This document discusses different types of impression materials used in dentistry, including their properties and uses. It covers elastic materials like alginate, polyether, polysulfide, and silicone impressions that can record undercuts, as well as rigid materials like plaster, wax, and zinc oxide eugenol. Key properties discussed include accuracy, elasticity, dimensional stability, and setting characteristics. Hydrocolloids like alginate provide good detail but poor stability, while synthetic elastomers offer improved tear resistance and stability at the cost of potential allergic reactions or toxicity. Mixture, properties, advantages, and disadvantages are described for each major material type.
The document provides information on various dental impression materials, including their history, composition, properties and uses. It discusses early materials like beeswax and impression compounds. It also covers alginate, which is the most widely used material due to its ease of use. Other elastic materials discussed include polysulfide, which was the first synthetic elastomer, and condensation silicone. The ideal properties of impression materials and their classifications are also outlined.
Elastomeric impression materials include polysulfide, condensation silicone, addition silicone, and polyether rubbers. They set via polymerization reactions, with setting times of 8-12 minutes on average. Polysulfide and condensation silicone set via condensation reactions producing water or alcohol as byproducts, while addition silicone and polyether set via addition reactions without byproducts. Polysulfide has the highest detail reproduction but all materials exhibit some polymerization shrinkage. Materials are available in light, medium, heavy or putty consistencies for use with stock or custom trays. Proper manipulation is required for accurate impressions.
This document discusses the properties and chemistry of alginate impression materials. Alginate sets via a chemical reaction between sodium alginate and calcium sulfate to form insoluble calcium alginate. Additives like retarders and fillers are included to control consistency and setting time. Proper control of water:powder ratio, mixing time, and water temperature is needed to achieve optimal gelation time and avoid distortion of the impression. Alginate is a commonly used irreversible hydrocolloid impression material.
This document discusses elastic hydrocolloid impression materials, specifically agar and alginate. It provides details on their composition, setting reactions, properties and applications. Agar is a reversible hydrocolloid used for secondary impressions that sets physically through a sol-gel transition upon cooling. Alginate is an irreversible hydrocolloid used for primary impressions that sets chemically through a gelation reaction involving calcium ions. Both materials are hydrophilic and require immediate pouring to minimize dimensional changes from imbibition, synersis or dehydration.
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.
This document discusses denture base resins. It provides a brief history of denture materials from ancient Egypt to modern times. Key definitions are provided, including classifications of denture base resins. Ideal requirements and properties of denture base materials are outlined. Stages of polymerization and manipulation of the resins are described. Recent advancements and a literature review are mentioned.
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.
The document provides information on various dental impression materials, including their history, composition, properties and uses. It discusses early materials like beeswax and impression compounds. It also covers alginate, which is the most widely used material due to its ease of use. Other elastic materials discussed include polysulfide, which was the first synthetic elastomer, and condensation silicone. The ideal properties of impression materials and their classifications are also outlined.
Elastomeric impression materials include polysulfide, condensation silicone, addition silicone, and polyether rubbers. They set via polymerization reactions, with setting times of 8-12 minutes on average. Polysulfide and condensation silicone set via condensation reactions producing water or alcohol as byproducts, while addition silicone and polyether set via addition reactions without byproducts. Polysulfide has the highest detail reproduction but all materials exhibit some polymerization shrinkage. Materials are available in light, medium, heavy or putty consistencies for use with stock or custom trays. Proper manipulation is required for accurate impressions.
This document discusses the properties and chemistry of alginate impression materials. Alginate sets via a chemical reaction between sodium alginate and calcium sulfate to form insoluble calcium alginate. Additives like retarders and fillers are included to control consistency and setting time. Proper control of water:powder ratio, mixing time, and water temperature is needed to achieve optimal gelation time and avoid distortion of the impression. Alginate is a commonly used irreversible hydrocolloid impression material.
This document discusses elastic hydrocolloid impression materials, specifically agar and alginate. It provides details on their composition, setting reactions, properties and applications. Agar is a reversible hydrocolloid used for secondary impressions that sets physically through a sol-gel transition upon cooling. Alginate is an irreversible hydrocolloid used for primary impressions that sets chemically through a gelation reaction involving calcium ions. Both materials are hydrophilic and require immediate pouring to minimize dimensional changes from imbibition, synersis or dehydration.
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.
This document discusses denture base resins. It provides a brief history of denture materials from ancient Egypt to modern times. Key definitions are provided, including classifications of denture base resins. Ideal requirements and properties of denture base materials are outlined. Stages of polymerization and manipulation of the resins are described. Recent advancements and a literature review are mentioned.
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.
Condensation silicone was the first type of silicone impression material developed. It sets via a condensation reaction at room temperature, producing an alcohol byproduct. While condensation silicones have lower cost and sufficient working time, their dimensional stability is compromised over time due to the volatile byproduct. More advanced addition silicone and polyether materials provide better accuracy due to less shrinkage.
This document discusses denture base materials, specifically acrylic resins. It begins by defining denture base and classifying denture base resins as non-metallic, metallic, temporary or permanent. Ideal requirements of dental resins are listed. Composition and differences between heat cure and self cure acrylic resins are provided. Processing techniques like compression molding and the curing cycle are described. Other resin types like light activated are also mentioned. Common processing errors in acrylic resins like porosity, crazing and warpage are listed.
This document discusses various materials used for fabricating dental dies, including their properties and uses. It covers gypsum products like dental stone (Type III and high-strength Type IV and V stones), electroformed dies using copper or silver plating, epoxy resins, and flexible die materials like polyvinyl and polyurethane. Each material has advantages like detail reproduction, strength and disadvantages like shrinkage, toxicity or incompatibility with some impression materials. Newer ceramic and CAD/CAM die materials are also introduced that are strong and dimensionally stable.
hydrocolloid impression materials, agar and alginate impression materials and properties of the same.
watch more
https://youtu.be/aaJ6gpQohcs
https://youtu.be/REMKSUty0cE
https://youtu.be/fv3_tWZPJIU
https://youtu.be/GeZIbCwqKYU
if you want me to make any ppt on any more topic do let me know on my youtube channel's comment section
impression materials in dentistry specially those used in Prosthodontics.
Impression compound
Zinc oxide Eugenol impression paste
Alginate
Agar-agar
Elastomeric impression compounds like Polysulfides, Condensation silicones, Addition silicones(PVS), Polyether
detailed description with properties, mixing time, working time, setting time ,physical and properties etc
Denture bases are typically fabricated from heat-activated poly(methyl methacrylate) (PMMA) resins using a compression molding technique. The resin is mixed as a powder and liquid, packed into a stone mold containing the wax denture pattern, and cured by heating in a water bath. This causes polymerization and hardening of the resin into the final denture base. Alternatively, self-curing or light-activated resins can be used that do not require heating to polymerize. Proper processing is important to achieve optimal physical properties of the denture base and prevent excess shrinkage, porosity, or warping.
