The document provides details on lab procedures for processing complete dentures after the try-in stage. It discusses acrylic resins used for denture bases, processing techniques including flasking, dewaxing, applying separating medium, mixing, packing, curing, and deflasking. Compression molding is the most common technique, involving preparing the trial denture, flasking, applying separating medium, mixing and packing the acrylic resin, curing using either a short or long cycle in a water bath, and finishing. The quality of processing is critical for the success of the final denture.
Ceramics have many applications in dentistry due to their esthetic qualities, strength, and biocompatibility. Ceramics are used in crowns, bridges, veneers, dentures, and more. There are several types of ceramics including metal-ceramics, which combine a ceramic material fused to a metal framework for strength, and all-ceramic options made of materials like alumina and zirconia. Ceramic materials are fabricated through processes like sintering, heat pressing, slip-casting, and CAD/CAM milling. Ceramics provide natural-looking and long-lasting restorations but also have limitations like brittleness which new materials continue to address
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.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Dental Ceramics and Porcelain fused to metal isabel
This document discusses ceramics and porcelain fused to metal restorations. It describes the composition and properties of dental ceramics and porcelains, including feldspathic and aluminous porcelains. The applications and parts of porcelain fused to metal restorations are outlined. The benefits and drawbacks of metal-ceramic restorations are summarized. Requirements for the metal coping and bonding of porcelain to the coping are also summarized.
This document provides an overview of gutta percha, including its discovery, historical uses, sources, evolution in dentistry, composition, chemistry, phases, properties, and commercial manufacture. Gutta percha is a natural polymer that has been used in dentistry as a root canal filling material since the 19th century due to its biocompatibility and ability to adapt to canal walls and provide a fluid-tight seal at the apex. It exists in alpha and beta crystalline forms that impact its viscosity and handling properties for different obturation techniques.
There have been several changes since inception in the field of dental ceramics. Need for newer materials with improved aesthetics, flexural strength and optical properties made it necessary for introduction of advanced technology in fabrication of dental ceramics.
The document discusses the history and advantages of using rubber dams in dentistry. It was introduced in 1864 and provides benefits such as isolating teeth, protecting tissues, and improving visibility and access. Recent advances include latex-free materials, frames with improved design for patient comfort and access, and pre-framed dams. A variety of retainers and frames exist to securely isolate teeth from saliva for endodontic procedures.
Ceramics have many applications in dentistry due to their esthetic qualities, strength, and biocompatibility. Ceramics are used in crowns, bridges, veneers, dentures, and more. There are several types of ceramics including metal-ceramics, which combine a ceramic material fused to a metal framework for strength, and all-ceramic options made of materials like alumina and zirconia. Ceramic materials are fabricated through processes like sintering, heat pressing, slip-casting, and CAD/CAM milling. Ceramics provide natural-looking and long-lasting restorations but also have limitations like brittleness which new materials continue to address
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.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Dental Ceramics and Porcelain fused to metal isabel
This document discusses ceramics and porcelain fused to metal restorations. It describes the composition and properties of dental ceramics and porcelains, including feldspathic and aluminous porcelains. The applications and parts of porcelain fused to metal restorations are outlined. The benefits and drawbacks of metal-ceramic restorations are summarized. Requirements for the metal coping and bonding of porcelain to the coping are also summarized.
This document provides an overview of gutta percha, including its discovery, historical uses, sources, evolution in dentistry, composition, chemistry, phases, properties, and commercial manufacture. Gutta percha is a natural polymer that has been used in dentistry as a root canal filling material since the 19th century due to its biocompatibility and ability to adapt to canal walls and provide a fluid-tight seal at the apex. It exists in alpha and beta crystalline forms that impact its viscosity and handling properties for different obturation techniques.
There have been several changes since inception in the field of dental ceramics. Need for newer materials with improved aesthetics, flexural strength and optical properties made it necessary for introduction of advanced technology in fabrication of dental ceramics.
The document discusses the history and advantages of using rubber dams in dentistry. It was introduced in 1864 and provides benefits such as isolating teeth, protecting tissues, and improving visibility and access. Recent advances include latex-free materials, frames with improved design for patient comfort and access, and pre-framed dams. A variety of retainers and frames exist to securely isolate teeth from saliva for endodontic procedures.
This document discusses glass ionomer cement and resin-modified glass ionomer cement in restorative dentistry. It describes the composition and setting reactions of glass ionomer cement, as well as its advantages like adhesion to tooth structure, fluoride release, and low shrinkage. However, it also notes disadvantages like poorer wear resistance and physical properties compared to resin composites, as well as ongoing moisture sensitivity issues. The document then discusses how resin-modified glass ionomer cements were developed to improve properties like strength and reduce moisture sensitivity issues. It concludes by describing clinical applications of resin-modified glass ionomer cements, such as for class V restorations, root caries treatment, and the sandwich technique.
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 provides an overview of CAD-CAM technology in dentistry. It discusses the history of CAD-CAM beginning in the 1980s with developers like Dr. Duret, Dr. Moermann, and Dr. Andersson. The key components of CAD-CAM systems include scanners to collect digital data, design software to process the data, and processing devices like milling machines. Common materials milled include metals, resins, ceramics, and oxides. CAD-CAM systems can be used chairside (in-office) or in dental laboratories. Both subtractive milling and additive manufacturing techniques are used to fabricate dental restorations with CAD-CAM.
