A simple and efficient garlic in vitro shoot regeneration protocol has been developed. This system uses axenic root tips cultivated from the beginning in the presence of light and does not require any change or refreshing of the original medium during the entire process. The application of light from the ...

OBJECTIVES: New blue, so called second generation light emitting diodes (LEDs) are now available with a high optical power output. These LEDs will potentially find widespread application in commercially available light curing units (LCUs). This study, therefore, investigated the curing performance of a prototype LCU containing one high power LED ...

This study evaluates the light-attenuating effects of enamel on the properties of light-cured restorative resins using simple experimental filters. Three filters were designed to replicate the light transmittance characteristics of 0.5, 1.0 and 1.5 mm thick human enamel. The bending strength, depth of cure, and levels of residual monomer for ...

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 ...

This study evaluated the depth of cure associated with commercial LEDs (light-emitting diodes) (Elipar FreeLight [FL], 3M-ESPE; GC e-Light [EL], GC), high intensity (Elipar TriLight [TL], 3M-ESPE) and very high intensity (Astralis 10 [AS], Ivoclar Vivadent) Quartz Tungsten Halogen (QTH) curing lights. Depth of cure of the various lights/curing modes ...

This study compared the cure and pulp-cell cytotoxicity of composites polymerized with light-emitting diode (LED) and halogen-based light curing units. A mini-filled resin composite (Tetric Ceram, Vivadent), two LED (E-light [EL], GC and Freelight [FL], 3M-ESPE), a conventional halogen (Max [MX], Dentsply) and a high-intensity halogen light (Astralis 10 [AS], ...

It has been reported that light-initiated prepolymerization at low intensity followed by a post-light-cure at full intensity (soft-start polymerization) may lead to light-cured composite fillings with improved marginal integrity. The aim of this study was to examine the influence of softstart polymerization with different protocols on Vickers hardness of different ...

PURPOSE: To evaluate the color differences of four tooth-colored restorative materials of the same designated Vita shade, and the color changes of the materials caused by light curing. METHODS: CIELAB coordinates (L* a* b*) of four tooth-colored materials: Clearfil ST (CL), Beautifil (BE), Reactmer (RE) and Z250 (Z2) were determined ...

The influence of a fixed number of agents with the same fixed behavior on the dynamics of the minority game is studied. Alternatively, the system studied can be considered the minority game with a change in the comfort threshold away from half filling. Agents in the frustrated, nonergodic phase tend ...

We tested the hypothesis that the degree of conversion of a light-cured dental composite relates to the calculated (s x mW cm-2 = mJ cm-2) rather than to the irradiance value (mW cm-2) of the light source. Two light-curable composite resins were cured with three different light irradiance values over ...

This study compared the effectiveness of cure of two LED (light-emitting diodes) lights (Elipar FreeLight [FL], 3M-ESPE and GC e-Light [EL], GC) to conventional (Max [MX] (control), Dentsply-Caulk), high intensity (Elipar TriLight [TL], 3M-ESPE) and very high intensity (Astralis 10 [AS], Ivoclar Vivadent) halogen lights at varying cavity depths. Ten ...

BACKGROUND: Light-emitting diode (LED) curing lights offer advantages over quartz-tungsten-halogen (QTH) lights, but the first-generation LED lights had some disadvantages. PURPOSE: This study compared a second-generation LED light with a QTH light to determine which was better at photopolymerizing a variety of resin composites. METHODS: The ability of a LED ...

OBJECTIVES: To investigate the color and microhardness changes of five chemically- and five light-curing composites as a function of accelerated aging from light exposure. MATERIALS AND METHODS: From each material five composite specimens were embedded in epoxy resin prior to determining the Knoop microhardness of the surface. For analyzing the ...

The fabrication of a battery operated 3-channel high voltage power supply for microchip capillary electrophoresis is described. The power supply consists of two positive and one negative DC-DC converters, a microprocessor controlled timer, a battery and a transformer to recharge the battery and feed the high voltage relays. This arrangement ...

This study was undertaken to assess the efficacy of 3 visible curing lights: a conventional halogen light and 2 high-intensity halogen lights in the polymerization of a polymer-based and resin-modified glass ionomer orthodontic cement. Degree of polymerization was measured by Fourier transform infrared spectroscopy and the development of mechanical properties ...

The aim of this in vitro investigation was to evaluate bond strength and debonding characteristics when a xenon plasma arc curing light is used to bond polycrystalline and monocrystalline ceramic brackets. Brackets were bonded to 240 extracted bovine mandibular incisors with a composite adhesive. Curing intervals of 1, 3, and ...

The purpose of this study was to examine the light transmittance characteristics of the paint-on resins for shade modification. Three shades of paint-on resin, one crown and bridge resin, and human enamel were used. Specimens with four different thicknesses (75-150 microm) were prepared. The light transmittances including its wavelength distribution ...