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 provides an overview of different elastomeric impression materials used in dentistry, including their composition, setting reactions, properties, advantages, and disadvantages. It discusses polysulfide rubber, condensation silicone, addition silicone, and polyether impression materials. It also covers general properties like working and setting times, dimensional stability, reproduction of details, disinfection, tear strength, biocompatibility, and effects of mishandling. Recently, visible light-cured polyether urethane dimethacryl materials have been introduced as well.
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 about various luting cements used in dentistry. It focuses on zinc phosphate cement, discussing its composition, setting reaction, properties and applications. The key points are:
1. Zinc phosphate cement is the oldest luting agent and consists of a powder made primarily of zinc oxide and a liquid of phosphoric acid. The acid reacts with zinc oxide to form zinc phosphate during setting.
2. It has a working time of 1.5-2 minutes and setting time of 2.5-8 minutes. Its compressive strength is 104MPa and it bonds mechanically rather than chemically.
3. Zinc phosphate cement is used for cementing permanent restorations
This document provides an overview of different types of dental cements, including their composition, properties, and applications. It discusses zinc phosphate cement, the oldest cement still in use today. It also covers silicate cement, one of the first direct tooth-colored materials; zinc polycarboxylate cement, the first cement with adhesive properties; and zinc oxide eugenol cement, commonly used as a temporary cement. Modified versions of these traditional cements are also presented, along with other contemporary cements like glass ionomer cement and resin cements.
This document discusses dental resin used for denture bases. There are several types of denture base resins classified by their polymerization method. Heat-activated denture base resin is most commonly used. It involves a powder made of polymethyl methacrylate and a liquid of methyl methacrylate. The powder and liquid are mixed together and packed into a mold made from the patient's impression. The packed resin is then cured using heat to initiate polymerization.
This document provides an overview of dental cements. It begins with definitions of dental cements and discusses their history. It describes ideal cement properties and classifications including based on ingredients/application, bonding mechanism, and setting reaction. Specific cement types are then outlined - silicate, zinc phosphate, zinc polycarboxylate, zinc oxide eugenol, calcium hydroxide, and their compositions, reactions, properties and uses. The document provides a detailed comparison of zinc phosphate and zinc polycarboxylate cements. In summary, it is a comprehensive review of different dental cement types, their characteristics and applications.
This document discusses dental impressions, including the definition of an impression, impression trays, and impression materials. It provides classifications of impression materials based on their mode of setting, elasticity, tissue displacement, and usage. Common impression materials are discussed such as alginate, zinc oxide eugenol paste, and elastomeric materials. Impressions can be classified based on their purpose, impression theories, and techniques. Key principles of impression making include retention, stability, support, preservation of residual structures, and esthetics.
The document discusses impression materials used in dentistry. It describes the process of making impressions and casts, as well as ideal requirements for impression materials. It classifies impression materials based on mechanical behavior, setting mechanism, and usage. Rigid impression materials like plaster, impression compound, and zinc oxide pastes are described. The properties, composition, setting reactions and uses of plaster, impression compound and zinc oxide pastes are summarized.
Classification of impression materials انواع مواد الطبعDenTeach
خاص بمادة Dental material
تقسيمة مختصرة ملمة بأنواع المواد المستخدمة في اخذ طبعة للفم والاسنان
SUBJECTIVE:- Dental Material
CHAPTER:- Impression Material
تمت مشاركته عبر: د. أحمد طه
The document discusses agar and alginate as hydrocolloid impression materials. It provides details on their composition, uses, types, preparation and properties. Agar is extracted from seaweed and forms a gel when cooled. It is used for full arch impressions and duplications. Alginate forms a gel through a chemical reaction with calcium sulfate. It is commonly used for complete dentures and orthodontic impressions due to its fast setting time. Both materials provide accurate impressions but alginate is more popular due to being easier to use.
This document discusses various die materials used for fixed prosthodontics. It begins by defining key terms like die and cast. It then describes the most commonly used die materials like gypsum products (dental stones), die stones, epoxy resins, and others. For each material, it covers properties, advantages, disadvantages and appropriate uses. It also discusses techniques to improve die properties and compatibility with different impression materials. Finally, it provides a comparison of different die materials in terms of their strengths and limitations. The overall document serves as a comprehensive guide to selecting and using die materials for fixed prosthodontic procedures.
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.
The document discusses impression materials and gypsum products used in dentistry. It defines impression materials as negative records of oral tissues used to create positive dental casts. Desirable properties include accuracy, strength, and compatibility. Common materials discussed are impression compound, zinc oxide-eugenol, and elastomeric materials. Gypsum products set from a fluid mix and are used to fabricate casts from impressions. Factors like water-powder ratio and temperature control setting times.
Condensation silicone was the first type of silicone impression material developed. It sets via a condensation reaction at room temperature, producing an alcohol byproduct. While condensation silicones have lower cost and sufficient working time, their dimensional stability is compromised over time due to the volatile byproduct. More advanced addition silicone and polyether materials provide better accuracy due to less shrinkage.
This document discusses denture base materials, specifically acrylic resins. It begins by defining denture base and classifying denture base resins as non-metallic, metallic, temporary or permanent. Ideal requirements of dental resins are listed. Composition and differences between heat cure and self cure acrylic resins are provided. Processing techniques like compression molding and the curing cycle are described. Other resin types like light activated are also mentioned. Common processing errors in acrylic resins like porosity, crazing and warpage are listed.
This document discusses various materials used for fabricating dental dies, including their properties and uses. It covers gypsum products like dental stone (Type III and high-strength Type IV and V stones), electroformed dies using copper or silver plating, epoxy resins, and flexible die materials like polyvinyl and polyurethane. Each material has advantages like detail reproduction, strength and disadvantages like shrinkage, toxicity or incompatibility with some impression materials. Newer ceramic and CAD/CAM die materials are also introduced that are strong and dimensionally stable.
hydrocolloid impression materials, agar and alginate impression materials and properties of the same.
watch more
https://youtu.be/aaJ6gpQohcs
https://youtu.be/REMKSUty0cE
https://youtu.be/fv3_tWZPJIU
https://youtu.be/GeZIbCwqKYU
if you want me to make any ppt on any more topic do let me know on my youtube channel's comment section
impression materials in dentistry specially those used in Prosthodontics.