This document discusses materials and techniques for fabricating dental dies. It describes common die materials like gypsum products, electroplated dies, epoxy resins and ceramic materials. Gypsum products are most commonly used due to their ability to reproduce fine detail, dimensional accuracy, and ease of use. The document outlines the basic requirements for die materials and manufacturing processes for gypsum dies, including the setting reaction and how factors like water-powder ratio and mixing time affect setting time.
Zinc oxide-eugenol (ZOE) is a dental cement that has been used for over 150 years. It is used for multiple applications including impressions, temporary fillings, root canal fillings, cementing, and surgical dressings. ZOE cement sets via a chemical reaction between zinc oxide and eugenol. It has low strength but is biocompatible. Modified versions with additions like EBA or polymers have improved properties but ZOE remains useful due to its favorable pulpal response and low cost.
This document discusses dental composites, including their:
- History dating back to the 1940s and developments since then
- Composition of a matrix, fillers, and coupling agent
- Classification based on filler size, curing method, area of use, and generations
- Properties including strength, smoothness, and polymerization shrinkage
- Advantages such as esthetics and bond strength, as well as disadvantages like polymerization shrinkage.
This document discusses various methods and materials used for pulp protection during restorative procedures. It describes the pulp-dentin complex and factors that can irritate the pulp. Methods for protecting the pulp include indirect and direct pulp capping. Direct pulp capping involves placing a biocompatible material over an exposed pulp. Indirect pulp capping leaves a thin layer of dentin and caries to avoid exposure. Materials traditionally used include calcium hydroxide, zinc oxide eugenol, and glass ionomers. Newer materials like Biodentine, a calcium silicate-based cement, have shown promising results for pulp capping and stimulation of reparative dentin formation.
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.
Tissue conditioners and denture liners are used to improve the fit and comfort of removable dentures. They can be classified based on their curing method, composition, durability, consistency and other properties. Tissue conditioners are temporary soft liners that help condition traumatized tissue, while hard and soft denture liners provide a more permanent resilient layer. Relining or rebasing dentures helps maintain proper fit as ridges resorb over time. Selection of the appropriate liner depends on the clinical situation and needs of the patient.
Composite Resin Luting cements (2nd edition) presentation powerpoint
A type of dental cement
Used for cementation of indirect restorations & brackets
A summary of five textbooks
This document provides information on cavity liners and bases used for pulp protection. It begins with an introduction and overview of steps for tooth preparation. It then discusses the objectives of pulp protection including sealing smear layers and providing chemical, electrical, thermal and mechanical protection.
It classifies intermediary bases according to different authors and lists ideal requirements. It describes different types of liners in detail - solution liners (varnishes), suspension liners, and cement liners. Their compositions, thicknesses, functions and applications are explained. Finally, it defines cavity bases, their types (high strength and low strength), and purposes of providing thermal protection and mechanical support to the pulp.
The document provides an overview of denture base resins including their definition, history, classification, key ingredients, and properties. It discusses the early use of materials like ivory, bone, and porcelain for dentures and the later development of vulcanite in the 1840s as the first affordable and workable material. Polymethyl methacrylate (PMMA) was introduced in the 1930s and became the standard material by 1946, providing improved properties over previous materials. The document outlines the polymerization process and ideal requirements for denture base resins based on biocompatibility, durability, and other factors. Heat-cured PMMA denture base resin is currently the most widely used material.
The document discusses dental ceramics, including their history, structure, composition, and classification. Some key points:
- Dental ceramics have been used since ancient times, with early developments including porcelain teeth in the late 18th century. Major advances included reinforced porcelains in the 1960s and all-ceramic systems in the 1980s-1990s.
- Ceramics can be crystalline or non-crystalline (glass). Dental ceramics are mainly composed of crystalline minerals and a glass matrix. Common components include feldspar, silica, kaolin, and glass modifiers.
- Ceramics are classified as non-crystalline or crystalline, with fel
Pulp protection in operative dentistry Nivedha Tina
This document discusses various materials used for pulp protection and their properties. It describes how remaining dentin thickness, depth of preparation, and prevention of bacterial microleakage are important factors for pulp health. Common pulp protection materials discussed include bases, liners, varnishes, and sealers. Calcium hydroxide and glass ionomer cements are highlighted as they promote reparative dentin formation, adhere to dentin, and release fluoride. The document emphasizes that proper isolation and sealing of restorations is key to preventing pulpal injury from bacteria and toxins.
This document discusses different types of all-ceramic dental restorations, including their compositions and manufacturing techniques. It describes sintered ceramics like alumina and leucite-based materials, heat pressed ceramics like IPS Empress and lithium disilicate, slip cast ceramics like In-Ceram alumina and spinel, and machinable ceramics milled using CAD/CAM or copy milling. The advantages of all-ceramic restorations are also summarized, such as superior esthetics, biocompatibility, and bond strength compared to ceramic-metal restorations.
Dental waxes are used to create patterns for dental restorations and appliances, with the main types being pattern waxes like inlay wax for dental restorations, processing waxes for tasks like boxing impressions, and impression waxes for corrections or bite registration. Inlay wax is a common pattern wax that comes in different types for direct or indirect use and has properties like thermal expansion and potential for distortion that make it suitable for creating wax patterns.
