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.
The document provides a history of denture materials and techniques from ancient times to modern day. It begins with early dentures made of materials like wood, bone, ivory and human teeth. Important developments include the introduction of porcelain and vulcanite dentures in the 18th-19th centuries. In the 1930s, polymethyl methacrylate (PMMA) was introduced and became the standard denture material due to its strength, biocompatibility and ease of use. The document also describes the compression molding technique for fabricating PMMA dentures, involving steps like flasking, packing, curing and finishing. Alternative techniques like injection molding are also mentioned.
OPTICAL PROPERTIES OF DENTAL MATERIALS AND SHADE SELECTIONHri M
This presentation describes the optical properties of dental materials, the different types of colour models, how colour is produced, dimensions of colour, problems in colour perception, shade guides available in markets and rules in shade selection
Gypsum is a mineral composed of calcium sulfate dihydrate that is used to produce several dental products, including plaster, dental stone, and die stone. These products differ in their physical properties based on how they are manufactured but have the same chemical structure. Plaster is produced by direct heating of gypsum powder, resulting in an irregular porous structure. Dental stone involves controlled calcination under steam pressure, producing stronger and more uniform particles. Die stone undergoes additional processing to form very dense cuboidal crystals and strong dies. The setting process involves the hydration of calcium sulfate hemihydrate back to calcium sulfate dihydrate, with crystal growth linking the particles. The water-powder ratio affects properties, with plaster requiring more water
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 document provides an overview of various types of dental cements. It begins with definitions and a brief history of dental cements. It then classifies cements based on their ingredients and discusses their ideal requirements. The document goes on to describe specific cement types in detail, including their characteristics, properties, and uses. It covers traditional cements like zinc phosphate, as well as contemporary materials like resin-modified glass ionomers. The document provides a comprehensive reference on the formulation and application of different dental cements.
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.
This document discusses color and optical effects in dentistry. It begins by explaining the nature of light and how the human eye perceives color. It then discusses how the properties of materials, such as opacity, translucency and roughness, determine how light interacts with objects and affects their appearance. The document also covers color perception in terms of hue, value and chroma. It describes color matching guides and factors that can influence color matching, such as lighting conditions, the observer, and fluorescence. The goal is to help dental professionals achieve optimal esthetic results when matching tooth colors.
The document provides a history of denture materials and techniques from ancient times to modern day. It begins with early dentures made of materials like wood, bone, ivory and human teeth. Important developments include the introduction of porcelain and vulcanite dentures in the 18th-19th centuries. In the 1930s, polymethyl methacrylate (PMMA) was introduced and became the standard denture material due to its strength, biocompatibility and ease of use. The document also describes the compression molding technique for fabricating PMMA dentures, involving steps like flasking, packing, curing and finishing. Alternative techniques like injection molding are also mentioned.
OPTICAL PROPERTIES OF DENTAL MATERIALS AND SHADE SELECTIONHri M
This presentation describes the optical properties of dental materials, the different types of colour models, how colour is produced, dimensions of colour, problems in colour perception, shade guides available in markets and rules in shade selection
Gypsum is a mineral composed of calcium sulfate dihydrate that is used to produce several dental products, including plaster, dental stone, and die stone. These products differ in their physical properties based on how they are manufactured but have the same chemical structure. Plaster is produced by direct heating of gypsum powder, resulting in an irregular porous structure. Dental stone involves controlled calcination under steam pressure, producing stronger and more uniform particles. Die stone undergoes additional processing to form very dense cuboidal crystals and strong dies. The setting process involves the hydration of calcium sulfate hemihydrate back to calcium sulfate dihydrate, with crystal growth linking the particles. The water-powder ratio affects properties, with plaster requiring more water
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 document provides an overview of various types of dental cements. It begins with definitions and a brief history of dental cements. It then classifies cements based on their ingredients and discusses their ideal requirements. The document goes on to describe specific cement types in detail, including their characteristics, properties, and uses. It covers traditional cements like zinc phosphate, as well as contemporary materials like resin-modified glass ionomers. The document provides a comprehensive reference on the formulation and application of different dental cements.
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.
This document discusses color and optical effects in dentistry. It begins by explaining the nature of light and how the human eye perceives color. It then discusses how the properties of materials, such as opacity, translucency and roughness, determine how light interacts with objects and affects their appearance. The document also covers color perception in terms of hue, value and chroma. It describes color matching guides and factors that can influence color matching, such as lighting conditions, the observer, and fluorescence. The goal is to help dental professionals achieve optimal esthetic results when matching tooth colors.
The document discusses the process of casting in dentistry. It begins with an introduction defining casting and its objective in dentistry. It then covers the history of casting in dentistry from ancient times through modern developments. The basic steps of casting are outlined, including spruing, investing, burnout, casting, recovery and cleaning. Different materials used for sprue formers, crucible formers, casting rings and liners are described. The document provides details on investing, burnout, and high and low heat techniques for casting gold and other alloys.
