The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This study compares the elastic properties of four orthodontic wire materials: stainless steel, cobalt-chromium, nickel-titanium, and beta-titanium. The study uses formulas to calculate ratios of bending strength, stiffness, and range for different wire configurations under bending and torsion stresses. The results show that nickel-titanium provides the most flexibility and is best for initial tooth alignment. Beta-titanium is superior for intermediate stages requiring flexibility. Stainless steel and cobalt-chromium are best for stability in the later stages.
The document discusses various engineering materials including metals, ceramics, polymers, and composites. It provides information on the properties and examples of different material classes. It also discusses standards (ASTM) for materials classification and specifications. Key properties discussed include strength, toughness, hardness, ductility, fatigue, and effects of processing such as heat treatment and alloying.
The document discusses various mechanical properties of metals including stiffness, strength, ductility, toughness, hardness, stress and strain. It defines key terms like elastic modulus, yield strength, ultimate strength, elongation, area reduction, fracture strain. It explains concepts such as engineering stress-strain curves, Hooke's law, elastic deformation, plastic deformation, Poisson's ratio, ductile vs brittle materials, and how properties relate to microstructure. Typical testing methods and how to calculate properties from raw data are also summarized.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Mechanical properties refer to how materials behave under forces or pressures. This document discusses key mechanical properties including brittleness, hardness, strength, stiffness, ductility, malleability, elasticity, plasticity, creep, and weldability. It describes how these properties are defined, measured, and their significance for material selection and design. Measurement techniques covered include indentation hardness tests like Rockwell and Brinell, and tension tests. The document also examines stress-strain diagrams and how they vary for different materials and temperatures.
The document discusses stress-strain curves, which plot the stress and strain of a material sample under load. It describes the typical stress-strain behavior of ductile materials like steel and brittle materials like concrete. For ductile materials, the curve shows an elastic region, yield point, strain hardening region, and ultimate strength before failure. The yield point marks the transition between elastic and plastic deformation. The document also discusses factors that influence a material's yield stress, such as temperature and strain rate, and implications for structural engineering like reduced buckling strength after yielding.
1) The document discusses various mechanical properties of dental materials including elastic properties like elastic modulus and plastic properties like yield strength.
2) Mechanical properties are quantified using concepts of stress and strain, and different tests are used to measure properties like hardness, tensile strength, and impact resistance.
3) Key mechanical properties discussed include elastic modulus, proportional limit, yield strength, ductility, toughness, and hardness. Different tests for measuring these properties are also described.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This study compares the elastic properties of four orthodontic wire materials: stainless steel, cobalt-chromium, nickel-titanium, and beta-titanium. The study uses formulas to calculate ratios of bending strength, stiffness, and range for different wire configurations under bending and torsion stresses. The results show that nickel-titanium provides the most flexibility and is best for initial tooth alignment. Beta-titanium is superior for intermediate stages requiring flexibility. Stainless steel and cobalt-chromium are best for stability in the later stages.
The document discusses various engineering materials including metals, ceramics, polymers, and composites. It provides information on the properties and examples of different material classes. It also discusses standards (ASTM) for materials classification and specifications. Key properties discussed include strength, toughness, hardness, ductility, fatigue, and effects of processing such as heat treatment and alloying.
The document discusses various mechanical properties of metals including stiffness, strength, ductility, toughness, hardness, stress and strain. It defines key terms like elastic modulus, yield strength, ultimate strength, elongation, area reduction, fracture strain. It explains concepts such as engineering stress-strain curves, Hooke's law, elastic deformation, plastic deformation, Poisson's ratio, ductile vs brittle materials, and how properties relate to microstructure. Typical testing methods and how to calculate properties from raw data are also summarized.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Mechanical properties refer to how materials behave under forces or pressures. This document discusses key mechanical properties including brittleness, hardness, strength, stiffness, ductility, malleability, elasticity, plasticity, creep, and weldability. It describes how these properties are defined, measured, and their significance for material selection and design. Measurement techniques covered include indentation hardness tests like Rockwell and Brinell, and tension tests. The document also examines stress-strain diagrams and how they vary for different materials and temperatures.
The document discusses stress-strain curves, which plot the stress and strain of a material sample under load. It describes the typical stress-strain behavior of ductile materials like steel and brittle materials like concrete. For ductile materials, the curve shows an elastic region, yield point, strain hardening region, and ultimate strength before failure. The yield point marks the transition between elastic and plastic deformation. The document also discusses factors that influence a material's yield stress, such as temperature and strain rate, and implications for structural engineering like reduced buckling strength after yielding.
1) The document discusses various mechanical properties of dental materials including elastic properties like elastic modulus and plastic properties like yield strength.
2) Mechanical properties are quantified using concepts of stress and strain, and different tests are used to measure properties like hardness, tensile strength, and impact resistance.
3) Key mechanical properties discussed include elastic modulus, proportional limit, yield strength, ductility, toughness, and hardness. Different tests for measuring these properties are also described.
Properties of materials / Mechanical Properties of materialsGulfam Hussain
The document discusses various mechanical properties of materials including strength, elasticity, stiffness, plasticity, ductility, malleability, brittleness, toughness, hardness, impact strength, resilience, fatigue, and creep. It explains these properties and how they are evaluated using stress-strain diagrams and testing machines. The properties are important for engineers to understand how materials will behave under different loading conditions for machine and structural design.
This document discusses mechanical properties that can be determined from tensile and shear tests. It defines key terms like stress, strain, elastic modulus, yield strength, and tensile strength. A typical stress-strain curve is shown and each region is explained. The elastic portion is linear up to the yield point, then the plastic region involves necking and strain hardening until ultimate failure. True stress and strain account for changes in cross-sectional area during deformation. The document also compares properties like ductility and toughness between different materials.
Strength of Materials Lecture - 2
Elastic stress and strain of materials (stress-strain diagram)
Mehran University of Engineering and Technology.
Department of Mechanical Engineering.
This document discusses various mechanical properties of materials including elastic deformation, engineering strain, tensile strength, toughness, yielding, modulus of elasticity, Poisson's ratio, ductility, malleability, hardness, and fatigue. It provides definitions and explanations of these key material properties and how they relate to a material's behavior under stress or loads over time.
Mechanical properties of dental materials / dental courses in indiaIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training
center with best faculty and flexible training programs for dental
professionals who wish to advance in their dental practice,Offers certified
courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry,
Prosthetic Dentistry, Periodontics and General Dentistry.
Physical and mechanical properties and its application in orthodonticshardik lalakiya
Hai this is very interesting topic for the dental students and also for the PG of orthodontics .So just have a glance over it and always your suggestions are heartly welcome.please free to suggest and make necessary suggestions.
Stress & Strain Properies of dental materials Drmumtaz Islam
This document discusses the properties of dental materials that are important to evaluate their performance. It explains that materials' properties depend on whether they are being tested unmixed on shelves, during mixing and setting, or as fully set materials. Key properties discussed include mechanical properties like stress, strain, tensile strength and compressive strength. The relationships between stress and strain are illustrated through stress-strain graphs. Other properties covered are modulus of elasticity, ductility, toughness, resilience, fatigue life, and different types of wear.
This document discusses various mechanical properties of materials including stress, strain, elasticity, strength, ductility, and creep. It defines key terms like stress as force over area, strain as the deformation of length, and explains concepts such as Hooke's law, yield strength, tensile strength, elastic modulus, and provides a table comparing typical mechanical properties for different materials.
Stress strain curve for ductile and brittle materialsHebron Ramesh
1) Hooke's law states that stress is proportional to strain within the elastic limit, with the constant of proportionality being Young's modulus.
2) Young's modulus (E) is typically 210 GPa for steel and describes the relationship between stress and strain in both tension and compression.
3) The stress-strain curve is unique for each material and shows the deformation (strain) at different levels of loading (stress).
The document discusses tensile strength and tensile testing. It defines tensile strength as the maximum stress a material can withstand under tension before necking and breaking. A tensile test measures how a material responds to tensile forces by recording the load and elongation of a test specimen. The results are used to determine various tensile properties including modulus of elasticity, yield strength, ultimate tensile strength, and measures of ductility. Hooke's law and concepts like strain, stress-strain curves, and necking are also explained in the context of understanding a material's tensile behavior.
This document discusses stress-strain curves, which show the relationship between stress and strain for materials. It explains that stress-strain curves are unique for each material and reveal many of its properties. The typical regions in a stress-strain curve are the elastic region, yielding point, plastic region, strain hardening region, necking, and failure point. A universal testing machine is used to generate stress-strain curves by applying loads and recording the resulting deformations. Stress-strain curves vary between different materials.
The document discusses tensile testing to determine material properties. Tensile testing involves applying a load to a test specimen and measuring the resulting elongation. This provides load-deformation data that can be converted to stress-strain data using the specimen's original dimensions. The stress-strain curve indicates material properties like elastic modulus, yield strength, and ductile vs. brittle behavior.
Mechanical properties describe how materials deform and fail when subjected to stress. This document outlines key mechanical properties including elastic deformation, plastic deformation, ductility, resilience, toughness, hardness, and design/safety factors. Elastic deformation is reversible, following Hooke's law, while plastic deformation permanently deforms materials. Yield strength marks the transition between elastic and plastic deformation. Ductility, resilience, and toughness measure a material's ability to deform plastically without fracturing. Hardness tests measure resistance to localized deformation. Design stresses and safe stresses are calculated using yield strengths and factors of safety/design to prevent failure under working loads.
