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...

This study determined the hardness and curing depth of a light-activated indirect composite polymerized with three laboratory light-polymerizing units for the purpose of comparing the curing performance of the three units. A light-activated composite material for indirect application (Vita Zeta) was polymerized with three light-polymerizing units equipped with the following light sources: 1) on...

Introduction: The aim of this study was to in-vestigate the effect of irradiation duration and distance of light tip to prepared samples in two different light curing unites on the degree of conversion of resin composite. Materials and Methods: Conventional halogen and blue Light emitting diode (LED) units were used for polymerization of an Opalis resin com-posite. The conversion measurements w...

The purpose of this study was to evaluate the microhardness of resin-based materials polymerized with a LED (light-emitting diode) light-curing unit (LCU) and a halogen LCU. Twenty cylindrical specimens (3.0 mm in diameter and 2.0 mm high) were prepared for each tested material (Z100, Definite and Dyract). Specimens were light-cured with two LCUs (Ultraled and Curing Light 2500) for either 40 o...

Halogen bonding is an emerging noncovalent interaction for constructing supramolecular assemblies. Though similar to the more familiar hydrogen bonding, four primary differences between these two interactions make halogen bonding a unique tool for molecular recognition and the design of functional materials. First, halogen bonds tend to be much more directional than (single) hydrogen bonds. Sec...

The purpose of this study was first to evaluate the elution of 2-hydroxyethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) monomers from resin-modified glass ionomer cement (RMGIC) and compomers cured with halogen and light-emitting diode (LED) light-curing units (LCUs). The effect of cured materials on the viability of L929 fibroblast cells was also evaluated. One RMGIC (...

A retrospective study of 34 sequential gamete intra-Fallopian transfer (GIFT) procedures suggested a significant effect on pregnancy rates associated with the different laparoscopic light sources, with a pregnancy rate of 50% in 22 cycles using a halogen light source and 9% in 12 cycles using a xenon light source. Other explanatory variables were explored, but none was to have a significant eff...

OBJECTIVE To test the hypothesis that bonding with a blue light-emitting diode (LED) curing unit produces no more failures in adhesive-precoated (APC) orthodontic brackets than bonding carried out by a conventional halogen lamp. MATERIALS AND METHODS Sixty-five patients were selected for this randomized clinical trial, in which a total of 1152 stainless steel APC brackets were employed. In or...