This document provides an overview of dental casting procedures and defects. It defines casting and describes the main steps which include making a wax pattern, spruing, investing, burnout of the wax, casting with different methods, cleaning the casting, and finishing and polishing. It also discusses common casting defects such as distortion, surface roughness, porosity, and missing details. The document is intended to educate dental students and professionals about casting techniques and potential defects.
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 finishing and polishing of restorative materials in dentistry. It defines finishing as removing surface defects from contouring, and polishing as providing luster to a surface. Finishing and polishing are important for oral health, function, and aesthetics as they reduce plaque accumulation, staining, and irritation. The document outlines the principles, mechanisms, instruments, and procedures for cutting, grinding, finishing and polishing restorative surfaces. It also reviews different types of abrasives and their uses.
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.
This document discusses dental porcelain, including its composition, manufacturing process, strengthening methods, and applications in ceramic and metal-ceramic restorations. Dental porcelain is a type of ceramic composed of kaolin, silica, and feldspar that is fired at high temperatures. It is used for ceramic crowns, veneers, and metal-ceramic restorations due to its biocompatibility, esthetics, and thermal properties matching enamel and dentin. However, porcelain is also brittle with low tensile strength, so various strengthening techniques are used. Metal-ceramic restorations bond porcelain to metal frameworks, requiring thermal and chemical compatibility between the materials.
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
Dr. Mayank Nahta presented on dental composites. Composites are polymers reinforced with filler particles that are bound together. Dr. Ray Bowen developed the first dental composite in 1962 using Bis-GMA resin and glass/quartz fillers. Composites are used for restorations, veneers, cores, and more. They are classified based on properties like filler size, composition, and curing method. Composites provide strength, polishability, aesthetics, and more depending on their formulation. Developments include microfilled, small particle, hybrid, and flowable composites to optimize properties.
Dental amalgam is an alloy used in dental restorations that is a mixture of mercury and other metals such as silver, tin, and copper. It has been used in dentistry since the 1800s. The document discusses the history, composition, manufacturing process, setting reactions, properties and strengths of dental amalgam. It provides details on the phases that form during setting and how composition affects properties such as strength, expansion and corrosion resistance. High copper amalgams have higher strengths compared to low copper amalgams. Proper manipulation of the amalgam is important to achieve optimal strength.
This document discusses procedures for boxing master impressions and making master casts. It describes two methods for boxing maxillary impressions using either pumice and plaster or wax rods and strips. For mandibular impressions, a layer of adhesive or wax is applied to the impression border before adding a wax land and boxing wax enclosure. Master casts are poured in stone, trimmed with a 4-6mm peripheral roll and notches added for remounting. Landmarks like the incisive papilla and retromolar pad midpoint are marked on casts.
This document discusses the principles of adhesion in dentistry. It begins by defining adhesion as the attraction between dissimilar molecules, while cohesion refers to attraction between similar molecules via chemical bonds. Cohesive forces within adhesives are important for bond strength and depend on curing conditions. Adhesion in dentistry can involve solid-solid bonding via surface irregularities or liquid-solid bonding using adhesives and bonding agents. The key types of bonding are mechanical via surface roughness, chemical bonding between adhesive and tooth structures, dispersive interactions like Van der Waals forces, diffusive bonding through molecule interdigitation, and electrostatic bonding in some cases. Factors that affect adhesion include properties of the adhesive like surface tension and viscosity,
This document provides an overview of recent advances in composite resins. It discusses the introduction and advantages of various types of composites developed over time, including packable composites in 1995, flowable composites in 1996, ormocers in 1998, and bulkfill composites in 2010. The document also summarizes different photoinitiators, self-healing composites, giomers, and various commercial composite materials like Tetric Evo Ceram Bulkfill, SonicFill, and Filtek BulkFill.
This document provides an overview of dental ceramics. It discusses the history, structure, composition, properties, classification, and fabrication of dental ceramics. The key points are: Dental ceramics can be crystalline or non-crystalline. Common components include feldspar, silica, alumina, and color pigments. Ceramics are classified based on firing temperature, microstructure, and indications. Metal-ceramic systems involve a cast metal framework with ceramic layers bonded to it. The fabrication process involves building and firing layers of ceramic powder to form the final restoration.
Gypsum Products commercially available are hemihydrate form of calcium sulfate. Gypsum products used in Dentistry are broadly classified into 5 types
Type 1- Impression Plaster
Type 2- Model Plaster
Type 3- Dental stone
Type 4- Die Stone high strength low expansion
Type 5- Die Stone high Strength High Expansion
Synthetic Resins used in ProsthodonticsKelly Norton
The document discusses synthetic resins used in prosthodontics. It provides a brief history of dentures from ancient bone and wood dentures to modern resins like polymethyl methacrylate. Ideal requirements for dental resins include biocompatibility, adequate physical properties, and ease of manipulation. The basic nature of polymers is explained including types of spatial arrangements and polymerization techniques like addition and condensation polymerization. Common denture base resins are classified and compression molding technique is summarized in 3 main steps: stone mold preparation, dewaxing, and resin manipulation.
