Search results for "Magnification"

Dimensional variability of nonstandardized greater taper finger spreaders with matching gutta-percha points

2001

Aim The purpose of this research was to determine the compatibility and dimensional variability between nonstandardized gutta-percha points and matching finger spreaders. Methodology The diameters of nonstandardized gutta-percha points (n = 15) and matching finger spreaders (n = 15) from different manufacturers (Kerr, Dentsply Maillefer, Vereignigte Dentalwerke and Roeko) were determined and statistically analysed using a profile projector under a magnification of 50 × (±0.002 mm). Results The dimensions of the finger spreaders and gutta-percha cones were inconsistent. Of the 29 groups of nonstandardized gutta-percha cones evaluated, 22 had standard deviations larger than 0.020 at D1. The s…

A comparison of the marginal adaptation of composite overlays fabricated with silicone and an intraoral scanner

2021

Background Intraoral scanners have been developing during last years. The aim of this study was to know if digital impressions achieve a marginal adaptation in overlays as well as conventional impressions with silicone. Material and methods Sixty-two extracted molars were selected. The samples were prepared for MOD overlays. The teeth were divided into two groups (n=31). Group 1: impressions were made with silicone (Express™ Impression, 3M ESPE) and overlays were manufactured with Sinfony composite (3M ESPE) by the laboratory technician. Group 2: impressions were taken with the scanner True Definition (TD, 3M ESPE) and under Lava Ultimate CAD/CAM Restorative composite (3M ESPE) were produce…

A preliminary analysis in the preparation and obturation of oval canals

2011

Objective: 1) to observe the appearance of uninstrumented recesses in oval canals after instrumentation using circumferential filing. 2) To determine the quality of obturation both with cold lateral compaction and thermo plasticized gutta-percha technique in these recesses Study design: Twenty non-carious, freshly extracted human mandibular incisors with single canals were divided into group I (n=10) and group II (n=10) according to the two different obturation methods. The sectioned roots were prepared with flexofiles (Dentsply, Maillefer) ranging from #15 to #40 by using circumferential filing. The obturated specimens were horizontally sectioned at 5 mm from the apex. Each section was obs…

In vitro comparison of root-canal measurements with conventional and digital radiology.

2002

Aim The present study compared the efficacy of digital and conventional radiology for root-canal length measurement. Methodology Seventy extracted teeth with pre-served roots were used. Root-canal length measurements were completed with K-Flexofiles (numbers 08, 10 and 15) with conventional and digital radiography using two systems (radiovisiography and photostimulate storage phosphor). All films and sensors were exposed at projections of 0 degrees and 20 degrees to the mesial. The images obtained were evaluated with and without magnification, and analysed using the Cohen's kappa test. The accuracy of the three systems to determine the root-canal length were evaluated by measuring the dista…

STUDIO DELLA BIODISTRIBUZIONE DI SOSTANZE BIOLOGICAMENTE ATTIVE IN ORGANISMI ACQUATICI

2022

Chromoendoscopy and Other Novel Imaging Techniques

2006

The newly developed high-resolution and magnification endoscopes offer features that allow more and new mucosal details to be seen. They are commonly used in conjunction with chromoendoscopy. The analysis of mucosal surface details is beginning to resemble histologic examination. More accurate recognition of small flat and depressed neoplastic lesions is possible. Endoscopic prediction of neoplastic and nonneoplastic tissue is possible by analysis of surface architecture of the mucosa, which influences the endoscopic management. For the diagnosis of flat adenomas, chromoendoscopy should be a part of the endoscopist's armamentarium. In inflammatory bowel disease, chromoendoscopy can be used …

Modified position-referenced microscopy for the analysis of low-magnification biological events: a case of study in the wound healing assay with a hu…

2016

Pseudo-Periodic Patterns embedded in cell-culture-plates are used for high-accurate-absolute retrieval of regions of interest in a wound healing assay of a hepatoma cell-line. The method shows more reliable results in the analysis of wound-area percentage.

NEW DEVELOPMENTS ON INVERSE POLYGON MAPPING TO CALCULATE GRAVITATIONAL LENSING MAGNIFICATION MAPS: OPTIMIZED COMPUTATIONS

2011

We derive an exact solution (in the form of a series expansion) to compute gravitational lensing magnification maps. It is based on the backward gravitational lens mapping of a partition of the image plane in polygonal cells (inverse polygon mapping, IPM), not including critical points (except perhaps at the cell boundaries). The zeroth-order term of the series expansion leads to the method described by Mediavilla et al. The first-order term is used to study the error induced by the truncation of the series at zeroth order, explaining the high accuracy of the IPM even at this low order of approximation. Interpreting the Inverse Ray Shooting (IRS) method in terms of IPM, we explain the previ…

Fraunhofer diffraction patterns from apertures illuminated with nonparallel light in nonsymmetrical Fourier transformers.

1985

In a recent paper, a 2-D axially nonsymmetrical Fourier transforming with an anamorphic system was presented. This work extends its performances with the use of spherical illumination. The results provide the conditions to obtain an exact Fourier transform and a greater angular magnification coefficient than with parallel illumination. Experimental results of the latter are shown.

Analysis of the imaging method for assessment of the smile of laser diode bars.

2009

We study imaging systems designed to assess the smile of laser diode bars (LDBs). The magnification matrix is derived from the required sampling period and the geometries of the LDBs and the charge-coupled device (CCD) array. These image-forming systems present in-plane pure translation invariance, but in the case of anamorphic ones, lack in-plane rotation invariance. It is shown that the smile parameters of the image of the LDB are linked with the smile parameters of the LDB by simple mathematical expressions. The spatial resolution of such optical systems is estimated at approximately 1 microm for a mean wavelength of lambda approximately 800 nm. Our results suggest that, with the current…