This document provides an overview of dental composite materials. It begins with an introduction and then discusses the history, definitions, indications, advantages, disadvantages, and classifications of composites. It describes the composition of composites including the resin matrix, inorganic fillers, and coupling agents. Different types of composites are explained such as traditional composites, small particle composites, microfilled composites, hybrid composites, and nanofilled composites. Recent advances like flowable composites, packable composites, antibacterial composites, nanocomposites, ormocers, compomers, and smart composites are also summarized.
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
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 summarizes the key steps in denture processing using compression molding technique:
1. A trial denture is prepared and disarticulated from the cast.
2. The cast and trial denture are invested in dental stone in a flask.
3. The wax is boiled out of the flask. Retention grooves are placed on the artificial teeth.
4. Acrylic resin is mixed, packed into the flask, cured, cooled, and deflasked to produce the final denture.
5. The denture is then finished and polished.
11.complete denture wax‐up and flasking procedureshammasm
This document discusses the process of waxing up dentures and flasking them for acrylic resin processing. It describes criteria for waxing the upper and lower dentures, including contouring the wax base and arranging the teeth. The flasking process involves investing the wax dentures and casts in dental stone in a flask, followed by wax elimination and packing of the flask with acrylic resin. The flask then undergoes polymerization cycling by heating in a water bath to cure the resin into the final denture bases.
This document discusses glass ionomer cement and resin-modified glass ionomer cement in restorative dentistry. It describes the composition and setting reactions of glass ionomer cement, as well as its advantages like adhesion to tooth structure, fluoride release, and low shrinkage. However, it also notes disadvantages like poorer wear resistance and physical properties compared to resin composites, as well as ongoing moisture sensitivity issues. The document then discusses how resin-modified glass ionomer cements were developed to improve properties like strength and reduce moisture sensitivity issues. It concludes by describing clinical applications of resin-modified glass ionomer cements, such as for class V restorations, root caries treatment, and the sandwich technique.
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 provides an overview of CAD-CAM technology in dentistry. It discusses the history of CAD-CAM beginning in the 1980s with developers like Dr. Duret, Dr. Moermann, and Dr. Andersson. The key components of CAD-CAM systems include scanners to collect digital data, design software to process the data, and processing devices like milling machines. Common materials milled include metals, resins, ceramics, and oxides. CAD-CAM systems can be used chairside (in-office) or in dental laboratories. Both subtractive milling and additive manufacturing techniques are used to fabricate dental restorations with CAD-CAM.
This document discusses materials and techniques for fabricating dental dies. It describes common die materials like gypsum products, electroplated dies, epoxy resins and ceramic materials. Gypsum products are most commonly used due to their ability to reproduce fine detail, dimensional accuracy, and ease of use. The document outlines the basic requirements for die materials and manufacturing processes for gypsum dies, including the setting reaction and how factors like water-powder ratio and mixing time affect setting time.
Zinc oxide-eugenol (ZOE) is a dental cement that has been used for over 150 years. It is used for multiple applications including impressions, temporary fillings, root canal fillings, cementing, and surgical dressings. ZOE cement sets via a chemical reaction between zinc oxide and eugenol. It has low strength but is biocompatible. Modified versions with additions like EBA or polymers have improved properties but ZOE remains useful due to its favorable pulpal response and low cost.
This document discusses dental composites, including their:
- History dating back to the 1940s and developments since then
- Composition of a matrix, fillers, and coupling agent
- Classification based on filler size, curing method, area of use, and generations
- Properties including strength, smoothness, and polymerization shrinkage
- Advantages such as esthetics and bond strength, as well as disadvantages like polymerization shrinkage.
This document discusses various methods and materials used for pulp protection during restorative procedures. It describes the pulp-dentin complex and factors that can irritate the pulp. Methods for protecting the pulp include indirect and direct pulp capping. Direct pulp capping involves placing a biocompatible material over an exposed pulp. Indirect pulp capping leaves a thin layer of dentin and caries to avoid exposure. Materials traditionally used include calcium hydroxide, zinc oxide eugenol, and glass ionomers. Newer materials like Biodentine, a calcium silicate-based cement, have shown promising results for pulp capping and stimulation of reparative dentin formation.
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.
Tissue conditioners and denture liners are used to improve the fit and comfort of removable dentures. They can be classified based on their curing method, composition, durability, consistency and other properties. Tissue conditioners are temporary soft liners that help condition traumatized tissue, while hard and soft denture liners provide a more permanent resilient layer. Relining or rebasing dentures helps maintain proper fit as ridges resorb over time. Selection of the appropriate liner depends on the clinical situation and needs of the patient.
Composite Resin Luting cements (2nd edition) presentation powerpoint
A type of dental cement
Used for cementation of indirect restorations & brackets
A summary of five textbooks
This document provides information on cavity liners and bases used for pulp protection. It begins with an introduction and overview of steps for tooth preparation. It then discusses the objectives of pulp protection including sealing smear layers and providing chemical, electrical, thermal and mechanical protection.
It classifies intermediary bases according to different authors and lists ideal requirements. It describes different types of liners in detail - solution liners (varnishes), suspension liners, and cement liners. Their compositions, thicknesses, functions and applications are explained. Finally, it defines cavity bases, their types (high strength and low strength), and purposes of providing thermal protection and mechanical support to the pulp.