Impression compound
Zinc oxide Eugenol impression paste
Alginate
Agar-agar
Elastomeric impression compounds like Polysulfides, Condensation silicones, Addition silicones(PVS), Polyether
detailed description with properties, mixing time, working time, setting time ,physical and properties etc
Denture bases are typically fabricated from heat-activated poly(methyl methacrylate) (PMMA) resins using a compression molding technique. The resin is mixed as a powder and liquid, packed into a stone mold containing the wax denture pattern, and cured by heating in a water bath. This causes polymerization and hardening of the resin into the final denture base. Alternatively, self-curing or light-activated resins can be used that do not require heating to polymerize. Proper processing is important to achieve optimal physical properties of the denture base and prevent excess shrinkage, porosity, or warping.
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 provides an overview of different elastomeric impression materials used in dentistry, including their composition, setting reactions, properties, advantages, and disadvantages. It discusses polysulfide rubber, condensation silicone, addition silicone, and polyether impression materials. It also covers general properties like working and setting times, dimensional stability, reproduction of details, disinfection, tear strength, biocompatibility, and effects of mishandling. Recently, visible light-cured polyether urethane dimethacryl materials have been introduced as well.
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 about various luting cements used in dentistry. It focuses on zinc phosphate cement, discussing its composition, setting reaction, properties and applications. The key points are:
1. Zinc phosphate cement is the oldest luting agent and consists of a powder made primarily of zinc oxide and a liquid of phosphoric acid. The acid reacts with zinc oxide to form zinc phosphate during setting.
2. It has a working time of 1.5-2 minutes and setting time of 2.5-8 minutes. Its compressive strength is 104MPa and it bonds mechanically rather than chemically.
3. Zinc phosphate cement is used for cementing permanent restorations
This document provides an overview of different types of dental cements, including their composition, properties, and applications. It discusses zinc phosphate cement, the oldest cement still in use today. It also covers silicate cement, one of the first direct tooth-colored materials; zinc polycarboxylate cement, the first cement with adhesive properties; and zinc oxide eugenol cement, commonly used as a temporary cement. Modified versions of these traditional cements are also presented, along with other contemporary cements like glass ionomer cement and resin cements.
This document discusses dental resin used for denture bases. There are several types of denture base resins classified by their polymerization method. Heat-activated denture base resin is most commonly used. It involves a powder made of polymethyl methacrylate and a liquid of methyl methacrylate. The powder and liquid are mixed together and packed into a mold made from the patient's impression. The packed resin is then cured using heat to initiate polymerization.
This document provides an overview of dental cements. It begins with definitions of dental cements and discusses their history. It describes ideal cement properties and classifications including based on ingredients/application, bonding mechanism, and setting reaction. Specific cement types are then outlined - silicate, zinc phosphate, zinc polycarboxylate, zinc oxide eugenol, calcium hydroxide, and their compositions, reactions, properties and uses. The document provides a detailed comparison of zinc phosphate and zinc polycarboxylate cements. In summary, it is a comprehensive review of different dental cement types, their characteristics and applications.
This document discusses dental impressions, including the definition of an impression, impression trays, and impression materials. It provides classifications of impression materials based on their mode of setting, elasticity, tissue displacement, and usage. Common impression materials are discussed such as alginate, zinc oxide eugenol paste, and elastomeric materials. Impressions can be classified based on their purpose, impression theories, and techniques. Key principles of impression making include retention, stability, support, preservation of residual structures, and esthetics.
The document discusses impression materials used in dentistry. It describes the process of making impressions and casts, as well as ideal requirements for impression materials. It classifies impression materials based on mechanical behavior, setting mechanism, and usage. Rigid impression materials like plaster, impression compound, and zinc oxide pastes are described. The properties, composition, setting reactions and uses of plaster, impression compound and zinc oxide pastes are summarized.
Classification of impression materials انواع مواد الطبعDenTeach
خاص بمادة Dental material
تقسيمة مختصرة ملمة بأنواع المواد المستخدمة في اخذ طبعة للفم والاسنان
SUBJECTIVE:- Dental Material
CHAPTER:- Impression Material
تمت مشاركته عبر: د. أحمد طه
The document discusses agar and alginate as hydrocolloid impression materials. It provides details on their composition, uses, types, preparation and properties. Agar is extracted from seaweed and forms a gel when cooled. It is used for full arch impressions and duplications. Alginate forms a gel through a chemical reaction with calcium sulfate. It is commonly used for complete dentures and orthodontic impressions due to its fast setting time. Both materials provide accurate impressions but alginate is more popular due to being easier to use.
This document discusses various die materials used for fixed prosthodontics. It begins by defining key terms like die and cast. It then describes the most commonly used die materials like gypsum products (dental stones), die stones, epoxy resins, and others. For each material, it covers properties, advantages, disadvantages and appropriate uses. It also discusses techniques to improve die properties and compatibility with different impression materials. Finally, it provides a comparison of different die materials in terms of their strengths and limitations. The overall document serves as a comprehensive guide to selecting and using die materials for fixed prosthodontic procedures.
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.
The document discusses impression materials and gypsum products used in dentistry. It defines impression materials as negative records of oral tissues used to create positive dental casts. Desirable properties include accuracy, strength, and compatibility. Common materials discussed are impression compound, zinc oxide-eugenol, and elastomeric materials. Gypsum products set from a fluid mix and are used to fabricate casts from impressions. Factors like water-powder ratio and temperature control setting times.
The document provides information on various impression materials used in dentistry. It discusses the ideal properties required for an impression material and classifies materials as either elastic or inelastic, and aqueous or non-aqueous. Specific materials discussed in detail include impression plaster, impression compound, zinc oxide eugenol paste, alginate, agar, polysulfide, silicones, and polyether. The composition, properties, advantages, disadvantages and manipulation of each material is explained.
agar agar and alginate impression materialsRenu710209
agar and alginate are the most commnly used impression material in dentistry for recording impression of the dental arches and for duplication of teeth and associated structures.
agar agar and alginate impression materialsRenu710209
agar and alginate are the most commnly used impression material in dentistry for recording impression of the dental arches and for duplication of teeth and associated structures.
This document provides an overview of impression materials. It begins with an introduction and history of impression materials, discussing early materials like wax and plaster. It then classifies materials based on properties and chemistry, covering non-elastic materials like plaster, zinc oxide eugenol, and impression compound, as well as elastic materials like hydrocolloids and synthetics. The document outlines ideal material requirements and discusses the composition, manipulation, and applications of various impression materials.
Impression materials for complete denture/certified fixed orthodontic courses...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
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.
The document provides an overview of elastomeric impression materials. It begins with an introduction and definitions of key terms like elastomer and elastomeric impression materials. It then discusses the history and classifications of impression materials. The document outlines the ideal requirements for impression materials and their clinical applications. It describes the properties and composition of various elastomers like polysulfide, condensation silicone, addition silicone, and polyether. It discusses recent advances in impression materials and effects of mishandling impressions. In conclusion, the document provides a comprehensive review of elastomeric impression materials.
