This document provides an overview of dental casting procedures and defects. It discusses the history of casting, the lost wax technique, and steps in the casting process including investing, wax burnout, alloy casting, and cleaning. Key aspects covered are sprue formation, crucible and ring usage, investing materials, and factors that influence dimensional changes like wax and alloy shrinkage. Causes of common casting defects are also mentioned but not described in detail.
This document provides information on spruing and investing for fixed prosthodontics. It discusses attaching a sprue former to wax patterns, and describes the purpose and proper attachment technique. It also discusses investing materials and techniques, including the components and purposes of gypsum-bonded and phosphate-bonded investments. The document provides step-by-step instructions for the vacuum-mix, vacuum-pour technique of investing a single-tooth wax pattern using a gypsum-bonded investment.
This document discusses casting procedures and defects in dentistry. It begins with definitions of casting and provides a brief history. It then outlines the key steps in the casting process including spruing, investing, burnout, casting machines, and defects. The main steps are spruing the wax pattern, investing it, burning out the wax during heating, and using casting machines to pour molten alloy into the mold. Common defects include distortion, surface roughness, porosity, and incomplete casting details. The document provides causes and prevention of defects.
The document provides an overview of the process of spruing, investing, and casting. It discusses constructing a wax pattern, creating a sprue to allow molten metal to flow into the mold, using a casting ring and liner to contain the investment material. It also covers investing materials, the investing process, burnout to eliminate wax, casting including melting alloys and techniques, quenching, pickling, divesting, and finishing processes like polishing. The overall process involves surrounding a wax pattern with a refractory investment material, heating to remove wax, and introducing molten metal to create a dental restoration.
This document discusses the casting procedure and defects in dentistry. It begins with a brief history of casting techniques from the 11th century to present. The basic steps of casting include attaching a sprue former to the wax pattern, investing the pattern in a ring, burnout of the wax, and casting of the alloy. Key aspects covered are types of sprue formers and their attachment, crucible formers, casting rings and liners, and the investing procedure. The goals of investing are to produce an accurate mold with adequate expansion to compensate for casting shrinkage.
The document discusses the process of investing and casting dental restorations, including the steps of investing wax patterns, burnout of the patterns to create molds, and casting molten alloys into the molds. It describes the requirements and mechanisms for investments to properly expand molds to compensate for alloy shrinkage during solidification. Details are provided on techniques, materials, and armamentarium for investing patterns using gypsum-bonded and phosphate-bonded investments.
The document discusses the process of casting fixed partial dentures. It describes the basic steps which include tooth preparation, impression making, wax pattern preparation, spruing, investing, burnout, alloy casting, and finishing. Key aspects covered include the types of sprue formers, crucible formers, casting rings, ring liners, and investing procedures. The objectives of casting and factors affecting quality such as sprue design, investing technique, and use of vacuum are also summarized.
This document discusses the process of casting in dentistry. It begins with definitions of casting and a brief history, noting it has been used for thousands of years. It then discusses the key steps in detail, including the lost wax technique, sprue formation, reservoirs, investing wax patterns, venting, casting machines and techniques, cleaning castings, and addressing shrinkage and defects. The overall process involves making a wax pattern, investing it in ceramic material, burning out the wax, and replacing it with molten metal to form a dental restoration.
This document discusses dental casting and investment materials. It defines casting as the process of replicating a wax dental restoration pattern in metal using the lost wax technique. There are three main types of investment materials used: calcium sulfate-bonded, phosphate-bonded, and silica-bonded. Each has specific properties and temperature limits suitable for different alloy types and restorations. The casting process involves making a wax pattern, investing it, burning out the wax, and pouring molten alloy into the mold. Common casting defects that can occur include distortion, porosity, roughness, and incomplete casting if the procedure is not followed correctly.
This document provides information on spruing and investing for fixed prosthodontics. It discusses attaching a sprue former to wax patterns, and describes the purpose and proper attachment technique. It also discusses investing materials and techniques, including the components and purposes of gypsum-bonded and phosphate-bonded investments. The document provides step-by-step instructions for the vacuum-mix, vacuum-pour technique of investing a single-tooth wax pattern using a gypsum-bonded investment.
This document discusses casting procedures and defects in dentistry. It begins with definitions of casting and provides a brief history. It then outlines the key steps in the casting process including spruing, investing, burnout, casting machines, and defects. The main steps are spruing the wax pattern, investing it, burning out the wax during heating, and using casting machines to pour molten alloy into the mold. Common defects include distortion, surface roughness, porosity, and incomplete casting details. The document provides causes and prevention of defects.