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.
Elastic impression materials include alginate, elastomers like polysulfides and polyethers, and addition and condensation silicone materials. They are capable of accurately reproducing both hard and soft oral structures. Elastic materials are advantageous over rigid materials for use in cases with undercuts. Elastic materials are classified as reversible or irreversible hydrocolloids and elastomeric materials. Agar is a reversible hydrocolloid extracted from seaweed that forms gels through secondary bonds that break and re-form with temperature changes. It requires specialized equipment and techniques for manipulation but provides accurate impressions.
Recent advances have improved dental composite materials. Composites contain resin and inorganic fillers to increase strength while decreasing problems from resin such as shrinkage. Larger filler particles improve strength but smoothness while smaller fillers enhance esthetics. Novel composites aim to reduce shrinkage through techniques like silorane resin which uses a different polymerization or bulk fill which can be placed in 4mm layers. Other trends include nano-filled composites with ultra-small particles achieving high filler loading and strength, and smart composites which release ions to prevent decay. Indirect composites can be contoured outside the mouth but still experience shrinkage during cementation. Overall composites continue advancing but shrinkage remains a challenge.
This document provides an overview of dental cements. It begins with an introduction to dental cements, their classification, uses, properties, and examples. Key points include that dental cements are used as luting agents, restorative materials, and bases/liners. They are classified based on their composition and setting reaction. Common cements discussed include silicate, zinc phosphate, zinc polycarboxylate, zinc oxide eugenol, glass ionomer, resin modified glass ionomer, and resin cements. The properties, compositions, uses and advantages/disadvantages of different cements are summarized.
This document discusses shade matching in fixed prosthodontics. It begins with an introduction to the importance of shade matching for esthetic restorations. It then covers topics related to light and color, including the visible light spectrum, color perception, and color measurement systems. The document discusses factors that affect shade matching like the type of light, hydration of the tooth, and observer variability. Methods of shade matching involving comparison tabs and dividing the tooth into regions are presented. Factors influencing accurate shade selection are also summarized.
The document discusses the process of casting in dentistry. It begins with an introduction defining casting and its objective in dentistry. It then covers the history of casting in dentistry from ancient times through modern developments. The basic steps of casting are outlined, including spruing, investing, burnout, casting, recovery and cleaning. Different materials used for sprue formers, crucible formers, casting rings and liners are described. The document provides details on investing, burnout, and high and low heat techniques for casting gold and other alloys.
This document provides an overview of dental casting procedures and defects. It defines casting and describes the main steps which include making a wax pattern, spruing, investing, burnout of the wax, casting with different methods, cleaning the casting, and finishing and polishing. It also discusses common casting defects such as distortion, surface roughness, porosity, and missing details. The document is intended to educate dental students and professionals about casting techniques and potential defects.
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 finishing and polishing of restorative materials in dentistry. It defines finishing as removing surface defects from contouring, and polishing as providing luster to a surface. Finishing and polishing are important for oral health, function, and aesthetics as they reduce plaque accumulation, staining, and irritation. The document outlines the principles, mechanisms, instruments, and procedures for cutting, grinding, finishing and polishing restorative surfaces. It also reviews different types of abrasives and their uses.
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.
This document discusses dental porcelain, including its composition, manufacturing process, strengthening methods, and applications in ceramic and metal-ceramic restorations. Dental porcelain is a type of ceramic composed of kaolin, silica, and feldspar that is fired at high temperatures. It is used for ceramic crowns, veneers, and metal-ceramic restorations due to its biocompatibility, esthetics, and thermal properties matching enamel and dentin. However, porcelain is also brittle with low tensile strength, so various strengthening techniques are used. Metal-ceramic restorations bond porcelain to metal frameworks, requiring thermal and chemical compatibility between the materials.
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
Dr. Mayank Nahta presented on dental composites. Composites are polymers reinforced with filler particles that are bound together. Dr. Ray Bowen developed the first dental composite in 1962 using Bis-GMA resin and glass/quartz fillers. Composites are used for restorations, veneers, cores, and more. They are classified based on properties like filler size, composition, and curing method. Composites provide strength, polishability, aesthetics, and more depending on their formulation. Developments include microfilled, small particle, hybrid, and flowable composites to optimize properties.
Dental amalgam is an alloy used in dental restorations that is a mixture of mercury and other metals such as silver, tin, and copper. It has been used in dentistry since the 1800s. The document discusses the history, composition, manufacturing process, setting reactions, properties and strengths of dental amalgam. It provides details on the phases that form during setting and how composition affects properties such as strength, expansion and corrosion resistance. High copper amalgams have higher strengths compared to low copper amalgams. Proper manipulation of the amalgam is important to achieve optimal strength.