Impression materials/dental implant courses by Indian dental academyIndian dental academy
This document provides an overview of impression materials used for complete dentures. It defines an impression as a negative imprint used to produce a positive replica for dental restorations. Desirable properties of impression materials include compatibility with patients, ease of manipulation, adequate storage properties, and affordability. Materials are classified based on rigidity, viscosity, setting mechanism, interaction with water, and chemistry. The document reviews the history of materials from beeswax to modern polymers and discusses the properties and uses of specific materials like impression plaster, compound, and zinc oxide eugenol paste.
This document discusses different types of impression materials used in dentistry. It begins by defining an impression and cast, and then provides the ideal characteristics of an impression material. It categorizes impression materials based on their setting mechanism, flexibility, amount of pressure on tissues, and type of tray used. Specific materials discussed in detail include impression plaster, impression waxes, impression compound, and zinc oxide eugenol paste. The document outlines the composition, properties, uses, advantages and disadvantages of each.
Hydrocolloids /certified fixed orthodontic courses by Indian dental academy Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The document discusses dental impression materials. It defines a dental impression as a negative record of the tissues in the mouth. Impressions are used to reproduce the teeth and surrounding areas to create positive models or casts. There are two main types of impression materials - rigid materials that cannot engage undercuts, and elastic materials that can engage undercuts. Common elastic materials discussed include alginate, polysulfide rubber, silicone, and polyether. The document outlines the characteristics and properties required of good impression materials.
This document provides information about hydrocolloids used for dental impressions. It discusses the history of impression materials, ideal requirements, classification systems, and specific hydrocolloids - alginate and agar. Alginate is an irreversible hydrocolloid that sets via a chemical reaction with calcium ions. It is easy to use but has low accuracy and dimensional stability. Agar is a reversible hydrocolloid that changes between sol and gel states with temperature changes, but it has been replaced by other materials. The document provides details on the composition, setting reactions, properties and uses of these hydrocolloid impression materials.
This document discusses types of impression materials used in dentistry. There are two main groups of impression materials: elastic materials and inelastic materials. The most widely used elastic materials are polyvinyl siloxane (PVS) and polyether. PVS has the smallest dimensional change, high elastic recovery, and good tear resistance making it the preferred material for final impressions for crowns and bridges. The document outlines techniques for using PVS, including putty/wash methods for subgingival margins, and notes the importance of accuracy, detail capture, and dimensional stability in impression materials.
The document provides information on impression materials, including their history, classification, and properties. It discusses both reversible (agar) and irreversible (alginate) hydrocolloid impression materials. For agar, it describes the composition, mode of supply, uses, advantages, and disadvantages. For alginate, it outlines the composition, setting reaction, classification according to setting time, manipulation, and properties. The document thus summarizes the key types of impression materials and their characteristics.
1) Impression materials are used to produce replicas of intraoral tissues and come in elastic or non-elastic varieties. Common elastic materials include alginate, agar, and elastomeric polymers like polysulfides, silicones, and polyethers.
2) The document discusses the history, ideal requirements, and classifications of impression materials. It provides details on agar and alginate hydrocolloids as well as elastomeric materials, their properties, advantages, disadvantages, and applications.
3) Recent advances include dustless alginates, two-paste alginate systems, siliconized alginates, and light-cured elastomers which offer improvements to traditional materials. Pro
This document discusses impression materials and techniques used in orthodontics. It begins with an introduction to impression materials and their importance in orthodontics. It then covers the history of impression materials, ideal requisites of materials, and classifications. Specific materials discussed include alginate, agar, and silicones. Impression techniques, trays, and applications for specific clinical situations like cleft palate are also summarized. The document provides an overview of common impression materials and techniques used in orthodontics.
This document discusses impression materials used in dentistry. It defines impression materials as those that accurately record oral tissues to create a negative reproduction called an impression, from which a positive model or cast is made. It classifies impression materials based on use (single tooth, partial denture, complete denture) and setting behavior (elastic vs non-elastic). Specific hydrocolloid materials discussed include alginate and agar. Alginate sets via a chemical reaction with calcium ions to form a gel, while agar sets reversibly based on temperature. Both require proper manipulation to ensure accurate impressions.
The document discusses dental impression materials. It provides details on the classification, composition, properties, manipulation and applications of various impression materials including alginate, agar, impression compound, zinc oxide eugenol and silicone impressions materials. Impression materials are classified based on their setting mechanism and elasticity into rigid or elastic materials that set via a chemical reaction or temperature change. The document describes the key ingredients, setting reactions, advantages and disadvantages of different impression materials.
Metals are commonly used in dentistry due to their hardness, strength, and corrosion resistance. The main metals used are gold, platinum, palladium, silver, and titanium. Gold is often used on its own or in alloys due to its biocompatibility, corrosion resistance, and ability to form solid solutions with other metals. This changes the properties of gold for different applications. Titanium is also widely used for implants and prosthetics due to its strength, corrosion resistance, and ability to integrate with bone. Dental amalgam is a mixture of silver alloy powder and liquid mercury that hardens into a filling material.
Plaque Indices commonly used in dentistryAmir Rajaey
This document summarizes several plaque indices used to assess oral hygiene:
1) The Plaque Index measures plaque on 6 key teeth using a scale of 0-3, with a total score divided by number of teeth indicating excellent to poor hygiene.
2) The Simplified Oral Hygiene Index assesses debris and calculus on 6 teeth using a scale of 0-3, with total scores for each indicating good to poor oral hygiene.
3) The Patient Hygiene Performance Index measures debris on 6 teeth using a scale of 0-5, with a total score divided by 6 indicating excellent to poor hygiene.
4) The Plaque Control Record examines all tooth surfaces for
immune & inflammatory responses that are harmful to the host.
The concept that the immune system is required for defending the host against infections has been emphasized throughout this book. How-ever, immune responses are themselves capable of causing tissue injury and disease. Injurious, or pathologic, immune reactions are called hyper-sensitivity reactions. An immune response to an antigen may result in sensitivity to challenge with that antigen, and therefore hypersensitivity is a reflection of excessive or aberrant immune responses. Hypersensitivity reactions may occur in two situations. First, responses to foreign anti-gens (microbes and noninfectious environmen-tal antigens) may cause tissue injury, especially if the reactions are repetitious or poorly con-trolled. Second, the immune responses may be directed against self (autologous) antigens, as a result of the failure of self-tolerance (see Chap-ter 9). Responses against self antigens are termed autoimmunity, and disorders caused by such responses are called autoimmune diseases.
Influenza viruses are enveloped, helical RNA viruses that are grouped into types A, B, and C. They contain hemagglutinin and neuraminidase proteins that play roles in attachment and virulence. There are multiple antigenic forms of these proteins that determine different subtypes like H1N1.