The document provides an overview of the process of spruing, investing, and casting. It discusses constructing a wax pattern, creating a sprue to allow molten metal to flow into the mold, using a casting ring and liner to contain the investment material. It also covers investing materials, the investing process, burnout to eliminate wax, casting including melting alloys and techniques, quenching, pickling, divesting, and finishing processes like polishing. The overall process involves surrounding a wax pattern with a refractory investment material, heating to remove wax, and introducing molten metal to create a dental restoration.
This document discusses the casting procedure and defects in dentistry. It begins with a brief history of casting techniques from the 11th century to present. The basic steps of casting include attaching a sprue former to the wax pattern, investing the pattern in a ring, burnout of the wax, and casting of the alloy. Key aspects covered are types of sprue formers and their attachment, crucible formers, casting rings and liners, and the investing procedure. The goals of investing are to produce an accurate mold with adequate expansion to compensate for casting shrinkage.
The document discusses the process of investing and casting dental restorations, including the steps of investing wax patterns, burnout of the patterns to create molds, and casting molten alloys into the molds. It describes the requirements and mechanisms for investments to properly expand molds to compensate for alloy shrinkage during solidification. Details are provided on techniques, materials, and armamentarium for investing patterns using gypsum-bonded and phosphate-bonded investments.
The document discusses the process of casting fixed partial dentures. It describes the basic steps which include tooth preparation, impression making, wax pattern preparation, spruing, investing, burnout, alloy casting, and finishing. Key aspects covered include the types of sprue formers, crucible formers, casting rings, ring liners, and investing procedures. The objectives of casting and factors affecting quality such as sprue design, investing technique, and use of vacuum are also summarized.
This document discusses the process of casting in dentistry. It begins with definitions of casting and a brief history, noting it has been used for thousands of years. It then discusses the key steps in detail, including the lost wax technique, sprue formation, reservoirs, investing wax patterns, venting, casting machines and techniques, cleaning castings, and addressing shrinkage and defects. The overall process involves making a wax pattern, investing it in ceramic material, burning out the wax, and replacing it with molten metal to form a dental restoration.
This document discusses dental casting and investment materials. It defines casting as the process of replicating a wax dental restoration pattern in metal using the lost wax technique. There are three main types of investment materials used: calcium sulfate-bonded, phosphate-bonded, and silica-bonded. Each has specific properties and temperature limits suitable for different alloy types and restorations. The casting process involves making a wax pattern, investing it, burning out the wax, and pouring molten alloy into the mold. Common casting defects that can occur include distortion, porosity, roughness, and incomplete casting if the procedure is not followed correctly.
The document discusses the process of metal casting in dentistry. It begins with an introduction to casting and defines it as a process where molten material is poured into a mold and allowed to harden. It then covers topics like dental waxes, sprue formation, investing materials, burnout procedures, casting machines, and alloy melting temperatures. The overall document provides an overview of the key steps and considerations for the dental metal casting procedure.
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 information on different types of casting investments used in dentistry, including their composition, properties, and applications. It discusses gypsum-bonded, phosphate-bonded, and ethyl silicate-bonded investments. Gypsum-bonded investments are the oldest and used for gold alloys. Phosphate-bonded investments are used for metal-ceramic restorations and base metal alloys due to their higher temperature resistance. Ethyl silicate-bonded investments were rarely used due to time-consuming processing and flammable byproducts. The document outlines the ideal requirements, composition, setting reactions, expansion properties, and limitations of the different investment materials.
The document discusses various metal casting processes including sand casting, shell molding, expanded polystyrene casting, and investment casting. Sand casting is the most widely used process and involves making a sand mold around a pattern and pouring molten metal. Shell molding uses a thin shell mold made of sand and resin. Expanded polystyrene casting uses a polystyrene foam pattern that vaporizes when metal is poured. Investment casting, also called lost wax casting, involves making a wax pattern, coating it with refractory material, and melting the wax out of the mold before pouring metal.
The document provides an overview of investment materials used in dental casting. It discusses the history of lost wax casting, defines investments, and outlines the key properties and composition of investments including refractory materials, binders like gypsum and phosphates, and other additives. It then classifies and describes different types of investments including gypsum-bonded, phosphate-bonded, and ethyl silicate-bonded investments.
This document discusses dental casting investments, which are materials used to form molds for casting dental restorations like crowns and bridges. It describes the components of investments, including refractory materials like silica, binders like gypsum or phosphate, and modifiers. It explains the properties investments must have like strength, expansion to compensate for shrinkage, and smooth surfaces. It covers the different types of investments including gypsum-bonded, phosphate-bonded, and silica-bonded and their appropriate uses and temperature ranges. It also discusses factors that affect the investments' setting expansion to help compensate for casting shrinkage.