This document discusses procedures for boxing master impressions and making master casts. It describes two methods for boxing maxillary impressions using either pumice and plaster or wax rods and strips. For mandibular impressions, a layer of adhesive or wax is applied to the impression border before adding a wax land and boxing wax enclosure. Master casts are poured in stone, trimmed with a 4-6mm peripheral roll and notches added for remounting. Landmarks like the incisive papilla and retromolar pad midpoint are marked on casts.
This document discusses the principles of adhesion in dentistry. It begins by defining adhesion as the attraction between dissimilar molecules, while cohesion refers to attraction between similar molecules via chemical bonds. Cohesive forces within adhesives are important for bond strength and depend on curing conditions. Adhesion in dentistry can involve solid-solid bonding via surface irregularities or liquid-solid bonding using adhesives and bonding agents. The key types of bonding are mechanical via surface roughness, chemical bonding between adhesive and tooth structures, dispersive interactions like Van der Waals forces, diffusive bonding through molecule interdigitation, and electrostatic bonding in some cases. Factors that affect adhesion include properties of the adhesive like surface tension and viscosity,
This document provides an overview of recent advances in composite resins. It discusses the introduction and advantages of various types of composites developed over time, including packable composites in 1995, flowable composites in 1996, ormocers in 1998, and bulkfill composites in 2010. The document also summarizes different photoinitiators, self-healing composites, giomers, and various commercial composite materials like Tetric Evo Ceram Bulkfill, SonicFill, and Filtek BulkFill.
This document provides an overview of dental ceramics. It discusses the history, structure, composition, properties, classification, and fabrication of dental ceramics. The key points are: Dental ceramics can be crystalline or non-crystalline. Common components include feldspar, silica, alumina, and color pigments. Ceramics are classified based on firing temperature, microstructure, and indications. Metal-ceramic systems involve a cast metal framework with ceramic layers bonded to it. The fabrication process involves building and firing layers of ceramic powder to form the final restoration.
Gypsum Products commercially available are hemihydrate form of calcium sulfate. Gypsum products used in Dentistry are broadly classified into 5 types
Type 1- Impression Plaster
Type 2- Model Plaster
Type 3- Dental stone
Type 4- Die Stone high strength low expansion
Type 5- Die Stone high Strength High Expansion
Synthetic Resins used in ProsthodonticsKelly Norton
The document discusses synthetic resins used in prosthodontics. It provides a brief history of dentures from ancient bone and wood dentures to modern resins like polymethyl methacrylate. Ideal requirements for dental resins include biocompatibility, adequate physical properties, and ease of manipulation. The basic nature of polymers is explained including types of spatial arrangements and polymerization techniques like addition and condensation polymerization. Common denture base resins are classified and compression molding technique is summarized in 3 main steps: stone mold preparation, dewaxing, and resin manipulation.
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.
Elastic impression materials include alginate, elastomers like polysulfides and polyethers, and addition and condensation silicone materials. They are capable of accurately reproducing both hard and soft oral structures. Elastic materials are advantageous over rigid materials for use in cases with undercuts. Elastic materials are classified as reversible or irreversible hydrocolloids and elastomeric materials. Agar is a reversible hydrocolloid extracted from seaweed that forms gels through secondary bonds that break and re-form with temperature changes. It requires specialized equipment and techniques for manipulation but provides accurate impressions.
Recent advances have improved dental composite materials. Composites contain resin and inorganic fillers to increase strength while decreasing problems from resin such as shrinkage. Larger filler particles improve strength but smoothness while smaller fillers enhance esthetics. Novel composites aim to reduce shrinkage through techniques like silorane resin which uses a different polymerization or bulk fill which can be placed in 4mm layers. Other trends include nano-filled composites with ultra-small particles achieving high filler loading and strength, and smart composites which release ions to prevent decay. Indirect composites can be contoured outside the mouth but still experience shrinkage during cementation. Overall composites continue advancing but shrinkage remains a challenge.
This document provides an overview of dental cements. It begins with an introduction to dental cements, their classification, uses, properties, and examples. Key points include that dental cements are used as luting agents, restorative materials, and bases/liners. They are classified based on their composition and setting reaction. Common cements discussed include silicate, zinc phosphate, zinc polycarboxylate, zinc oxide eugenol, glass ionomer, resin modified glass ionomer, and resin cements. The properties, compositions, uses and advantages/disadvantages of different cements are summarized.
This document discusses shade matching in fixed prosthodontics. It begins with an introduction to the importance of shade matching for esthetic restorations. It then covers topics related to light and color, including the visible light spectrum, color perception, and color measurement systems. The document discusses factors that affect shade matching like the type of light, hydration of the tooth, and observer variability. Methods of shade matching involving comparison tabs and dividing the tooth into regions are presented. Factors influencing accurate shade selection are also summarized.
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.
Physical and mechanical properties of dental materialsPrabu Ps
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.
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.
