Download or read book Torsional Cyclic Fatigue of an Endodontic Nickel titanium Rotary Instrument microform written by Andrew Sheldon Best and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2003 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fractographic and Fatigue Analyses of Nickel Titanium Rotary Endodontic Instruments written by Thomas A. Karn and published by . This book was released on 2003 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fracture Length of Rotary Ni Ti Files Used in Curved Roots of Molars written by Pardeep Khurana and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel Titanium alloy was developed in 1963 by Bhuler et al.The ability of Nickel-Titanium to undergo extensive deformation resulting from a stress assisted phase transformation, with the reverse transformation occurring on unloading is called Super elasticity.Ni-Ti files also have ability to revert back to its original straight form without any sign of lasting deformation, this property is called 'Shape memory'. Nevertheless, without any prior notice, a fracture can occur suddenly. Fracture of Ni-Ti files is main concern regarding there clinical use. Fracture of rotary instruments takes place in two different ways, due to torsion or ductility and due to cyclic fatigue through flexure.Ni-Ti rotary files causes small but consistent change in working length.There are number of factors associated with distortion and fracture of rotary Ni-Ti including speed of rotation, angle and radius of curvature of root. This aim of research in this book is evaluation of breakage, distortion and loss of working length in curved root canals by using different Nickel-Titanium rotary endodontic instruments.

Download or read book Torsional Evaluation of Common Endodontic Lubricants Used During Nickel Titanium Rotary Instrumentation written by Warren Amedeo Lawson and published by . This book was released on 2000 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Torsional Fatigue Profiles of ProTaper Nickel titanium Rotary Instruments written by Gregory M. Soo Chan and published by . This book was released on 2008 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: The torsional fatigue profiles of the original ProTaper RTM F2, F3 and ProTaperRTM Universal F2, F3, F4, F5 nickel-titanium rotary instruments were determined using a reversible geared motor assembled according a modification of ANSI/ADA Specification No. 28. The motor was programmed to continuously deflect to a set deflection angle (DA) and then return to zero (rest) until instrument fracture occurred. Ten instruments of each size were tested at various DAs. The mean number of cycles to fracture and standard deviation were determined for each DA. All instruments cycled at larger DAs demonstrated fewer cycles to fracture than those cycled at smaller DAs. The ProTaperRTM Universal F2 and F3 instruments had a significant reduction in torsional fatigue at each tested DA compared to the original ProTaperRTM F2 and F3 instruments. Torsional fatigue is only one mode whereby a nickel-titanium rotary instrument may fracture.

Download or read book Low cycle Cyclic Fatigue Properties of Novel Nickel titanium Rotary Endodontic Instruments in the Single and Double curvatures written by Frédéric Duke and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Management of Fractured Endodontic Instruments written by Theodor Lambrianidis and published by Springer. This book was released on 2017-09-28 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: This superbly illustrated book provides detailed information on the causes of instrument failure during endodontic treatment, the factors influencing the management of such cases, and the diverse management options that may be employed to resolve the problem. Readers will find clear descriptions and comparative evaluation of the available methods, techniques, and devices. Complications that may arise during the management of fractured instruments are described, and the impact of retained file fragments on the prognosis of endodontic treatment is discussed. In addition, means of preventing iatrogenic errors from occurring in the first place (the best form of management) are explained, emphasizing that the risk of instrument failure is reduced if proper guidelines are carefully considered and followed. The book will assist both endodontists and general dental practitioners in achieving an optimal outcome when confronted with the time-consuming and challenging task of dealing with a fractured instrument within the root canal – a still frequent circumstance despite the plethora of improvements in instrument design, alloy composition, and manufacturing processes.