This document discusses dental casting investments, which are materials used to form molds for casting dental restorations like crowns and bridges. It describes the components of investments, including refractory materials like silica, binders like gypsum or phosphate, and modifiers. It explains the properties investments must have like strength, expansion to compensate for shrinkage, and stability at high temperatures. It discusses different types of investments like gypsum-bonded, phosphate-bonded, and silica-bonded and their appropriate uses and temperature ranges. It also covers topics like setting expansion, thermal expansion, and how silica allotropes contribute to expansion properties.
The document discusses the history of sand casting, including early uses by the Assyrians in the 8th century BC and developments in the early 20th century with the invention of the sand slinger and sand mixer. It then provides details about the group's project to produce an exhaust manifold using sand casting, including explaining the process, materials, defects, and alternative manufacturing methods. Within the group, members will explain the different types of casting processes, the function of an exhaust manifold, suitable materials for an exhaust manifold, and details about the sand casting process.
Permanent mould casting is a metal casting process that uses reusable molds to produce castings. There are four main permanent mould casting processes: gravity, slush, low pressure, and vacuum. Gravity process involves preheating the mold and pouring molten metal in. Slush casting produces hollow castings by allowing a shell to solidify before draining the remaining liquid. Low pressure uses gas pressure to push molten metal into the mold, while vacuum casting pulls molten metal into the mold in a vacuum. Permanent mould casting produces castings with good surface finish and dimensional accuracy.
This document provides an overview of the lost wax casting technique used in dentistry. It discusses the history of casting, outlines the key steps including preparation of a die, wax pattern fabrication, spruing, investing, burnout and casting. The objectives of casting are to heat the alloy quickly to melt it completely, prevent oxidation during heating, and produce a casting with sharp details by forcing the molten metal into the mold. Successful casting depends on attention to detail and consistency of technique at each step.
The document discusses the process of sand casting. It describes the key steps which include preparing the mould and molten metal, pouring the molten metal into the mould, solidification, and removing the cast part. Several types of patterns are discussed along with their materials and uses. The document also covers moulding sand properties and testing methods. Common defects in castings are described. The overall document provides details on the sand casting manufacturing process.
dental Investments 1/ orthodontic course by indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
This document provides information on casting processes and terms. It defines casting as pouring molten metal into a mold cavity. Key terms discussed include patterns, cores, gates, risers, and molds. Sand casting is described as the most common casting method, using sand mixtures to form temporary molds. The document outlines the sand casting process and discusses mold properties. It also covers heating metal, pouring, solidification, and using risers to compensate for shrinkage. Overall, the document provides an overview of casting techniques and terminology.
The document provides information on various forming processes including rolling, extrusion, shearing, spinning, deep drawing, and forging. It describes the basic principles, key advantages, common materials used, and brief histories for each process. Rolling is used to reduce thickness and increase length of materials like metals. Extrusion forces pre-heated material through a die to form a constant cross-section. Shearing uses blades to make straight cuts in sheet metal. Spinning forms tubular parts by stretching sheet material against a rotating form. Deep drawing stretches sheet metal into cups or pans using a punch and die. Forging shapes heated metal using dies or hammers to develop strength.
The document discusses the key elements of a gating system for metal casting, including the pouring cup, sprue, runner, ingates, choke, and riser. It explains the functions of each element in filling the mold cavity and regulating metal flow. Design considerations for elements like the pouring cup, sprue, choke, runner, and riser are provided based on principles like Bernoulli's theorem and the law of continuity of mass. Factors that influence metal fluidity and the solidification process like nucleation, grain structure, and shrinkage are also summarized.
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.
This document provides information on the casting procedure for dental restorations. It discusses the history of casting, defines key terms, and outlines the basic steps of the casting process including fabrication of the wax pattern, spruing, investing, casting, and finishing. The optimal sprue design is described, noting that the sprue should be attached to the bulkiest part of the pattern away from margins, directed at a 45 degree angle, and of a length that positions the pattern 6mm from the casting ring. Proper sprue design is important to allow gases to escape and molten metal to fully enter the mold cavity.
Diffusion bonding is a solid-state welding technique that joins materials together through atomic diffusion without melting. It involves applying high pressure and moderate heat to join carefully cleaned and mated surfaces. Diffusion occurs in two stages - initial metal-to-metal contact formation followed by atomic diffusion and grain growth across the interface to form a complete bond. Various factors like temperature, pressure, time and surface preparation influence the diffusion rate. Common diffusion bonding methods include gas pressure bonding, vacuum fusion bonding and eutectic bonding. Diffusion bonding finds applications in the fabrication of components for industries like aerospace, nuclear and others.
Sand casting, investment casting, and die casting are the main casting methods discussed. Key topics include the casting process basics for each, phase change and shrinkage during solidification, heat transfer considerations, and pattern design guidelines. Variations and developments like continuous casting and 3D printing of investment tooling are also covered. Environmental impacts of casting such as energy use and emissions are reviewed.