This document discusses shade selection techniques in dentistry. It defines shade selection and color properties. Factors that influence color perception include the light source, object being viewed, observer, and surrounding structures. Techniques include visual assessment using shade guides or instrumental methods using devices like spectrophotometers. Accuracy is improved by considering the tooth's hydration, region viewed, and background colors. Proper technique, instruments, and composites can help replicate the natural appearance of teeth.
Major challenges in cosmetic dentistry are to accomplish appropriate and satisfactory reproduction of natural shade of teeth.1
The kind of shade guide, individual ability to choose shades and conditions the choice is made under, all have influence on reliability and accuracy of the procedure.
Shade selection in dental practice is an important but difficult task.
Dentists are challenged to satisfy the aesthetic requirement of patients when they select the shades for fabrication of prosthesis. Most dentists are usually not trained for shade selection.2
1) Electron beam therapy uses high-energy electrons between 6-20MeV to treat superficial tumors less than 5cm deep. It is useful for cancers of the skin, eye, breast, head and neck, and gastrointestinal tract.
2) Electron beams have distinct advantages over x-rays and brachytherapy in minimizing dose to deeper tissues and providing dose uniformity.
3) The depth that receives 90% of the maximum dose, called R90, is typically one-third to one-fourth of the electron energy in MeV. This determines the maximum treatment depth.
This document provides an overview of ultrasonic testing. It begins with an introduction and outline. It then covers the basic principles of sound generation and propagation. The principles of ultrasonic inspection using pulse-echo and through transmission techniques are described. Details are provided about ultrasonic test equipment including transducers, instrumentation, and calibration standards. The advantages and limitations of ultrasonic testing are summarized.
This document discusses guidelines for clinical shade selection, including recommendations for lighting, selection time, patient positioning, tooth condition, selection distance, and use of digital images. It provides details on:
- Using daylight-balanced lighting with a CRI over 90 for optimal color matching
- Allowing sufficient time for multiple shade selections to avoid eye fatigue
- Positioning the patient upright at eye level for natural viewing of teeth
- Ensuring clean, dry tooth surfaces isolated with a rubber dam
- Comparing shades at a distance of 1-2 feet to evaluate value more easily
- Using digital images and diagrams to document shade zones and characteristics for the technician.
This document provides an overview of ultrasound use for eye and orbit examination. It discusses the history, principles, instrumentation, techniques, indications, advantages, and types of scans (A-scan and B-scan) used. Key points include:
- Ultrasound uses high frequency sound waves to image ocular structures. It is non-invasive and avoids radiation.
- A-scans show echo amplitude over time as a line, while B-scans provide a cross-sectional image in shades of grey.
- Examination involves transverse, longitudinal, and axial scans using contact or immersion techniques.
- Ultrasound is useful for evaluating opaque media, tumors, detachments, injuries,
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 information about testing methods for ceramics. It discusses several techniques for analyzing the chemical composition, optical properties, and mechanical properties of ceramics. Specifically, it describes X-ray photoelectron spectroscopy for elemental analysis, secondary ion mass spectrometry for surface composition analysis, energy dispersive X-ray spectroscopy for elemental quantification, and various tests for measuring hardness, strength, gloss, refractive index, and color.
Radiographic techniques are used to inspect castings and welds for defects. Common casting defects appear on radiographs as gas porosity, sand inclusions, shrinkage cavities, core shifts, metallic inclusions, cracks, and cold shuts. Weld defects include lack of penetration, incomplete fusion, slag inclusions, porosity, and undercut. Proper film processing, viewing conditions, and knowledge of defect appearances are required to accurately interpret radiographs and evaluate component quality.
This document provides an overview of ultrasound physics, transducers, and transducer jelly. It discusses the characteristics of sound waves including their need for a medium, generation through vibration, and properties like frequency and wavelength. It describes the history and components of ultrasound transducers, focusing on how piezoelectric crystals convert electrical signals to sound and vice versa. It also summarizes the key properties and roles of transducer jelly in ultrasound imaging.
This document provides an overview of ultrasound physics, transducers, and transducer jelly. It discusses the characteristics of sound waves including their generation through mechanical vibration and their transmission through solids, liquids, and gases. The history of ultrasound and piezoelectricity is summarized. Key ultrasound concepts like wavelength, frequency, propagation velocity, amplitude, and absorption are defined. The components and function of ultrasound transducers including the piezoelectric crystal and backing block are described. Finally, the properties and ingredients of transducer jelly used to couple the transducer to the skin are outlined.
Extraction of Heavy Metals From Industrial Waste WaterHashim Khan
This was my topic of research during Bachelors. I made this presentation to give a brief overview of what apparatus i used and the methodologies of my experimentation.
