objective: shear bond strength is an important property inherent to the durability of tooth-colored restorative materials namely composite resins. it has been years that halogen light sources have been used for polymerization of composite resins. in recent years light emitting diodes (led) have been introduced for this purpose. with respect to their longer bulb life, needless of a filter and no...

OBJECTIVES To compare curing performance of a second generation LED curing light with a high power tungsten quartz halogen (QTH). METHODS A hybrid composite resin (Filtek Z 250, 3M, USA) was used as test material and cured using a second generation LED light (Translux Power Blue™, Heraus Kulzer ,Germany) or a very high power QTH light unit (EMS, Switzerland). A two split aluminum mold was use...

If G is a finitely generated profinite group then the verbal subgroup Gq is open. In a d-generator finite group every product of qth powers is a product of f(d, q) qth powers. 20E20, 20F20.

Introduction: One factor affecting the degree of polymerization is the type of light-curing device. The aim of this study was to compare the effects of LED and QTH light curing units on the surface hardness of composite and compomer. Materials & Methods: In this experimental study, 30 samples of composite and compomer were divided into 3 groups of 10 each. One-half of the subgroups in each g...

introduction: discoloration of resin composites is a common reason for replacement of these restorations. the aim of this study was to eva-luate the influence of different light curing de-vices on color stability of a microhybrid resin composite. materials and methods: 80 disc-shaped speci-mens (8 mm in diameter, 2-mm height) were fabricated from filtek z250 resin composite. specimens were divid...

introduction : this in vitro study was designed to measure and compare the amount of temperature rise in the pulp chamber of the teeth exposed to different light curing units (lcu), which are being used for curing composite restorations. methods: the study was performed in two settings; first, an in vitro and second was mimicking an in vivo situation. in the first setup of the study, three grou...

The purpose of this study was to evaluate, in vitro, the color stability of three composite resins of two different shades (A3 and C3) cured with either a quartz tungsten halogen (QTH) or a light emitting diode (LED) source. Forty specimens (20 x 2 mm) were prepared for each composite (Tetric Ceram, Heliomolar and Esthet-X), being 20 for each shade. In each group, 10 specimens were light-cured ...

OBJECTIVE The objective of this study was to compare the conversion degree of six different composite materials (Filtek Z 250, Filtek P60, Spectrum TPH, Pertac II, Clearfil AP-X, and Clearfil Photo Posterior) using three different light sources (blue light-emitting diode [LED], plasma arc curing [PAC], and conventional halogen lamp [QTH]). METHODS Composites were placed in a 2 mm thick and 5 ...