This document summarizes key aspects of three metal casting methods: sand casting, investment casting, and die casting. It covers the basic processes, materials used, tolerances, surface finishes, design considerations, solidification and heat transfer principles, variations and developments in the technologies, and potential environmental issues. The goal is to provide an overview of the fundamentals and tradeoffs of different casting approaches.
This document discusses different methods for delivering fluorides, including topical and systemic methods. It focuses on topical fluoride delivery methods which are applied directly to teeth. Topical fluorides can be divided into professionally applied and self-applied products. Professionally applied products contain higher fluoride concentrations and include neutral sodium fluoride, acidulated phosphate fluoride, and stannous fluoride solutions, gels, pastes, and varnishes. Application techniques for professionals include the paint on and tray methods. Stannous fluoride and sodium fluoride are discussed in more detail regarding their preparation, mechanisms of action, advantages, and application procedures. Repeated topical fluoride treatments over time help strengthen tooth enamel and reduce the risk of dental caries.
Megaloblastic anaemia . And all anout anaemia, pernicious anaemia,GaurishChandraRathau
Megaloblastic anemia is a type of deficiency anemia characterized by abnormally large nucleated red blood cell precursors called megaloblasts in the bone marrow. It is most commonly caused by vitamin B12 or folic acid deficiencies, which lead to defective DNA synthesis. The pathophysiology involves an imbalance between the cytoplasm and nucleus in red blood cells due to improper nucleoprotein synthesis. Laboratory diagnosis shows macrocytic anemia with large red blood cells, hypersegmented neutrophils, and giant platelets in peripheral blood smears.
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The document discusses the process of metal casting in dentistry. It begins with an introduction to casting and defines it as a process where molten material is poured into a mold and allowed to harden. It then covers topics like dental waxes, sprue formation, investing materials, burnout procedures, casting machines, and alloy melting temperatures. The overall document provides an overview of the key steps and considerations for the dental metal casting procedure.
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 information on different types of casting investments used in dentistry, including their composition, properties, and applications. It discusses gypsum-bonded, phosphate-bonded, and ethyl silicate-bonded investments. Gypsum-bonded investments are the oldest and used for gold alloys. Phosphate-bonded investments are used for metal-ceramic restorations and base metal alloys due to their higher temperature resistance. Ethyl silicate-bonded investments were rarely used due to time-consuming processing and flammable byproducts. The document outlines the ideal requirements, composition, setting reactions, expansion properties, and limitations of the different investment materials.
The document discusses various metal casting processes including sand casting, shell molding, expanded polystyrene casting, and investment casting. Sand casting is the most widely used process and involves making a sand mold around a pattern and pouring molten metal. Shell molding uses a thin shell mold made of sand and resin. Expanded polystyrene casting uses a polystyrene foam pattern that vaporizes when metal is poured. Investment casting, also called lost wax casting, involves making a wax pattern, coating it with refractory material, and melting the wax out of the mold before pouring metal.
The document provides an overview of investment materials used in dental casting. It discusses the history of lost wax casting, defines investments, and outlines the key properties and composition of investments including refractory materials, binders like gypsum and phosphates, and other additives. It then classifies and describes different types of investments including gypsum-bonded, phosphate-bonded, and ethyl silicate-bonded investments.
This document discusses dental casting investments, which are materials used to form molds for casting dental restorations like crowns and bridges. It describes the components of investments, including refractory materials like silica, binders like gypsum or phosphate, and modifiers. It explains the properties investments must have like strength, expansion to compensate for shrinkage, and smooth surfaces. It covers the different types of investments including gypsum-bonded, phosphate-bonded, and silica-bonded and their appropriate uses and temperature ranges. It also discusses factors that affect the investments' setting expansion to help compensate for casting shrinkage.
This document discusses dental casting investments, which are materials used to form molds for casting dental restorations like crowns and bridges. It describes the components of investments, including refractory materials like silica, binders like gypsum or phosphate, and modifiers. It explains the properties investments must have like strength, expansion to compensate for shrinkage, and stability at high temperatures. It discusses different types of investments like gypsum-bonded, phosphate-bonded, and silica-bonded and their appropriate uses and temperature ranges. It also covers topics like setting expansion, thermal expansion, and how silica allotropes contribute to expansion properties.
The document discusses the history of sand casting, including early uses by the Assyrians in the 8th century BC and developments in the early 20th century with the invention of the sand slinger and sand mixer. It then provides details about the group's project to produce an exhaust manifold using sand casting, including explaining the process, materials, defects, and alternative manufacturing methods. Within the group, members will explain the different types of casting processes, the function of an exhaust manifold, suitable materials for an exhaust manifold, and details about the sand casting process.
