Objectives To determine the incidence of crack formation and propagation in apical root dentin after retreatment procedures performed using ProTaper Universal Retreatment (PTR), Mtwo-R, ProTaper Next (PTN), and Twisted File Adaptive (TFA) systems. Materials and Methods The study consisted of 120 extracted mandibular premolars. One millimeter from the apex of each tooth was ground perpendicula...

INTRODUCTION The aim of this study was to compare several metallurgic properties of Neoniti instrument with four other commonly used endodontic rotary files. METHODS AND MATERIALS Neoniti A1 (25/0.08), RaCe (25/0.06), Mtwo (25/0.06), Twisted file (25/0.06) and ProTaper Next X2 (25/0.06) were examined by differential scanning calorimetry (DSC) before and after heat treatment at 500°C. X-ray di...

abstractthe liquid crystal director distribution is determined for a confined chiral nematic slab. the molecular director distribution of the field-controlled chiral nematic slab is directly calculated. the director profiles for the tilt and the twist angles, under different applied fields, are calculated in the slab with weak boundary conditions. then, the dependence of the threshold field on ...

Advances in endodontics have enabled the evolution of file manufacturing processes, improving performance beyond that of conventional files. In the present study, systems manufactured using state of the art methods and possessing special properties related to NiTi alloys (i.e., CM-Wire, M-Wire and R-Phase) were selected. The aim of this review was to provide a detailed analysis of the literatur...

INTRODUCTION The aim of the present study was to comparatively evaluate the physical surface changes and incidence of separation in rotary nickel-titanium (NiTi) instruments using scanning electron microscope (SEM). METHODS AND MATERIALS A total number of 210 freshly extracted human maxillary and mandibular first molars were selected and distributed between three groups. Three different syste...

We study twisted Spin-manifolds over a paracompact Hausdorff space X with a twisting α : X → K(Z, 3). We introduce the topological index and the analytical index on the bordism group of α-twisted Spin-manifolds over (X,α), taking values in topological twisted K-homology and analytical twisted K-homology respectively. The main result of this paper is to establish the equality between the topolog...