The document discusses various physical and mechanical properties of dental materials. It defines terms like viscosity, viscoelasticity, creep, thermal conductivity, coefficient of thermal expansion, force, stress, strain, elastic limit, resilience, elongation, elastic modulus, flexibility and more. It provides examples of these properties for different dental materials and their clinical significance. For example, it notes that the rheological properties of a material influence its handling characteristics and some materials are susceptible to distortion.
Mechanical properties of dental materialsalka shukla
The document provides an overview of mechanical properties of dental materials. It defines key terms like stress, strain, elastic modulus, strength properties, and more. Stress is the force per unit area acting on materials and is expressed as force over area. Strain is the change in length under stress. Elastic modulus describes stiffness and is the ratio of stress to strain within the elastic region. Strength properties include elastic limit, yield strength, tensile strength, and flexural strength. The document discusses these properties for different dental materials like enamel, dentin, gold, and ceramics.
This document provides an overview of the physical properties of dental materials. It discusses topics like the structure of matter, interatomic bonds, adhesion and bonding, concepts of stress and strain, and rheology. The document is intended to explain the underlying physics and chemistry that determine the mechanical, thermal, optical and other observable qualities of dental materials. It focuses on topics like crystalline structure, bonding forces, surface energy, wetting, and how stresses and strains impact materials at the atomic level. The overall aim is to describe the fundamental physical principles that govern the behavior and performance of different dental materials.
Physical properties of dental material [autosaved]shailjakatiyar2
The document discusses various physical properties of dental materials that are important for clinicians to understand. It describes properties like abrasion and abrasion resistance, viscosity, structural and stress relaxation, and creep and flow. Hardness tests are also covered, including macrohardness tests like Brinell and Rockwell, and microhardness tests like Knoop and Vickers. Understanding these physical properties helps clinicians select appropriate materials and improves the success of dental treatments.
physical and mechanical properties of dental materialsKisCha1
The document discusses the mechanical and physical properties of dental materials that are important for prosthodontics. It describes key mechanical properties like stress, strain, strength, elasticity and hardness. It also outlines important physical properties such as color, viscosity, thermal expansion and corrosion resistance. Understanding the properties of dental materials helps in selecting appropriate materials that can withstand the challenges of the oral environment.
Dental cements have evolved significantly since the first cements were introduced in the late 1800s. Zinc phosphate cement, introduced in the late 1800s, was one of the earliest dental cements and remains the gold standard against which newer cements are compared. In the 1960s, polycarboxylate cement was introduced and was the first cement system to provide an adhesive bond to tooth structure. Glass ionomer cement, introduced in the 1970s, also chemically bonds to tooth structure and was a significant development as it was the first cement with anticariogenic properties.
This document discusses the mechanical properties of dental materials. It defines key terms like force, stress, strain, elastic deformation and plastic deformation. It describes different types of stresses like tensile, compressive, shear and flexural stresses. It also discusses strength properties and how they are measured. Factors like stress concentration and flaws can reduce the clinical strength of dental materials. Understanding mechanical properties is important for optimizing the performance of dental materials.
The document discusses dental casting alloys. It begins by introducing the major classes of materials used in dentistry - metals, ceramics, and polymers. Metals are further divided into dental amalgams, noble metal alloys containing gold, palladium, silver, and base metal alloys containing nickel or cobalt.
The document then discusses the history of metals in dentistry from ancient times to modern developments like porcelain fused to metal techniques. It also discusses how the price of gold led to new alloys replacing it with palladium or eliminating it entirely in the 1970s.
The rest of the document covers topics like alloy compositions, microstructure, physical properties, corrosion resistance, and the effects of noble metals like
This document discusses different types of dental waxes, including their definitions, classifications, components, properties and uses. The main types covered are modelling wax, inlay wax, casting wax, boxing wax and sticky wax. For each type, the document outlines their composition, melting range, properties and intended uses. Thermal properties like solid-solid transition temperature, coefficient of thermal expansion and melting range are discussed for dental waxes in general.
Mechanical properties of dental materialsalka shukla
The document provides an overview of mechanical properties of dental materials. It defines key terms like stress, strain, elastic modulus, strength properties, and more. Stress is the force per unit area acting on materials and is expressed as force over area. Strain is the change in length under stress. Elastic modulus describes stiffness and is the ratio of stress to strain within the elastic region. Strength properties include elastic limit, yield strength, tensile strength, and flexural strength. The document discusses these properties for different dental materials like enamel, dentin, gold, and ceramics.
This document provides an overview of the physical properties of dental materials. It discusses topics like the structure of matter, interatomic bonds, adhesion and bonding, concepts of stress and strain, and rheology. The document is intended to explain the underlying physics and chemistry that determine the mechanical, thermal, optical and other observable qualities of dental materials. It focuses on topics like crystalline structure, bonding forces, surface energy, wetting, and how stresses and strains impact materials at the atomic level. The overall aim is to describe the fundamental physical principles that govern the behavior and performance of different dental materials.
Physical properties of dental material [autosaved]shailjakatiyar2
The document discusses various physical properties of dental materials that are important for clinicians to understand. It describes properties like abrasion and abrasion resistance, viscosity, structural and stress relaxation, and creep and flow. Hardness tests are also covered, including macrohardness tests like Brinell and Rockwell, and microhardness tests like Knoop and Vickers. Understanding these physical properties helps clinicians select appropriate materials and improves the success of dental treatments.
physical and mechanical properties of dental materialsKisCha1
The document discusses the mechanical and physical properties of dental materials that are important for prosthodontics. It describes key mechanical properties like stress, strain, strength, elasticity and hardness. It also outlines important physical properties such as color, viscosity, thermal expansion and corrosion resistance. Understanding the properties of dental materials helps in selecting appropriate materials that can withstand the challenges of the oral environment.
Dental cements have evolved significantly since the first cements were introduced in the late 1800s. Zinc phosphate cement, introduced in the late 1800s, was one of the earliest dental cements and remains the gold standard against which newer cements are compared. In the 1960s, polycarboxylate cement was introduced and was the first cement system to provide an adhesive bond to tooth structure. Glass ionomer cement, introduced in the 1970s, also chemically bonds to tooth structure and was a significant development as it was the first cement with anticariogenic properties.