Permanent mould casting is a metal casting process that uses reusable molds to produce castings. There are four main permanent mould casting processes: gravity, slush, low pressure, and vacuum. Gravity process involves preheating the mold and pouring molten metal in. Slush casting produces hollow castings by allowing a shell to solidify before draining the remaining liquid. Low pressure uses gas pressure to push molten metal into the mold, while vacuum casting pulls molten metal into the mold in a vacuum. Permanent mould casting produces castings with good surface finish and dimensional accuracy.
This document provides an overview of the lost wax casting technique used in dentistry. It discusses the history of casting, outlines the key steps including preparation of a die, wax pattern fabrication, spruing, investing, burnout and casting. The objectives of casting are to heat the alloy quickly to melt it completely, prevent oxidation during heating, and produce a casting with sharp details by forcing the molten metal into the mold. Successful casting depends on attention to detail and consistency of technique at each step.
The document discusses the process of sand casting. It describes the key steps which include preparing the mould and molten metal, pouring the molten metal into the mould, solidification, and removing the cast part. Several types of patterns are discussed along with their materials and uses. The document also covers moulding sand properties and testing methods. Common defects in castings are described. The overall document provides details on the sand casting manufacturing process.
dental Investments 1/ orthodontic course by indian dental academyIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
This document provides information on casting processes and terms. It defines casting as pouring molten metal into a mold cavity. Key terms discussed include patterns, cores, gates, risers, and molds. Sand casting is described as the most common casting method, using sand mixtures to form temporary molds. The document outlines the sand casting process and discusses mold properties. It also covers heating metal, pouring, solidification, and using risers to compensate for shrinkage. Overall, the document provides an overview of casting techniques and terminology.
The document provides information on various forming processes including rolling, extrusion, shearing, spinning, deep drawing, and forging. It describes the basic principles, key advantages, common materials used, and brief histories for each process. Rolling is used to reduce thickness and increase length of materials like metals. Extrusion forces pre-heated material through a die to form a constant cross-section. Shearing uses blades to make straight cuts in sheet metal. Spinning forms tubular parts by stretching sheet material against a rotating form. Deep drawing stretches sheet metal into cups or pans using a punch and die. Forging shapes heated metal using dies or hammers to develop strength.
The document discusses the key elements of a gating system for metal casting, including the pouring cup, sprue, runner, ingates, choke, and riser. It explains the functions of each element in filling the mold cavity and regulating metal flow. Design considerations for elements like the pouring cup, sprue, choke, runner, and riser are provided based on principles like Bernoulli's theorem and the law of continuity of mass. Factors that influence metal fluidity and the solidification process like nucleation, grain structure, and shrinkage are also summarized.
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.
This document provides information on the casting procedure for dental restorations. It discusses the history of casting, defines key terms, and outlines the basic steps of the casting process including fabrication of the wax pattern, spruing, investing, casting, and finishing. The optimal sprue design is described, noting that the sprue should be attached to the bulkiest part of the pattern away from margins, directed at a 45 degree angle, and of a length that positions the pattern 6mm from the casting ring. Proper sprue design is important to allow gases to escape and molten metal to fully enter the mold cavity.
Diffusion bonding is a solid-state welding technique that joins materials together through atomic diffusion without melting. It involves applying high pressure and moderate heat to join carefully cleaned and mated surfaces. Diffusion occurs in two stages - initial metal-to-metal contact formation followed by atomic diffusion and grain growth across the interface to form a complete bond. Various factors like temperature, pressure, time and surface preparation influence the diffusion rate. Common diffusion bonding methods include gas pressure bonding, vacuum fusion bonding and eutectic bonding. Diffusion bonding finds applications in the fabrication of components for industries like aerospace, nuclear and others.
Sand casting, investment casting, and die casting are the main casting methods discussed. Key topics include the casting process basics for each, phase change and shrinkage during solidification, heat transfer considerations, and pattern design guidelines. Variations and developments like continuous casting and 3D printing of investment tooling are also covered. Environmental impacts of casting such as energy use and emissions are reviewed.
This document summarizes key aspects of three metal casting methods: sand casting, investment casting, and die casting. It covers the basic processes, materials used, tolerances, surface finishes, design considerations, solidification and heat transfer principles, variations and developments in the technologies, and potential environmental issues. The goal is to provide an overview of the fundamentals and tradeoffs of different casting approaches.
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This document discusses different methods for delivering fluorides, including topical and systemic methods. It focuses on topical fluoride delivery methods which are applied directly to teeth. Topical fluorides can be divided into professionally applied and self-applied products. Professionally applied products contain higher fluoride concentrations and include neutral sodium fluoride, acidulated phosphate fluoride, and stannous fluoride solutions, gels, pastes, and varnishes. Application techniques for professionals include the paint on and tray methods. Stannous fluoride and sodium fluoride are discussed in more detail regarding their preparation, mechanisms of action, advantages, and application procedures. Repeated topical fluoride treatments over time help strengthen tooth enamel and reduce the risk of dental caries.