Paramyxoviruses are enveloped RNA viruses that include mumps, measles, and respiratory syncytial virus. Mumps is transmitted through air or contact and infects the nasopharynx and lymph nodes, causing swelling of the salivary glands. Measles causes an infectious rash and is transmitted through the respiratory tract, with symptoms of fever and rash. Resp
Enteroviruses are a genus of picornaviruses that mainly replicate in the gut. There are at least 71 serotypes divided into 5 groups: polioviruses, coxsackie A viruses, coxsackie B viruses, echoviruses, and newly identified enteroviruses. Enterovirus infections can range from subclinical to abortive infections with minor illness to major illness with paralysis. Prevention is focused on vaccination with oral or intramuscular poliovirus vaccines. While poliovirus has been largely eradicated, surveillance continues to monitor outbreaks and achieve global eradication.
Spirochetes generally refer to bacteria with a spiral morphology ranging from loose coils to a rigid corkscrew shape. The three medically important genera include the cause of syphilis, the ancient scourge of sexual indiscretion, and Lyme disease, a newly discovered consequence of an innocent walk in the woods.
T. pallidum is the causative agent of syphilis, a venereal disease first recognized in the 16th century as the “great pox” that rapidly spread through Europe in association with urbanization and military campaigns. Some argue that it was brought back from the New World by the sailors with Christopher Columbus. Its extended course and the protean, often dramatic nature of its findings (genital ulcer, ataxia, dementia, ruptured aorta) are due to a state of balanced parasitism which spans decades. The cause of syphilis is actually a subspecies (T. pallidum subsp. pallidum) closely related to other agents which cause rare non venereal treponematoses. T. pallidum is used here to indicate the pallidum subspecies.
The periodontium consists of cementum, periodontal ligament, alveolar bone, and gingiva. Cementum covers and protects the root dentin. It provides attachment for the periodontal ligament fibers. The periodontal ligament is a soft connective tissue that connects the cementum to the alveolar bone and provides nutrition and sensory function. The alveolar bone surrounds and supports the teeth. It consists of alveolar bone proper and supporting bone.
Tooth bioengineering and the next generation of dentistryAmir Rajaey
Tooth bioengineering and the next generation of dentistry.
As a result of numerous rapid and exciting developments in tissue engineering technology, scientists are able to regenerate a fully functional tooth in animal models, from a bioengineered tooth germ. Advances in technology, together with our understanding of the mechanisms of tooth development and studies dealing with dentally derived stem cells, have led to significant progress in the field of tooth regeneration
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Kat...rightmanforbloodline
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
Rasamanikya is a excellent preparation in the field of Rasashastra, it is used in various Kushtha Roga, Shwasa, Vicharchika, Bhagandara, Vatarakta, and Phiranga Roga. In this article Preparation& Comparative analytical profile for both Formulationon i.e Rasamanikya prepared by Kushmanda swarasa & Churnodhaka Shodita Haratala. The study aims to provide insights into the comparative efficacy and analytical aspects of these formulations for enhanced therapeutic outcomes.
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
• Equipping health professionals to address questions, concerns and health misinformation
• Assessing risk and mitigating harm from adverse health narratives in communities, health workforce and health system
2. Chairside Impression
- negative likeness of the denture
bearing tissues
Laboratory Cast
- positive likeness of the denture
bearing tissues
3.
4.
5. Placing some soft, semi fluid material in the mouth
and allowing the material to set…
6.
7. Impression materials after setting
Rigid
Non undercut areas
Plaster of Paris
Elastic
Undercut areas allowed
AlginatePlaster of Paris
Compound
Zinc-oxide
eugenol paste
Wax
Alginate
Polysulphide
Polyether
Silicone
8. Impressions trays
Stock tray
prefabricated
range of sizes and
Special tray
constructed onto the
primary castrange of sizes and
shapes,
metal or plastic,
perforated or
nonperforated
primary impressions
preliminary or anatomic
primary cast
spaced trays
close fitting trays
aluminium filled shellac
acrylic resins
secondary impressions
9.
10.
11.
12. Basic properties of impression materials
Fluid
obtained by - mixing the components
- heating- heating
→ until it exhibits plastic flow
Setting period
changing from fluid to solid
Set
end form of the material
13. Certain properties
I. Consistency of the
fluid material
high viscosity
heavy bodied, puttyheavy bodied, putty
regular viscosity
intermediate flow
low viscosity
light bodied
very low viscosity
light bodied
14. Certain properties
II. Setting characteristics of the material
Inital setting time
- beginning of the setting process- beginning of the setting process
- for manipulating the material (working time)
- the impression material should be inserted
Final setting time
- the material is completely set, it can be
removed from the mouth
15. Certain properties
III. Properties of the set material
Dimensional stability (shape and size
changing)changing)
a) more than 0,2% in six hours → dimensionally
unstable
alginates - shrinkage !
b) less than 0,2 % in six hours → dimensionally
stable
Elastic recovery
16. Impression materials: required propertiesImpression materials: required properties
Non toxic
Accurate
Easy to handle
Easy to manipulateEasy to manipulate
Consistency
Setting time
Elasticity
Dimensionstability
Wettability
Thixotropic
Economy
Disinfection
Flavour
17. Impression materials after setting
Elastic
These materials can be stretched and bent to a fairly large degree without
suffering any deformation. These are used for recording the patient's
mouth where undercuts are present. Usually used for partial dentures,
overdentures, implants and crown and bridge work
The elastic impression materials can be divided into two groups: the
hydrocolloids and the synthetic elastomers.
Rigid
Non undercut areas
Impression Plaster
Compound
Zinc-oxide eugenol paste
Wax
hydrocolloids and the synthetic elastomers.
Hydrocolloid:
Alginate
Synthetic elastomers:
Polysulphide
Polyether
Silicone
18. Hydrocolloides
A colloid is a state of matter in which individual particles of
one substance, are uniformly distributed in a dispersion
medium of another substance. When the dispersion
medium is water it is termed a hydrocolloid.
Fluid: when the solute particles present are dispersed
throughout the liquid, this is called a sol.
particles attached to each other, forming a loose network:
the colloid becomes viscous and jelly like, and is called a
gel.gel.
ability to change reversibly from the sol state to the gel
state.
A sol can be converted into a gel in one of two ways :
1. Reduction in temperature, reversible because sol is
formed again on heating (eg agar).
2. Chemical reaction which is irreversible (eg alginates). A
gel can lose (syneresis which results in shrinkage) or take
up (imbibition which results in expansion) water or other
fluids.
Hydrocolloids are placed in the mouth in the sol state when
it can record sufficient detail, then removed when it has
reached the gel state.