Similar to Physical properties of dental materials (1) (20)
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
share - Lions, tigers, AI and health misinformation, oh my!.pptxTina Purnat
• Pitfalls and pivots needed to use AI effectively in public health
• Evidence-based strategies to address health misinformation effectively
• Building trust with communities online and offline
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2. CONTENTS -
• Introduction
• Properties of importance in manufacturing or finishing process
• Optical properties and parameters
• Thermal properties and parameters
• Electrochemical properties
• Conclusion
3. INTRODUCTION
• A physical property is any measurable parameter that describes the
state of a physical system.
• Physical properties are based on the laws of mechanics , acoustics,
optics, thermodynamics, electricity , magnetism , radiation , atomic
structure or nuclear phenomenon .
• Dental materials may fall into any of
the following classes: metals, ceramics, polymers, or composites.
4. • In order to ensure the successful performance of the dental
material , it is imperative to know about their properties.For
example -
• The physical properties of color and thermal expansion are of
particular importance to the performance of dental ceramics .
• Flow and viscosity (the resistance of a fluid to flow) are essential
properties of impression materials .
• Creep (slow deformation under a static load) is relevant to the
clinical performance of amalgam .
• Tarnish and corrosion are electrochemical properties that strongly
affect the performance of metals and their alloys.
5. • Physical properties can be divided into
the following categories –
1. Properties important in manufacturing
and finishing process
2. Optical properties
3. Thermal properties
6. 1.
PROPERTIES OF IMPORTANCE IN MAN
UFACTURING OR FINISHING PROCESSES
Castability Brittleness Creep resistance Hardness
Melting temperature
or melting
temperature range
Flowability under hot-
isostatic-pressing
(HIP) temperature and
pressure conditions
Machinability Polishability
7. 1 . Rheology —
It deals with deformation and flow of matter , whether solid or liquid .
It includes viscosity.
Viscosity is the resistance of a fluid to flow.
High viscosity – material will flow slowly and vice versa.
Most dental materials are initially in a fluid state so that they can be placed
and shaped as required; then they undergo transformation to a solid state, in which
they are durable and perform their function.
8. • Viscosity (h) can be calculated by shear stress divided by strain rate.
• h = τ/ε
• Stress is the force per unit area that develops within a structure when an external
force is applied. This stress causes a deformation, or strain, to develop.
• Strain is calculated as a change in length divided by the initial reference length. If
the two surfaces have an area (A) in contact with the liquid, a shear stress (τ) can be
defined as τ = F/A.
• Strain = Change in length / Original length
• Shear stress is the external force acting on an object or surface parallel to the
slope or plane in which it lies; the stress tending to produce shear.
• The shear strain rate, or rate of change of deformation, is ε = V/d, where d is the
shear distance of the upper surface relative to the fixed lower surface and V is the
velocity of the moving surface . It is the speed or velocity at which deformation of
an object from its original form occurs.
10. COLOR
• An important aspect of dentistry is esthetics – color and
appearance of the dentition.
• The dental materials used should match the natural hard and
soft tissues in appearance.
• Colour is a somewhat subjective phenomenon which may
be judged differently by different observers.
• The eye is sensitive to wavelengths from approximately 400
nm (violet) to 700 nm (dark red) .
• Using the CIE (Commission International de l’Eclairage)
method of colour measurement colour is defined by three
parameters, L, a and b .
Spectrum of visible light ranging in wavelength from 400
nm ( violet ) to 700 nm ( red )most visually perceptible
region of the equal energy spectrum under daylight
conditions is between wavelengths of 540 and 570 nm,
with a maximum value of visual perceptibility at 555 nm
INFRARED
ULTRAVIOLET
11. • The dominant wavelength or hue is represented by the
relative values of a and b and their signs. It is defined as
the dominant color of an object; for example, red, green,
or blue.
• The brightness ( value ) is represented by the value of L,
which indicates the position on the vertical column .
relative lightness or darkness of a color.
• Value is also expressed by the “lightness” factor with
varying levels of gray between the extremes of white and
black.
• Gray scale.
• The colour intensity or chroma is represented by
the distance from the centre of the chart as indicated by
the magnitude of the values of a or b. Defined as degree
of saturation of a particular hue .For example, red can
vary from “scarlet” to light pink, where scarlet has a high
saturation and pink has a low saturation.The higher the
chroma, the more intense the color.
Three dimensions of color space –
Hue , Value and Chroma
12. •The three dimensions of color space-
•Value increases from black at the bottom center
to white at the top center. Chroma increases from
the center radially outward, and changes in hue
occur in a circumferential direction.
•A, 3-D Munsell Color Space.
•B, Partial color space revealing hue, value, and
chroma regions. (Courtesy of Minolta
Corporation, Instrument Systems Division,
Ramsey, NJ.)
13. • Chroma is not considered separately in dentistry. It is always
associated with the hue and value of dental tissues, restorations, and
prostheses.
• The hue and chroma are inherent properties of materials whereas the
brightness may be affected by factors such as surface finish.
• In many materials (e.g. resin-based products) the initial hue and
chroma are controlled by the manufacturer through the incorporation
of pigments and the use of fillers having varying translucency/opacity
.