This document discusses the mechanical properties of dental materials. It defines key terms like force, stress, strain, elastic deformation and plastic deformation. It describes different types of stresses like tensile, compressive, shear and flexural stresses. It also discusses strength properties and how they are measured. Factors like stress concentration and flaws can reduce the clinical strength of dental materials. Understanding mechanical properties is important for optimizing the performance of dental materials.
The document discusses dental casting alloys. It begins by introducing the major classes of materials used in dentistry - metals, ceramics, and polymers. Metals are further divided into dental amalgams, noble metal alloys containing gold, palladium, silver, and base metal alloys containing nickel or cobalt.
The document then discusses the history of metals in dentistry from ancient times to modern developments like porcelain fused to metal techniques. It also discusses how the price of gold led to new alloys replacing it with palladium or eliminating it entirely in the 1970s.
The rest of the document covers topics like alloy compositions, microstructure, physical properties, corrosion resistance, and the effects of noble metals like
This document discusses different types of dental waxes, including their definitions, classifications, components, properties and uses. The main types covered are modelling wax, inlay wax, casting wax, boxing wax and sticky wax. For each type, the document outlines their composition, melting range, properties and intended uses. Thermal properties like solid-solid transition temperature, coefficient of thermal expansion and melting range are discussed for dental waxes in general.
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 properties of dental materials by Dr Mujtaba AshrafDr Mujtaba Ashraf
This document discusses the physical properties of dental materials. It begins with an introduction and definition of physical properties. It then discusses various physical properties like hardness, stress and strain, viscosity, creep and flow. It provides details on different hardness tests like Brinell, Knoop, Vickers, Rockwell, Barcol and Shore hardness tests. It also discusses concepts of stress, strain, viscosity and creep. The document concludes with discussing other properties like color and color perception, thermophysical properties, corrosion and types of corrosion.
This document discusses the history and classification of dental ceramics. It begins with definitions of ceramics and discusses Greek and Sanskrit origins of the word. It then categorizes dental ceramics according to their use, firing temperature, processing method, microstructure, composition, translucency, and application. The document provides a historical perspective on the development of dental ceramics from ancient times to modern CAD/CAM systems. It also covers the composition, properties, advantages, and disadvantages of various dental ceramics.
There have been several changes since inception in the field of dental ceramics. Need for newer materials with improved aesthetics, flexural strength and optical properties made it necessary for introduction of advanced technology in fabrication of dental ceramics.
The document discusses the biocompatibility of dental materials. It defines biocompatibility as the ability of a material to elicit an appropriate biological response. Dental materials must not be harmful, toxic, carcinogenic, or allergenic. Biocompatibility is evaluated through primary, secondary, and usage tests involving cell cultures, animals, and human clinical trials. The summary discusses the various tests conducted on different dental materials like metals, ceramics, polymers, and how their composition and interactions in the oral cavity impact biocompatibility.
This document discusses various materials used for fabricating dental dies, including their properties and uses. It covers gypsum products like dental stone (Type III and high-strength Type IV and V stones), electroformed dies using copper or silver plating, epoxy resins, and flexible die materials like polyvinyl and polyurethane. Each material has advantages like detail reproduction, strength and disadvantages like shrinkage, toxicity or incompatibility with some impression materials. Newer ceramic and CAD/CAM die materials are also introduced that are strong and dimensionally stable.
Zinc polycarboxylate cement sets through an acid-base reaction between zinc oxide and polyacrylic acid. It exists as a powder containing zinc oxide, magnesium oxide, and polyacrylic acid, and as a liquid containing polyacrylic acid and water. The powder and liquid are mixed together, with the polyacrylic acid chelating with the zinc oxide to form a matrix of zinc polyacrylate salt surrounded by undispersed zinc oxide particles. Zinc polycarboxylate cement has mechanical strength comparable to zinc phosphate cement, adheres chemically to tooth structure and metals, and has a film thickness similar to zinc phosphate cement. It is less irritating to the pulp than zinc phosphate cement due to becoming
The document discusses different types of dental waxes, their properties, uses, and classifications. Key points include:
- Dental waxes can be natural, synthetic, or a blend and are used for patterns, impressions, bite registration, and other clinical and laboratory applications.
- Waxes are classified based on their origin, chemical composition, melting range, and intended use (e.g. pattern, processing, or impression wax).
- Common waxes discussed include inlay wax, casting wax, baseplate wax, boxing wax, utility wax, corrective wax, and bite registration wax.
- Ideal properties for dental waxes include dimensional stability when carved and no residue left during burnout
Several properties of dental materials must be considered to predict their performance. No single property defines a material's quality. Properties evaluated include those during storage, mixing, setting, and of set materials. Set material properties include physical (optical, thermal, electrical, rheological), chemical, biological, and mechanical properties. Optical properties include color, translucency and surface texture. Thermal properties include temperature, heat of fusion, thermal conductivity and coefficient of thermal expansion.
Ceramics have many applications in dentistry due to their esthetic qualities, strength, and biocompatibility. Ceramics are used in crowns, bridges, veneers, dentures, and more. There are several types of ceramics including metal-ceramics, which combine a ceramic material fused to a metal framework for strength, and all-ceramic options made of materials like alumina and zirconia. Ceramic materials are fabricated through processes like sintering, heat pressing, slip-casting, and CAD/CAM milling. Ceramics provide natural-looking and long-lasting restorations but also have limitations like brittleness which new materials continue to address
A teamwork of specialized dentists, general dentists, dental assistants, dental hygienists, and dental technicians is needed in providing good oral health services. A bad workman always blames his tools. It is mandatory that the associated dental personnel have adequate knowledge of the material science. This not only enables them to select and handle the appropriate materials for the given clinical situation, but also ensures optimal properties of the material.
This document defines dentures and their components. It discusses the different types of dentures - total versus partial. The main parts of a denture are the denture base and artificial teeth. Heat-cured polymethyl methacrylate (PMMA) is described as the most common denture base material. The setting process and requirements of denture base materials are outlined. Compression molding and injection molding techniques for constructing denture bases are also summarized.
The document provides an overview of base metal alloys used in dentistry. It discusses the history and classification of dental casting alloys including cobalt-chromium, nickel-chromium, and titanium-based alloys. The ideal requirements, composition, properties, applications and references of various base metal alloys are described in detail over multiple pages.
