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 A Scanning Electron Microscope Investigation of the Deterioration and Failure Mechanisms for Nickel titanium Rotary Endodontic Instruments written by Satish Babu Alapati and published by . This book was released on 2003 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phase Transformations in Nickel rich Nickel titanium Alloys Influence of Strain rate Temperature Thermomechanical Treatment and Nickel Composition on the Shape Memory and Superelastic Characteristics written by Raghavendra R. Adharapurapu and published by . This book was released on 2007 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nearly four decades of academic research and industrial interest on Nitinol has largely focused on the superelastic applications in the bio-medical sector and in the development of 'smart' shape-memory based sensors involving the low-strain rate (∼0.001/s) response of NiTi. It is only within the last decade that there has been a growing interest in the exploitation of Nitinol towards high-strain rate applications such as seismic damping, blast-mitigation or energy-absorbing applications. However, a systematic study of the influence of high-strain rate and temperature on the shape memory characteristics of NiTi is severely lacking. The current research program reports the findings on: (1) The phase-transformation mechanisms in Ni-rich Ni-Ti alloys. These include (a) diffusionless multiple-stage martensitic transformations and (b) diffusion-based phase transformations that govern the precipitation reactions in Ni-rich alloys and the overall time-temperature-transformation (TTT) curves. (2) The systematic study of the high-strain rate response of Ni-rich NiTi alloys as a function of temperature (between -196°C and 400°C) and thermomechanical treatment, viz., fully annealed, work-hardened and precipitation hardened conditions. Two Ni-rich Nitinol alloys, a commercial 50.8-NiTi (at.%) and a new 55-NiTi (at.%), were selected for the study, since the Ni composition determines the precipitation processes and, critically, the transformation temperatures in NiTi alloys. It was observed that the presence of dislocations (through work-hardening) and the presence of Ni-rich precipitates (through age-hardening) contribute to a more complex two-stage or multiple-stage transformations and also improve the overall strength of the NiTi alloy. Based on the microstructural changes, such as recovery, recrystallization and precipitation formation in 50.8-NiTi alloys, the current work uniquely provides a unified and general understanding of the various multiple-stage transformations reported in the literature, specifically providing the transition between two main transformation sequence mechanisms rationalized on the basis of partial differential scanning calorimetry (DSC) studies. Additionally, the work also identified unusual multiple-stage transformations in 55-NiTi. Aging in Ni-rich 55NiTi elicited precipitation reactions with the formation of Ti3Ni4, Ti2Ni3 and TiNi 3 in sequence. A time-temperature-transformation diagram for 55NiTi was constructed, as well as the upper temperature limit of formation for several precipitates has been estimated for Ni-rich NiTi alloys system as a function of Ni concentration between 50.6--56 at.%. Superelasticity and shape memory characteristics in Ni-rich 55NiTi, thought to be unfeasible, have been successfully demonstrated with recoverable strains up to ∼4-6%.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Thermal Analysis and Calorimetry written by and published by Elsevier. This book was released on 2011-09-22 with total page 781 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is Volume 5 of a Handbook that has been well-received by the thermal analysis and calorimetry community. All chapters in all five volumes are written by international experts in the subject. The fifth volume covers recent advances in techniques and applications that complement the earlier volumes. The chapters refer wherever possible to earlier volumes, but each is complete in itself. The latest recommendations on Nomenclature are also included. Amongst the important new techniques that are covered are micro-thermal analysis, pulsed thermal analysis, fast-scanning calorimetery and the use of quartz-crystal microbalances. There are detailed reviews of heating - stage spectroscopy, the range of electrical techniques available, applications in rheology, catalysis and the study of nanoparticles. The development and application of isoconversional methods of kinetic analysis are described and there are comprehensive chapters on the many facets of thermochemistry and of measuring thermophysical properties. Applications to inorganic and coordination chemistry are reviewed, as are the latest applications in medical and dental sciences, including the importance of polymorphism. The volume concludes with a review of the use and importance of thermal analysis and calorimetry in quality control.* Updates and complements previous volumes* Internationally recognized experts as authors * Each chapter complete in itself

Download or read book Endodontics Clinical and Scientific Updates An Issue of Dental Clinics of North America written by Mo K. Kang and published by Elsevier Health Sciences. This book was released on 2016-12-03 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue of Dental Clinics of North America focuses on Endodontics, and is edited by Dr. Mo Kang. Articles will include: Endodontic Microbiology and Pathobiology: Current State of Knowledge; Conventional Endodontic Therapies: Innovation in Biomechanics; Endodontic Retreatments: Non-surgical and Surgical Approaches; Pain Management in Endodontics: Opportunity for New Therapeutics; Pulpal Management of Immature Teeth: Use of New Biomaterials for Conservative Therapies; Innovation in Bioactive Restorative Materials; Topic in Regenerative Endodontics; Biological Molecules for the Regeneration of the Pulp-dentin Complex; Cell Homing Approach in Endodontic Regeneration; Stem Cell Therapies for Oral and Systemic Diseases; Endodontic Treatment Outcomes, and more!