• To distinguish these two processes the terms intrinsic and extrinsic
staining are often used. The latter is normally related to the surface
roughness of the material .
14. • Reflection of light from the surface of material and tooth , absorption,
refraction, or transmission (i.e, by passing through unchanged) determine
the opacity, translucency, or transparency of the object.
• Opaque material – absorbs all light falling on it , reflects none.
• Translucent material – absorbs some light and reflects most . E.g. Enamel
• Transparent material - absorb no lights , transmits 100 % .
15. COLOR MATCHING
• In dental practice, color matching is most
often performed with the use of a shade guide
• The individual shades are grouped according
to hue -
1. A – RED BROWN
2. B – RED YELLOW
3. C - GRAY
4. D – RED GRAY , followed by value ( 1 – 4 ;
lightest to darkest )
• This arrangement follows the “classical” order
originated by Vita for porcelain .
• Recent trend is to arrange the shades in
decreasing order of value (lightest to darkest:
B1, A1, B2, D2, A2, C1, C2, D4, A3, D3, B3,
A3.5, B4, C3, A4, C4) .
Tab arrangements of the Vitapan classical shade guide.
A, Manufacturer’s arrangement No. 1: group division according to hue.
B, Manufacturer’s arrangement No. 1: “value scale,” no group division.
C, Alternative arrangement: according to color difference in relation to
the Lightest tab, group division
A
B
C
16. 1. Send drawings , descriptions and
photographs
2. Visual inspection
3. Subjective preference of the patient
4. Effect of the observer
• Bezold-Brucke effect – At low light , rods are
more active than cones , so color perception lost.
As brightness increase , color appears to change
.
A, Two central incisor metal-ceramic crowns
with porceain margins. The value (L*) of these
crowns is higher than that of the
adjacent lateral incisor teeth.
B, Closeup view of the metal ceramic crowns
on the left.
Factors to consider while shade selection
17. • According to a recent study on the repeatability of the human eye compared
to an intraoral scanner in dental shade matching , it was concluded that the
TRIOS intraoral scanner ensured better repeatability than the visual method
in dental shade matching .
• Also ambient lighting had a direct effect on the repeatability of the shade
selection for the visual method, whereas the observer's sex and clinical
experience did not .
• For the visual method, the repeatability in dental shade matching depended
on the dimension studied, with the best results in value, followed by hue and
chroma; however, such dependence was not detected for the intraoral
scanner. ("Repeatability of the human eye compared to an intraoral scanner in dental shade matching " ; Juan Reyes Pamela Acosta Dalina
VenturaAlumnus, Stomatology School, Pontificia Universidad Catolica Madre y Maestra, Santiago de los Caballeros, Santiago, Dominican Republic )
18. 5. The effect of light source -
• the appearance of an object is dependent on the nature of the light in which the
object is viewed. ( spectral content )
• Common sources of light in the dental operatory - Daylight, incandescent, and
fluorescent lamps
• Metamerism
• Color matching should be done under two or more different light sources,
one of which should be daylight .
19. • 6 . Fluorescence - It is the phenomenon in which a TOOTH absorbs
energy ( light ) of shorter wavelength and converts them into light of
longer wavelength. The emitted light, a blue-white color, is primarily
in the 400- to 450-nm range .
• Affects the brightness and vital appearance of a human tooth .
• 7. Radiopacity - the interaction of dental biomaterials with x-radiation
may be classified as an optical property .
• Sufficient radiographic contrast is required in an x-ray image in
order to assess restorations for marginal defects or breakdown,
help differentiate composite restorations from dental caries, and detect
microleakage.
20. • Polymers and resins are inherently radiolucent, whereas metals with atomic
numbers above about 19 (potassium) are inherently radiopaque. To impart
radiopacity, restorative resins often utilize strontium- or barium-containing glass
reinforcing particles ; denture polymers may (but rarely contain barium-sulfate
or other heavy-metal compound additives to render them radiopaque .
• Radiopacity = too low, the resin will not be visible on an x-ray image; when =
too high, it may block out and obscure details of adjacent anatomy.
22. 3. THERMAL PROPERTIES AND PARAMETERS
Coefficient of thermal expansion or contraction
Eutectic temperature
Fusion temperature
Glass transition temperature
Heat of vaporization
Heat of fusion
Liquidus temperature
24. • The transmission of a certain amount of thermal energy is desirable to convey
the sensations of heat and cold associated with food and beverages .
• However large amounts of transmitted heat to the pulp can result in thermal
shock and injury.
• These depend on the thermal properties of conductivity and diffusivity.
1. Thermal conductivity (κ) is the physical property that governs heat
transfer through a material by conductive flow.
• It is defined as the quantity of heat in calories per second passing through a
material l cm thick with a cross section of 1 cm2 having a temperature
difference of l K (1 °C) and is measured under steady-state conditions in which
the temperature gradient does not change.
25. • In general, thermal conductivities increase in the following order: polymers <
ceramics < metals .