Megaloblastic anaemia . And all anout anaemia, pernicious anaemia,GaurishChandraRathau
Megaloblastic anemia is a type of deficiency anemia characterized by abnormally large nucleated red blood cell precursors called megaloblasts in the bone marrow. It is most commonly caused by vitamin B12 or folic acid deficiencies, which lead to defective DNA synthesis. The pathophysiology involves an imbalance between the cytoplasm and nucleus in red blood cells due to improper nucleoprotein synthesis. Laboratory diagnosis shows macrocytic anemia with large red blood cells, hypersegmented neutrophils, and giant platelets in peripheral blood smears.
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This document summarizes the key properties and characteristics of different elastomeric impression materials, including polysulfide, condensation silicone, addition silicone, and polyether elastomers. It describes the composition, setting reactions, available consistencies, and mechanical properties of each material. Properties like viscosity, working and setting times, dimensional stability, hardness, tear strength, and detail reproduction are compared between the different elastomers. The document also discusses techniques for mixing and using impression materials, as well as their wettability and hydrophilicity.
The document discusses cell injury and its causes, pathogenesis, and morphology. It defines cell injury as stress encountered by cells due to changes in their internal or external environment. Cell injury can be caused genetically or acquired through various external factors like hypoxia, physical or chemical agents, microbes, immunological reactions, nutritional imbalances, aging, and psychological stress. The pathogenesis of cell injury depends on the type of cell, extent of injury, and underlying biochemical processes. Reversible cell injury causes changes like hydropic swelling, fatty changes, and hyaline changes. Irreversible injury leads to autolysis, necrosis, apoptosis, or gangrene.
Neoplasia refers to abnormal tumor growth. Benign tumors are non-invasive and localized, while malignant tumors are invasive and spreading. Tumors are named based on the tissue of origin, such as carcinomas arising from epithelial tissue and sarcomas from connective tissue. Well-differentiated tumors resemble normal cells, while poorly-differentiated tumors have primitive, undifferentiated cells. Malignant tumors exhibit features like irregular growth, invasion, increased size and mitosis, and lack of differentiation. Dysplasia refers to disordered cell growth showing abnormalities but remaining in situ.
Pathological calcification involves the abnormal deposition of calcium salts in tissues other than bone. There are two main types: dystrophic calcification occurs in dead or damaged tissue with normal calcium levels, while metastatic calcification affects normal tissues and is caused by high calcium levels in the blood (hypercalcemia). Dystrophic calcification is seen in areas of necrosis, atherosclerosis, and infarcts. Metastatic calcification is associated with disorders that cause hypercalcemia like hyperparathyroidism and bone destruction. The deposits appear histologically as basophilic intracellular and extracellular calcium salt accumulations.
Amyloidosis is a condition characterized by the abnormal deposition of amyloid protein fibrils in tissues and organs. The fibrils form when normally soluble proteins misfold and aggregate extracellularly. Amyloidosis has many subtypes classified by the precursor protein involved, pattern of organ involvement, and hereditary versus inflammatory causes. Diagnosis involves tissue biopsy with Congo red staining to identify the apple-green birefringence of amyloid under polarized light, as well as immunohistochemistry to determine the subtype. Advanced imaging and molecular PET can also detect amyloid plaques in neurodegenerative diseases like Alzheimer's.
This document discusses various types of cellular adaptations, including atrophy, hypertrophy, hyperplasia, and metaplasia. It also discusses pathologic calcification. The main types of cellular adaptation are a decrease in cell size and number through atrophy, an increase in individual cell size through hypertrophy, an increase in cell number through hyperplasia, and the replacement of one cell type with another through metaplasia. Pathologic calcification can occur through either dystrophic or metastatic calcification and results in the abnormal deposition of calcium salts in tissues.
The document discusses various methods of sterilization including physical agents like heat, radiation and filtration, as well as chemical agents. It defines sterilization as a process that eliminates all microorganisms, while disinfection only destroys pathogenic organisms. Several sterilization techniques are described in detail, such as moist heat methods using steam under pressure in an autoclave, dry heat methods using hot air ovens, and chemical agents like alcohols, aldehydes, and dyes. The ideal properties of chemical disinfectants are also outlined.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
5. ACCORDING TO GPT (7th edition): Casting is defined as something
that has been cast in a mold, an object formed by the solidification
of a fluid that has been poured or injected into a mold
ACCORDING TO CRAIG (13th Edition): Casting is the process
by which a wax pattern of a restoration is converted to a
replicate in a dental alloy
ACCORDING TO WILLIAM J. OBRIEN (3rd edition): Casting is a
process of forming objects by pouring molten metals in molds that
are cooled to cause solidification.