This document discusses biocompatibility of dental materials. It defines biocompatibility as the ability of a material to function with an appropriate host response. Dental materials must meet biocompatibility requirements to avoid allergic reactions, biodegradation, toxicity, and harm to tissues. Tests are used to evaluate materials for biocompatibility, including in vitro tests, animal tests, and human usage tests in a structured testing hierarchy. Materials are assessed for safety of patients and dental staff as well as regulatory compliance and legal liability.
This document provides an overview of dental ceramics and CAD-CAM systems. It discusses the historical background, classification, composition, properties, and fabrication methods of ceramic restorations. Key points include that ceramics are classified based on their content, use, processing method, and firing temperature. Their composition includes feldspar, kaolin/clay, quartz, glass formers, modifiers, and coloring agents. Fabrication involves condensation, firing, and glazing techniques. All-ceramic restorations such as porcelain jacket crowns, alumina-reinforced ceramics, castables, pressables, infiltrated ceramics, and CAD-CAM systems are summarized.
This document discusses casting alloys used in dentistry. It begins with a brief history of casting alloys and their evolution since the 1900s. It then covers the key properties casting alloys must have including biocompatibility, corrosion resistance, hardness, castability and bonding to ceramics. The document classifies casting alloys and discusses commonly used types such as gold alloys, silver-palladium alloys, cobalt-chrome alloys and titanium alloys. It provides details on the composition and characteristics of different alloy groups.
The document discusses various types of corrosion that can occur in dental materials including crevice corrosion, galvanic corrosion, pitting corrosion, stress corrosion, and concentration cell corrosion. It also discusses tarnish, which is the dulling or discoloration of metal surfaces through chemical film formation. Factors that can lead to corrosion and tarnish of dental restorations include dietary and oral hygiene habits, bacterial activity, and presence of acids, chlorides, and other chemicals in the oral environment. Protection against corrosion involves use of alloys with noble metals, polishing of surfaces, and application of protective coatings.
This document discusses corrosion of dental materials. It defines corrosion as an electrochemical process that causes metal deterioration and failure. Corrosion can cause pulpal pain, toxic reactions, and metallic taste. It occurs via chemical or electrochemical mechanisms. Electrochemical corrosion requires an electrolyte and occurs via galvanic, heterogeneous surface composition, stress, or concentration cell corrosion when different areas of a restoration have different electrolyte compositions. Protection against corrosion can come from using passive metals like chromium, keeping surfaces polished, or using protective coatings.
This document provides information about various luting cements used in dentistry. It focuses on zinc phosphate cement, discussing its composition, setting reaction, properties and applications. The key points are:
1. Zinc phosphate cement is the oldest luting agent and consists of a powder made primarily of zinc oxide and a liquid of phosphoric acid. The acid reacts with zinc oxide to form zinc phosphate during setting.
2. It has a working time of 1.5-2 minutes and setting time of 2.5-8 minutes. Its compressive strength is 104MPa and it bonds mechanically rather than chemically.
3. Zinc phosphate cement is used for cementing permanent restorations
This document summarizes key physical properties of dental materials, including properties related to force application (e.g. creep, flow, abrasion) and non-force related properties (e.g. density, thermal conductivity). It discusses these properties in detail, providing definitions, factors that influence each property, clinical importance, and examples comparing properties across different dental materials. The summary focuses on creep, thermal conductivity, and coefficient of thermal expansion which are important for material selection and preventing pulpal irritation or marginal leakage.
A comprehensive slideshow covering all the basics relating to dental materials and their physical properties. Based on standard text books - Phillips Science of Dental Materials (11th Edition).
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 properties of dental materials by Dr Mujtaba AshrafDr Mujtaba Ashraf
This document discusses the physical properties of dental materials. It begins with an introduction and definition of physical properties. It then discusses various physical properties like hardness, stress and strain, viscosity, creep and flow. It provides details on different hardness tests like Brinell, Knoop, Vickers, Rockwell, Barcol and Shore hardness tests. It also discusses concepts of stress, strain, viscosity and creep. The document concludes with discussing other properties like color and color perception, thermophysical properties, corrosion and types of corrosion.
This document discusses the history and classification of dental ceramics. It begins with definitions of ceramics and discusses Greek and Sanskrit origins of the word. It then categorizes dental ceramics according to their use, firing temperature, processing method, microstructure, composition, translucency, and application. The document provides a historical perspective on the development of dental ceramics from ancient times to modern CAD/CAM systems. It also covers the composition, properties, advantages, and disadvantages of various dental ceramics.
There have been several changes since inception in the field of dental ceramics. Need for newer materials with improved aesthetics, flexural strength and optical properties made it necessary for introduction of advanced technology in fabrication of dental ceramics.
The document discusses the biocompatibility of dental materials. It defines biocompatibility as the ability of a material to elicit an appropriate biological response. Dental materials must not be harmful, toxic, carcinogenic, or allergenic. Biocompatibility is evaluated through primary, secondary, and usage tests involving cell cultures, animals, and human clinical trials. The summary discusses the various tests conducted on different dental materials like metals, ceramics, polymers, and how their composition and interactions in the oral cavity impact biocompatibility.
This document discusses various materials used for fabricating dental dies, including their properties and uses. It covers gypsum products like dental stone (Type III and high-strength Type IV and V stones), electroformed dies using copper or silver plating, epoxy resins, and flexible die materials like polyvinyl and polyurethane. Each material has advantages like detail reproduction, strength and disadvantages like shrinkage, toxicity or incompatibility with some impression materials. Newer ceramic and CAD/CAM die materials are also introduced that are strong and dimensionally stable.
Zinc polycarboxylate cement sets through an acid-base reaction between zinc oxide and polyacrylic acid. It exists as a powder containing zinc oxide, magnesium oxide, and polyacrylic acid, and as a liquid containing polyacrylic acid and water. The powder and liquid are mixed together, with the polyacrylic acid chelating with the zinc oxide to form a matrix of zinc polyacrylate salt surrounded by undispersed zinc oxide particles. Zinc polycarboxylate cement has mechanical strength comparable to zinc phosphate cement, adheres chemically to tooth structure and metals, and has a film thickness similar to zinc phosphate cement. It is less irritating to the pulp than zinc phosphate cement due to becoming
The document discusses different types of dental waxes, their properties, uses, and classifications. Key points include:
- Dental waxes can be natural, synthetic, or a blend and are used for patterns, impressions, bite registration, and other clinical and laboratory applications.
