statement of the problem: various methods such as light emitting diode (led) have been used to enhance the polymerization of resin-based orthodontic adhesives. there is a lack of information on the advantages and disadvantages of different light curing systems. purpose: the aim of this study was to compare the effect of led and halogen light curing systems on the shear bond strength of orthodon...

This in vitro study evaluated the shear bond strength (SBS) between ceramic brackets (CBs) and resin composite restorations (RCRs) prepared using different surface treatments. The findings were also compared with a similar study that used stainless steel brackets (SSBs). Forty-five premolars were restored with a nano-hybrid composite resin (Tetric EvoCeram) and randomly assigned to three surfac...

We present a computational, atomistic study of electric field effects on the Young's modulus of metal nanowires. The simulations are electromechanically coupled, where the mechanical forces on the atoms are obtained from realistic embedded atom method potentials, and where the electrostatic forces on the atoms are obtained using a point dipole electrostatic model that is modified to account for...

Biquandle brackets define invariants of classical and virtual knots links using skein biquandle-colored links. coloring quivers categorify the biquandle counting invariant in sense defining quiver-valued enhancements which decategorify to invariant. In this paper, we unite two ideas bracket quivers, providing new categorifications brackets. particular, our construction provides an infinite fami...

introduced in 1991 to save the clinician the time spent in preparing the adhesive for direct bonding and applying it to the bracket.1 The APC brackets, which are packaged in individual capsules for ease of identification and infection control, are applied with finger pressure.2 A uniform factory precoating purportedly ensures an even amount and consistency of composite beneath each bracket. Any...

The objective of this investigation was to assess and compare the in vitro tribological behaviour of four commercially available self-ligating bracket systems. The frictional characteristics of the Damon3, Speed, In-Ovation R, and Time2 bracket systems were studied using a jig that mimics the three-dimensional movements that occur during sliding mechanics. Each bracket system was tested on the ...

background : in anterior endodontically treated teeth a better esthetic can be achieved by using all-ceramic post -core restorations instead of metal post systems. maximum retention and fracture resistance of the post are the criteria upon which selection of a post system is based. the aim of this study was to evaluate the fracture resistance and retention of two all-ceramic post and core syste...

We define Gerstenhaber’s graded Lie bracket directly on complexes other than the bar complex, under some conditions, resulting in a practical technique for explicit computations. The Koszul complex of a Koszul algebra in particular satisfies our conditions. As examples we recover the Schouten-Nijenhuis bracket for a polynomial ring and the Gerstenhaber bracket for a group algebra of a cyclic gr...