BACKGROUND: The authors conducted a study to determine whether high-intensity curing lights in high and ramped intensity modes affect microleakage of resin-based composite restorations and whether different types of resin-based composites meet American National Standards Institute/American Dental Association Specification no. 27 (1993): 7.7 for depth of cure when polymerized using ...

OBJECTIVE: Two visible light sources (tungsten-quartz-halogen and xenon-arc plasma) with vastly different intensities (200 and 1800 mW/cm(2)) but similar spectral outputs, were used to examine the effects of light intensity on conversion and flexural strength of a model dental resin formulation (75/25wt% bis-GMA/TEGDMA). METHODS: The exact same polymer samples were ...

OBJECTIVES: The aim of this study was to characterize the thermal expansion and dimensional changes of fiber-reinforced composite (FRC) according to the fiber orientation, brand of FRC product and polymerization conditions. METHODS: Cubic specimens (n=5) were prepared from different brands of FRC and particulate filler composites and dimethacrylate monomer resin. ...

OBJECTIVES: Recent developments have led to the introduction of high power curing lights, which are claimed to greatly reduce the total curing time. This study evaluated the effectiveness of a plasma-curing device (Apollo 95 E) and a halogen device (Heliolux DLX), in different curing conditions. METHOD: Vicker's micro-hardness values were ...

In contrast to motion, matter will be conserved in all eternity. Structure and function will arise by the angular momentum of spinning spherical particles and their composites. Symmetry prevails in physics by equal amounts of left- and right-hand spinning entities, while life is asymmetric in this respect. Very rare deviations ...

INTRODUCTION: The aim of this study was to investigate the effect of two novel curing systems (a plasma arc light, and a 'turbo-boosted' conventional curing light) on cuspal movement and gingival microleakage of 'packable' resin-based composite (RBC) restorations placed in extracted maxillary premolar teeth. MATERIALS AND METHODS: Forty sound extracted ...

AIM: To determine the microhardness of several light-curing dental restorative materials at the top surface as well as at a depth of 2mm. METHODS: Comparisons were made using different light sources. Four groups of five specimens each (3mm diameter, 2mm thick) of Z250 (composite), Filtek Flow (flowable composite), Dyract AP ...

With the introduction of photosensitive (light-cured) restorative materials in dentistry, various methods were suggested to enhance their polymerization and to shorten the curing time including layering and the use of more powerful light-curing devices. The purpose of this study was to determine the effect of using a new light-curing apparatus ...

Indirect composites are becoming more popular as technology yields materials with increased mechanical properties while reducing occlusal wear with opposing teeth. Several of the indirect systems currently on the market use both light and heat catalysts in the same resin, which results in higher polymerization rates than light-curing alone. However, ...

OBJECTIVES: A potential problem with high-intensity lights might be failure of polymer chains to grow and cross-link in a desired fashion, thereby affecting the structure and properties of the polymers formed. The purpose of this study was to evaluate mechanical properties of resin composites polymerized using four different light-curing units. ...

PURPOSE: This study evaluated the dynamic mechanical properties of silicone elastomers for maxillofacial applications and the influence of frequency and temperature on their properties. MATERIALS AND METHODS: Seven currently used silicone maxillofacial prosthetic materials were used. Storage modulus, loss modulus, and loss tangent were determined over the frequency range from ...

This study investigated the effectiveness of cure and post-gel shrinkage of three visible light-cured composite resins (In Ten-S [IT], Ivoclar Vivadent; Z100 [ZO], 3M-ESPE; Tetric Ceram [TC], Ivoclar Vivadent) when polymerized with a very high intensity (1296 +/- 2 mW/cm2) halogen light (Astralis 10, Ivoclar Vivadent) for 10 seconds. Irradiation ...

PURPOSE: The possibility of polymerizing glass fiber-reinforced composite (FRC) material into the root canal was preliminarily evaluated by determining the depth of light-initiated polymerization of FRC. MATERIALS AND METHODS: The material used was polymer-preimpregnated E-glass fiber reinforcement, which was further impregnated with light-polymerizable dimethacrylate monomer resin. The same resin without ...

Commercially available light activated dental composites were used in this study to compare the shrinkage following curing with plasma light (Apollo95E, DMDS) and a convention halogen dental curing light (Prismetics Lite II, Dentsply). Polymerization shrinkage was determined by measuring the strain in one dimension by means of a contacting transducer. ...

rSP-C surfactant monolayers spread on a native physiological model substrate show two plateau regions in the pi/A-isotherm. The first corresponds to the main phase transition in the monolayer from a LE to a LC phase. Its course is non-horizontal because of the complex composition of the lung surfactant. The second ...

This study compared the effectiveness of cure of two LED (light-emitting diodes) lights (Elipar FreeLight [FL], 3M-ESPE; GC e-Light [EL], GC) to conventional (Max [MX], Dentsply-Caulk [control]), high intensity (Elipar TriLight [TL], 3M-ESPE) and very high intensity (Astralis 10 [AS], Ivoclar Vivadent) halogen lights. The 10 light-curing regimens investigated were: ...