The document provides an overview of denture base resins including their definition, history, classification, key ingredients, and properties. It discusses the early use of materials like ivory, bone, and porcelain for dentures and the later development of vulcanite in the 1840s as the first affordable and workable material. Polymethyl methacrylate (PMMA) was introduced in the 1930s and became the standard material by 1946, providing improved properties over previous materials. The document outlines the polymerization process and ideal requirements for denture base resins based on biocompatibility, durability, and other factors. Heat-cured PMMA denture base resin is currently the most widely used material.
The document discusses dental ceramics, including their history, structure, composition, and classification. Some key points:
- Dental ceramics have been used since ancient times, with early developments including porcelain teeth in the late 18th century. Major advances included reinforced porcelains in the 1960s and all-ceramic systems in the 1980s-1990s.
- Ceramics can be crystalline or non-crystalline (glass). Dental ceramics are mainly composed of crystalline minerals and a glass matrix. Common components include feldspar, silica, kaolin, and glass modifiers.
- Ceramics are classified as non-crystalline or crystalline, with fel
Pulp protection in operative dentistry Nivedha Tina
This document discusses various materials used for pulp protection and their properties. It describes how remaining dentin thickness, depth of preparation, and prevention of bacterial microleakage are important factors for pulp health. Common pulp protection materials discussed include bases, liners, varnishes, and sealers. Calcium hydroxide and glass ionomer cements are highlighted as they promote reparative dentin formation, adhere to dentin, and release fluoride. The document emphasizes that proper isolation and sealing of restorations is key to preventing pulpal injury from bacteria and toxins.
This document discusses different types of all-ceramic dental restorations, including their compositions and manufacturing techniques. It describes sintered ceramics like alumina and leucite-based materials, heat pressed ceramics like IPS Empress and lithium disilicate, slip cast ceramics like In-Ceram alumina and spinel, and machinable ceramics milled using CAD/CAM or copy milling. The advantages of all-ceramic restorations are also summarized, such as superior esthetics, biocompatibility, and bond strength compared to ceramic-metal restorations.
Dental waxes are used to create patterns for dental restorations and appliances, with the main types being pattern waxes like inlay wax for dental restorations, processing waxes for tasks like boxing impressions, and impression waxes for corrections or bite registration. Inlay wax is a common pattern wax that comes in different types for direct or indirect use and has properties like thermal expansion and potential for distortion that make it suitable for creating wax patterns.
This document provides an overview of dental composite materials. It begins with an introduction and then discusses the history, definitions, indications, advantages, disadvantages, and classifications of composites. It describes the composition of composites including the resin matrix, inorganic fillers, and coupling agents. Different types of composites are explained such as traditional composites, small particle composites, microfilled composites, hybrid composites, and nanofilled composites. Recent advances like flowable composites, packable composites, antibacterial composites, nanocomposites, ormocers, compomers, and smart composites are also summarized.
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
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 summarizes the key steps in denture processing using compression molding technique:
1. A trial denture is prepared and disarticulated from the cast.
2. The cast and trial denture are invested in dental stone in a flask.
3. The wax is boiled out of the flask. Retention grooves are placed on the artificial teeth.
4. Acrylic resin is mixed, packed into the flask, cured, cooled, and deflasked to produce the final denture.
5. The denture is then finished and polished.
11.complete denture wax‐up and flasking procedureshammasm
This document discusses the process of waxing up dentures and flasking them for acrylic resin processing. It describes criteria for waxing the upper and lower dentures, including contouring the wax base and arranging the teeth. The flasking process involves investing the wax dentures and casts in dental stone in a flask, followed by wax elimination and packing of the flask with acrylic resin. The flask then undergoes polymerization cycling by heating in a water bath to cure the resin into the final denture bases.
The document outlines the steps for processing a complete denture, which involves converting a trial denture base into a permanent base that fits the patient's mouth. The main steps are:
1. Flasking - investing the dental cast and trial denture in a flask to create a mold.
2. Acrylic mixing and pressing - mixing heat-cured acrylic resin and pressing it into the flask mold.
3. Curing - curing the acrylic in a water bath using either a short or long cycle to fully polymerize the resin.
4. Finishing and polishing - removing excess acrylic, adjusting the bite, and polishing the final denture.
03 01 01_45-(flasking and processing complete denture)Serag Amer
This document discusses the flasking process for fabricating complete dentures. It describes the materials and techniques used, including the compression molding process of investing the master cast and wax denture set-up in dental stone inside a denture flask. It also briefly covers microwave and injection molding processing techniques. The key steps of boil out, packing of acrylic, curing, deflasking, and remounting are outlined. Remounting allows correction of any occlusal errors from the processing.
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.
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.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
This document provides an overview of complete dentures and removable partial dentures. It discusses the clinical and laboratory steps involved, including preliminary impressions, final impressions using specialized trays, and jaw relation records. Techniques for fabricating special trays and occlusal rims are described. The document also covers arranging artificial teeth on the dentures, including guidelines for positioning individual teeth, and mounting the dentures on an articulator. Common materials used for various stages are listed.
steps of processing of complete denture (2).pptxmohamedalloush8
The document discusses the key steps in processing a complete denture:
1. The flasking (investing) procedure where the dental cast and waxed denture are enclosed in dental stone inside two-piece metal flask to create a mold.