This document discusses various fundamental mechanical properties of materials including tensile strength, hardness, and impact strength. It provides definitions and testing methods for each property. Tensile strength is the maximum stress a material can withstand before breaking, and is measured through tension tests. Hardness tests measure a material's resistance to plastic deformation, and there are several methods like Rockwell, Brinell, and Vickers. Impact strength refers to a material's ability to absorb energy during dynamic loading like impacts without fracturing.
This document discusses the stress-strain curve for textile fibers. It defines stress as the force per unit area applied to a material, and strain as the increase in length from an applied stress. A typical stress-strain curve shows four regions: the elastic region where deformation is recoverable, yielding where permanent deformation begins, strain hardening where the curve rises continuously, and necking and failure where the material fractures.
My first individual presentation.It is unforgettable because the marks i got, was beyond my expectation.....(full marks).Thanks to galib sir and sabrina mam for arranging this presentation.special thank to razia mam for her valuable advices that helped me to enrich my presentation.
The document discusses various mechanical properties of materials including stress and strain, strength, elasticity, plasticity, stiffness, ductility, malleability, resilience, hardness, brittleness, creep, and fatigue. It defines each property and provides examples. Mechanical properties determine a material's behavior under applied forces and loads and are important for predicting how materials will perform and designing components.
The document provides an overview of a student project using a combination of thin structure machining and single point incremental forming (SPIF) to reduce weight while maintaining stiffness. The goals are to model parts to test stiffness and weight reduction, improve wall straightness, and determine factors that affect cracking during forming such as speed and depth. The current status includes preliminary finite element analysis, bulkhead research, simple part modeling, preparing samples to measure wall straightness, and planning new sample preparation.
This chapter provides an introduction to mechanical metallurgy, including the behavior of metals under stress and strain. It discusses key concepts such as elastic and plastic deformation, ductile versus brittle behavior, and the types of failures that can occur in metals. The objectives are to describe the stress-strain response of metals and the defect mechanisms that lead to flow and fracture. Factors influencing failure like temperature, loading conditions, and material properties are also addressed.
This document provides an overview of metal forming processes, including definitions, classifications, and comparisons of hot and cold working. It discusses key topics such as plastic deformation, strain hardening, yield criteria, temperature effects, lubrication, and considerations in process selection. The objectives are to understand elastic and plastic deformation, strain hardening concepts, yield criteria, and differences between hot and cold working processes.
Properties of materials / Mechanical Properties of materialsGulfam Hussain
The document discusses various mechanical properties of materials including strength, elasticity, stiffness, plasticity, ductility, malleability, brittleness, toughness, hardness, impact strength, resilience, fatigue, and creep. It explains these properties and how they are evaluated using stress-strain diagrams and testing machines. The properties are important for engineers to understand how materials will behave under different loading conditions for machine and structural design.
This document discusses mechanical properties that can be determined from tensile and shear tests. It defines key terms like stress, strain, elastic modulus, yield strength, and tensile strength. A typical stress-strain curve is shown and each region is explained. The elastic portion is linear up to the yield point, then the plastic region involves necking and strain hardening until ultimate failure. True stress and strain account for changes in cross-sectional area during deformation. The document also compares properties like ductility and toughness between different materials.
Strength of Materials Lecture - 2
Elastic stress and strain of materials (stress-strain diagram)
Mehran University of Engineering and Technology.
Department of Mechanical Engineering.
This document discusses various mechanical properties of materials including elastic deformation, engineering strain, tensile strength, toughness, yielding, modulus of elasticity, Poisson's ratio, ductility, malleability, hardness, and fatigue. It provides definitions and explanations of these key material properties and how they relate to a material's behavior under stress or loads over time.
Mechanical properties of dental materials / dental courses in indiaIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training
center with best faculty and flexible training programs for dental
professionals who wish to advance in their dental practice,Offers certified
courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry,
Prosthetic Dentistry, Periodontics and General Dentistry.
Physical and mechanical properties and its application in orthodonticshardik lalakiya
Hai this is very interesting topic for the dental students and also for the PG of orthodontics .So just have a glance over it and always your suggestions are heartly welcome.please free to suggest and make necessary suggestions.
Stress & Strain Properies of dental materials Drmumtaz Islam
This document discusses the properties of dental materials that are important to evaluate their performance. It explains that materials' properties depend on whether they are being tested unmixed on shelves, during mixing and setting, or as fully set materials. Key properties discussed include mechanical properties like stress, strain, tensile strength and compressive strength. The relationships between stress and strain are illustrated through stress-strain graphs. Other properties covered are modulus of elasticity, ductility, toughness, resilience, fatigue life, and different types of wear.
This document discusses various mechanical properties of materials including stress, strain, elasticity, strength, ductility, and creep. It defines key terms like stress as force over area, strain as the deformation of length, and explains concepts such as Hooke's law, yield strength, tensile strength, elastic modulus, and provides a table comparing typical mechanical properties for different materials.
Stress strain curve for ductile and brittle materialsHebron Ramesh
1) Hooke's law states that stress is proportional to strain within the elastic limit, with the constant of proportionality being Young's modulus.
2) Young's modulus (E) is typically 210 GPa for steel and describes the relationship between stress and strain in both tension and compression.
3) The stress-strain curve is unique for each material and shows the deformation (strain) at different levels of loading (stress).
The document discusses tensile strength and tensile testing. It defines tensile strength as the maximum stress a material can withstand under tension before necking and breaking. A tensile test measures how a material responds to tensile forces by recording the load and elongation of a test specimen. The results are used to determine various tensile properties including modulus of elasticity, yield strength, ultimate tensile strength, and measures of ductility. Hooke's law and concepts like strain, stress-strain curves, and necking are also explained in the context of understanding a material's tensile behavior.
This document discusses stress-strain curves, which show the relationship between stress and strain for materials. It explains that stress-strain curves are unique for each material and reveal many of its properties. The typical regions in a stress-strain curve are the elastic region, yielding point, plastic region, strain hardening region, necking, and failure point. A universal testing machine is used to generate stress-strain curves by applying loads and recording the resulting deformations. Stress-strain curves vary between different materials.
The document discusses tensile testing to determine material properties. Tensile testing involves applying a load to a test specimen and measuring the resulting elongation. This provides load-deformation data that can be converted to stress-strain data using the specimen's original dimensions. The stress-strain curve indicates material properties like elastic modulus, yield strength, and ductile vs. brittle behavior.
Mechanical properties describe how materials deform and fail when subjected to stress. This document outlines key mechanical properties including elastic deformation, plastic deformation, ductility, resilience, toughness, hardness, and design/safety factors. Elastic deformation is reversible, following Hooke's law, while plastic deformation permanently deforms materials. Yield strength marks the transition between elastic and plastic deformation. Ductility, resilience, and toughness measure a material's ability to deform plastically without fracturing. Hardness tests measure resistance to localized deformation. Design stresses and safe stresses are calculated using yield strengths and factors of safety/design to prevent failure under working loads.
This document discusses various fundamental mechanical properties of materials including tensile strength, hardness, and impact strength. It provides definitions and testing methods for each property. Tensile strength is the maximum stress a material can withstand before breaking, and is measured through tension tests. Hardness tests measure a material's resistance to plastic deformation, and there are several methods like Rockwell, Brinell, and Vickers. Impact strength refers to a material's ability to absorb energy during dynamic loading like impacts without fracturing.
This document discusses the stress-strain curve for textile fibers. It defines stress as the force per unit area applied to a material, and strain as the increase in length from an applied stress. A typical stress-strain curve shows four regions: the elastic region where deformation is recoverable, yielding where permanent deformation begins, strain hardening where the curve rises continuously, and necking and failure where the material fractures.
My first individual presentation.It is unforgettable because the marks i got, was beyond my expectation.....(full marks).Thanks to galib sir and sabrina mam for arranging this presentation.special thank to razia mam for her valuable advices that helped me to enrich my presentation.
The document discusses various mechanical properties of materials including stress and strain, strength, elasticity, plasticity, stiffness, ductility, malleability, resilience, hardness, brittleness, creep, and fatigue. It defines each property and provides examples. Mechanical properties determine a material's behavior under applied forces and loads and are important for predicting how materials will perform and designing components.
The document provides an overview of a student project using a combination of thin structure machining and single point incremental forming (SPIF) to reduce weight while maintaining stiffness. The goals are to model parts to test stiffness and weight reduction, improve wall straightness, and determine factors that affect cracking during forming such as speed and depth. The current status includes preliminary finite element analysis, bulkhead research, simple part modeling, preparing samples to measure wall straightness, and planning new sample preparation.
This chapter provides an introduction to mechanical metallurgy, including the behavior of metals under stress and strain. It discusses key concepts such as elastic and plastic deformation, ductile versus brittle behavior, and the types of failures that can occur in metals. The objectives are to describe the stress-strain response of metals and the defect mechanisms that lead to flow and fracture. Factors influencing failure like temperature, loading conditions, and material properties are also addressed.
This document provides an overview of metal forming processes, including definitions, classifications, and comparisons of hot and cold working. It discusses key topics such as plastic deformation, strain hardening, yield criteria, temperature effects, lubrication, and considerations in process selection. The objectives are to understand elastic and plastic deformation, strain hardening concepts, yield criteria, and differences between hot and cold working processes.
The document discusses material properties relevant to metal forming processes. It notes that metals must have low yield strength and high ductility to be successfully formed. Temperature affects these properties, with ductility increasing and yield strength decreasing at higher temperatures. It also discusses independent variables like starting material and geometry that engineers control, and dependent variables like forces produced. The material behavior in forming is characterized by stress-strain curves and flow curves, which describe how properties change with deformation. The document provides information on determining and applying flow curves for different forming processes that occur at various temperature ranges, like cold, warm, and hot working.
