCU (Bluephase Style, Ivoclar Vivadent AG) was used with two different light guides: a regular tip (RT, 935 mW/cm emittance) and a homogenizer tip (HT, 851 mW/cm emittance). Two conventional RBCs (Herculite Ultra [HER], Kerr Corp; Tetric EvoCeram [TEC], Ivoclar Vivadent AG) and two bulk-fill RBCs (SonicFill [SOF], Kerr Corp; Tetric EvoCeram Bulk Fill [TBF], Ivoclar Vivadent AG) were tested. Disc-shaped samples (10 mm Ø), 2-mm thick for conventional composites and 4-mm thick for bulk-fill composites were prepared. Samples were light cured according to manufacturer-recommended times. Knoop microhardness values (KHN) were obtained on the top and bottom surfaces of each specimen at locations correlated with the output of the three LED chips emitting blue (456 nm) or violet light (409 nm). Beam profile analysis using both light guides was also performed. Microhardness of each composite was analyzed using three-way analysis of variance and Tukey honestly significant difference test (α=0.05). Beam profile images showed better light distribution across the surface of the HT light guide. Use of the HT decreased KHN of HER at the locations of the blue LED chips at bottom of the sample but had no effect on the top surface. For TEC, use of HT increased KHN of all three LED locations at the top surface. Use of the HT increased KHN of SOF at locations corresponding to one of the blue and the violet LED chips at the bottom surface. For TBF, HT increased KHN at all top surface locations. All RBCs showed higher mean KHN at the top compared with the bottom surfaces. In general, all composites presented a higher KHN at the blue LED areas regardless of the surface or the tip used. Results suggest that the homogenizer light guide resulted in significantly increased microhardness at the top, in composite resins containing alternative photoinitiators; however, that effect was not observed at the bottom surfaces.
This article was published in the following journal.
Name: Operative dentistry
Therapeutic applications of light emitting diode-red light (LED-RL) are expanding, yet data on its clinical effects are lacking.
The aim of this study was to evaluate the influence of different light-emitting diode (LED) curing units and battery levels on the chemical, mechanical, and physical properties of composite resins. Th...
Here we report a quantum dot light emitting diode (QLED), in which a layer of colloidal silicon quantum dots (SiQDs) works as the optically active component, exhibiting a strong electroluminescence (E...
An innovative endoscopic system using 4-color light-emitting diodes (LED) was released between 2016 and 2017 in locations that had not approved laser endoscopes for use, including the United States an...
The purpose of this study was to evaluate the intensity of light-curing units and its relationship with the color stability and microhardness of composite resins with different shades subjected to a t...
Effects of Phototherapy by Low-level Light-emitting Diode Therapy (LEDT) on Clinical, Biochemical, Biomechanical, Histologic and Genetic Responses of Muscle Performance of Young Males Submitted to Physical Strength Training
Muscle performance is largely influenced by modulations in gene expressions of muscle tissue. In this context, light-emitting diode therapy (LEDT) has been used to improve muscle performan...
The purpose of this study was to determine whether light emitting diode (LED) therapy can improve skin appearance of human subjects with aged/photoaged skin. A reduction in rhytid depth a...
Light Emitting Diode (LED) therapy has been investigated in burns and skin ulcers, as it has a bactericidal effect and promotes tissue repair. This study aims to evaluate LED therapy at di...
Skin scarring (fibrosis) is a common complication in the wound healing process and remains a therapeutic challenge. Scar formation often occurs following injury to the skin such as surgery...
Bacterial Vaginosis (BV) is a infectious process of the female genitourinary tract, an important health issue due to the high incidence and high rate of recurrence of the infection. Theref...
Lasers with a semiconductor diode as the active medium. Diode lasers transform electric energy to light using the same principle as a light-emitting diode (LED), but with internal reflection capability, thus forming a resonator where a stimulated light can reflect back and forth, allowing only a certain wavelength to be emitted. The emission of a given device is determined by the active compound used (e.g., gallium arsenide crystals doped with aluminum or indium). Typical wavelengths are 810, 1,060 and 1,300 nm. (From UMDNS, 2005)
Light sources used to activate polymerization light-cured orthodontic adhesives (DENTAL CEMENTS). Degree of cure and bond strength depends on exposure time, wavelength, and intensity of the curing light.
The hardening or polymerization of bonding agents (DENTAL CEMENTS) via exposure to light.
Chemical compound used to initiate polymerization of dental resins by the use of DENTAL CURING LIGHTS. It absorbs UV light and undergoes decomposition into free radicals that initiate polymerization process of the resins in the mix. Each photoinitiator has optimum emission spectrum and intensity for proper curing of dental materials.
A photoprotein isolated from the bioluminescent jellyfish Aequorea. It emits visible light by an intramolecular reaction when a trace amount of calcium ion is added. The light-emitting moiety in the bioluminescence reaction is believed to be 2-amino-3-benzyl-5-(p-hydroxyphenyl)pyrazine (AF-350).