2. Wax elimination by boiling the flasked mold to remove the wax.
3. Packing of acrylic resin into the mold cavity and curing in water bath.
4. Deflasking after curing to remove the cured denture from the mold.
5. Finishing and polishing the denture.
The document summarizes the key steps in processing a denture: mixing, packing, curing, de-flasking, shaping, and polishing. The mixing step involves combining powder and liquid acrylic to form dough. Packing involves placing the dough in the flask mold. Curing involves polymerizing the acrylic through heating, either through a short or long heating cycle. De-flasking removes the cured denture from the mold. Shaping removes excess acrylic and polishing makes the denture smooth.
1. Elastomers are polymers that are crosslinked and easily stretched and recover their original shape when stress is released. There are four main types: polysulfides, condensation silicones, polyethers, and addition silicones.
2. Polysulfides impressions involve mixing a base paste with a catalyst paste containing lead dioxide. The lead dioxide reacts with sulfide groups on the polymer chains, lengthening and crosslinking them into a network.
3. Condensation silicones involve crosslinking a polydimethylsiloxane polymer with alkyl silicates using stannous octoate. Ethyl alcohol is a byproduct, causing shrinkage. They require a putty
- Record bases help transfer accurate jaw relationships to an articulator to enable setting artificial teeth for a trial denture. They can be temporary or permanent.
- Temporary record bases include shellac, reinforced shellac, cold cure acrylic, and vacuum formed bases. Permanent bases are not discarded and become part of the final denture base, like heat cure acrylic, gold, or cobalt-chromium alloys.
- Occlusion rims are built on record bases to make jaw relation records and arrange teeth. They must be in the anticipated tooth position, securely attached to the base, and have a smooth, flat occlusal surface that supports lips and cheeks.
Problems encountered in dental impressions and their impact on final restoration discusses common issues that can arise during the dental impression process and their effects. It covers prerequisites for impressions like tissue health and saliva control. Impression materials like polysulfide, condensation silicone, and polyether are described. Techniques like putty wash are explained. Errors like inadequate marginal detail, bubbles, tears and improper tray selection can result in open margins or missing arch details. Proper disinfection and storage is needed to prevent dimensional instability. Attention to details in each step of the impression process helps ensure an accurate restoration.
Recent advances in dental materials /certified fixed orthodontic courses by I...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
This document discusses soft tissue liners and tissue conditioners used in dentistry. It defines key terms like relining, rebasing and tissue conditioning. It describes the indications and contraindications for using liners. Various classification systems are covered based on curing method, composition, durability and consistency. The basic requirements, types and uses of hard liners, soft liners like silicone and acrylics, and tissue conditioners are summarized. Different laboratory techniques for relining like articulator, flask and jig methods are outlined. The conclusion states that soft liners have an important role but require improved strength and adhesion properties.
Indirect bonding involves placing orthodontic brackets onto dental models or casts in the lab, then transferring them to the patient's teeth using transfer trays. There are several methods for indirect bonding, including the Thomas method using double sealant technique, Knights method bonding brackets directly to casts, and Sondhi's method using Bioplast trays. Indirect bonding provides more accurate bracket placement compared to direct bonding but requires extra lab time and carries risks of adhesive flash or bracket loss during transfer.
Similar to 5.Lab procedures for cd after try-in.pptx (20)
The document describes the "All-on-4" treatment concept for completely edentulous mandibles involving placement of 4 dental implants. Developed in 1993, it involves inserting 4 implants, at least 10mm long and 3.75/4mm wide, for anchorage with angled abutments to increase spread and reduce cantilever forces. The case report then describes using this technique with 4 Noble Active implants to fully restore an edentulous mandible. Advantages include high success rates, reduced bone grafts and costs, while disadvantages include unsuitability for large bone defects and technical sensitivity.
CONNECTORS IN FIXED PARTIAL DENTURE(devesh rathi).pptSusovanGiri6
This document discusses different types of connectors used in fixed partial dentures. It describes rigid connectors which provide a cast, soldered, or fused union between retainers and pontics. Non-rigid connectors allow limited movement and include dove-tail, split pontic, and tapered pin designs. The document outlines appropriate sizes, shapes, and positions for connectors and provides illustrations of different connector designs.
Oral submucous fibrosis is a chronic condition characterized by fibrosis of the submucous tissues in the oral cavity. It is caused by chewing areca nut and has a high malignant potential. The document discusses the etiology, pathogenesis, clinical features, grading, management and challenges in prosthodontic treatment for patients with oral submucous fibrosis. Special techniques like sectional trays and dentures are often required due to limited mouth opening. Cessation of areca nut chewing is important to prevent progression, but the condition remains irreversible.
This document discusses factors related to dental esthetics. It begins with a brief history of esthetics and outlines seven principles of esthetics including composition, unity, symmetry, proportion, balance, lines, and dominance. It then describes factors that contribute to esthetic dentofacial composition, including the facial component, dental component, gingival component, and physical component. Specific references like horizontal lines and smile analysis are examined. The document emphasizes creating harmony between the teeth and other facial features for a pleasing esthetic result.