• Materials with high thermal conductivity are called conductors, whereas
materials of low thermal conductivity are insulators.
• The higher its thermal conductivity, the greater the ability of a substance to
transmit thermal energy and vice versa.
26. 2. Thermal diffusivity is a measure of the speed with which a temperature
change will spread through an object when one surface is heated. It is calculated
from the thermal conductivity divided by the product of density and
heat capacity:
• h = κ/cp x ρ
• where h = thermal diffusivity, κ is thermal conductivity, cp = heat capacity at
constant pressure, and ρ = temperature dependent density in grams per cm3 .
• CHANGE IN TEMPERATURE GRADIENT INSIDE THE MOUTH -
THERMAL DIFFUSIVITY – determines the amount of heat transferred from
the material to the tooth.
• NO CHANGE IN TEMPERATURE GRADIENT -
THERMAL CONDUCTIVITY
27. 3. Specific heat - It is the quantity of heat needed to raise the temperature of a
unit mass by l °C.
• If a material has high specific heat and high density , it will take more time
to change its temperature and it will have low thermal diffusivity .
• If a material has high thermal conductivity and high diffusivity , temperature
change will occur rapidly an transmitted rapidly too. This can cause
thermal damage to pulp as it can withstand moderate slowly changing / rise
in temperature.
• Glass ionomer cement - thermal conductivity and diffusivity almost similar to
that of dentin .
28.
29. • Ideally dental restorative materials should have low diffusivity .
• Metallic restorations like Gold and Amalgam also have high thermal
conductivity and diffusivity .Therefore it is important to use a liner or
protective base before placing these materials.
• Thermal diffusivity of a dental restorative material is more important than its
thermal conductivity.
• 4. COEFFICIENT OF THERMAL EXPANSION - defined as the change
in length per unit of the original length of a material when its temperature is
raised 1 °C (1 K) .
• The result is expansion in volume of the material.
• This has an important implication in cast restorations , amalgam and composite
restorations , metal-ceramic crowns and bridges and while preparing wax
patterns.
30.
31. • A tooth restoration may expand or contract more than the tooth during a
change in temperature; thus there may be marginal microleakage adjacent to
the restoration, or the restoration may debond from the tooth.
• Aluminous porcelain and Commercially pure titanium have coefficient of
thermal expansion values similar to that of dentin while Type II glass ionomer
• Gold-palladium alloy , Gold (pure) , Palladium-silver alloy, Amalgam and
Composite have COEF values higher than dentin.
33. • One of the main factors which determines the durability of a material used in
the mouth is its chemical stability. Materials should not dissolve, erode or
corrode, nor should they leach important or toxic constituents into the oral
fluids.
• Tarnish—Process by which a metal surface is dulled or discolored when a
reaction with a sulfide, oxide, chloride, or other chemical causes surface
discoloration through formation of a thin oxidized film.
• Early indication and precursor of corrosion.
34. • The most important electrochemical effects are toxic and allergic responses to
metal ions released by corrosion, which may affect both nearby tissues and
distant organs .
• BENEFICIAL IN AMALGAM RESTORATION within a limit because it
reduces microleakage by sealing the gap at the margins.
• Corrosion—Chemical or electrochemical process in which a solid, usually
a metal, is attacked by an environmental agent, resulting in partial or
complete dissolution .
• Corrosion and its influence on durability and appearance are the major ways
in which electrochemistry affects oral well-being.
35. • BASIS OF CORROSION
Gold - Exists in free form
Ceramics - are already fully oxidized
EXCEPTIONS :-
37. • Chemical corrosion is the direct combination of metallic and
nonmetallic elements to yield a chemical compound through
oxidation reactions.
• A good example is the discoloration of silver by sulfur, where silver
sulfide forms by chemical corrosion. It can also be a corrosion
product of dental gold alloys that contain silver.
• Dry corrosion
38. • Electrochemical corrosion, also known as
galvanic corrosion, requires the presence
of water or some other fluid electrolyte and
a pathway for the transport of electrons
(i.e., an electrical current).
• It is also referred to as wet corrosion,
since it requires a fluid electrolyte .
39. Electromotive /
galvanic series
Electrode potential
+ ve EP = less
susceptible to
corrosion .
More –ve EP = lose
electrons, corrode
easily
Cathode – Oxidation Anode – Reduction Galvanic corrosion
Single metallic
restoration - GC
Heterogenous surface
composition – GC
Dissimilar metals - GC
Concentration cell
corrosion
Crevice corrosion
Pitting corrosion
40.
41. An electrolytic cell involving different phases within one
alloy. Saliva acts as the electrolyte. Phase A is more
electronegative than phase B. Arrows represent
flow of ELECTRONS
42. Conclusion
• The dental materials used in different clinical conditions depend
on their physical properties which also affect their handling and
storage properties.
• Therefore knowledge of their properties is a must to ensure their
long term survival inside the oral cavity.