- Waxes are classified based on their origin, chemical composition, melting range, and intended use (e.g. pattern, processing, or impression wax).
- Common waxes discussed include inlay wax, casting wax, baseplate wax, boxing wax, utility wax, corrective wax, and bite registration wax.
- Ideal properties for dental waxes include dimensional stability when carved and no residue left during burnout
Several properties of dental materials must be considered to predict their performance. No single property defines a material's quality. Properties evaluated include those during storage, mixing, setting, and of set materials. Set material properties include physical (optical, thermal, electrical, rheological), chemical, biological, and mechanical properties. Optical properties include color, translucency and surface texture. Thermal properties include temperature, heat of fusion, thermal conductivity and coefficient of thermal expansion.
Ceramics have many applications in dentistry due to their esthetic qualities, strength, and biocompatibility. Ceramics are used in crowns, bridges, veneers, dentures, and more. There are several types of ceramics including metal-ceramics, which combine a ceramic material fused to a metal framework for strength, and all-ceramic options made of materials like alumina and zirconia. Ceramic materials are fabricated through processes like sintering, heat pressing, slip-casting, and CAD/CAM milling. Ceramics provide natural-looking and long-lasting restorations but also have limitations like brittleness which new materials continue to address
A teamwork of specialized dentists, general dentists, dental assistants, dental hygienists, and dental technicians is needed in providing good oral health services. A bad workman always blames his tools. It is mandatory that the associated dental personnel have adequate knowledge of the material science. This not only enables them to select and handle the appropriate materials for the given clinical situation, but also ensures optimal properties of the material.
This document defines dentures and their components. It discusses the different types of dentures - total versus partial. The main parts of a denture are the denture base and artificial teeth. Heat-cured polymethyl methacrylate (PMMA) is described as the most common denture base material. The setting process and requirements of denture base materials are outlined. Compression molding and injection molding techniques for constructing denture bases are also summarized.
The document provides an overview of base metal alloys used in dentistry. It discusses the history and classification of dental casting alloys including cobalt-chromium, nickel-chromium, and titanium-based alloys. The ideal requirements, composition, properties, applications and references of various base metal alloys are described in detail over multiple pages.
This document discusses biocompatibility of dental materials. It defines biocompatibility as the ability of a material to function with an appropriate host response. Dental materials must meet biocompatibility requirements to avoid allergic reactions, biodegradation, toxicity, and harm to tissues. Tests are used to evaluate materials for biocompatibility, including in vitro tests, animal tests, and human usage tests in a structured testing hierarchy. Materials are assessed for safety of patients and dental staff as well as regulatory compliance and legal liability.
This document provides an overview of dental ceramics and CAD-CAM systems. It discusses the historical background, classification, composition, properties, and fabrication methods of ceramic restorations. Key points include that ceramics are classified based on their content, use, processing method, and firing temperature. Their composition includes feldspar, kaolin/clay, quartz, glass formers, modifiers, and coloring agents. Fabrication involves condensation, firing, and glazing techniques. All-ceramic restorations such as porcelain jacket crowns, alumina-reinforced ceramics, castables, pressables, infiltrated ceramics, and CAD-CAM systems are summarized.
This document discusses casting alloys used in dentistry. It begins with a brief history of casting alloys and their evolution since the 1900s. It then covers the key properties casting alloys must have including biocompatibility, corrosion resistance, hardness, castability and bonding to ceramics. The document classifies casting alloys and discusses commonly used types such as gold alloys, silver-palladium alloys, cobalt-chrome alloys and titanium alloys. It provides details on the composition and characteristics of different alloy groups.
The document discusses various types of corrosion that can occur in dental materials including crevice corrosion, galvanic corrosion, pitting corrosion, stress corrosion, and concentration cell corrosion. It also discusses tarnish, which is the dulling or discoloration of metal surfaces through chemical film formation. Factors that can lead to corrosion and tarnish of dental restorations include dietary and oral hygiene habits, bacterial activity, and presence of acids, chlorides, and other chemicals in the oral environment. Protection against corrosion involves use of alloys with noble metals, polishing of surfaces, and application of protective coatings.
This document discusses corrosion of dental materials. It defines corrosion as an electrochemical process that causes metal deterioration and failure. Corrosion can cause pulpal pain, toxic reactions, and metallic taste. It occurs via chemical or electrochemical mechanisms. Electrochemical corrosion requires an electrolyte and occurs via galvanic, heterogeneous surface composition, stress, or concentration cell corrosion when different areas of a restoration have different electrolyte compositions. Protection against corrosion can come from using passive metals like chromium, keeping surfaces polished, or using protective coatings.
This document provides information about various luting cements used in dentistry. It focuses on zinc phosphate cement, discussing its composition, setting reaction, properties and applications. The key points are:
1. Zinc phosphate cement is the oldest luting agent and consists of a powder made primarily of zinc oxide and a liquid of phosphoric acid. The acid reacts with zinc oxide to form zinc phosphate during setting.
2. It has a working time of 1.5-2 minutes and setting time of 2.5-8 minutes. Its compressive strength is 104MPa and it bonds mechanically rather than chemically.
3. Zinc phosphate cement is used for cementing permanent restorations
This document summarizes key physical properties of dental materials, including properties related to force application (e.g. creep, flow, abrasion) and non-force related properties (e.g. density, thermal conductivity). It discusses these properties in detail, providing definitions, factors that influence each property, clinical importance, and examples comparing properties across different dental materials. The summary focuses on creep, thermal conductivity, and coefficient of thermal expansion which are important for material selection and preventing pulpal irritation or marginal leakage.
A comprehensive slideshow covering all the basics relating to dental materials and their physical properties. Based on standard text books - Phillips Science of Dental Materials (11th Edition).
The document discusses the physical properties of dental materials. It begins by acknowledging those who provided the opportunity to conduct research on this topic. It then outlines the various sections that will be covered, including rheology, viscosity, creep and flow, color and optical effects, thermal properties, and electrochemical properties. The introduction explains that understanding the physical properties of dental materials is important for assessing characteristics and improvements in materials under development.