The document discusses the mechanical properties of dental materials. It defines mechanical properties as those defined by the laws of mechanics, including forces and their effects on materials. Mechanical properties need to be considered collectively based on the intended application of the material. The success of any dental restoration depends on the mechanical properties of the material used. Key mechanical properties discussed include stress, strain, strength, elastic modulus, resilience, toughness, ductility and hardness. Various testing methods are used to evaluate these properties.
The document provides an overview of key concepts in metal forming including:
1) Metal forming processes use plastic deformation to change the shape of metal workpieces using dies that exceed the metal's yield strength.
2) Material properties like low yield strength and high ductility are desirable and affected by temperature.
3) Processes are classified by the scale of deformation from bulk to sheet metal and include rolling, forging, extrusion, drawing, bending, and shearing.
4) Temperature, strain rate, and friction influence how metal flows during forming. Lubricants are used to reduce friction.
Metallurgy P R O P E R T I E S And DefinitionsMoiz Barry
Engineering concepts of metals document discusses various hardness testing methods like Brinell and Rockwell. It explains that hardness is the resistance to deformation and depends on factors like grain size and work hardening. The document also covers tensile stress, shear stress, heat treatment processes to alter material properties like hardening and softening, and concepts like modulus of rigidity and stiffness.
This document discusses the mechanical properties of viscoelastic materials. It covers topics like stress/strain behavior, creep, toughness, reinforcement, and modifiers. It explains how polymer chemistry, structures, and properties influence product performance. Key factors that determine a plastic's mechanical response are intermolecular forces, temperature, time under load, degree of crystallinity, and molecular weight. A plastic can behave as an elastic solid, viscoelastic solid, viscoelastic fluid, or viscous fluid depending on these factors. Tests like tensile testing, impact testing, and dynamic mechanical analysis are used to characterize mechanical properties.
The document discusses various fundamentals of metal forming processes including hot working, cold working, and warm working operations. It describes different metal forming techniques like forging, rolling, extrusion, and describes tools used in smithy like anvil, hammers, swages, and forging operations like upsetting, drawing, bending, and punching.
Metal forming processes are used to shape metals into useful products. Rolling is the most common forming process and accounts for around 90% of metal forming. It involves passing metal between rolls to reduce thickness or change cross-section. Forging uses dies and compression to shape hot or cold metal. Extrusion forces heated metal through a die to create shapes like rods, tubes and structural sections. Drawing pulls metal through a die to make wires, rods and tubes from both hot and cold workpieces. Deep drawing specifically makes cylindrical parts like cups from sheet metal.
The document discusses various mechanical properties of materials including stress-strain relationships, hardness, and the effect of temperature on properties. It describes common tests used to evaluate these properties such as tensile, compression, bending, and hardness tests. The tensile test is used to generate a stress-strain curve and determine properties like elastic modulus, yield strength, ultimate tensile strength, and ductility. The shape of the stress-strain curve provides information about the material's behavior and properties.
The document discusses various defects that can occur in metal forming processes. It describes the different types of bulk metal forming processes like rolling, forging, extrusion, and drawing. It also covers sheet metalworking processes like bending, drawing, and shearing. The document discusses factors that influence metal forming like material behavior, temperature, strain rate, friction, and lubrication. It explains defects like springback, wrinkles, and provides methods to minimize them.
This document provides an overview of metal cutting processes on a center lathe. It discusses [1] the basic components and operation of a center lathe, [2] the types of single-point cutting tools used, [3] the theory behind metal cutting, and [4] important factors that influence tool life and cutting performance such as tool angles, cutting speed, feed, and use of cutting fluids. Safety procedures are also emphasized.
The section will cover the behaviour of materials by introducing the stress-strain curve. The concepts of elastic and plastic deformation will be covered. This will then lead to a discussion of the micro-structure of materials and a physical explanation of what is happening to a polycrystalline material as it is loaded to failure.
Plant layout refers to the physical arrangement of equipment, machines, tools, and furniture in a manufacturing facility. The goal is to optimize material flow from raw materials to finished goods with the lowest costs and least amount of handling. There are four main types of layouts: product layout arranges machines in a straight line based on production steps; process layout groups similar machines together; combined layout uses aspects of both; and fixed position layout keeps products stationary while workers and machines move between positions. The optimal layout depends on factors like production volume and product standardization.
Orthodontic archwires /certified fixed orthodontic courses by Indian dental a...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The document discusses the physical properties of archwire materials used in orthodontics. It describes various properties including stress, strain, modulus of elasticity, proportional limit, yield strength, ductility, resilience, flexibility, and springback. It then focuses on the stress-strain curve and explains properties like tensile stress, compressive stress, shear stress, modulus of elasticity, proportional limit, elastic limit, yield strength, elongation, resilience, formability, flexibility, load deflection rate, and springback. Finally, it discusses how the size, shape, and material composition of archwires can impact their strength, stiffness, and range of action.
The document discusses the history and properties of different types of archwire materials used in orthodontics. It describes the evolution from early gold alloy wires to more recent materials like stainless steel, cobalt-chromium, and nickel-titanium wires. For each material, it covers aspects like composition, heat treatment process, mechanical properties including strength, stiffness, flexibility and factors important for clinical use. The document serves as a comprehensive reference on archwire materials.
Mechanical properties of materials (lecture+2).pdfHeshamBakr3
The document discusses the mechanical properties of materials when subjected to different types of loading like axial, lateral, and torsional loads. It defines concepts like stress, strain, elastic and plastic deformation. It explains stress-strain diagrams and how they are used to determine properties like modulus of elasticity, yield strength, tensile strength, ductility, toughness, and resilience. Typical stress-strain behaviors of ductile and brittle materials are compared. Examples of determining properties from stress-strain curves are also provided.
This document discusses various concepts related to stress and strain. It begins by explaining the three main types of loads - tension, compression, and shear. It then provides diagrams demonstrating these different types of loads. The document goes on to define engineering stress and strain and discuss their units. Several mechanical properties are also defined, including yield strength, ultimate tensile strength, and elongation. Finally, the document discusses various tests used to determine mechanical properties, including tensile, compression, hardness, and impact tests.
The document discusses tensile strength and tensile testing. It defines tensile strength as the maximum stress a material can withstand under tension before necking and breaking. A tensile test measures how a material responds to tensile forces by recording the load and elongation of a test specimen. The results are displayed as a stress-strain curve which can show properties like yield strength, ultimate tensile strength, modulus of elasticity, and ductility measures.
1. Orthodontic wires- SS, Co-Cr, Australian shrestha.pptxanweshagarg49
This document discusses orthodontic archwires, including their basic properties and types of stainless steel wires. It begins with definitions of archwires and wire dimensions. It then discusses the evolution of orthodontic wires from early noble metals to modern materials like stainless steel, nickel-titanium, and beta-titanium alloys. The document focuses on the basic properties of orthodontic wires, including strength, stiffness, resilience, formability, and others. It explains these properties with diagrams and definitions. Finally, it discusses how wire size and shape can affect elastic properties.
This document provides an introduction to strength of materials (SOM). It defines key terms like strength, stiffness, stability, and durability. It discusses the basic problem in SOM as developing methods to design structural elements that consider strength, stiffness, stability, and economy. It also outlines the main hypotheses in SOM, including the material being continuous, homogeneous, and isotropic. It then discusses different types of stresses like tensile, compressive, and shear stresses. It provides stress-strain curves for ductile materials and defines modulus of elasticity. Examples of calculating stresses and strains in structural elements are also provided.
Mechanical properties of dental materials/ orthodontic course by indian denta...Indian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
physical and mechcanical properties of dental materials..pptmanjulikatyagi
The document discusses various mechanical properties of materials including stress, strain, tensile strength, compressive strength, shear strength, modulus of elasticity, ductility, resilience, toughness, and hardness. It defines these terms and describes methods for measuring properties such as stress, strain, hardness, and strength. For example, stress is defined as force per unit area and can be measured using a three-point bending test. Hardness is the resistance of a material to indentation and can be measured using Knoop or Vickers indentation tests.
Physical and mechanical properties and its application in orthodonticsHardik Lalakiya
This is a nice seminar about the physical and mechanical properties and some nice images and almost some good concepts are there so just watch this and any suggestions are heartly welcome feel free to advise and suggest thanks.
Mechanical, physical and aesthetic properties of dentalChaithraPrabhu3
This document provides an overview of various mechanical, physical, and aesthetic properties of dental materials. It discusses key concepts such as stress, strain, elastic limit, yield strength, tensile strength, compressive strength, shear strength, flexural strength, fatigue, impact strength, elastic properties, and optical properties. Various strength properties are defined, including proportional limit, elastic limit, yield strength, and ultimate tensile/compressive/shear/flexural strengths. Strength is important for withstanding forces from mastication. Material properties must also account for the physiological environment of the oral cavity.
The document discusses various topics relating to material properties and crystal structure:
- Crystal structure determines material properties and is the arrangement of atoms in the material. The smallest repeating unit that can generate the crystal structure is called the unit cell.
- Metallic crystals have densely packed structures due to small atomic radii and non-directional metallic bonding. Common unit cell structures are simple cubic, body centered cubic, and face centered cubic.
- Mechanical properties like stress, strain, elastic moduli, ductility, and toughness are influenced by the crystal structure and affect how the material responds to forces. The stress-strain curve provides information on a material's elastic and plastic deformation.
- Other topics covered
Tensile testing is used to determine the strength and ductility of materials. A specimen is placed in grips and pulled apart under increasing tensile force while measuring elongation. The resulting stress-strain curve provides properties like yield strength, tensile strength, and Young's modulus. Tensile tests are important for engineering design and quality control by ensuring materials can withstand expected loads and comparing new materials. Common applications include testing aircraft components, bolts, and other loaded structures.