The purpose of this study was to measure and compare the hardness of a light-cured luting resin cured under different shades and thicknesses of porcelain with a halogen and a light-emitting diode (LED) light. Square (11 mm x 11 mm) specimens of a commercially available porcelain with thicknesses of 1 ...

This study evaluated the shear-peel bond strength and mode of bond failure of 3 curing devices (plasma arc light, argon laser, and conventional halogen light) and 2 orthodontic bracket adhesives with different filler contents (Transbond XT and Adhesive Precoated [APC]). Observations of microleakage were also reported. Ninety human adolescent premolars ...

This study quantified and compared the thermal emission of different light curing units (LCU). Three LED (Elipar Freelight [3M]; GC e-light [GC]; Coolblu [Dentalsystems.com]) and three halogen (Max [Dentsply-Caulk]; Elipar Trilight [3M]; Astralis 10 [Ivoclar-Vivadent]) lights were selected for the study. Thermal emission of the LCUs, when used in various ...

The cavitation on the mechanical heart valves (MHVs) is thought to be a cause of the mechanical failure of the occluder; also, the free radicals that would be generated when the cavitation bubbles implode might affect the patients chemically. These cavitation effects are attributed to the bubble collapse. Therefore, it ...

This study verified the polymerization depth of the composite Z100 (3M Dental Products) by Knoop Hardness test using four photoactivation methods. Twenty cylindrical specimens (5 mm in diameter by 5 mm in height) were prepared in a metallic mold and photoactivated by one of the four methods: continuous light (520 ...

OBJECTIVE: The hypothesis that low light intensity and long but sufficient curing time can produce composites with volumetric shrinkage, degree of conversion (DC%) and Young's modulus (E-modulus) comparable to those of high light intensity cured composite was tested, when the contraction strain and heat generation were lower with low light ...

Following a pilot study which determined that autoclaving a disposable tip resulted in physical deformation, rendering the tip ineffective for photocuring, this study evaluated the effects of two FDA-cleared high-level disinfectants on the light output and physical integrity of disposable and nondisposable curing light tips. Nine disposable and five nondisposable ...

When growing in a stress gradient, cracks have a directional growth. We investigate here this type of instability in the case of a colloidal gel deposited on a substrate and left to dry. The use of various materials reveals the existence of two distinct types of dynamics. When the crack ...

PURPOSE: First, to determine whether a silicone light-adjustable intraocular lens (IOL) can be fabricated and adjusted precisely with a light delivery device (LDD). Second, to determine the biocompatibility of an adjustable IOL and whether the lens can be adjusted precisely in vivo. METHODS: After fabrication of a light-adjustable silicone formulation, ...

A comparative kinetic study of the polymerization of tetraethyleneglycol dimethacrylate (TEEGDM) under visible light irradiation was carried out in order to determine the effectiveness of titanocene as photoinitiator in this process. The pair camphorquinone/dimethylaminoethyl methacrylate, CQ/DMAEMA (0.5/0.5%, by weight), was used as a reference photoinitiatior system. The reactions were carried ...

PURPOSE: This study determined which light source was best at photopolymerizing five representative brands of resin composite. The hypothesis was that there would be no difference in the hardness of the composites when irradiated by any of the lights. MATERIALS AND METHODS: Six curing light/tip combinations were used to photopolymerize ...

BACKGROUND: Dental chair lights can rapidly polymerize light-reactive composites beyond the point of workability, preventing adequate time for the shaping and sculpting of large direct composite restorations. PURPOSE: The purpose of this study was to determine whether yellow plastic food wrap placed over a dental chair light would perceptibly retard ...

A method to investigate light and radiation field congruence utilizing a commercially available amorphous silicon electronic portal imaging device (EPID) was developed. This method employed an EPID, the associated EPI software, and a diamond-shaped template. The template was constructed from a block tray in which Sn/Pb wires, 1 mm in ...

OBJECTIVE: Two recently marketed light-emitting diode polymerization units were compared with a conventional halogen curing unit. Selected properties of resin composites polymerized with the three curing units were determined. METHOD AND MATERIALS: Three different brands of resin composite were used in the investigation. The properties that were determined were flexural ...

INTRODUCTION: Besides the halogen curing lights, already accepted as standard equipment, diode and plasma-arc units for polymerization of filling materials have also been commercially available in Bulgaria in recent years. The present study was prompted by the lack of detailed scientific information about these novel light curing devices. AIM: 1. ...

Diel protein and carbohydrate content in Trichodesmium thiebautii was measured to evaluate the relationship to buoyancy status. Carbohydrate:protein ratio was the best predictor of buoyancy and fit a cosine curve with increasing values during the day and decreasing values at night in cycles that paralleled observed diel buoyancy patterns. This ...

Xenon plasma arc lights were introduced recently for light-cured orthodontic bonding. Compared with a conventional tungsten-quartz-halogen light source, these high-intensity lights promise a dramatic reduction in curing time. The purpose of this in vitro investigation was to evaluate bond strength with 2 commercially available plasma arc lights and reduced curing ...