PHYSICAL AND MECHANICAL PROPERTIES OF DENTAL MATERIALS.pptxAbhidha Tripathi
This document discusses the physical and mechanical properties of dental materials. It begins by introducing physical properties, which are based on laws of physics and include properties like abrasion resistance, creep, thermal conductivity, viscosity, tarnish and corrosion, and color and optical effects. It then discusses mechanical properties, which describe a material's ability to withstand forces and include properties like elasticity, strength, and fracture toughness. The document provides details on specific physical properties, such as defining viscosity, describing different fluid types, and outlining thermal conductivity and diffusion. It also covers optical properties like reflection, refraction, absorption, and how these impact a material's appearance.
Power point presentation of applied chemistry.Anam Fatima
This document provides information about dental materials from a group of students at Women's University in Sialkot, Pakistan. It defines dental materials and the science of dental materials. It discusses the ideal characteristics, selection, evaluation, and properties of dental materials. The properties discussed include thermal, optical, corrosion, hardness, adhesion, cohesion, electrical, biological, and mechanical properties. It provides examples and definitions for each type of material property.
This document provides an overview of a summer course on dental materials taught in 2007-2008. It discusses the challenges posed by the oral environment for dental materials and the need for biocompatibility, aesthetics and durability. It then examines various intraoral factors like forces, moisture, acid levels and temperature that affect dental materials. The document outlines different material properties including physical, mechanical, thermal, electrical, solubility and optical properties. It provides examples of how these properties are measured and their significance for material selection and performance.
Physical properties of dental materials (1)Dr Ambalika
This document discusses the physical properties of dental materials. It begins by introducing physical properties and their importance for dental materials performance. It then categorizes physical properties into those important for manufacturing/finishing processes, optical properties, and thermal properties. Under optical properties, it discusses properties like color, translucency, fluorescence, and radiopacity. It explains how color is measured and factors that influence color matching in dentistry like lighting conditions. The document provides details on parameters used to describe color like hue, value, chroma and explains challenges in shade matching.
PHYSICAL PROPERTIES OF DENTAL MATERIALSAswati Soman
The document discusses various physical properties of dental materials, including rheological, thermal, electrical, chemical, and optical properties. It describes properties such as viscosity, viscoelasticity, thermal conductivity, color, and fluorescence. Viscosity is defined as the resistance of a fluid to flow and is important for materials used in dentistry. The document also discusses various mechanical models that can be used to characterize the viscous and elastic behaviors of different materials. Thermal properties like conductivity are important because materials in the oral cavity are exposed to temperature changes. Optical properties such as color, transparency, and fluorescence also impact how materials appear in the mouth.
This lecture discusses the physical, chemical, and mechanical properties of dental materials. It focuses on the mechanical properties of stress, strength, elastic limit, strain, ductility, stress-strain curves, elastic modulus, proportional limit, resilience, and hardness. Thermal properties discussed include thermal conductivity, coefficient of thermal expansion and contraction. Electrical properties examined are electrical activity and galvanism in dentistry. Finally, the optical properties of transparency, opacity, and translucency are covered. Understanding these properties helps with manipulating dental materials and using them to their best advantage.
This document discusses various optical and physical properties of dental materials that are important for their selection and use. It provides details on properties like opacity, color, thermal conductivity, viscosity, water sorption and solubility. It explains how these properties are measured and their significance for different dental applications like composite resins, cements, impression materials and dental alloys. The document also covers interactions of light with materials, principles of color measurement, and factors influencing color perception in dentistry.
Physical and Chemical Properties of Dental Materials part - 1Dr.shiva sai vemula
Explore the world of dental materials in dentistry! This SlideShare guides pre-clinical students through the physical, thermal, rheological and electrical properties. Unlock the essentials for mastering the art and science of dental materials.
This document discusses the optical properties of polymers, including refractive index, gloss, haze, yellowness index, transmittance, and photoelasticity/birefringence. It explains how each property is defined and measured, how it relates to the material composition and structure, and the relevant ASTM standard test methods. The refractive index, gloss, haze, and yellowness index sections provide specific examples of how these properties are affected by materials, additives, and processing.
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.
This document provides an overview of the various physical properties of dental materials, including rheological properties like viscosity and viscoelasticity, thermal properties such as thermal conductivity and coefficient of thermal expansion, mechanical properties like modulus of elasticity and hardness, electrical properties like galvanism, and chemical properties such as corrosion and tarnish. It discusses these properties in the context of how they impact dental materials during storage, mixing, setting and as a set material. The properties are important to consider when selecting materials to ensure their successful performance for the intended dental application.
Description :
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
Glass is a hard but brittle, non-crystalline amorphous solid that is often transparent and has many practical uses. It has good electrical and thermal insulation properties but is very fragile. Glass is formed through the rapid cooling of molten material and can have its properties modified by adding chemical compounds. It transmits light through reflection and refraction while being highly resistant to weathering, chemicals, and pressure when of sufficient thickness. However, glass is very fragile and susceptible to breaking under stress or thermal shock.
The document provides an overview of material science and engineering materials. It discusses the history and origin of materials from prehistoric times to modern age. Materials are classified based on their properties and applications. Key properties discussed include physical, chemical, mechanical, electrical and thermal properties. Examples are given for different types of materials like metals, alloys, ceramics, polymers, composites and biomaterials. The document also outlines the syllabus and modules to be covered for material science, including crystal structures, metals and alloys, heat treatment processes, and various engineering materials.
The document provides an overview of material science and engineering materials. It outlines the syllabus which covers topics like crystallography, metals and alloys, steels, heat treatment processes, non-ferrous materials, engineering plastics, ceramics, composites, and more. The syllabus is divided into two modules which delve deeper into various material types, properties, manufacturing processes, applications and more. The document emphasizes why the study of material science is important for understanding how materials are made and behave, selecting materials for engineering applications, and research.
Assessment of mechanical,physical,chemical and biological properties of dental alloys .
This presentation discusses the assessment of the properties of different alloys used in dentistry such as gold,NiTi and base metal alloys .
Similar to Physical and mechanical properties of dental materials (20)
Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
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Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
3. Introduction
Rheological properties
Properties of materials in relation to light transmission and
absorption
Color – Three dimension of color
Measurement of color
Metamerism
Fluorescence
Thermo physical properties
Galvanism
Force
Stress
Flexural stress
Strain
Contents
5. Introduction
Dental materials are developed by the producer
and selected by the dentist on the basis of
characteristic physical, chemical, mechanical,
and biological properties.