The Carolina bridge is an all-porcelain bonded prosthesis that can replace single missing anterior teeth without tooth preparation. It involves bonding a custom porcelain pontic to the adjacent teeth using resin composite connectors. It requires adequate surface area between teeth for bonding. The Carolina bridge provides an esthetic and reversible interim solution as it preserves teeth and bone for future implants. It is contraindicated when there is inadequate interproximal space, deep overbite, short teeth, or teeth with large restorations.
J - BASIC PRINCIPLES IN IMPRESSION MAKING.pptxSusovanGiri6
This document discusses basic principles for making dental impressions. It addresses several key points:
1) Impressions should aim to record the mucosa in an unstrained resting position, however complete recording of rest position is difficult to achieve in practice.
2) Mucosa can be displaced by forces without detaching from the denture base. Impressions must consider direction and magnitude of forces.
3) Retention refers to preventing dislodgement, while stability prevents noticeable movement under function. Both are important for successful dentures.
4) Preservation of underlying alveolar bone is the primary goal, as bone provides better support and stability than soft tissue alone. The strategy should be to use
The document describes a case study of a dental restoration procedure using semi-direct techniques and bioactive materials for a patient undergoing radiotherapy treatment for oral cancer. It discusses how the patient's oral health was compromised by the radiation treatment and chemotherapy. The restorative treatment involved selectively removing radiation-induced caries using RMGIC for cervical lesions and a semi-direct resin composite technique for a posterior tooth. The semi-direct technique improved marginal adaptation and reduced clinical time and patient discomfort compared to direct placement. The case study demonstrates the benefits of these materials and techniques for restoring teeth in oncology patients undergoing radiotherapy.
Retention in complete dentures is influenced by physical, biologic, chemical, psychological, and mechanical factors. Physical factors include adhesion, cohesion, capillarity and atmospheric pressure. Biologic factors involve neuromuscular control, saliva, mucosal health, and ridge characteristics. Denture adhesives are a chemical method to enhance retention. Retentive features like magnets, implants, and ultra suction chambers are mechanical approaches. Proper consideration of all relevant factors leads to optimal complete denture retention.
The document discusses major connectors for removable partial dentures. Major connectors join components on one side of the dental arch to the other, providing support and retention. For maxillary arches, common connectors include palatal straps, bars, and complete palates. For mandibular arches, lingual bars are most common but lingual plates can also be used. Proper design of the connector depends on factors like remaining teeth, jaw anatomy, and required rigidity.
The trigeminal nerve is the fifth cranial nerve that has both motor and sensory components. It has three main divisions - the ophthalmic, maxillary, and mandibular nerves. The ophthalmic nerve innervates the eye and surrounding structures. The maxillary nerve provides sensation to the midface and upper teeth. The mandibular nerve is a mixed nerve that supplies motor innervation to the muscles of mastication and sensation to the lower face and teeth. Disorders of the trigeminal nerve include trigeminal neuralgia, which causes severe facial pain, and herpes zoster ophthalmicus, which causes shingles in the eye region.
4.NON-ODONTOGENIC TUMOURS OF EPITHELIAL TISSUE ORIGIN.pptxSusovanGiri6
The document provides an overview of oral tumors, including the contrasting features of benign and malignant tumors, cellular adaptations, carcinoma in situ, metastasis, diagnosis, TNM staging, and classifications of non-odontogenic tumors. Specific benign and malignant tumors of epithelial tissue origin are discussed, including squamous papilloma, basal cell carcinoma, squamous cell carcinoma, and verrucous carcinoma. Diagnostic methods like biopsy and cytology are also summarized.
The document discusses the preparation of the mouth for removable partial dentures, including oral surgical procedures like extractions to eliminate detrimental conditions, periodontal treatment to establish healthy gums, and optimization of tissues through conditioning to provide support, retention and stability for the denture. The goal of mouth preparation is to create an optimum environment for the functional success of the removable partial denture through eliminating issues and establishing healthy tissues and structures.
This document summarizes the current state of knowledge regarding intraoral appliances used to treat temporomandibular disorders (TMDs). It discusses what is known about how these appliances work, their various designs, and the mechanisms by which they may provide relief from TMD pain and dysfunction. However, the evidence from clinical trials supporting their use is still limited. More research is needed to determine which appliance designs are best suited for specific TMD diagnoses and whether long-term wear provides ongoing benefits or risks changes to occlusion. Overall, oral appliances are considered a reasonable first-line treatment option for managing TMD pain when used appropriately.
This document provides an overview of the major and minor salivary glands, including their anatomy, histology, embryology, innervation, and functions. It discusses the parotid, submandibular, and sublingual glands. It also covers the role of saliva in prosthodontics, noting how different saliva types can impact impression making and denture retention. Maintaining adequate salivary flow is important for denture wearers' oral health and comfort.
2.VIRTUAL IMPRESSIONS AND VIRTUAL AND STEREOLITHOGRAPHIC MODELS.pptxSusovanGiri6
This document discusses virtual impressions and stereolithographic models in dentistry. It provides a brief history of dental impressions, describes recent digital impression technologies like iTero and CEREC, and discusses how digital impressions can eliminate lab steps and provide benefits like accuracy. It also covers virtual model technologies like stereolithography, how they work using layer-by-layer additive manufacturing, and their applications in areas like implant planning and prosthodontics. The conclusion reiterates that while digital technologies provide benefits, traditional impressions still have roles and digital methods have limitations like equipment costs.