Mechanical properties of dental materials are important for understanding how materials will behave under forces during clinical use. Three key properties discussed are:
1. Modulus of elasticity (stiffness) determines a material's ability to resist bending or deformation and is important for bridges and wires. Cobalt-chromium alloys have the highest modulus.
2. Strength properties like proportional limit, yield strength, and ultimate strength indicate the stress level at which permanent deformation begins, important for ensuring restorations maintain their intended fit.
3. Impact strength is the energy required to fracture a material and is measured using impact testing devices to evaluate resistance to sudden forces. Materials with higher impact strength are less brittle.
The document discusses materials testing and various types of tests, including destructive and non-destructive tests. Destructive tests include tensile tests, compression tests, torsion tests, impact tests, hardness tests, fatigue tests, and creep tests. Non-destructive tests include scanning electron microscopy, radiography, atomic force microscopy, liquid penetration testing, and ultrasonic testing. The document focuses on tensile tests and provides details on how they are conducted, what properties they measure (e.g. yield strength, ultimate tensile strength, modulus of elasticity), and how to interpret stress-strain curves. Examples of calculations using data from tensile tests are also provided.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Demonstration of Mechanical Behaviour of Material Using a Practical Approach Dr.Gaurav Kumar Gugliani
This document announces an online workshop on demonstrating the mechanical behavior of materials using practical approaches. The workshop will be held on May 10, 2020 from 11:00 AM to 12:30 PM and will be conducted by Dr. Gaurav Gugliani and Mr. Pawan Bhawsar from the Department of Mechanical Engineering at Mandsaur University. The workshop will provide an introduction to mechanical engineering and mechanical properties, discuss stress-strain and its types, material properties, and elastic moduli. It will also demonstrate stress-strain diagrams and the universal testing machine along with the types of tests performed on it.
Demonstration of Mechanical Behaviour of Material Using a Practical Approach Dr. Gaurav Kumar Gugliani
This document announces an online workshop on demonstrating the mechanical behavior of materials using practical approaches. The workshop will be held on May 10, 2020 from 11:00 AM to 12:30 PM and presented by Dr. Gaurav Gugliani and Mr. Pawan Bhawsar. The presentation will introduce mechanical engineering, mechanical properties, stress-strain types, material properties, elastic moduli, and stress-strain diagrams. It will also demonstrate the use of a universal testing machine and the types of tests it can perform.
Opportunity for Dentists (BDS/MDS )to relocate to United kingdom -Register as a DENTAL HYGIENIST/ DENTAL THERAPIST without Board exams and after approval you can register in GDC as a DH/DT and start working as a DH/DT Immediately and get paid.
You can complete the whole process in 3-4 months.Salary range for DH/DT is around 2500-3500 Pounds per month.
Eligibility / requirements-
1. An International English Language Testing System (IELTS) certificate
at the appropriate level.(Within 2 yrs of application date )
2: A recent primary dental qualification that has been taught and examined in English..(Within 2 yrs of application date )
3: A recent pass in a language test for registration with a regulatory authority in a country where the first language is English.
If you are interested Please contact us for more details.
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...Indian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals
who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry,
Periodontics and General Dentistry.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
I –Aligners are made with FDA approved transparent thermoplastic materials using 3D scanning, 3D Printing and finally Trays with Pressure vacuum formers.
Dear Doctor,
Indian Dental Academy Now offers comprehensive online Orthodontics course.
Course includes:
1.whiteboard lecture presentations
2.Case Discussions
3.with hundreds of pictures.
4.Demo on Models
5.Demo on Patients
6. subtitles in your own language
12 months unlimited access and support @350 USD only.
For Demo please visit :www.idalectures.com/preview/
For more details visit: www.idalectures.com
Please contact us for any clarifications:
idalectures@gmail.com
indiandentalacademy@gmail.com
Thanks & Regards
Indian Dental Academy
--
Indian Dental Academy
Leader in continuing dental education
www.indiandentalacademy.com
skype:indiandentalacademy
+919248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Diagnosis and treatment planning in completely endntulous arches/dental coursesIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Properties of Denture base materials /rotary endodontic coursesIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Use of modified tooth forms in complete denture occlusion / dental implant...Indian dental academy
This document discusses dental occlusion concepts and philosophies for complete dentures. It introduces key terms like physiologic occlusion and defines different occlusion schemes like balanced articulation and monoplane articulation. The document discusses advantages and disadvantages of using anatomic versus non-anatomic teeth for complete dentures. It also outlines requirements for maintaining denture stability, such as balanced occlusal contacts and control of horizontal forces. The goal of occlusion for complete dentures is to re-establish the homeostasis of the masticatory system disrupted by edentulism.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This document discusses dental casting investment materials. It describes the three main types of investments - gypsum bonded, phosphate bonded, and ethyl silicate bonded investments. For gypsum bonded investments specifically, it details their classification, composition including the roles of gypsum, silica, and modifiers, setting time, normal and hygroscopic setting expansion, and thermal expansion. It provides information on how the properties of gypsum bonded investments are affected by their composition. The document serves as a comprehensive overview of dental casting investment materials.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
Reimagining Your Library Space: How to Increase the Vibes in Your Library No ...Diana Rendina
Librarians are leading the way in creating future-ready citizens – now we need to update our spaces to match. In this session, attendees will get inspiration for transforming their library spaces. You’ll learn how to survey students and patrons, create a focus group, and use design thinking to brainstorm ideas for your space. We’ll discuss budget friendly ways to change your space as well as how to find funding. No matter where you’re at, you’ll find ideas for reimagining your space in this session.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
3. Orthodontic wires which generate the biomechanical
forces communicated through brackets for tooth
movement ,are central to the practice of profession.
In the rational selection of wires for a particular
treatment ,the orthodontist should consider a variety of
factors ,including the amount of force delivery that is
desired ,the elastic range or springback ,formability and
the need for soldering and welding to assemble the
appliance
www.indiandentalacademy.com
4. With the need to maintain a relatively large
inventory ,orthodontists must be concerned with
the costs of wires ,which can vary considerably
among wire alloys as well as among companies
www.indiandentalacademy.com
5. PROPERTIES OF
ORTHODONTIC WIRES
Physical properties of materials can be considered as
the ways that Materials respond to changes in their
environment
Physical properties : Descriptive of size, shape and appearance.
Material properties : Subdivided into
.
•Characteristics that are independent of external influences
simply termed “Material” properties.
•Those that are associated in someway with the
conditions of use or the use environment.
e.g : Mechanical, Chemical, Thermal and Magnetic
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7. 1. Elastic or reversible deformation
Proportional limit, Resilience, Modulus of
Elasticity.
2. Plastic or irreversible deformation
e.g :- Percent elongation.
3. Combination of Elastics Plastic deformation
e.g :- Toughness and Yield strength
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8. STRESS :-
When a force acts on a body tending to produce
deformation a resistance is developed to this external
force application. The INTERNAL reaction is equal in
intensity and opposite in direction to the applied external
force and is called stress.
Stress( ) = Force/Area
Commonly expressed as Pascal 1Pa = 1N/m2
. It is
common to report stress in units of Megapascals (MPa)
where 1 MPa = 106
Pa.
TYPES OF STRESS :- tensile ,compressive & shear
6
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9. STRAIN :-
Whenever a force is applied to a body it undergoes
deformation.
Strain is described as the change in length (Δ L = L –
LO) per unit length of the body when it is subjected to a
stress.
Change in length L – Lo ΔL
Strain (∈ ) = = =
Original length Lo Lo
• Strain has no units of measurement.
• It is a Dimensionless quantity.
• Reported as an absolute value or as a percentage.
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10. Strain Elastic
Plastic
Each type of stress is capable of producing a
corresponding deformation in a body.
• Tensile stress produces tensile strain.
• Compressive stress produces compressive
strain.
• Shear stress produces shear strain.
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11. STRESS STRAIN CURVE:-
Represents energy storage capacity of the wire so
determines amount of work expected from a particular
spring in moving a tooth.
Engineering Stress-Strain Curve
In the calculation of stress it is assumed that the
cross sectional area of the specimen remains constant
during the test. Stresses are calculated based on
original cross sectional area.
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12. True Stress Strain Curve :-
A stress strain curve based on stresses calculated from
a Non Constant Cross sectional area is called a true
stress strain Curve.
A true-stress strain curve may be quite different from an
engineering stress-strain curve at high loads because
significant changes in the area of specimen may occur.
www.indiandentalacademy.com
14. Poisson’s ratio –
When a tensile force is applied to an object ,the
object becomes longer & thinner ,the ratio of
accompanying strain in direction perpendicular
to force application to the strain in the force
direction is poisson’s ratio
www.indiandentalacademy.com
15. Important mechanical properties based on Elastic or
reversible deformation are :-
ELASTIC MODULUS
FLEXIBILITY.
RESILIENCE
Other properties that are determined from stresses at the
end of elastic region of stress -strain plot and at
beginning of plastic deformation region.
PROPORTIONAL LIMIT.
ELASTIC LIMIT.
YIELD STRENGTH
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16. ELASTIC MODULUS (Young’s Modulus or Modulus of
Elasticity)
• The term elastic modules describes the relative
STIFFNESS or rigidity of a material which is measured
by the elastic region of stress – strain diagram.
• It is denoted by letter E
• determined from stress stain curve by calculating ratio
of stress to strain or slope of linear portion of curve.
Stress
Elastic Modulus = =
Strain ∈
6
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17. • Modulus of elasticity is independent of the
ductility of a material and it is not a measure of
its strength.