6. PHYSICAL PROPERTIES
Physical properties are based on laws of mechanics,
acoustics, thermodynamics, optics, magnetism,
radiation, atomic structure, or nuclear phenomena.
MECHANICAL PROPERTIES
Mechanical properties are defined by the laws mechanics
(ie) the physical science that deals with energy and forces
and their effects on bodies.
7. RHEOLOGICAL PROPERTIES
Rheology Is The Study Of Flow Of Material
For Liquid Flow Is Measured By Viscosity
For Solid Flow Is Measured by Creep And Flow
Viscoelasticity
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8. VISCOSITY
Viscosity Is The Resistance Of The Fluid To Flow
When a substance flows under the influence of external forces
(Gravity) the molecules or atom come into contact. Thus the bond
must be broken and remade and give rise to resistance to flow known
as viscosity.
9. Low Viscosity :Liquid such as water. The force
binding the molecules together are weak and easily
overcome
High Viscosity: Fluid with stronger intermolecular
attraction with large molecules
Viscosity Of Most Liquid Decreases
Rapidly With Increases In Temperatue
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10. Material Temperature ⁰c Viscosity cp
Agar 45 281,000
Alginate 37 252,000
Impression
Plaster 37 23.800
Polysulfide, 37 57,200
light
Polysulfide, 36 1,360,000
heavy
Silicone, 37 95,000
syringe
Silicone, 36 420,000
regular
Zinc oxide eugenol 31 99,600
Viscosity of dental impression materials
11. THIXOTROPIC
A liquid of this type becomes less viscous and more fluid under
repeated application of pressure.
Eg:
Zinc Oxide Eugenol Shows Reduced
Viscosity After Vigorous Mixing
Clinical significance
The rheological properties of a material are important ,as these
have a major influence on the handling characteristics of the
material
12. VISCOELASTICITY
Materials that have mechanical properties independent of strain are
termed elastic.
Materials that have mechanical properties dependent on strain are
termed viscoelastic. (ie) these materials have characteristics of an
elastic solid and a (viscous) fluid.
Material such as agar, alginate, elastomeric
impression materials and waxes are
viscoelastic
Clinical significance
Some materials have properties
between that of a solid and a
liquid,which makes them susceptible
to distortion.
13. • To explain viscous nature of some materials, shear stress v/s
shear strain rate curve can be plotted.
13
14. 14
NEWTONIAN FLUID:
- an ideal fluid,Shear stress proportional to strain rate,
-Viscosity(η)= shear stress(τ)/strain rate (ε)
-Constant velocity.eg. Water and newly mixed zinc phosphate cement
PSEUDOPLASTIC FLUID:
-viscosity decreases with increasing strain rate, until it reaches a nearly
constant value.
e.g. elastomeric Impression materials,poly carboxylate cements,
DILATANT FLUID
Viscosity increase with increasing stress.
The material become more rigid under stress(disadvantage)
e.g.-Acrylic denture base material, sand in water
PLASTIC FLUID
Material behaves rigid until a minimum of stress is applied ,then it starts
behaving like Newtonian fluid.
e.g.- clay suspension, composite material
15. CREEP AND FLOW
Creep is defined as the slow change in dimensions of an object
as a result of prolonged exposure to high temperature or stress.GPT9
Static Creep: Time dependent deformation produced complete set of
solid subject to constant stress. Dental amalagam.
Dynamic Creep: produced when applied stress is fluctuating.
Flow is similar to creep generally used in dentistry to
describe the rheology of amorphous material such as waxes.
16. Properties of materials in relation to light
transmission and absorption
Transparency is a property of a material, that allows the passage
of light in such a manner that little distortion takes place so that
objects can be clearly seen through them Eg: glass, pure acrylic
resin.
17. • Translucency having the appearance between complete opacity and
complete transparency; partially .GPT9.
• In such manner, the object cannot be clearly seen through them .
Eg: tooth enamel, porcelain, and pigmented acrylic resin.
Opacity is a property of the material that prevents the passage of
light. Opaque material absorbs all of the light. Objects cannot be
seen through them.
19. COLOR
•Light is a form of electromagnetic radiant energy that can be
detected by human eye
•Eye is sensitive to wave length for approximately 400nm(violet) to
700nm(red)
•The combined intensities of the wave length present in a beam of
light determines the property called color
21. THREE DIMENSION OF COLOR
• HUE
• VALUE
• CHROMA
Hue : Refers to as dominant color of an object Eg: Blue, Green, Red
Value: Color can be separated in to light (High value) and dark
(Lower Value)This Lightness or Darkness which can be measured
independently of color hue is Called VALUE .
Eg: Tooth of low value appears Gray is non-vital
22. •Chroma: the purity of a color, or its departure
from white or gray;
•the intensity of a distinctive hue; saturation of
a hue;
• chroma describes the strength or saturation
of the hue
•A particular color may be dull or vivid this difference in color
intensity is called CHROMA
Chroma represent the degree of saturation of particular hue (color)
• Higher the Chroma more intense and darker is the color
24. • Clinical significance
The colour of an object is a human perception which
is a function of a triplet composed of the light source
,the object and the observer.
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25. Vita Classic Shade Guide
Four categories representing hue
A, yellow-red
B, yellow
C, gray
D, red-yellow-gray
Chroma is selected from gradations
within 1, 2, 3, 4
Eg: A3 = hue of red-yellow,
Chroma of 3
Yellow-red Yellow gray Red-Yellow-Red
30. METAMERISM
The appearance of an object depend on the nature of light by which
the object is viewed.
Object that appears to be color matched under one type of light may
appear very different under another light source. This phenomenon
is called METAMERISM.
31. FLUORESCENCE
Fluorescence is the emission of light by an object at wavelength
different from those of incident light.
Fluorescence makes a definite contribution to the brightness and
vital appearance of human tooth.
32. THERMAL CONDUCTIVITY
THERMO PHYSICAL PROPERTIES
Heat transfer through the solid substance commonly occurs
through by means of conduction
Thermal conductivity or coefficient of thermal conductivity is the
quantity of Heat in calories per second that passes through a
specimen 1cm thick having a Cross sectional area of 1cm2 . When
the temperature difference between surface perpendicular to the
heat flow of the specimen is 1⁰.
Conductors
Insulators.
33. Thermal Diffusivity
• It is a measure of the rate at which a body with
a no uniform temperature reaches a state of
thermal equilibrium.