This document provides a detailed history and overview of dental ceramics. It discusses the origins and composition of different types of ceramics used in dentistry like feldspathic porcelain, leucite-reinforced porcelain, and aluminous porcelain. The document also outlines the various methods used to classify and fabricate dental ceramics, including processes like condensation and sintering, casting and ceramming, machining, pressure molding, and glass infiltration. Key developments in the history of using ceramics in dentistry are highlighted from the 1700s to present day.
This document summarizes factors for successful bonding of indirect dental restorations using adhesive cementation. It discusses advantages of adhesive cementation, factors to consider when planning for adhesive versus passive cementation, and provides an overview of current adhesive strategies for resin cements. Key factors discussed include the adhesive system used, compatibility with bonding agents, polymerization mechanism of the cement, and shade matching the clinical situation. Immediate dentin sealing is presented as a promising approach that seals dentin before impression taking.
ABDOMINAL TRAUMA in pediatrics part one.drhasanrajab
Abdominal trauma in pediatrics refers to injuries or damage to the abdominal organs in children. It can occur due to various causes such as falls, motor vehicle accidents, sports-related injuries, and physical abuse. Children are more vulnerable to abdominal trauma due to their unique anatomical and physiological characteristics. Signs and symptoms include abdominal pain, tenderness, distension, vomiting, and signs of shock. Diagnosis involves physical examination, imaging studies, and laboratory tests. Management depends on the severity and may involve conservative treatment or surgical intervention. Prevention is crucial in reducing the incidence of abdominal trauma in children.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
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).
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Integrating Ayurveda into Parkinson’s Management: A Holistic ApproachAyurveda ForAll
Explore the benefits of combining Ayurveda with conventional Parkinson's treatments. Learn how a holistic approach can manage symptoms, enhance well-being, and balance body energies. Discover the steps to safely integrate Ayurvedic practices into your Parkinson’s care plan, including expert guidance on diet, herbal remedies, and lifestyle modifications.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
1. LAB PROCEDURES FOR
COMPLETE DENTURES AFTER
TRY-IN
GUIDED BY- PRESENTED BY-
DR. ASHISTARU SAHA DR. POOJAAGRAWAL
DR. TUSHAR TANWANI
DR. ANUPAM PURWAR
DR. NEHA NAVLANI
2. CONTENT-
INTRODUCTION
ACRYLIC RESINS
DENTURE PROCESSING TECHNIQUES
FLASKING
DEWAXING
APPLICATION OF SEPARATING MEDIUM
MIXING AND PACKING
CURING
DEFLASKING
4. INTRODUCTION
The Glossary of Prosthodontic terms defines a complete
denture as a removable dental prosthesis that replaces the
entire dentition and associated structures of the maxilla or
mandible.
Processing converts the trial denture into a denture in its final
form.
Success of complete denture is completely dependent on the
quality of processing.
5. ACRYLIC RESINS
Since the mid-1940s, the majority of denture bases have
been fabricated using poly (methyl methacrylate) resins.
Such resins are resilient plastics formed by joining multiple
methyl methacrylate molecules or “mers”.
Poly methyl methacrylate denture base material usually is
supplied as a powder-liquid system.
6. Based on the method used for activation or curing
types of resins are-
Chemically activated denture base resin.
Light activated denture base resin.
Heat activated denture base resin.
7. Chemically activated denture
base resin
chemical activators used to induce the
polymerization or curing of denture base resin.
referred to as cold curing, self curing or
autopolymerizing resins.
8. Light activated denture base
resin
activator
initiator
This material has been described as a composite
having a matrix of urethane dimethacrylate,
microfine silica, and acrylic resin monomers.
Visible light
camphoroquinone
9. Heat activated denture base
resin
activator
Water bath/micro-oven
As previously noted, denture base resin contain
benzoyl peroxide.
When heated above 60 degree, molecules of
benzoyl peroxide decompose to yield free
radicals.
Thermal
energy
14. Compression moulding
technique
Compression molding is a molding process during
which resin is placed between two dies of a mold
and subjected to pressure and heat to create a
finished part.
15. Injection moulding technique
It is a complicated procedure requiring special
flask and equipment. In this technique the wax
pattern is sprued and the material is injected into
the mold. This process allows injection of further
material during polymerization to compensate for
the polymerization shrinkage.
16. COMPRESSION MOULDING
TECHNIQUE
The most commonly used technique for acrylic resins-
1.Preparation of the trial denture
2. Disarticulation
3. Flasking produce
4. Dewaxing ( Boil out )
5. Application of the separation medium
17. 6. Mixing of powder and liquid
7. Packing
8. Curing
9. Deflasking
10. Finishing and Polishing
18. PREPARATION OF TRIAL
DENTURE
After try-in, the trial dentures are placed on the cast and
sealed to the cast using additional wax.
This is done so that the relationship of the trial denture and
the cast is not altered during disarticulation.
19.
20. DISARTICULATION
The junction between the mounting plaster and the
cast is split with the help of a wax knife and a
plastic mallet.
21.
22.
23. FLASKING
Flask: Is a metal case or tube used in investing
procedures.