19. AlginateAlginate
CompositionComposition
sodium or potassium alginatesodium or potassium alginate 20%20%
salts of alginic acid, preparedsalts of alginic acid, prepared
ffrom various species of seaweedrom various species of seaweed
fillers: diatomaceous earthfillers: diatomaceous earth 44%44%fillers: diatomaceous earthfillers: diatomaceous earth 44%44%
gives body to the impressiongives body to the impression
CaSO4 · 2 H2OCaSO4 · 2 H2O 15%15%
sodium tripolyphosphatesodium tripolyphosphate 8%8%
retardantretardant
modifiersmodifiers magnesium oxide, sodiummagnesium oxide, sodium
fluoride 11fluoride 11%%
good setting, good surfacegood setting, good surface
20. MixingMixing
PowderPowder : W: Waterater = 1 : 3 in a flexible bowl with a curved, rigid spatula= 1 : 3 in a flexible bowl with a curved, rigid spatula
Container of powder should be shaken before use to get an even distribution ofContainer of powder should be shaken before use to get an even distribution of
constituents. Powder and water should be measured to manufactures instructions.constituents. Powder and water should be measured to manufactures instructions.
Water at room temperature should be used, this gives a reasonable working time of aWater at room temperature should be used, this gives a reasonable working time of a
couple of minutes.couple of minutes.
On mixing the powder with water a sol is formed, a chemical reaction takes place and aOn mixing the powder with water a sol is formed, a chemical reaction takes place and a
gel is formed.gel is formed.
ddimensionally unstableimensionally unstable
syneresis (Hsyneresis (H22O loss from the surface)O loss from the surface)
shrinkage → impression should be cast in 15 minutes, or stored in hygroforshrinkage → impression should be cast in 15 minutes, or stored in hygroforshrinkage → impression should be cast in 15 minutes, or stored in hygroforshrinkage → impression should be cast in 15 minutes, or stored in hygrofor
do not adhere to the impression traydo not adhere to the impression tray –– adhesiveadhesives, or perforateds, or perforated traystrays
pH changes during settingpH changes during setting -- chromaticchromatic alginatesalginates
21.
22. PROPERTIES
Good surface detail
Reaction is faster at higher temperatures
Elastic enough to be drawn over the undercuts, but tears over the
deep undercuts
Not dimensionally stable on storing due to evaporation
Non toxic and non irritant
Setting time can depend on technique
Alginate powder is unstable on storage in presence of moisture or in
warm temperatures
Alginate powder is unstable on storage in presence of moisture or in
warm temperatures
ADVANTAGES
1. Non toxic and non irritant
2. Good surface detail
3. Ease of use and mix
4. Cheap and good shelf life
5. Setting time can be controlled with temperature of water used
DISADVANTAGES
1. Poor dimensional stability
2. Incompatibility with some dental stones
3. Setting time very dependent on operator handling
4. Messy to work with
25. Impression materials are used to
record the shape of the teeth
and alveolar ridges. There are a
wide variety of impression
materials available each with
their own properties, advantages
and disadvantages.and disadvantages.
Materials in common use can be
classified as elastic or
rigid (non-elastic) according to
the ability of the set material to
be withdrawn over undercuts.
26. Impression materials: required propertiesImpression materials: required properties
Non toxic
Accurate
Easy to handle
Easy to manipulateEasy to manipulate
Consistency
Setting time
Elasticity
Dimensionstability
Wettability
Thixotropic
Economy
Disinfection
Flavour
27. Impression materials after setting
Elastic
These materials can be stretched and bent to a fairly large degree without
suffering any deformation. These are used for recording the patient's
mouth where undercuts are present. Usually used for partial dentures,
overdentures, implants and crown and bridge work
The elastic impression materials can be divided into two groups: the
hydrocolloids and the synthetic elastomers.
Rigid
Non undercut areas
Impression Plaster
Compound
Zinc-oxide eugenol paste
Wax
hydrocolloids and the synthetic elastomers.
Hydrocolloid:
Alginate
Synthetic elastomers:
Polysulphide
Polyether
Silicone
28. The synthetic elastomers
First introduced in the late 1950s, synthetic elastomeric impression
materials quickly became popular as dental materials because they
significantly reduced the two main problems associated with the
hydrocolloids, namely poor dimensional stability and inadequate tear
resistance. These are used where a high degree of accuracy is needed,
especially in crown and bridge work.
Albert Einstein in Princeton, ca. 1950
They have two main advantages
over the Hydrocolloids - good tear
resistance and dimensional
stability.They are mainly hydrophobic
rubber based materials. All of these
materials come in different viscosity's
ranging from low to high viscosity.
The light bodied material maybe used
as a wash impression over a medium
or heavy-bodied material.
29. ONE STAGE IMPRESSION
Light bodied impression material is placed in a syringe, and
placed over the areas where high detail is required (e.g.
over a crown preparation). Some is then squirted over
the heavy-bodied impression material which has been
loaded into an impression tray. The impression is then
taken as normal. This technique saves time, but it can be
very labour intensive because the two need to mixed atvery labour intensive because the two need to mixed at
the same time.
TWO STAGE IMPRESSION
An impression is taken with the heavy-bodied material. This
is then removed from the mouth and inspected. The light
bodied material is then prepared and again placed in a
syringe. This is then squirted over heavy-bodied material
and then impression relocated.
30. Silicone elastomersSilicone elastomers
Polymers of silicone and oxygen atoms → polysiloxanePolymers of silicone and oxygen atoms → polysiloxane
Elastic properties can be obtained by cross linking andElastic properties can be obtained by cross linking and
additionaddition of the long chainsof the long chains
Viscosity types: high viscosityViscosity types: high viscosity -- heavy bodied,heavy bodied, puttyputty
regular viscosityregular viscosity -- intermediate flowintermediate flow
low viscositylow viscosity -- light bodiedlight bodiedlow viscositylow viscosity -- light bodiedlight bodied
very low viscosityvery low viscosity -- light bodiedlight bodied
31. Supplied as a paste andSupplied as a paste and
Condensation cured siliconesCondensation cured silicones
polysiloxane chains are terminated withpolysiloxane chains are terminated with
silanolsilanol, dibutilyn dilaurate catalyst present, dibutilyn dilaurate catalyst present
during setting, condensation reaction occursduring setting, condensation reaction occurs
and theand the byproduct is alcoholbyproduct is alcohol
Supplied as a paste andSupplied as a paste and
liquid or two pastes, inliquid or two pastes, in
light, medium, heavy orlight, medium, heavy or
very heavy bodied (putty).very heavy bodied (putty).
do not adhere todo not adhere to impressionimpression
traytray--adhesive solutions!adhesive solutions!
32.