• it is an inherent property of a material and
cannot be altered appreciably by heat
treatment, work hardening or any other kind of
conditioning. This property is called
STRUCTURAL INSENSITIVITY.
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18. FLEXIBILITY :-
The maximum flexibility is defined as the strain that
occurs when the material is stressed to its proportional
limit.
RESILIENCE :-
Popularly the term Resilience is associated with
“springiness”.
It is defined as the amount of energy absorbed by a
structure when it is stressed to its proportional limit.
Area bounded by the elastic region is measure of
Resilience
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19. SPRINGINESS :-
Proportional to slope of elastic portion stress-strain
curve.
More Horizontal the slope
Springier the wire having low stiffness
TOUGHNESS
Higher the strength and higher the ductility (total plastic
strain) greater the toughness.
The total area under the entire stress-strain curve is a
measure of the energy required to fracture the material
A tough material is generally strong although a strong
material is not necessarily tough
www.indiandentalacademy.com
20. BRITTLENESS :-
It is the relative inability of a material to sustain plastic
deformation before fracture of a material occurs.
ULTIMATE STRENGTH :-
Ultimate tensile strength or stress is defined as the maximum
stress that a material can withstand before failure in tension.
YIELD STRENGTH
( Yield Stress, Proof Stress)
It is defined as the stress at which a material exhibits a
specified limiting deviation from proportionality of stress to
strain.
Amount of permanent strain is arbitrarily selected for material
being examined and may be indicated as 0.1%, 0.2% or 0.5%
(0.001, 0.002, 0.005) permanent strain
Amount of permanent strain may be referred to as PERCENT
OFFSET. Many specifications use 0.2% as convention.
www.indiandentalacademy.com
21. Proportional Limit :- (PL)
It is defined as the greatest stress that a
material will sustain without a deviation
from the linear proportionality of stress to
strain.
Hooke’s Law :- States that stress – strain
ratio is constant upto the proportional
limit, the constant in this linear stress-
strain relationship is Modulus of
Elasticity.
Below PL no permanent deformation
occurs in a structure.
Region of stress stain Curve.
Below PL – ELASTIC REGION
Above Pl – PLASTIC REGION
www.indiandentalacademy.com
22. ELASTIC LIMIT :- (EL)
It is defined as maximum stress that a material can
withstand before it undergoes permanent deformation.
• For all practical purposes PL and EL represent same
stress. But they differ in fundamental concept :-
• PL deals with proportionality of strain to
stress in structure.
• EL describes elastic behavior of the material.
EL & PL limits are usually assumed to be identical
although their experimental values may differ slightly.
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23. DUCTILITY AND MALLEABILITY :-
Ductility represents the ability of a material to sustain a large
permanent deformation under tensile load without rupture.
A material that may be drawn readily into a wire is said to be
DUCTILE.
Malleability :-
Ability of a material to sustain considerable permanent
deformation without rupture under compression as in hammering
or rolling into a sheet.
- Gold is most ductile and malleable pure metal
- Silver is second.
- Platinum ranks 3rd
in ductility.
Copper ranks 3rd
in malleability
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24. Formability :-
It is defined as the amount of permanent
deformation that a wire can withstand before
failing.
Represents the amount of permanent bending
the wire will tolerate before it breaks.
Can be interpreted as area under plastic region
of stress – strain curve.
www.indiandentalacademy.com
26. SPRING BACK
It represents the elastic strain recovered on unloading from
permanent deformation range.
Given by Expression :- YS/E. ( Yield strength / elastic modulus).
In many clinical situations, orthodontic wires are deformed
beyond their Elastic limit. Their spring back properties in portion
of load deflection curve between elastic limit and ultimate
strength are important in determining clinical performance.
Unloading curve from the permanent deformation range for well
behaved orthodontic wire alloys (i.e., other than NiTi wires) is
parallel to the elastic loading curve the value of YS/E represents
the approximately amount of elastic strain released by archwire
on unloading
www.indiandentalacademy.com
28. . THREE BASIC ELASTIC PROPERTIES
Three basic properties of elastic materials and devices
follow :-
STIFFNESS
STENGTH
RANGE
STIFFNESS :- It is a force / distance ratio that is a
measure of resistance to deformation. It is a measure of
the force required to bend or otherwise deform the
material a definite distance.
www.indiandentalacademy.com
29. STRENGTH : - It is a force value that is a measure of the maximum
possible load, the greatest force the wire or arch arrangement
can sustain or deliver if it is loaded to the limit to the material.
RANGE :- (WORKING RANGE) It is defined as the distance that
the wire will bend elastically before permanent deformation.
Relationship b/w three elastic properties :-
Strength = Stiffness x Range.
Factors that influence Strength Stiffness and Range :
• Mechanical arrangement by which force is applied to teeth e.g :-
bracket width, length of archwire, span and loops.
• Form of wire itself – size and shape of cross section.
Material including the alloy formula, its hardness etc
www.indiandentalacademy.com
30. BEHAVIOUR OF ARCHWIRE IN BENDING :-
When an archwire is bent the metal is
stretched along the outside curvature and
compressed along the inside curvature.
This combination of tension and compression
that resists bending and actually accomplishes
energy storage in the spring action of wire
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31. Bending Moment :-
A measure of bending effort at any specified point in a
beam, measured in units of force times distance (Ounce
inches, grams-centimeters etc.)
critical (dangerous) section :-
Maximum bending moment in a cantilever is at the
supported end. In beam terminology the location of this
maximum bending moment is called CRITICAL or
DANGEROUS section
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33. NEUTRAL AXIS:
The part of a beam
that is neither
elongated nor
compressed in
bending. The neutral
axis is like a flat
ribbon through the
center of the wire,
midway between
outer and inner
curved sides.
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34. . EFFECTS OF LENGTH AND CROSS SECTION ON ELASTIC
PROPERTIES:
EFFECTS OF LENGTH :-
IN BENDING :-
1
Stiffness
(Length)3
1
Strength
(Length)
Range (Length)2
www.indiandentalacademy.com
36. BEHAVIOUR OF ARCHWIRE IN TORSION
TORSION :-
Torsion is the actual twisting (strain) that takes
place in the material as s result of the torque
Torque is the force (Stress) that causes twist.
In case of rectangular wire ”C” is the distance from
center of wire to an outer corner instead of to
one of the sides.
www.indiandentalacademy.com
37. IN TORSION :-
There are no exponential
effects of length in torsion.
1. Strength :- Length has
absolutely no effect on
strength.
2. Range :- Range in torsion is
directly proportional to
length
3. Stiffness :- Stiffness in
torsion is inversely
proportional to length.
www.indiandentalacademy.com
38. EFFECTS OF CROSS SECTION - Most potent single
factor available for control of orthodontic force
application.
IN BENDING
Round Wires
1. Range
‘C’ It is the distance b/w extreme fiber and neutral axis.
‘Index of working range of a bending wire
1
Range α
C
Therefore range is inversely proportional to diameter.
www.indiandentalacademy.com
39. 2. Stiffness :-
Stiffness of wires
depends on value called
the Moment of Inertia (I).
Moment of Inertia
Property of the cross
section of a beam that is
proportional to the effect
of the cross section on
resistance to bending or
twisting (Stiffness).
Stiffness α (diameter)4
www.indiandentalacademy.com
40. 3. Strength : -
Engineering term that
defines strength in terms of
wire’s cross section is
SECTION MODULUS –
Denoted by letter Z.
Z = I/C.
Strength α (Diameter)3
www.indiandentalacademy.com
41. Rectangular wires:
In round wires → width and thickness are always same .
Both are called Diameter and treated as single
dimension.
Width & Thickness → Vary independently of one another
in rectangular wires.
Width:→ Used to describe dimension perpendicular to
direction of bending in plane of neutral axis.
Thickness: → dimension in plane of bend
www.indiandentalacademy.com
42.
1. Effect of width & thickness on range: Width has no
effect on bending range of wire. Range is inversely
related to thickness.
2. Effect of width on stiffness and strength: Width is
directly proportional to strength and stiffness in
rectangular wires.
3. Effect of thickness on stiffness and strength:
Stiffness α (Thickness)3
Strength α (Thickness)2
www.indiandentalacademy.com
45. LABORATORY TESTS
In 1977, ADA specification No. 32 was published. This ADA
specification No. 32 for orthodontic wires not containing precious
metals contains directive on testing, packaging and marketing of
orthodontic arch wires.
Properties of orthodontic arch wires are commonly determined by
means of various laboratory tests.
Mechanical properties of orthodontic wires are determined from:-
- Tension test
- Bending test
- Torsion test.
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46. Bending test: Considered more representative of clinical
conditions than the tension test.
Provides information on behaviour of wires when
subjected to 1st and 2nd
order bends.
Torsion tests: Reflect wire characteristics in third order
direction
Graphic descriptions:
- Stress against strain in tension
- Bending moment against angular deflection.
Torsional moment against torque angle.
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47. Elastic Bending test:
Bending couple is applied at one end of specimen where
only rotation is permitted ; at the other end of test span
wire is held against fixed knife edge stop.
- Angular deformation measured is rotation of the shaft
(θ ).
- A typical plot of applied couple versus angular
deformation is done.
- Specified offset (2.9° according to ADA Sp. No. 32) is
used to determine yield strength.
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48. MANUFACTURING OF
ORTHODONTIC WIRES
Metallic orthodontic wires are manufactured by a series of
proprietary steps, typically involving more than one company.
Sources:- Stainless steel orthodontic wires are procured by
suppliers from commercial sources of stainless steel.
