Hardness of both the top and bottom surfaces were determined for five different composite resins varying the thickness and exposure time to light. Specimens of the five different composite resins (Durafill®, Visio-Dispers ®, Prisma-Fil®, Estilux®, and Visio-Fil ®) were prepared in brass rings with thicknesses of 1.5, 2.0, and 2.5 ram. A Barcol Hardness Number (BHN) of the top or bottom surfaces...

OBJECTIVE This study evaluated the surface hardness of a resin cement (RelyX ARC) photoactivated through indirect composite resin (Cristobal) disks of different thicknesses using either a light-emitting diode (LED) or quartz tungsten halogen (QTH) light source. MATERIAL AND METHODS Eighteen resin cement specimens were prepared and divided into 6 groups according to the type of curing unit and...

OBJECTIVE Development of a new device to be coupled to light-curing units for bonding orthodontic brackets and accessories, and test its efficacy in an in vitro mechanical trial. The inner surface of the device is mirrored and is based on physical concepts of light refraction and reflection. The main advantage of such device is the reduced clinical time needed for bonding and the low possibilit...

BACKGROUND Bulk-fill resin composite has been introduced, their manufacturers claimed that they can be applied in bulks of 4mm, without necessitating a prolonged curing time, or a light curing unit with increased irradiance. Thus this study was conducted to evaluate the effect of resin thickness, and curing time on the micro-hardness of two bulk -fill resin composites; Tetric Evo-Ceram [TE], an...

objective: nowadays light-cured composites are used widely by orthodontists to bond brackets. as these composites require 20-40 seconds time per tooth to be light cured, more chair-time in needed compared to self-cured composites. in recent years, the argon laser and plasma arc lights have been introduced in dentistry to reduce this curing time. the purpose of this study was to compare bond str...

OBJECTIVES The aim of this study was to evaluate the effects of different light sources and curing time on the degree of conversion and microhardness of two surfaces within a nanofilled composite resin. METHODS Four experimental groups (n=10) were formed in accordance with the light source (quartz-tungsten halogen (QTH - 600mW/cm(2)), or light-emitting-diode (LED - 800mW/cm(2))) and the time ...

BACKGROUND Endodontically treated teeth with excessive loss of tooth structure are frequently restored using fiber posts. In this in vitro study, the apical leakage of self- and dual-activated curing modes for dual-curing resins cementing a translucent fiber post was evaluated using computerized fluid filtration meter and dye extraction method. MATERIAL AND METHODS One hundred and four extrac...

We developed a new laboratory polymerizing unit (Twinkle MIII: M3) equipped with different light sources (a metal halide and two halogen lamps) that could illuminate independently. This study introduced the structure of the curing unit and examined the curing depth of a representative indirect composite (Artglass). The composite material was cured with the following modes: 1) M3 - halogen only;...

OBJECTIVE We present a holographic near-the-eye display system enabling optical approaches for sight restoration to the blind, such as photovoltaic retinal prosthesis, optogenetic and other photoactivation techniques. We compare it with conventional liquid crystal displays (LCD) or digital light processing (DLP)-based displays in terms of image quality, field of view, optical efficiency and saf...