33. PROPERTIES
Hydrophobic
Hydrogen gas evolution on setting
Moderate shelf life
Moderate tear strength
Good surface detail
Shrinking of impression over time
Non toxic and non irritant
Very elastic (near ideal)
ADVANTAGES
Accurate
Ease of use
Can be used on severe undercuts
DISADVANTAGES
Hydrogen evolution
Liquid component of paste/liquid system may cause irritation
34. Addition cured siliconesAddition cured silicones
Supplied in 2 pastes or in aSupplied in 2 pastes or in a
gun and cartridge form as light,gun and cartridge form as light,
during setting, additionduring setting, addition reaction occursreaction occurs
Platinic compound catalyst presentPlatinic compound catalyst present
no byproductno byproduct
no polymerizationno polymerization contractioncontraction
--
gun and cartridge form as light,gun and cartridge form as light,
medium, heavy and very heavymedium, heavy and very heavy
bodied.bodied.
On mixing, in equalOn mixing, in equal
proportions, crosslinkingproportions, crosslinking
occurs to form a siliconeoccurs to form a silicone
rubber. Setting occurs in aboutrubber. Setting occurs in about
66--8 minutes.8 minutes.
do not adhere todo not adhere to impressionimpression
traytray--adhesive solutions!adhesive solutions!
expensiveexpensive
35.
36. PROPERTIES
Good shelf life
Dimensionally stable
Moderate tear strength
Excellent surface detail
No gas evolution
Non toxic and non irritant
ADVANTAGES
AccurateAccurate
Ease of use
Fast setting
Wide range of viscosity's
DISADVANTAGES
Hard to mix
Sometimes difficult to remove the impression from the mouth
Too accurate in some circumstances (cast produced is not
sufficiently oversized)
37. Polyether elastomersPolyether elastomers
CompositionComposition::
supplied as two pastessupplied as two pastes
base paste:base paste:
liquid polyetherliquid polyether
fillersfillersfillersfillers
inert oilsinert oils
activator paste:activator paste:
sulphonic acid esulphonic acid esstherther inin hydrocarbonshydrocarbons
fillersfillers
During setting reaction cross linking reaction occurs withDuring setting reaction cross linking reaction occurs with
thethe aziazirirididinno groups of the base and the end product is ao groups of the base and the end product is a
rubberrubber--likelike polymerpolymer
38. A popular polyether impression material,
Impregum (Espe GmbH, Germany), was
the first elastomer to be developed
specifically for use in dentistry and
introduced in the
late 1970s.late 1970s.
39. Impregum™ Penta™ Soft Heavy
Body/Light Body Impression Material
Polyether precision impression material
that is accurate and hydrophilic,
resulting in outstanding detail even in
a moist environment
Impregum™ Penta™ Soft Medium
Body Impression Material,
Polyether precision impression material
medium viscosity and is intended for
use in the monophase technique.
40. Polyether impression materials tendPolyether impression materials tend
to have a fast setting time of lessto have a fast setting time of less
than 5 minutesthan 5 minutes
In contrast to polysulphides, theyIn contrast to polysulphides, they
undergo an addition curedundergo an addition cured
polymerisation reaction onpolymerisation reaction on
setting which has no reaction bysetting which has no reaction by--
product resulting in a materialproduct resulting in a material
with very good dimensionalwith very good dimensionalwith very good dimensionalwith very good dimensional
stability.stability.
The set material may however swellThe set material may however swell
and distort because of theand distort because of the
absorption of water on storage inabsorption of water on storage in
conditions of high humidity.conditions of high humidity.
Impressions should therefore beImpressions should therefore be
stored dry.stored dry.
DDo not adhere to impressiono not adhere to impression
traytray--special adhesives!special adhesives!
41. PROPERTIES
Hydrophillic (ie absorbs water)
Good shelf life of up to 2 years
Good elastic recovery
Non toxic
Low setting contraction
Low tear strength
Excellent surface detail
Good dimensional stability
ADVANTAGES
Accuracy
Good on undercuts
Ease of use
DISADVANTAGES
May cause allergic reaction due to the sulphonic acid ester
Poor tear strength
Rapid setting time (ie short working time)
Stiff set material (sometimes hard to remove from mouth)
42. ••CompositioComposition :n :
supplied as two pastessupplied as two pastes
base paste: liquid polysulphidebase paste: liquid polysulphide 55%55%
fillers (ZnSO4, TiO2)fillers (ZnSO4, TiO2) 44%44%
perfumeperfume 1%1%
Polysulphide elastomersPolysulphide elastomers
activator paste: leadactivator paste: lead--dioxidedioxide 10%10% causescauses
colloidal sulfurcolloidal sulfur 1%1% polymerizationpolymerization
oleic and stearic acidoleic and stearic acid 2%2% stabilizesstabilizes
fillers (ZnSO4, TiO2)fillers (ZnSO4, TiO2) 50%50% settingsetting
inert oilinert oil 37%37% characteristicscharacteristics
Mixing should continue until a streak-free mass is obtained
43. do not adhere to impression traydo not adhere to impression tray--adhesives:rubber solution inadhesives:rubber solution in
acetoneacetone
During setting reactionDuring setting reaction terminal hydrogen atoms of the liquidterminal hydrogen atoms of the liquid
polisulfide arepolisulfide are oxidizoxidized by the lead dioxideed by the lead dioxide with a resultantwith a resultant
increase in the degree of polymerizationincrease in the degree of polymerization
acetoneacetone
lead dioxide may have toxic effectlead dioxide may have toxic effect--alternative oxidizing systemsalternative oxidizing systems
ttypes:ypes: heavy bodiedheavy bodied
regularregular
light bodiedlight bodied
44. relatively unpopular materials, setting
reaction of polysulphides tends to be
long with setting times often in excess of
10 minutes (acceleration is possible by
adding a small drop of water to the mix)
messy to handle
objectionable odour
Dies wider and shorter than the tooth
preparation. This distortion, which
worsens the longer the delay in pouring
up, is the result of impression shrinkageup, is the result of impression shrinkage
which is directed towards the impression
tray - hence the wider die. Shrinkage
occurs firstly as a result of a continued
setting reaction after the apparent setting
time, and secondly through the
evaporation of water produced as a by-
product of the setting reaction.
A special tray, providing a 4 mm uniform
space, is needed to reduce distortion
from the shrinkage of a large bulk of
material. The recommended maximum
storage time of the set impression is
about 48 hours
45. PROPERTIES
Dimensional stability
Excellent surface detail (is only used in special trays)
Viscosity depends on the brand used
Very small setting contraction (0.3-0.4% over the first 24 hrs)
Contraction on cooling from mouth to room temperature
Very good tear resistance
Good shelf life
Viscoelastic
ADVANTAGES
Dimensional stabilityDimensional stability
Accuracy
Comes in a number of different viscosity's
Long working time (although this may be a disadvantage in some clinical situations)
Long shelf life
DISADVANTAGES
Lead oxide in base paste may have toxic effects
Staining of clothes due to the Lead oxide
Messy to work with - unpleasant rubbery smell
Can only be used in a special tray
46. Impression materials after setting
Rigid
Non undercut areas
Impression PlasterImpression Plaster
Compound
Zinc-oxide eugenol paste
Wax
Elastic
Undercut areas allowed
Alginate
Polysulphide
Polyether
Silicone
47. Rigid materials
These materials are rigid and therefore exhibit little or no
elasticity. Any significant deformation produces a
permanent deformation. They are used where there are
no undercuts and are mainly used for edentulous patient
cases.