Ingot:- Initially the wire alloy is cast in the form of an ingot which
must be subjected to successive deformation stages until cross
section becomes sufficiently small for wire drawing.
Rolling: The first mechanical step is rolling the ingot into a long bar.
This is done by series of rollers that gradually reduce the ingot to
a relatively small diameter.
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49. Considerable work hardening of the alloy occurs during
rolling.
⇓
It may fracture if rolling is continued beyond this point.
⇓
TO PREVENT THIS:
- Rolling process is interrupted
Metal is ANNEALED by heating to a suitably high
temperature
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50. . Drawing:
After ingot has been reduced to a fairly small diameter
by rolling, it is further reduced to its final size by
drawing.
It is a forming process that is used to fabricate metal
wire and tubing. Deformation is accomplished by pulling
the material through a die by means of tensile force
applied to the exit side of a die.
Before it is reduced to orthodontic size, a wire is drawn
through many series of dies and annealed several times
along the way to relieve work hardening.
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51. Important proprietary details include:
Rate of drawing.
Amount of cross section reduction per pass.
Nature of intermediate heat treatments.
Die material.
Ambient atmosphere
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52. RECTANGULAR WIRES:
Rectangular cross section wires are fabricated
from round wires by a rolling process using
TURK’S HEAD which contains series of rolls.
Rectangular or square cross section wires –
have some degree of rounding at corners
(EDGE BEVEL).
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53. SPRING PROPERTIES OF WIRES:
Hardness and spring properties of most orthodontic
wires depend almost entirely on effects of work
hardening during manufacture.
If metal is almost in need of another annealing at its
final size – it will have maximum work hardening and
spring properties.
If drawing is carried too far enough after last annealing
– wire will be brittle.
If drawing is not carried far enough after last annealing –
too much residual softness and very low working range
and strength
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54. STRUCTURE OF METALS AND ALLOYS
ALLOY: A solid mixture of a metal with one or more other
metals or with one or more non metals which are
mutually soluble in molten state is called an alloy.
e.g., Steel – Alloy of iron and carbon
Stainless steel alloy of iron, carbon and chromium.
PHASE: A phase is any physically distinct, homogenous
and mechanically separable portion of a system.
SOLID SOLUTION: An alloy phase in which one alloying
elements enters space lattice of the other.
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55. GRAIN:- Metal is made up of
thousands of tiny crystals. Such
a metal is said to be
polycrystalline and each crystal
in a structure is called GRAIN.
UNIT CELL:- The smallest division
of the crystalline metal that
defines the unique packing is
called unit cell.
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57. DEFORMATION IN METALS – ATOMIC LEVEL VIEW:
1. Elastic strain:
Atoms are shifted from their equilibrium positions by fraction of
their atomic spacing.
When stress is removed atoms return to equilibrium atomic
spacing.
2. Plastic Deformation:
This mode of deformation requires that atoms be shifted to new
atomic sites on lattice.
Mechanism of plastic deformation is called “DISLOCATION
MOTION”.
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59. LINE DEFECTS
(DISLOCAITONS):
e.g., Edge dislocation:
Dislocation line:- The
lattice is regular except
for one plane of atoms
which is discontinuous
forming a dislocation
line.
The plane along which
dislocation moves is
known as SLIP PLANE.
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61. STRAIN HARDENING / WORK HARDENING:-
Process resulting from cold working (i.e., deformation at room
temperature) as a result of which greater stress is required to
produce further slip and the metal becomes stronger, harder and
less ductile.
Ultimate result of strain hardening with further increase in cold
working is FRACTURE.
RESULTS OF STRAIN HARDENING:-
Increased surface hardness, strength and PL.
Decreased ductility and resistance to corrosion.
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62. CAUSES OF STRAIN HARDENING:-
If dislocation during translation meets some other type of lattice
discontinuity, its gliding movement under stress might be
inhibited.
Such discontinuities are:-
POINT DEFECTS.
Collision of one dislocation with different type
Foreign atom or group of atoms of different lattice
characteristics.
GRAIN BOUNDARIES
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63. . HEAT TREATMENT:
A process characterized by the transfer of energy in the
form of heat to a metallic material to alter its mechanical
and / or thermal properties.
Carried out in 3 Steps:-
1. System temperature is elevated by placing it in a high
temperature environment. (e.g., furnance or a hot salt
bath or by electric resistance/ induction heating).
2.Upon reaching desired temperature the system is
maintained there for a specific period of time.
3.System is returned to its initial state temperature.
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66. 1. Stress relief heat treatment:-
Releases the stresses incorporated in metal due to cold
working procedures.
Mechanism: Internal stresses are relieved by minute
slippages and readjustments in intergranular relations
without loss of hardening.
e.g., - Recommended temperature for stress relieving
stainless steel is 750°F (399°C) for 11min.
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67. 2.Annealing heat treatment:
A heat treatment process employing a relatively high
temperature that results in recrystallisation of
microstructure and produces marked changes in
mechanical properties.
Stages of annealing: Recovery
Recrystallisation
Grain growth.
Temperature are substantially above that of stress relief
– Annealing of stainless steel requires few minutes at
1800-2000°F.
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68. 3. Hardening heat treatment (precipitation hardening):
Process by which a metal alloy is hardened and
strengthened by extremely small and uniformly
dispersed particles that precipitate from a
supersaturated solid solution.
- Also called Age hardening.
- Long term process (of several hours).
- Carried out at temperature somewhat below that
necessary to anneal followed by rapid quenching.
e.g., heat treatment of Co-Cr alloy to increase their
strength and resilience.
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69. CHEMICAL INFLUENCES:
Oral cavity environment is inherently corrosive. The oral
fluids are strong, potential reactants toward oxidation of metals.
CORROSION: A chemical or electrochemical process through
which a metal is attacked by natural agents such as air and
water, resulting in partial or complete dissolution, deterioration or
weakening of any solid substance.
TARNISH: A process by which a metal surface is dulled in
brightness or discolored through formation of chemical film such
as sulfide and an oxide.
Tarnish is often forerunner of corrosion
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70. 1. Galvanic corrosion: An accelerated attack occurring on a less
noble metal when electrochemically dissimilar metals are in
electrical contact in presence of liquid corrosive environment.
- Also known as Dissimilar metals corrosion.
2. Stress corrosion:
Cold working of an alloy by bending, burnishing etc localizes
stresses in some parts of the structure.
⇓
A couple composed of stressed metal, saliva and unstressed metal
is formed.
⇓
Stressed area is more readily dissolved by the electrolyte
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71. 3. Concentration cell corrosion:
e.g., crevice corrosion.
Accelerated corrosion in narrow spaces caused by localized
electrochemical processes and chemistry changes such as
acidification and depletion of O2
content.
OTHER TYPES OF CORROSION:
Pitting corrosion.
Microbiologically induced corrosion.
Fretting corrosion
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72. . WIRE CHARACTERISTICS OF CLINICAL RELEVANCE :-
Several characteristics of orthodontic wires are considered for
optimum performance during treatment which include :-
SPRING BACK
STIFFNESS / LOAD DEFLECTION RATE
FORMABILITY
MODULUS OF RESILIENCE OR STORED ENERGY
BIOCOMPATIBILITY AND ENVIRONMENTAL STABILITY
JOINABILITY
FRICITION
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75. EVOLUTION OF ORTHODONTIC ARCHWIRES
GOLD :-
Up until 1930’s the only orthodontic wires available were made
of Gold and their alloys.
1887 – Angle tried replacing noble metals with German silver
(Neusilber) a Brass (65% Cu, 14% Ni, 21% Zn).
Gold alloys Esthetically pleasing
Excellent Corrosion resistance
Low proportional limit.
The material that was to truly displace noble metals was stainless
steel.
1940’s :-
With the substantial rise in the cost of gold Austenitic stainless
steel began to displace gold.
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76. In early 1940 s Begg partner with Wilcock to make what they
envisioned to the ultimate in resilient orthodontic wires –
AUSTRALIAN STAINLESS STEELS.
By 1960s gold was universally abandoned in favour of stainless
steel.
In 1960s :-
Cobalt –Chromium alloys were introduced. Their physical
properties were very similar to stainless steel. However they had
the advantage that they could be supplied in softer and more
formable state that could be hardened by heat treatment
. In 1962 :-
Buehler discovers Nitinol at Naval Ordinance laboratory.
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77. In 1970 :- Andreasen brought this intermetallic composition of 50%
Ni and 50% Ti to orthodontics through University of Iowa.
Unitek company licensed the patent (!974) and offered a
stabilized martensitic alloy that doesn’t exhibit shape memory
effect under the name NITINOL.
In 1977 :
Beta titanium was introduced to orthodontic profession by C.J
Burstone and Jon Goldberg. This beta titanium alloy had a
modulus closest to that of traditional gold along with good
springback, formability and weldability.
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78. In 1984 :
Mr. A.J Wilcock Jr. as per request of Dr. Mallenhauer of
Melbourne Australia resulted in production of Ultra high tensile
stainless steel round wires – The SUPREME GRADE.
In 1985 :-
Burstone reported of an alloy, Chinese NiTi developed by Dr.
Tien Hua Cheng and associates at the General Research
Institute for nonferrous metals in Beijing china.
In 1986 :
Miura et al reported on Japanese NiTi, an alloy developed at
Furukawa Electric Company Limited Japan in 1978. Both of
these alloys i.e Chinese NiTi and Japanese NiTi are active
austenitic alloys that form Stress Induced Martensite (SIM)
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79. In 1988 :
Mr. A.J Wilcock Jr. develops much harder. Alpha Titanium
archwires.
In 1990 :
Neo-Sentalloy is introduced as a true active martensitic alloy.