Download or read book Low Cycle Fatigue of Nickel Titanium Rotary Root Canal Instruments written by Shun-Pan Gary Cheung and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Low cycle Fatigue of Nickel titanium Rotary Root canal Instruments written by Shun-pan Cheung (Gary) and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Torsional Testing of RaCe K3 and Profile Nickel Titanium Endodontic Files written by Sean D. Fessenden and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Rotary endodontic instruments have different cross sectional designs that may effect their resistance to torsional stress. The purpose of this study is to evaluate the static torsional properties of two nickel titanium files that have recently been introduced for use in endodontics and compare them to the same size Profile instruments. Ten new files of each brand and size were tested. The files tested were: RaCe 25 tip 0.02, 0.04, 0.06 taper, K3 and Profile 25 and 40 tip in 0.02, 0.04 and 0.06 taper. The diameter of each file was measured at 3mm from tip. The last three millimeters of the working area of the file was grasped with a non-rotating stainless steel chuck and the handle was held in freely rotating chuck. Torque was applied with the Instron Universal Tester in a counter-clockwise direction to simulate the direction of torque encountered clinically. The crosshead speed was set to produce 2 rotations per minute until fracture occurred. The maximum torque achieved and the rotations to fracture were recorded. A multi-way ANOVA of rotations revealed that RaCe 25-0.02 exhibited significantly less rotations to fracture than Profile and K3 of the same size (p

Download or read book Torsional Properties of Proprietary Heat treated Nickel titanium Rotary Instruments Versus Conventional Nickel titanium written by Ryan P. Romero and published by . This book was released on 2016 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fractographic and Fatigue Analyses of Nickel Titanium Rotary Endodontic Instruments written by Thomas A. Karn and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Cyclic Fatigue on Static Fracture Loads in ProTaper Nickel Titanium Rotary Instruments written by Cheryl Joy Ullmann and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of Surface Coatings and Surface active Liquid Lubrication on Cyclic Fatigue of Nickel titanium Rotary Endodontic Files in an Artificial Canal written by Yousef Abdulhadi Alnowailaty and published by . This book was released on 2012 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: The late 1980's witnessed the introduction of superelastic Nickel-Titanium (NiTi)alloy as an endodontic file. NiTi showed superior performance in root canal treatment compared to the conventional Stainless Steel files. After a few years of the use of rotary NiTi files, a greater tendency of fracture was noticed compared to Stainless Steel files, occurring unexpectedly and without previous permanent deformation. Recent research used electro-polished, smooth, triangular-shaped EndoSequence files in smooth glass surrogates of curved tooth-root canals, demonstrating extended times to file fracture during rotational bending at 300 rpm when the files were pre-coated with low-Critical Surface Tension (CST) silanes or lubricated in low-surface-tension surfactant solutions. A common feature was NiTi file fracture at a Surface Strain Amplitude of 3-4%, indicating that reduction of surface friction was by delay of surface crack opening. Earlier failure in NaOCl (bleach) lubricant was noted.^That prior work tested files held at stepped, static locations in curved glass tubes. The aim of this follow-up research was to further evaluate the cyclic fatigue resistance of rough-surfaced, triple-U-shaped Protaper® endodontic files, operated in more clinically relevant up/down filing motion, when their surface character also was modified through coating the files with two types of silanes, as "dry" lubricants. The first coating was Octadecylsilane (ODS) and the second was (3-Hepta-fluoroisopropoxy)propylsilane (3-HEPT). The cyclic fatigue of untreated control files and surface-modified files was tested dry and with five different irrigation solutions, some of which are commonly used in endodontic treatment. The irrigants used were distilled water, 5% sodium hypochlorite NaOCl, 17% ethylenediaminetetraacetic acid (EDTA), Surface Active Displacement Solution (SADS; an emulsion of water, butanol, and a surfactant), and Delmopinol (an aqueous solution of an aminoalcohol surfactant).^Bent glass tubes simulated curved root canals, in which an AEU-20 Endodontic System ITR motor rotated files at 300 RPM and high torque. More than 300 samples were tested in this research. After testing, the files were viewed under the scanning electron microscope to evaluate the fractured area, and it was shown that all the tested files showed signs of abrasion on the edges of the fractured areas. Analysis of Variance (one way ANOVA) and Multivariate Tests were the main statistical methods to compare the number of cycles to fatigue fracture (NCF). NCF of the coated files was significantly higher than for files tested as received F (2,321)=6. 887, P=0. 001. When sodium hypochlorite was used as an irrigant, the files demonstrated the shortest fatigue life in the 45o bent glass tube due to high friction and corrosion of the nickel when the applied stresses were above the critical stress for martensite transformation.^When low-surface-tension irrigants (SADS and Delmopinol) were used, the files demonstrated the longest fatigue life in the 45 o bent glass tube due to better lubrication and friction reduction. It was confirmed that NiTi file failure occurs at mean surface strain values of 3-4%, irrespective of surface finish or degree of file curvature. Number of cycles to failure is significantly increased in the presence of surface-energy-reducing substances, both as coatings and as lubricants, separately or in combination. Failure is accelerated by corrosive attack of NaOCl (bleach) during rotational bending producing tensile-compressive transitions from the austenitic to martensitic atomic structures. Even in this latter case, reduction of crack-opening surface friction is the proposed beneficial mechanism.