Non-elastic impression materials are generally not used
for obtaining impressions of crown preparations
because of their inability to accurately record undercuts.because of their inability to accurately record undercuts.
48. Impression Plaster „History „History „History „History „
Composition – CaSO4 . ½ H2O
Potassium-SO4 or salts of strong
acids (2,5%)
→ accelerators
→ reduce of the setting expansion→ reduce of the setting expansion
Salts of weak acids or borax
(0,25%)
→ retarders
Coloring agent
49.
50. Manufacturing
CaSO4 · 2 H2O CaSO4 · ½ H2O + 1 ½ H2O
Mineral gypsum: CaSO4 · 2 H2O - heating 110-130 °C
dry → β-hemihydrate - irregular particles
plaster of Paris, model stoneplaster of Paris, model stone
autoclave → α-hemihydrate - more perfect crystals
model stone, die stone
52. Setting reaction
hydration reaction
quick, exothermic, setting expansion
CaSO4 · ½ H2O + 1 ½ H2O crystallization CaSO4 · 2 H2O
100g powder + 60 ml water - mixed in a flexible bowl with a spatula
Visible signs:
1. Dissolution - light surface → fluid
2. Colloidal state - matt surface → paste2. Colloidal state - matt surface → paste
3. Crystal formation - solid → hardening
4. Breaks with a special sound
Influence on the setting time
and expansion:
water/powder ratio
spatulation time
Temperature
53. PROPERTIES
Excellent at recording fine detail (because very fluid when inserted in mouth)
Dimensionally stable if anti expansion solution used
Fractures if undercuts present
Mucostatic
Needs to be treated with a separating medium (e.g. varnish or soap solution)
before being cast in stone or plaster
Exothermic setting reaction
On storage dimensionally stable but a small amount of shrinkage may occur
Non toxic but may be unpleasant due to dryness and heat evolved during
setting
ADVANTAGES
Good surface detail
Excellent dimensional stability
Rate of the setting reaction can be controlled by the clinician
DISADVANTAGES
Cannot be used for mucocdisplacive impressions
Cannot be added to
Properties affected by operator handling technique
Taste and roughness may cause the patient to vomit
54. Impression compound
Composition:
mixture of thermoplastic resins and waxes 47%
with fillers (talcum) and pigments 53%
becomes soft between 55 °C and
60 °C in water bath
at mouth temperature reverts to a
solid state
(slow reaction because of poor
heat conduction)
55. Dental application
Type I. -used for impression
taking
sheet (black, brown, red)
primary impressions for
complete dentures
green stick
border trimming materialborder trimming material
56. PROPERTIES
Poor surface detail
High coefficient of thermal expansion (contraction of up to 0.3% when removed from
mouth to room temperature)
Distorts wen removed over undercut areas
Hardens in the mouth in suitable time
Mucodisplacive
Poor dimensional stability
Can be modified by re-heating
Tray borders can be progressively developed with greenstick
During manipulation internal stresses can be set up
Non toxic and non irritantNon toxic and non irritant
Good shelf life
ADVANTAGES
1. Non irritant and non toxic
2. Reusable (but with re-use the constituents are leached out)
3. Can be reheated and readapted
4. Can support other materials for wash impressions
5. Mucocompressive
DISADVANTAGES
1. Poor dimensional stability
2. Poor surface detail
3. Expansion coefficient
4. Will distort if removed from undercuts
57. Zinc-oxide eugenol paste
Composition:
supplied as two pastes
base paste activator paste
white brownish, transparent
ZnO eugenol
Hydrogenated resin fillers: talc, diatomaceous earth
inert oil
MgCl as acceleratorMgCl as accelerator
Some pastes contain a substitute for eugenol e.g. a
carboxylic acid.
The 2 pastes come in contrasting colours and mixed
to give a paste of even colour.
The material is mixed in a 1:1 paste ratio and used in thin
sections only (2-3mm) as a wash impression.
Dental application:
secondary impression for complete dentures
temporary luting of fixed appliances
58. PROPERTIES
Non toxic
Adherence to tissues
Mucostatic or mucocodisplacive (depending on brand used)
Good surface detail in thin section
Good dimensional stability (little or no dimensional change on
setting, 0.1% dimensional change during setting)
Can be added to with fresh zinc oxide eugenol
Stable on storage and good shelf life
ADVANTAGES
1. Dimensional stability
2. Good surface detail
3. Can be added to
4. Mucostatic or mucocodisplacive
DISADVANTAGES
1. Cannot be used in very deep undercuts
2. Only sets quickly in thin section
3. Eugenol allergy in some patients
59. WaxesWaxes
Origin of waxesOrigin of waxes::
mineral waxmineral wax ––
obtained from petroleum distillationobtained from petroleum distillation
paraffin waxparaffin wax ––
brittle at room temperaturebrittle at room temperature
melting temperature: 48melting temperature: 48--7070 °° CCmelting temperature: 48melting temperature: 48--7070 °° CC
microcrystalline waxmicrocrystalline wax -- less brittleless brittle
melting temperature: 65melting temperature: 65--9090 °°CC
animal wax (beeswax)animal wax (beeswax)
adding to paraffin wax → less brittleadding to paraffin wax → less brittle
vegetable waxvegetable wax
carnauba wax: derived from palm treecarnauba wax: derived from palm tree
candenilla wax: derived from plantscandenilla wax: derived from plants
60. Dental applicationDental application
modeling wax (rose)modeling wax (rose)
inlay wax (blue, green)inlay wax (blue, green)
sticky wax (yellow)sticky wax (yellow)
baseplate waxbaseplate wax
border trimming impression waxborder trimming impression wax
undercut waxundercut wax
PropertiesProperties::
Waxes are thermoplastic materials,Waxes are thermoplastic materials,
which flow at mouth temperature and arewhich flow at mouth temperature and arewhich flow at mouth temperature and arewhich flow at mouth temperature and are
soft a room temperature. They do not setsoft a room temperature. They do not set
by chemical reaction. Normally used toby chemical reaction. Normally used to
correct small imperfection (e.g. airblows)correct small imperfection (e.g. airblows)
in other impressions, especial zinc oxidein other impressions, especial zinc oxide
impressions.impressions.
A cast should be poured up immediately
after taking the impression to avoid
distortion which readily occurs in wax.
Because of easy deformationBecause of easy deformation
not widely used as impressionot widely used as impressionn
material!material!