• The thermal conductivity of zinc oxide-
eugenol is slightly less than that of dentin, its
thermal diffusivity is more than twice that of
dentin.
34. COEFFICIENT OF THERMAL EXPANSION
Coefficient of thermal expansion is defined as the fractional
change in length of a given material per degree change in
temperature.GPT9
Eg: Coefficient of thermal expansion of inlay wax is important
because it is susceptible to temperature change. An accurate wax
pattern that fits a prepared tooth contract significantly when it is
removed from tooth or die in warmer area and the stored in cooler
area.
35. • Material Coefficient
• Inlay waxes 350-450
• Silicone impression material 210
• Polysulfide impression material 140
• Acrylic resin 76.0
• Porcelain 12.0
Clinical significance
The thermal properties of a dental material can influence the
sensation of hot and cold food and can cause mechanical failure
due to differential expansion and contraction.
36. TARNISH
TARNISH is the surface discoloration on a metal , or as a slight
loss or alteration of the surface finish or luster.
CORROSION
Chemical or electrochemical process in which a solid, usually a
metal, is attacked by an environmental agent, resulting in partial or
complete dissolution.
TYPES OF CORROSION REACTION
Chemical corrosion--- a) Dry corrosion
b) Wet corrosion
37. •Accelerated corrosion of a metal as a result of
electrical contact with a more noble metal in
a corrosive electrolyte; the resulting current flow
can produce nerve stimulation, unpleasant tastes, and other
physiological reactions commonly associated with this term-GPT9
•This results from a difference in potential between dissimilar fillings
in opposing or adjacent teeth. These fillings, in conjunction with saliva
as electrolytes, make up an electric cell.
•When two opposing fillings contact each other, the cell is
short-circuited, and if the flow of current occurs through the pulp, the
patient experiences pain and the more anodic restoration may corrode.
GALVANISM
40. Force is generated through one body pushing or
pulling on another
The unit of force is the Newton, N
•Occlusal forces
•The maximum biting force on tooth ranges from 200 to 3500 N.
•The average biting forces on permanent teeth were 665,
450, and 220 N on molars, bicuspids, and incisors, respectively
•Biting force measurements on patients with removable partial
dentures are in the range of 65 to 235 N
•Patients with complete dentures, the average force on the molars
And bicuspids was about 100 N, whereas the forces on the
Incisors averaged 40 N.
FORCE
41. Tuesday, 17 March 2020
CORROSION OF NICKEL-BASED
DENTAL CASTING ALLOYS
• By Christopher & Richard shelton from journal of oral
&Craniofacial biomaterial sciences. Vol.23 No.6 2007
This study showed the importance of the level of Cr in Ni-
based alloys.
• The presence of higher Cr (25wt%) in bulk alloy led to a
superior corrosion resistance compared with lower Cr
(12.6wt%).
• At ph 2.5 the stability is greatly reduced for the alloy that
contained a lower Ch level where crevice corrosion was
observed.
42. STRESS
•A force exerted on one body that presses on, pulls on, pushes
against, or tends to invest or compress another body; an internal
force that resists an externally applied load or force.GPT9
Clinical significance
•When a load is applied to a tooth, this load is transmitted through the
material ,giving rise to stresses and strains. If these stresses and
strains exceed the maximum value the material can withstand ,fracture
is the most likely outcome.
Stress =
Force/Area
43. TYPE OF STRESS
Tensile stress
Compressive stress
Shear Stress
TENSILE STRESS
•Two set of forces that are directed away from each other in the same
straight line
•Tensile stress is caused by load that tends to stretch or elongate a body
Eg: A sticky candy can be used to remove crowns by means of tensile
force
44. COMPRESSIVE STRESS
Two set of forces in the same straight line but directed towards each other.
If a body is placed under a load that tends to
compress or shorten it the internal resistance
to such a load is called compressive stress.
SHEAR STRESS
Two forces directed parallel to each other a stress that tends to
resist a twisting motion or a sliding of one portion of a body
over another is a shear or shearing stress.
45. FLEXURAL (Bending) STRESS
Flexural stress is caused by bending force.
Flexural stress that are produced in a three unit bridge or fixed partial
denture
In fig: A tensile stress develops on the tissue side of FPD and
compressive stress develop on the occlusal side by bending force
The area tension represent potential fracture initiation site.
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46. Tuesday, 17 March 2020
Effect of 180 week water storage of flexural
properties of E-Glass & Silica fibre acrylic
resin composite
• By Pekkat.K.Vallittu
• 1)Storing test specimen in water decreased
their transverse strength & flexural modulous
• 2)Major reduction of the flexural properties
occured at first 4weeks of H2O storage
• I.J.P 2000; 13; 334-337
47. STRAIN
Strain is change in length per unit length when stress is applied; the
change in length/original length; the deformation caused in a body by
an external force.GPT9
Strain may be elastic or plastic.
Elastic strain is reversible
Plastic strain represent permanent deformation.
49. ELASTIC LIMIT
•The greatest stress to which a material may be subjected and still
be capable of returning to its original dimensions when such
forces are released.GPT9
•Below the proportional limit point ‘p’ a material is elastic in
nature.
(ie) if the load is removed the material will return to its original
shape.
P
50. YIELD STRENGTH
•The strength at which a small amount of permanent (plastic)
strain occurs, usually 0.1% or 0.2%,and most frequently
measured in MPa or psi .GPT9
•The prosthesis becomes permanently
deformed if stress is equal to or greater
than the yield strength.
Clinical significance
•If at any point in a metal restoration
such as a three unit bridge the tensile
stress exceeds the yield stress , the
restoration will deform permanently.
51. RESILIENCE
•The term resilience is associated with “springiness”the
ability of the material to resist permanent deformation.
•RESILIENCE is defined as the amount of energy absorbed
by a structure when it is stressed not to exceed its
proportional limit.
52. •The deformation that results from the application of a tensile
force is elongation. GPT9
•Elongation is extremely important because it gives an indication of
the work ability of an alloy.