10. Benevento Cellini (1500-1571) in his autobiography described his method
of casting in both gold and bronze by coating his finely detailed wax model
with a reinforced refractory shell
13. direct wax pattern of the
lost tooth structure
His process was
sprue
Plaster of Paris 37.5%
silica 57.5%
graphite 5%.
Invest
cast gold into space formed using air pressure
14. setting expansion - 0.45%
hygroscopic expansion -
1%
thermal expansion- 0.77%
Investment
Taggart was unable to overcome the problem of casting shrinkage
which resulted in restorations which were under size.
Lane believed that all castings made by Taggart method were undersize and attributed this to
the shrinkage of gold.
15. Van Horn introduced a different method of compensation recommending
that the wax pattern be invested at a temperature equal to mouth
temperature
the idea of casting into an enlarged mould which he achieved by using an
investment containing high percentage of silica (75% approx) plus plaster of
Paris, heated to about 650ºC.
Lane
1910
High silica
content
investment
warm
water
(46ºC)
sealed inlay ring in a water bath held at 43ºC until the investment had set
16. The low heat casting technique was finally abandoned in 1928 when
Coleman published his research paper No.32 for the United States National
Bureau of Standards in which he demonstrated the great shrinkage which
occurred when investment is cooled after heating.
Weinstein in 1929 found that adding boric acid to customary investment
mixtures prevented the shrinkage which occurred when the investments
were heated to about 370ºC and with the addition of this chemical quartz
based investments expanded approximately 0.9% when heated to 700ºC.
Moore(1993) discovered by the addition of chlorides to investments he
could obtain a thermal expansion of as much as 1.1% from quartz based
investment.
17. Two important developments occurred in the next few years were
use of Cristobalite in investment
Hygroscopic setting
expansion technique
Sweeney, Paftenbarger (1930-33)
use of a “Control powder” mixed with a cristobalite investment in varying
proportions designed to give different thermal expansion to the investment.
Phillips
(1935)
18. In 1932 Scheu presented a end technique which used the setting expansion of
investment to compensate totally for the gold alloy shrinkage.
Dr. Wilmer souder recognized that the thermal expansion of
the investment was greatly inhibited by the rigid metal casting
ring and advocated lining the ring with soft asbestos to act as a
heat resisting cushion which would permit the investment to
undergo its full thermal expansion.
20. Dimensional changes in the Lost wax Technique
Can be summarized by the equation
Wax shrinkage + metal shrinkage = wax expansion + setting expansion
+ Hygroscopic expansion + Thermal expansion
Goldberg (1937) recommended the use of the wax with 0.1% Contraction for
the direct technique and the wax with 0.38% contraction for the a patterns
made on a die at room temperature in the indirect technique
22. The shrinkage occurs in 3 stages:
• The thermal contraction of the liquid metal between the temperature to which it is
heated and the liquidus temperature.
• The contraction of the metal inherent in its change from the liquid to the solid state.
• The thermal contraction of the solid metal that occurs on further cooling to room
temperature.
23. Coleman used the expression ‘casting shrinkage’ to include the contraction which
occurred during all the three stages already described and employed the term ‘net
casting shrinkage’ to describe the casting contraction measured in his experiments.
Earnshaw (1957) suggested the following nomenclature to give a more precise
meaning for the term “casting shrinkage”.
Inherent casting
shrinkage
Actual casting
shrinkage
Net casting
shrinkage
24. Effect of alloy composition on casting shrinkage: varies with alloy composition, the
variation amongst gold alloys normally used for ordinary cast inlays, crowns and bridges is not
large enough to warrant changes in investment expansion (Morey 1991).
26. Interferences could have a greater effect in castings of more complex shapes,
especially if those shapes allow interlocking of the solidified alloy and the mould.
Size and shape of the casting effect the linear casting shrinkage (Paffenbarger).
An investment with high compressive strength at the
casting temperature will be more effective than a weaker
one in restricting casting shrinkage of a complex casting
and the effect will be greatest when interlocking of casting
and mould in maximal (Earnshaw, R) 1969.
27. least in buccolingual and occluso-
gingival directions
MOD inlay casting
greatest in the mesiodistal direction
Restraint imposed by the walls of the mould
28. Effect of alloy shrinkage on the fit of MOD
inlay casting
masked by the marginal bevel
29. For a given alloy the inherent casting shrinkage is determined by its coefficient of
thermal expansion and its solidus temperature, the actual or observed casting
shrinkage will be lower by a varying amount depending on the size and shape of the
casting and the compressive strengths of the investment mould at its burnout
temperature (Moorey 1991)
Linear solidification shrinkage of casting alloys
Type I (Au-based) 1.56%
Type II (Au-Based) 1.37%
Type III (Au-based 1.42%
Type IV (Ni-Cr based) 2.30%
Type IV (Co-Cr) 2.30%
30. Theory of compensation
Compensation for the shrinkage of wax and gold by
investment expansion was studied scientifically in the early
1920s when Weinstein and Coleman at the United States
National Bureau of Standards.