Download or read book NiTi Materials written by Yoshiki Oshida and published by Walter de Gruyter GmbH & Co KG. This book was released on 2020-08-24 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel-Titanium alloys are smart materials exhibiting unique properties such as superelasticity and shape-memory effect. The material has been used as orthodontic wires in the dental field for over 20 years. This book is a comprehensive overview to the field of Ni-Ti Materials and the physical, chemical and mechanical properties of this versatile alloy. In addition, complications and challenges exhibited in applications are also discussed.

Download or read book Phillips Science of Dental Materials E Book written by Chiayi Shen and published by Elsevier Health Sciences. This book was released on 2021-05-13 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: **Selected for Doody's Core Titles® 2024 with "Essential Purchase" designation in Dentistry** Keep current with the evolving technology of dental materials! Phillips' Science of Dental Materials, 13th Edition provides comprehensive, up-to-date information on the materials used in cosmetic and restorative procedures in dentistry. It introduces the physical and chemical properties that are related to selection and use of dental biomaterials, including their composition, mechanical properties, manipulative variables, and the performance of dental restorations and prostheses. This edition adds three new chapters and hundreds of new full-color photographs. Written by dental scientists Chiayi Shen and H. Ralph Rawls along with prosthodontist Josephine Esquivel-Upshaw, this leading text/reference helps dentists select the right materials for oral procedures and helps dental labs ensure high-quality restorations. - 500 full-color photos and illustrations show concepts, dental instruments, and restorations. - Key terms are defined at the beginning of each chapter, covering terminology related to dental biomaterials and science. - Critical thinking questions stimulate thinking and emphasize important concepts and principles. - Logical, five-part organization of chapters makes the content easier to read and understand, with units on General Classes and Properties of Dental Materials, Direct Restorative Materials, Indirect Restorative Materials, Fabrication of Prostheses, and Assessing Dental Restorations. - Balance between materials science and manipulation bridges the gap of knowledge between dentists and lab technicians. - Major emphasis on biocompatibility serves as a useful guide to the principles and clinical implications of restorative materials safety. - Diverse and respected pool of contributors lends credibility and experience to each dental science topic. - NEW! Three new chapters are added: Digital Technology in Dentistry, In Vitro Research of Dental Materials, and Clinical Research of Restorations.

Download or read book Cohen s Pathways of the Pulp Expert Consult E Book written by Louis H. Berman and published by Elsevier Health Sciences. This book was released on 2010-05-10 with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt: The definitive endodontics reference, Cohen’s Pathways of the Pulp is known for its comprehensive coverage of leading-edge information, materials, and techniques. It examines all aspects of endodontic care, from preparing the clinician and patient for endodontic treatment to the role the endodontist can play in the treatment of traumatic injuries and to the procedures used in the treatment of pediatric and older patients. Not only does Hargreaves and Cohen’s 10th edition add five chapters on hot new topics, it also includes online access! As an Expert Consult title, Cohen’s Pathways of the Pulp lets you search the entire contents of the book on your computer, and includes five online chapters not available in the printed text, plus videos, a searchable image collection, and more. For evidence-based endodontics research and treatment, this is your one-stop resource!

Download or read book A Study of Phase Transformation for Superelastic Nickel titanium Orthodontic Archwires written by Michael Louis Fletcher and published by . This book was released on 1992 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of Composition Phase Transformation and Mechanical Properties of Nickel titanium Orthodontic Arch Wire written by Rutchadakorn Isarapatanapong and published by . This book was released on 2006 with total page 226 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 Characterization of New Rotary Endodontic Instruments Fabricated from Special Thermomechanically Processed NiTi Wire written by Jie Liu and published by . This book was released on 2009 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Although NiTi rotary instruments are very popular for endodontic treatment, instrument separation is still a challenge in clinic. A new NiTi rotary instrument has recently been marketed that is machined from M-Wire that has been subjected to a proprietary novel thermomechanical processing procedure. The manufacturer has claimed that this new M-Wire instrument has considerably improved flexibility and resistance to cyclic fatigue, compared to conventional rotary instruments that are machined from superelastic (SE) austenitic NiTi wire. Clinical use has confirmed that these new M-Wire rotary instruments have outstanding clinical fatigue resistance. However, the mechanism for the improved clinical performance of these instruments is unknown. The objective of this study was to employ a variety of metallurgical laboratory techniques to determine the origin of these improved mechanical properties for the new rotary instruments. Specimens from as-received M-Wire instruments, clinically used M-Wire instruments, and conventional instruments were prepared for evaluation. The temperature range for phase transformation was examined by differential scanning calorimetry (DSC). Vickers hardness measurements were made since hardness variations for the same type of alloy has been found to correlate with variations in mechanical properties. The microstructures of the NiTi alloys were revealed by acid etching and examined with an optical microscope and a scanning electron microscope. Wear resistance of clinically used M-Wire instruments was investigated by examining their surfaces with an SEM. In a complementary study, bright-field images of M-Wire blanks were obtained by scanning transmission electron microscopy (STEM). DSC study showed that M-Wire instruments have much higher Af (austenite-finish) temperatures (over 40°C) than conventional superelastic rotary instruments (below room temperature), and are a mixture of martensite, R-phase and austenite at room temperature. The Vickers hardness of M-Wire instruments is significantly higher than that of conventional rotary NiTi instruments. Mean Vickers hardness number for the tip, intermediate region and shank region of size 30/.04 taper M-Wire instruments were about 374, 380 and 392 each. Better wear resistance was observed with the SEM on clinically used M-Wire instruments, which presented less microcracks and evidence of permanent deformation on the surface compared with surfaces of clinically used conventional NiTi instruments. This improved wear resistance is attributed to increased hardness for surface region of the M-Wire instrument. Acid-etched M-Wire instruments presented a classical lenticular martensite structure when observed with the optical microscope and SEM. EDS analyses of the microstructures of the M-Wire instruments revealed titanium-rich precipitates. STEM examinations of M-Wire blanks revealed much coarser grains, twinning, and a high density of dislocations, which were not observed in starting superelastic NiTi wire blanks for conventional instruments. In summary, increased hardness was found for M-Wire instruments, compared with conventional superelastic NiTi rotary instruments, which served as a control for this study. The STEM observations show that the improved mechanical properties of the starting M-Wire (and the rotary instruments manufactured from this special NiTi wire) arise from strengthening mechanisms in the martensitic structure, which were induced by extensive thermomechanical processing.