Download or read book Cyclic And Torsional Fatigue Resistance Of Heat Treated And Conventional Super Elastic Nickel Titanium Files written by Steven J. Todd and published by . This book was released on 2017 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of Phase Transformation Mechanisms for Nickel titanium Rotary Endodontic Instruments written by Satish B. Alapati and published by . This book was released on 2006 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Nickel-titanium rotary instruments based upon the intermetallic compound NiTi have gained considerable popularity among endodontists because the very low elastic modulus of NiTi enables these instruments to readily negotiate curved root canals during endodontic therapy with a slow-speed handpiece. However, concern about in vivo separation (fracture) of nickel-titanium instruments during treatment is still a major challenge confronting every manufacturer and endodontist, since this often happens without prior warning signs from permanent deformation. NiTi exists in two major microstructural phases: austenite, and martensite. Transformations between these NiTi phases occur rapidly by twinning on the atomic level and are reversible for stresses below the onset of permanent deformation. An intermediate R-phase is also sometimes observed for the transformation between austenite and martensite. The nickel-titanium rotary instruments are intentionally manufactured in the superelastic condition having the fully austenitic structure, which provides the capability of accommodating extensive elastic strain without fracture under clinical conditions associated with conventional root canal therapy. The overall objective of this study was to gain new insight into the microstructural phases in commercial NiTi rotary instruments and their transformations, which would be of scientific importance for development of new instruments with improved clinical performance. The phases present were identified by Micro-XRD (micro-x-ray diffraction) and TMDSC (temperature-modulated differential scanning calorimetry), using clinically popular ProFile GT and ProTaper nickel-titanium rotary instruments, which have two different cross-sectional designs. Instruments were analyzed in the as-received condition, after clinical use, and following elevated-temperature heat treatments. The first null hypothesis was that microstructural phases and phase transformations do not have an impact on clinical performance and instrument failure. The second null hypothesis was that appropriate heat treatments previously used for orthodontic wires would not result in beneficial changes in microstructural phases that may significantly affect the clinical life of these instruments. Based upon the present research and complimentary previous studies by this investigator, both null hypotheses were rejected. Information obtained from this research should aid future development of improved instruments with reduced likelihood of failure during clinical use.

Download or read book Comparative Analysis of Torsional Strength Between Profile GT and GT Series X TM Nickel Titanium Rotary Instruments written by Jake Reynolds and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study was to compare the resistance to fracture by the twisting of two nickel titanium (NiTi) rotary file systems. The Profile® GT® (GT) and the GT® Series X(TM) (GTX) files were tested to analyze the maximum torsional strength and the maximum angular deflection at the time of separation of the files. For each system, ten new files were tested at each of the following eight taper/size designations for a total of 160 files: 20/0.04, 20/0.06, 30/0.04, 30/0.06, 30/0.08, 40/0.04, 40/0.06, and 40/0.08. The American National Standards Institute / American Dental Association Specification No. 28 was implemented to evaluate torsional limits for these intruments. Files were mounted in a Maillefer Torsiometre machine, which records maximum torsional strength and angular deflection at separation for each file. A two-way ANOVA revealed significant differences after comparing the size and type of file. The GT files required significantly more torque to separate than the GTX files in all groups tested except the GTX file size 20/0.06, which required significantly more maximum torque than the GT file, with no significant difference between the GT and GTX files for size 30/0.04. The GT files exhibited values for angular deflection at separation that were significantly higher than those for the GTX files at sizes 30/0.04 and 40/0.08 and the GTX files exhibited higher values at size 30/0.08 with no significant difference between the brands at the remaining five file sizes. In summary, the GT files required significantly more torque to fracture and exhibited values for angular deflection at separation that were significantly higher than the GTX files for in 6 of 8 and 2 of 8 file sizes, respectively.