In 1992 :
Optiflex a new Orthodontic archwire – developed by M.F Talass.
Combined unique mechanical properties with a highly esthetic
appearance.
In 1994 :-
Copper NiTi, a new quaternary alloy containing Ni, Ti, Cu and Cr
was invented by Dr. Rohit Sachdeva. Display phase transition at
27° C, 35° C, 40°C.
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80. In 2000 :-
Titanium Niobium – an innovative new arch wire
designed for precision tooth to tooth finishing reported
by Dalstra et al.
Additional progress in orthodontic arch wire materials
including composite “plastic” wires is being made.
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82. . COMPOSITION :-
Similar to type IV gold casting alloys. Two types
of gold wires are recognized in ADA Sp. No. 7
Type I wire (75% gold) High noble or
Type II wire (65% gold) Noble Metal
alloys
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84. General effects of Constituents
Pt and Pd → ↑ the fusion temperature.
Copper → Contributes to ability of alloy to
AGE HARDEN
Nickel→ Strengthens the alloy.
Zinc → Scavenger agent.
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85. . MECHANICAL PROPERTIES : -
Yield strength - 50 x 103
– 160 x 103
p.s.i
Elongation - 3 – 16%.
Modulus of Elasticity - 15 x 106
p.s.I
. HEAT TREATMENT:-
Strengthened to variable stiffnesses with proper heat
treatment, although they are typically used in the as –
drawn condition.
Accomplished by :-
Heating at 450° C (842° F) for 2 min.
Cooling to 250° C (482° F) over a period of 30 min .
Quenching to room temp.
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86. ADVANTAGES :-
• Good formability.
• Capable of delivering lower forces than stainless steel.
• Easily joined by soldering.
• Excellent corrosion resistance.
DISADVANTAGES :-
• High Cost.
• Low proportional limit / yield strength.
USES :-
Only the Crozat appliance is still occasionally made
from gold following original design of early 1900s.
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88. . HISTORICAL BACKGROUND :-
→ The corrosion resisting steel was reported by
Berno Strauss and Edward Maurer of Germany in
Journal Stahl Undeisen in 1914.
→ Stainless steel (SS) entered dentistry in 1919
Introduced at Krupp’s Dental Polyclinic in Germany by the
company’s dentist Dr. F. Hauptmeyer.
He first used it to make a prosthesis and called it Wipla
(Wieplatin ; In German like platinum).
By 1937 – value of SS as an orthodontic material had
been confirmed.
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89. . METALLURGICAL ASPECTS :-
Steels – Iron based alloys that usually contain less that 1.2%
carbon.
Lattice arrangements of Iron Ferrite
Austentite
Martensite
Ferrite :- (α - iron)
• Pure iron has BCC structure at room temp
• Stable upto 912° C.
• Carbon has a very low solubility in ferrite (0.02 wt %) – because
spaces between atoms in BCC structure are small and oblate.
Austenite :- (γ - Iron )
• Face centred Cubic (FCC) structure.
• Exists between 912° C - 1394°C.
Maximum carbon solubility of 2.1 weight %.
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90. Martensite :
• It Austenite is cooled rapidly (quenched).
⇓
Undergoes a spontaneous DIFFUSIONLESS
transformation to Body
Centered tetragonal (BCT) structure.
• Highly distorted and strained lattice.
• Hard, strong, brittle.
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91. TEMPERING :-
Heat
Martensite Ferrite + Carbide
Treatment (525° C)
This process results in
- ↓ The hardness
↑ toughness
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92. COMPOSITION AND TYPES OF STAINLESS STEEL :-
Steel + 12-30% Chromium → STAINLESS STEEL
• When at least 10-12% Chromium is present.
⇓
• A Coherent oxide layer formed that passivated the surface
rendering the alloy ‘STAINLESS’
CLASSIFICATION :
Steels are classified according to the American Iron and Steel
Institute (AISI) system.
Ferritic
Three types of stainless steel Austenitic
Martensitic
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94. Ferritic Stainless steels – AISI 400 series
• Provide good corrosion resistance at a low cost
provided that high strength is not required.
• Not readily work hardenable.
• Finds little application in dentistry.
Martensitic Stainless steels – AISI 400 Series
• High strength and hardness.
• Less corrosion resistant and less ductile.
Used for surgical and cutting instruments
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95. Austenitic Stainless Steel – AISI 300 series
Most commonly used for orthodontic materials. Most
corrosion resistant of the stainless steels.
AISI 302
Three Types AISI 304
AISI 316 L
18% Chromium.
AISI 302 8% Nickel.
0.15% Carbon.
Balance iron
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96. Function of Nickel - Stabilizes Austenite phase at room temp so it
is an “AUSTENIZING ELEMENT”. Other e.g :- Mn and N.
Mechanism : Makes diffusion of carbon so low that Austenite
cannot decompose to pearlite and temperature is too low to allow
formation of Martensite.
AISI 304 :- Similar Composition
Chief difference → Carbon content (0.08%)
Both 302 and 304 stainless steel are designated as 18-8
stainless steel
Type 316 L – ‘L’ → Low Carbon Content
Carbon content → 0.03% max. carbon
Used for implants.
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97. Austenitic stainless steel is preferable to
Ferritic SS b’coz
• Greater ductility and ability to undergo more
cold work without fracturing.
• Substantial strengthening during cold working
• Greater ease of welding.
• Ability to fairly readily overcome sensitization.
•
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98. 1. STIFFNESS :- High stiffness demonstrated by large values of
Modulus of Elasticity.
→ Necessitate use of smaller wires for alignment of
moderately or severely displaced teeth.
→ Advantageous in resisting deformation caused by extra
and intraoral tractional forces.
160-180 GPa
2. SPRING BACK :-
SS has lower spring back than those of newer titanium based
alloys.- .0060-.0094
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99. 3. RESILIENCE OR STORED ENERGY :-
Represents work available to move teeth.
Resilience of activated SS wires is substantially less than that of
Beta titanium and Nitinol wires.
Clinical Relevance : Implies that stainless steel wires produce higher
forces that dissipate over shorter periods of time than either beta
titanium or nitinol wires, thus requiring more frequent activation or
archwire changes.
4. FORMABILITY :-
Excellent formability,yield strength- 1100-1500MPa
5. JOINABILITY :-
SS wires can be soldered and welded. Stainless steel wires can
be fused together by welding but this generally requires
reinforcement with solder.
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100. Important Considerations in Soldering SS :-
• SS wire should not be heated to too high temp
→ To minimize Carbide precipitation.
→ To Prevent excessive softening of wire.
• Use of low fusing sliver solders (620° C - 665° C). Silver
solders corrode in use because they are anodic to stainless steel.
• Fluoride containing fluxes should be used because they
dissolve the passivating film formed by chromium. Solder does
not wet the metal when such a film is present.
Welding :
Needs reinforcement by solder
Bands and Brackets are usually welded.
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101. BIOCOMPATIBILITY AND ENVIRONMENTAL STABILITY :-
CORROSION RESISTANCE :-
SS owes it corrosion resistance to Chromium – a highly reactive
base metal .
A thin transparent but tough and impervious oxide layer ( Cr2
O3
forms [PASSIVATION] on surface of alloy when it is subjected to
oxidizing atmosphere such as room air.
O2
is necessary to form and maintain the film.
Causes of Corrosion of Stainless Steel :-
• Any surface roughness or unevenness.
• Incorporation of bits of Carbon steel or similar metal in its
surface.
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102. • Stress Corrosion.
Severe strain hardening may produce localized electric
couples in presence of an electrolyte such as saliva.
• Soldered joints.
Attack by solutions containing chlorine
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103. Classification Example
Acetic acid Vinegar
Copper chloride Certain appliance cleansers
Fatty acids By - products of the micro-organism, Streptococcus mutans
General foods Beet juice
Hydrogen sulfide Effluent of mouth air
Lactic acid Spoiled milk
Phosphoric acid Colas
Salt water Saliva
Sodium hypochlorite Certain appliance cleansers
Sulfite solution Wine
Zinc chloride Certain mouth washes and certain appliance cleansers
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104. SENSITIZATION OF 18-8 SS :-
18–8 stainless steel may loose its resistance to corrosion if it is
heated b/w 400° C-900°C. The reason for decrease in
corrosion resistance is :
⇒ Precipitation of Chromium Carbide (Cr3
C) at the grain
boundaries.
⇒ Formation of Cr3-
C is most rapid at 650°C. Chromium is depleted
adjacent to grain boundaries.
When chromium combines with carbon its passivating qualities
are lost
⇓
Chromium is depleted adjacent to grain boundaries.
⇓
Alloy becomes susceptible to INTERGRANULAR CORROSION.
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105. Methods to Minimize Sensitization :-
1. Keeping out of sensitizing temp range (425° - 650° C)
2. Controlling the Carbon.
1. Controlling temp to prevent intergranular
corrosion :-
Speed in handling metal in sensitizing temp range –
effective means of minimizing sensitization.
e.g Quenching immediately after soldering.
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106. 2. Stabilization of stainless steel :-
Objective
→ To make Carbon unavailable for sensitizing
action Introduction of some element that precipitates
as a carbide in preference to chromium. e.g :- Titanium
and Columbium.
→ Titanium is introduced in an amount approx 6
times the carbon content. Steel that has been treated in
any of the foregoing ways to reduce the available
Carbon is called STABILIZED STEEL.
→ Stabilized steel is less susceptible to
Intergranular corrosion, but it is still not 100% safe.