ELONGATION
Alloy % Elongation
Gold (type 111) 34.0
40% Au-Ag-CU 02.2
Nickel-chromium 01.1
Alloy % Elongation
Gold (type TV) 6.5
Nickel-chromium 2.4
Cobalt-chromium 1.5
Iron-chromium 9.0
Cobalt-nickel-chromium 8-10
Crown and bridge
Partial denture
53. ELASTIC MODULUS
The coefficient found by dividing the unit stress, at any point up to
the proportional limit, by its corresponding unit of elongation
(tension) or strain.GPT9
It represent the relative stiffness and rigidity of materials within
the elastic range.Young's modulus is the ratio of stress to strain
Material Elastic Modulus GPa*
Cobalt-chromium partial 218.0
denture alloy
Acrylic denture resin 2.65
Silicone rubber 0.002
(maxillofacial)
54. FLEXIBILITY
The flexibility is defined as the strain that occurs when the
material is stressed to its proportional limit and modulus of
elasticity
Flexibility = Proportional limit/ modulus of elasticity
55. TEAR STRENGTH
•Tear strength is a measure of the resistance of a material to
tearing forces.
•Tear strength depends on the rate of loading.
•More rapid loading rates result in higher values of tear strength.
•Clinically, the rapid removal of an alginate impression is
recommended to maximize the tear strength and also to minimize
permanent deformation.
Material Tear strength kN/m
Agar duplicating material 0.22
Denture liners 2.6-45
Impression materials
Agar 0.99
Alginate 0.47
Polysulfide 4.0
Tear strength of Dental materials
56. FATIGUE
• To break or fracture a material caused by repeated cyclic or applied
loads below the yield limit.GPT9
Application: Restorations in the mouth are often subjected to
cyclic forces of mastication. Metal clasp of removable partial
denture, complete denture made of various resins.
Clinical significance
•Whereas a material may be strong enough to withstand the loads
placed on it when initially put into use, this does not mean it will
always be able to withstand those loads
57. TOUGHNESS
The ability of a material to withstand stresses and strains without
breaking; resistance to fracture-GPT9.
The area under the elastic and plastic portions of a stress strain
curve
58. BRITTLENESS
Brittleness is the relative inability of a material to sustain
plastic deformation before fracture of a material occurs.
Eg: Ceramics are brittle at oral temperatures they sustained little
or no plastic strain before they fracture (ie) A brittle material
fractures at or near its proportional limits
59. DUCTILITY
It represents a ability of a material to sustain a large permanent
deformation under a tensile load without rupture.GPT9
A metal that can be drawn readily in to a wire is said to be ductile.
Ductility depend on tensile strength. ductility decreases as the
temperature is raised
60. MALLEABILITY
The ability of a material to sustain considerable permanent
deformation without rupture under compression.
Ex: Hammering or rolling in to a sheet
Most malleable and ductile metals
Gold
Sliver
Platinum – Ductility
Copper - Malleability
61. Strength it is the maximal stress required to fracture a structure
The three type of strength are:-
-Tensile strength
-Compressive strength
-Shear strength
Tensile strength
Tensile strength is defined as the maximal
stress the structure will withstand before
rupture
62. DIAMETRAL COMPRESSION TEST
In this method, the compressive load is place by a flat plate against
the side of a short cylindrical specimen. The vertical compressive
force along the side of the disk produce as a tensile stress that is
perpendicular to the vertical plane that passes
through the center of the disk. Fracture
occur along the vertical plane. In this
situation the tensile stress is directly
proportional to the compressive load
applied.
(Brazilian test)
63. COMPRESSIVE STRENGTH
Compressive strength or crushing strength is determined by
subjecting a cylindrical specimen to a compressive load. The
strength value is obtained from the cross sectional area and force
applied. Though the load is compressive in nature the failure is
due to complex stresses
64. SHEAR STRENGTH
Shear strength is a maximum stress that a material can
withstand before failure in a shear mode of loading. It is
tested using the punch or push out method
Application: It is used to study the inter face between
the two materials Eg: Porcelain fused to metal
Punch tool
65. Shear bond strength of denture reline
polymers to denture base polymer;
• By Yutaka Takahashi & John Chai
• To characterize the shear bond strength
established between 4 denture base polymer 4
denture reline polymer
• Affected Bond Strength found to be relatively
low.
• I.J.P 2001-14-271
Tuesday, 17 March 2020
66. HARDNESS
Hardness is resistance to indentation. Hardness of a material
is influenced by various factors such as strength,
proportional limit, ductility, malleability.
Hardness Test:-
-Brinell's Hardness Test
-Rockwell Hardness Test
-Vickers hardness Test
- Knoop Hardness Test
67. Brinell’s Hardness Test:-
Hardened steel ball is pressed in to a polished surface of a material under a
specified load the load is divided by the area of the surface of the indentation
and the value is referred to as Brinell's Hardness Number
BHN = Load /Area of indentation
Application:- Used for measuring hardness of metals Not suitable for
brittle materials
Brinells hardness tester
68. Rockwell Hardness Test:-
A steel ball or a conical diamond point is used, in this test the depth
is measured directly by a dial gauge on the instrument
Application:- Used for measuring hardness of metals
Rockwell hardness tester
69. Vickers hardness Test:-
It is similar to Brinell's test however instead of steel ball, a diamond in the
shape of square pyramid is used here impression is square. The load is divided
by the area of the indentation.
Application:- Suitable for brittle materials, measuring hardness of
tooth structure
Vickers hardness tester
70. Knoop Hardness Test:-
A diamond indenting tool is used. The impression is rhombic in shape.
Values of exceeding hard and soft materials can be obtained
by this test.
71. The Shore And The Barcol
Tuesday, 17 March 2020
Barcol test
The shore test
A metal indenter that is spring loaded is used .The hardeness
number is based depth of penetration and is read directly from a
guage .
Application: Measure the hardness of rubber and plastics
72. SUMMARY
• The physical properties of oral restorations must adequately
withstand the stresses of mastication. Restorations and
appliances should be designed so resulting forces of
mastication are distributed as uniformly as possible. Lastly,
remember that dental material behavior depends on
interrelated physical, chemical, optical, mechanical, thermal,
electrical, and biological properties, and improvement of one
specific property often leads to a reduction in another
property.
Tuesday, 17 March 2020
73.
74. Reference
phillips science of dental materials –
Eleventh Edition
Mc cabe Applied Dental Materials Ninth
Edition
William O Brian Dental Materials Selection
fourth Edition
Craig Restorative Dental Materials– thirteen
Edition
Journal for oral&craniofacial biomaterial
sciences vol.23 no.2 feb. 2007
vol.23 no.6 june 2007
vol.23 no.3 march 2007