Download or read book Shape Memory Alloys for Biomedical Applications written by T Yoneyama and published by Elsevier. This book was released on 2008-11-21 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shape memory alloys are suitable for a wide range of biomedical applications, such as dentistry, bone repair and cardiovascular stents. Shape memory alloys for biomedical applications provides a comprehensive review of the use of shape memory alloys in these and other areas of medicine.Part one discusses fundamental issues with chapters on such topics as mechanical properties, fabrication of materials, the shape memory effect, superelasticity, surface modification and biocompatibility. Part two covers applications of shape memory alloys in areas such as stents and orthodontic devices as well as other applications in the medical and dental fields.With its distinguished editors and international team of contributors, Shape memory alloys for biomedical applications is an essential reference for materials scientists and engineers working in the medical devices industry and in academia. - A comprehensive review of shape memory metals and devices for medical applications - Discusses materials, mechanical properties, surface modification and biocompatibility - Chapters review medical and dental devices using shape memory metals, including stents and orthodontic devices

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 Cohen s Pathways of the Pulp E Book written by Louis H. Berman and published by Elsevier Health Sciences. This book was released on 2020-09-08 with total page 1092 pages. Available in PDF, EPUB and Kindle. Book excerpt: **Selected for Doody's Core Titles® 2024 with "Essential Purchase" designation in Dentistry** Stay up on the latest research and techniques in endodontics with Cohen's Pathways of the Pulp, 12th Edition. Written by a team of internationally renowned experts and trusted for more than 40 years, this definitive guide covers the science, theory, and practice of endodontics. Full color illustrations and detailed radiographs guide readers through each step of endodontic care — from diagnosis and treatment planning to proven techniques for managing pulpal and periapical diseases. This new twelfth edition also boasts the very latest evidence-based research and techniques, reorganized and condensed chapters, plus other features designed to help you locate important information quickly and easily. Complete with access to Expert Consult, it's everything you need to stay ahead in the field of endodontics. - Extensive illustration collection includes over 2,000 full-color photos, line art, and radiographs to clearly demonstrate core concepts and reinforce the essential principles and techniques of endodontics. - Video clips and case studies demonstrate key procedures such as palpation of the masseter muscle, introsseous anesthesia with the X-tip system, dentin hypersensitivity, and more. - Diverse and respected contributor pool includes experts from many national- and international-based dental education programs. - NEW! Updated content and new images incorporate the most recent developments in research and clinical endodontic techniques. - NEW! Additional topics cover pulp biology, pathobiology, diagnosis, treatment planning, pain control, isolation, access, cleaning and shaping, obturation, restoration, assessment of outcomes, emergencies and surgery. Each online topic comes with assigned reading lists, a PowerPoint lecture, written lesson objectives, and example exam questions. - NEW! Compliance with the Commission on Dental Accreditation Curriculum ensures that the needs of all dental programs are met. - NEW! Reorganized sections now divide chapters by those covering clinical endodontics, those covering the biological basis of endodontics, and chapters which detail endodontics in private practice to make content easier for both clinicians and students to navigate. - NEW! Condensed chapters remove unnecessary duplication of content across the text and make the physical text lighter and easier to use.

Download or read book Metallic Biomaterials written by Takao Hanawa and published by CRC Press. This book was released on 2024-11-14 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallic materials are used in many medical devices due to their high mechanical reliability and their excellent strength and toughness. They account for more than 70% of internally implantable devices (implants). This book helps understand the necessity and problems of metal materials used in medical applications. This book was written with the goal of helping students learn the essentials of metallic biomaterials and acquire knowledge that can be applied in a progressive manner. The target audience for this book are students, graduate students, engineers, medical doctors, and others who need knowledge about metallic biomaterials.