The last decade has been witness to phenomenal growth in endodontic technology. The introduction of these new technologies has resulted in endodontics becoming easier, faster and most importantly, better. Principal among these is Nickel Titanium (NiTi) rotary instrumentation that results in consistent, predictable, and reproducible shaping. The purpose of this article is to review the design fe...

This study investigated the incidence of hand and rotary instrument separation (IS) in the endodontics graduate program at the University of Pennsylvania between 2000 and 2004. In 4,865 endodontic resident cases the incidence of hand and rotary IS was 0.25% and 1.68%, respectively. The odds for rotary IS were seven times more than for hand IS. The probability of separating a file in apical thir...

In the clinical practice, it is much more efficient to use NiTi rotary files compared to hand instrumentation. However, misuse of NiTi rotary files can result in procedural errors such as transportation, ledge, perforation, and file separation. Generally, following suggestions could be considered to avoid these errors. 1. Enlarge the coronal half of the root canal before preparing the apical pa...

The original cotton particulates analyzer used stationary screens to separate aerodynamically the coarse and fine dust fractions from small samples of cotton. By replacing stationary with rotary screens that were continuously cleaned, larger supplies of respirable dust were obtained without interruption. A ginned and a waste cotton were used to test two methods of separation: a rotating 38-micr...

Vacuolar H(+)-ATPases are multisubunit complexes that operate with rotary mechanics and are essential for membrane proton transport throughout eukaryotes. Here we report a ∼ 1 nm resolution reconstruction of a V-ATPase in a different conformational state from that previously reported for a lower-resolution yeast model. The stator network of the V-ATPase (and by implication that of other rotary ...

Control of the direction of motion is an essential feature of biological rotary motors and results from the intrinsic chirality of the amino acids from which the motors are made. In synthetic autonomous light-driven rotary motors, point chirality is transferred to helical chirality, and this governs their unidirectional rotation. However, achieving directional rotary motion in an achiral molecu...

background and aims. the superiority of rotary systems has been reported in several clinical studies on permanent teeth. this study consisted of radiographic assessment and chair time of rotary instruments in the pulpectomy of primary second molar teeth. materials and methods. in this randomized controlled clinical study, 46 children, 3-6 years of age, were selected. the patients were divided r...

at this study, after designing and manufacturing a rotary tool, its machining parameters and their effects on surface roughness of aluminum alloy of al99 which  is one of the most consumable alloys in aerospace industry, is  studied and optimized. first, the rotary tool is designed and manufactred. then according to taguchi method, the experiments have been designed to record surface roughness,...

introduction: all instrumentation techniques have been reported to be associated with extrusion of infected debris. the aim of this study was to evaluate the number of bacteria extruded apically from extracted teeth ex vivo after canal instrumentation using the two engine-driven techniques utilizing nickel-titanium instruments (flex master and mtwo). materials and methods: seventy extracted max...

introduction: the purpose of the present study was to quantify and compare the amount of extruded debris from apical foramen after instrumentation of the root canal system with hand and rotary instruments. materials and methods: root canals of forty five fresh extracted single rooted human teeth with mature apexes and less than 15 degree of root curvature were instrumented in group a with stain...