BACKGROUND Fixed orthodontic mechanotherapy is associated with friction between the bracket - wire - ligature interfaces during the sliding mechanics. A sound knowledge of the various factors affecting the magnitude of friction is of paramount importance. The present study was done to analyze and compare the frictional forces generated by a new ceramic (Clarity Advanced) bracket with the conven...

Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used...

OBJECTIVES The aim of this study was to evaluate the sealing ability of lateral compaction and tapered single cone gutta-percha techniques in root canals prepared with stainless steel and rotary nickel titanium root canal instruments by fluid filtration method. STUDY DESIGN The root canals were prepared with stainless steel (SS) and nickel titanium (NiTi) instruments. The canals prepared with...

In this paper, a high voltage normally-off trenched-and-implanted vertical JFET (TIVJFET) in 4H-SiC is investigated by way of two-dimensional numerical simulations. The structure is simple to fabricate and is expected to be able to achieve a high current density. Detailed designs are presented for 1.7kV to 14kV normally-off 4H-SiC VJFETs. A good agreement has been reached between computer model...

This study was done to evaluate new manufactured rotary spreaders one made from stainless steel material and second from nickel titanium and compared them with conventional finger spreader for their affect on the amount of gutta percha (in mg) that can be applied to fill the root canal and evaluation of apical extension of first, second, third and fourth auxiliary gutta percha cones for the sta...

AIM The aim of this study was to firstly evaluate the esthetics of a dielectric multilayer coating on titanium below porcine tissue (in vitro porcine model). Secondly, a polymer model was used to investigate the same samples to compare the models to each other and discuss their validity for optical assessment of esthetic coatings for implant applications. MATERIALS & METHODS A dielectric mirr...

The adsorption and dissociation of NH(3) on the clean and hydroxylated TiO(2) rutile (110) surfaces have been investigated by the first-principles calculations. The monodentate adsorbates such as H(3)N-Ti(a), H(2)N-Ti(a), N-Ti(a), H(2)N-O(a), HN-O(a), N-O(a) and H-O(a), as well as the bidentate adsorbate, Ti-N-Ti(a) can be formed on the clean surface. It is found that the hydroxyl group enhance...

Low carbon ferritic steel alloyed with Ti, Mo and Cu was hot rolled and interrupt cooled to produce nano-sized precipitates of copper and (Ti,Mo)C carbides. The steel had a tensile strength of 840 MPa, an increase in yield strength of 380 MPa over that of the plain carbon steel and reasonable ductility. Transmission electron microscopy and small angle neutron scattering were used to characteriz...

OBJECTIVES The aim of this study was to assess and compare the characteristics of commonly used initial archwires by their load deflection graphs. MATERIALS AND METHODS This study tested three wire designs namely copper nickel titanium (CNT), nickel titanium (NiTi), and multi-strand NiTi (MSNT) archwires engaged in passive self-ligating (PSL) brackets, active self-ligating (ASL) brackets or c...

INTRODUCTION The aim of this in vitro study was to compare the effect of hand and rotary instruments on fracture strength of tooth roots. MATERIALS AND METHODS Thirty two teeth were randomly divided into two experimental groups of 15 each and one negative control group with two samples. In group 1, step-back technique with conventional stainless steel K-files was used, and in group 2, instrum...