Contraction occurs both during cooling of the liquid alloy
and during solidification.
Price, Coleman, Sonder
35. The following factors tend to increase hygroscopic
expansion:
Increased silica content of the investment & hemihydrate as the binder.
Increased setting expansion of the binder
Thicker mix of investment
Increasing mixing time (spatulation)
Immersion of the investment at or before its initial set length of time it is
immersed.
Temperature of water bath
Lining the ring with asbestos liner
Using a split ring or one made of flexible rubber
Storage at 100% humidity
Hygroscopic technique with the pattern in the upper apart of the ring.
36. Wax pattern expansion
while the investment is still fluid occurs when the wax is
warmed above the temperature at which it was formed
37. Heat may come from
chemical reaction of the investment warm water bath
39. Should be directed away from thin or delicate
parts of the pattern, because the molten
metal may abrade or fracture investment in
this area and resulting in casting failure.
It should be directed away from or at 45º to
these details.
45. Wax is added around the sprue former 1-2 mm from the
pattern in order to create an area in the mold (a reservoir)
with dimensions far exceeding that of the thickest portion
of the pattern.
49. • Stainless steel has been found to produce the most
acceptable rings.
• The thermal expansion of SS is 1.20% at 700ºC which
is compatible with the expansion of investments
provided a liner is used (Ray 1933).
29mm
38mm
50. Ringless casting system
• This method uses paper or plastic casting ring
and is designed to allow unrestricted expansion
(Engelman 1989)
• Also called as power cast ringless system
consisting of three sizes of rings and formers,
preformed wax sprues and shapes, investment
powder, and a special investment liquid.
• The crucible former and plastic ring are removed
before wax elimination, leaving the invested wax
pattern.
51. to provide a buffer of pliable material against which the
investment can expand to enlarge the mould
Ring liners
Need
Liner
semi hygroscopic expansion of the
investment
52. Asbestos liner
• no longer be used because its carcinogenic potential
can cause
• asbestosis
• bronchogenic lung cancer
• mesothelioma
The currently accepted threshold limit value for asbestos fibers range from 2 x 105 – 20×105
fibres/m3
Material of liner
53. manufactured by standard
paper making technique from
fibers of alumino silicate glass
derived from Kaolin
Cellulose fibers readily absorb
water when immersed and
therefore like asbestos wetted
before use
absorbent
cellulose
non absorbent
ceramic
Alternatives to asbestos liners have been introduced
54. How to use liner
can be used dry or wet
The maximum thickness of liner is 1 mm
55. Preparing the wax pattern for investment
wax pattern should be cleaned of any debris, grease or oils
thin films of cleanser left on the pattern reduces the
surface tension of the wax
56. The distortion of the wax pattern after its removal from the die is
a function of the temperature and time interval before investing.
The nearer the room temperature
approaches the softening point of the
wax the more readily internal stresses are
released
a pattern should not stand for more
than 20 to 30 minutes before being
invested
60. INVESTMENT MATERIALS
A heat resistant or a refractory material used to form a mold into which a metal or
alloy is cast .
(OR)
A molding material that surrounds the pattern & subsequently hardens & forms the
mold after the wax pattern is eliminated.
The operation of forming the mold is called Investing .
Types – Gypsum bonded investments
Phosphate bonded investments
Ethyl silicate bonded investments
62. Once the investment has set for approximately 1 hour
for most gypsum and phosphate bonded investments it
is ready for burnout
The crucible former and any metal sprue
former are carefully removed
63. If the burnout procedure does not immediately follow the
investing procedure, the invested ring is placed in a humidor
at 100% humidity
Dehydration of set investment that has been stored for
an extended period in 100% humidity may not replenish
all of the lost water
65. The alloys are melted
separate crucible by a torch flame and cast into mold by centrifugal force
electrically by resistance heating or induction furnace then cast into the
mold by motor or spring action
vaccum arc melted and cast by pressure in an argon atmosphere
induction heating then cast into the mold centrifugally by motor or
spring action
66. All casting machines accelerate the molten metal into the
mold either by centrifugal force or air pressure
67. Centrifugal machines
Each of these machines depends on the centrifugal force applied to the molten
metal to cause it to completely fill the mold with properly melted metal
Advantages
• Simplicity of design and operation
• the opportunity to cast both large and small castings on the same machine
68. Operative Dentistry Modern theory and practice-Marzouk
Dental materials – Philiphs – Anusavice
Restorative Dental materials – Craig
Fixed prosthodontics – Rosenstiel
Fundamentals of fixed prosthodontics – Schillinburg.
REFERENCES