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107. FRICTION :-
Low levels of bracket / wire friction have
been reported with experiments using
stainless steel wires. This signifies that
stainless steel arch wires offer lower
resistance to tooth movement than other
orthodontic alloys
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108. . HEAT TREAMENT :-
STRESS RELIEVING HEAT TREATMENT
Only heat treatment used with stainless steel after bending
wire into an arch, loops or coils.
Purpose :-
→ Causes significant decrease in residual stress.
→ Enhances elastic properties of wire – slight ↑
resilience.
Temperature :- Recommended temperature time
schedule is
750° F (399° C) for 11 min
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109. Funk (1951) :-
Recommends use of color Index to determine when
adequate heat treatment is achieved. He suggests a
straw colored wire indicates that optimum heat
treatment has been attained.
METHODS OF HEATING :-
1. Oven is most reliable medium for heat Rx because of
its relatively uniform temperature.
2. Heating the wire with Electric current from a welder or
special heat treating power source.
Disadvantage: Lack of uniform temperature.
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110. I. SOLID STAINLESS STEEL ARCH WIRES
Are available in :-
1. Various sizes and cross sections
Round → 0.012, 0.014, 0.016, 0.018, 0.020 etc.
Rectangular → 0.016x 0.022, 0.017x 0.025, 0.018x 0.025,
0.019x 0.025 etc.
Square → 0.016 x 0.016 , 0.017 x 0.017
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112. 2. Various Grades :-
American Orthodontics Standard
Gold tone
Super Gold tone
Dentaurum Super special spring hard
Extra spring hard
Spring hard
Unitek Standard
Resilient
RMO Resilient arch wire temper
Retainer wire temper
Clasp wire temper
Ligature wire temper
Available in Spooled forms
Straight lengths
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113. Preformed arches :-
• Tru – Arch arch forms (A company)
• Natural arches (American Orthodontics)
• Preformed Anatomically Refined arches (Ormco)
• Pentamorphic arches (RMO)
• Standard and Proform (Ortho Organizers).
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114. . MULTISTRANED STAINLESS STEEL WIRES :-
Composed of specified numbers of thin wire
sections coiled around each other to provide round or
rectangular cross section.
Idea behind Multistranded Wires :-
To improve strength and at the same time to
maintain desirable stiffness and Range properties,
many small wires are twisted together and even swaged
or spot welded.
Result is an inherently high elastic modulus
material behaving as a low stiffness member because of
its Co-axial spring like nature.
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115. overall stiffness of the orthodontic appliance (S) is
determined by the wire stiffness (Ws) and design
stiffness (As) as represented by:
S = Ws x As
Design stiffness (As) is dependent on factors such as
interbracket distance and the incorporation of loops
and coils into the wire. Altering the cross-sectional
stiffness (Cs) and/or the material stiffness (MS) as
designated by the formula, on the other hand, can
bring about changes in wire stiffness (Ws).
Ws = Ms x Cs
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117. PROPERTIES :
Kusy and Dilley (1984) :-
Investigated strength, stiffness and spring back properties of
Multistranded SS wires in a bending mode of stress. They noted
that
→ Stiffness of triple stranded 0.0175 inch (3 x 0.008 inch) SS
arch wire was similar to that of 0.010 inch single stranded SS
wire.
→ 25 % stronger than 0.010 inch SS wire.
→ 0.0175 inch triple stranded wire and 0.016 Nitinol
demonstrated similar stiffness. Nitinol tolerated more than 50%
greater activation than multistranded wire.
Triple stranded wire – half as stiff as 0.016 inch Beta titanium
wire.
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118. Ingram, Gipe and Smith (1986)
• Titanium alloy wires and multistranded SS wires have
low stiffness when compared with solid SS wires.
• Multistranded wires – spring back similar to Nitinol but
greater as compared to solid SS or Beta titanium wires.
• Multistranded and titanium wires have spring back
properties that are relatively independent of wire size
unlike solid stainless steel wires in which springback
decreases with increasing thickness.
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119. Clinical applications
- Compare favourably with titanium wires.
- Provide a viable alternative to more expensive
titanium wires for initial leveling.
- Braided rectangular steel wires are available
in variety of stiffnesses and the stiffest of these
is 0.021 x 0.025 – useful in 0.022 slot for
finishing.
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121. . AUSTRALIAN ARCH WIRES
Historical Background :-
Wilcock archwires have been the mainstay of Begg technique.
In 1940 S :-
Dr. Begg met Mr. Arthur J. Wilicok Sr. of Whittlesea, Victoria
who was directing metallurgical research projects at University of
Melbourne. After many years of research and development
introducing high tensile wires Mr. Wilcock produced cold drawn
heat treated wire that combined the balance between hardness
and resiliency with unique property of zero stress relaxation.
Different grades of Australian wires formerly used
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122. Regular Grade :-
Lowest grade and easiest to bend.
Used for practice bending.
Regular plus : Used for auxiliaries and archwires when more
pressure and resistance to deformation is required.
Special Grade :-
0.016 is often used for starting archwires in many techniques.
Special plus :-
Routinely used by experienced operators Hardness and
resiliency of 0.016 is excellent for supporting anchorage and
reducing deep overbites. Must be bent with care.
Extra Special plus grade (ESP) :
→ This grade is unequalled in resiliency and hardness
→ Difficult to bend and brittle.
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123. RECENT ADVANCES IN AUSTRALIAN WIRES
A.J Wilcock scientific and Engineering Company. Announced
new series of wire grades and sizes.
The fundamental difference for the superior properties for these
new wires is use of new manufacturing process called PULSE
STRAIGHTENING.
Wires are straightened by use of 2 processes :-
1. SPINNER STRAIGHTENING.
2. PULSE STRAIGHTENING.
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124. 1. SPINNER STRAIGHTENING :-
Mechanical process of straightening materials usually in cold
drawn condition. Wires are straightened by process of
REVERSE STRAINING.
Flexing in a direction opposite to that of original bend (This is
what is done manually in clinical setting). In conventional
manufacturing wire is pulled through high speed rotating Bronze
rollers which torsionally twist the wire into straight condition.
Disadvantage :-
→ Resultant deformation.
→ Decreased yield strength in tension and compression as
compared to that of the “as drawn” material.
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125. 2. PLUSE STRAIGHTENING :
This process was developed to overcome above
mentioned difficulties.
Has several advantages over other straightening
methods :-
• Permits higher tensile wires to be straightened.
• Material yield strength is not diminished in any way.
Wire has smoother surface and hence less bracket friction.
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126. NEWER GRADES OF WILCOCK WIRES :-
3 more grades have been introduced :
→ Premium
→ Premium plus
→ Supreme
PROPERTIES :-
Higher yield strength of newer grade wires influences
following properties :-
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127. 1. SPRINGBACK - (YS/E) :–
Newer grade wires have better springback than lower grade wires.
2. RESILIENCY – (YS2
/2E) :-
For the same material (ie with same modulus of elasticity) higher
yield strength results in greater resiliency. This means that
higher grade wires store or absorb more energy per unit volume
before they get permanently deformed.
Higher YS results in greater resiliency.
3. ZERO STRESS RELAXATION :-
Ability of wire to deliver over long periods a constant force when
subjected to an external load. Newer wires maintain their
configuration over long periods against deforming forces (forces
of occlusion).
Forces generated by them remain practically unaffected over
long periods.
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128. 4. FORMABILITY :- For the same material
greater resiliency lesser the formability.
Theses wires are more brittle than lower
grade wires and need to be bent in
specific way.
→ Warm the wire by pulling
through fingers before bending because
these wires have a ductile brittle transition
temp. slightly above room temp.
→ Bend the wire around square beak
of pliers.
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129. CLINICAL USAGE OF NEW GRADES OF AUSTRALIAN WIRES :-
Their specific applications are :-
1. When relatively high load deflection rate is required :-
a) For generating relatively lighter forces in stage I (for incisor
intrusion and lateral contraction or expansion of post teeth).
→ 0.016 or 0.018 Premium + or P wires are used.
b) Large resistance to deformation is required e.g., :-
Maintaining arch from
→ 0.018 P or P + or 0.020 P wires are indicated.
→ Similarly for overcoming undesired reactions of a
torquing auxiliary or uprighting springs in IIIrd stage –
0.020 P wire is employed
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130. 2. When a low load deflection rate is required.
Supreme grade arch wires of sizes 0.008 – 0.011
are used for :-
→ Unravelling of crowded anterior teeth.
→ MAA (Mollenhauer aligning auxiliary)
→ Miniuprighting springs.
0.010 Supreme :-
• Used to form Reciprocal torquing auxiliaries.
• Best indicated for incisially activated mouse traps
and Minisprings.
0.011 /0.012 supreme :
Used for aligning second molars towards and of stage
III.
0.012 Supreme – Torquing Auxiliary in Stage III
because of its high resiliency and springback
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131. IV. RECENT ADVANCES IN STAINLESS STEEL
METALLURAGY :-
1. NICKEL FREE STAINLESS STEEL :-
The steel Din 1.4456 with its variations is one of them.
COMPOSITION :-
15 – 18% Chromium.
3 – 4% Molybdenum
10 - 14% Manganese.
0.9 % Nitrogen – To compensate for Ni.
Nickel is no more an alloying element (but only an impurity).
Orthodontic wires
→Menzamium (Scheu Dental)
→Noninium (Dentaurum
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132. Menzanium Wire :-
→ SS is fabricated in a patented high
pressure melting process where Manganese and
Nitrogen replace allergic components of Ni.
• Ideal for Ni sensitive patient.
• Corrosion resistant and durable.
Availability :-
Supplied by Great lakes orthodontics.
Grade :- Hard and spring Hard.
Sizes :- 0.028, 0.032, 0.036.
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