Flasking: The process of investing the cast and a
waxed denture in a flask to make a sectional
mould used to form the acrylic resin denture base.
24. The flask is made of 3 major parts,
(1) lower half (which contains the cast),
(2) upper half and
(3) the cover or lid.
The lower half may have a round plate, covering a
round hole in the base of the lower half.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35. Steps in flasking
The waxed maxillary denture on its wetted cast is
placed in the bottom part of a denture flask that has
been partially filled with plaster.
It is forced into the plaster until the land of the cast is
relatively level with the brass sides.
The wet plaster is then smoothened from the brass
edge toward the land of the cast so that no undercuts
exist, and all plaster is wiped from the edge of the
flask.
36. When the plaster has set, a film of separating
medium is painted on the plaster and the land of
cast. This medium will separate this layer from the
next.
The upper half of the flask is now placed in
position making certain that it is completely
seated on the lower half.
The remaining part of the investment may be
totally of stone or totally of plaster.
37. A combination of plaster and stone is
recommended. The stone is painted with a brush
into the interproximal spaces and around the
gingival spaces; it is then poured to the level of
the incisal and occlusal surfaces of the teeth.
The remaining space is filled with plaster.
38. DEWAXING
When the flasking materials have set, the flask
should be heated in boiling water for 4 minutes.
The object is to soften the wax, not to melt it.
If the wax is properly softened, it can be easily
lifted from the teeth, almost in one piece with the
trial base, and discarded.
39.
40.
41. APPLICATION OF THE
SEPARATION MEDIUM
The flask is now allowed to cool to a point where
it can be held in the hand, and separating medium
is applied to separate the denture base material
from the investing stone or plaster.
All the gypsum mold surfaces must be painted.
42. Various types of separating media used are-
Tin foil
Cellulose lacquers
Solution of alginated compounds
Calcium oleate
Soft soaps
Sodium sillicate
Starches
43. Sodium alginate solution- It is commonly known
as “Cold mould Seal” and is the widely used
separating media because of it’s effective and easy
manipulation.
Composition-
Sodium alginate solution
Sodium phosphate
Glycerine
Alcohol
Preservatives
44. MIXING AND PACKING
The monomer and polymer are mixed according
to the instructions supplied by the manufacturer.
The ratio is 1 part monomer to 3 part polymer by
volume or 1 part to 2 parts by weight.
When the powder and liquid components are
mixed in the proper proportions, a doughlike mass
results.
47. DOUGH- FORMING TIME- The time required
for the resin mixture to reach a doughlike stage is
termed the dough-forming time.
WORKING TIME- Working time may be defined
as the time that a denture base material remains in
the doughlike stage.
48. PACKING
The placement and adaptation of denture base
resin within the mold cavity is termed packing.
The placement of too much material, that is
overpacking leads to a denture base that exhibits
excessive thickness and resultant malpositioning
of prosthetic teeth.
The use of too little material, that is underpacking
leads to denture base porosity.
49. The packing process should be performed while
the denture base resin is in a doughlike stage.
The resin form is bent into a horseshoe shape and
placed into the portion of the flask that houses the
prosthetic teeth.
50.
51.
52.
53.
54.
55. Then a polyethelene(nylon sheet) is placed over
the dough in the upper half and then the two
halves of the flask are closed until they are almost
in approximation, this is done to spread the dough
evenly throughout the mold.
Then the two halves of the flask are separated, the
excess material at the borders of the denture is
removed by a wax knife, and additional resin is
added at any places that are deficient.
At least two trial closures are done and before the
final closure the polyethelene sheet is removed
and then the two halves of the flask are closed
under pressure by bench press.
56. CURING
After the final closure of the flask in the
compress, they should remain at room temperature
for a minimum of 1 hour or as much as 4 hours.
This is termed as bench curing.
57. It offers several advantages-
-it provide longer flow period,
thus permitting an equalization of pressures
throughout the mold.
-it allows time for a more uniform dispersion of
monomer throughout the mass of dough,
-it also provides longer exposure of resin teeth,
to the monomer in the dough.
58. Curing is polymerization of the heat cure acrylic,
to produce the final denture.
The material is cured by heating in a water bath.
pressure is applied during curing for the following
reasons:
1- To decrease the effect of thermal expansion.
2- To decrease the polymerization shrinkage.
59. Curing cycle
The heating process used to control
polymerization is termed the polymerization cycle
or curing cycle.
Types of curing cycles for heat cure acrylic:
1- Short curing cycle .
2- Long curing cycle
3- Ultra short curing cycle
60. 1- Short curing cycle: rapid processing
Submerge the closed flask in water at 71o C for
one and half hour followed by boiling for one
hour.
61. 2- Long curing cycle: slow processing:-
9 hours at a constant 71o C is considered adequate
for the average denture.
If boiling also is desired in the slow cure, the
temperature should be held at 71oC for 9 hrs and
then raised to 100o C for 30 minutes.
62. The amount of heat must be controlled while
processing acrylic resin, as the reaction is
exothermic and becomes very rapid at temperature
between 60o and 71oC.
Once polymerization has begun , the temperature
of the resin may be considerably higher than the
temperature of water bath.
63. For this reason, the temperature of the water
should be maintained at ,or below , 71oC for at
least 1 and ½ hrs so that the exothermic heat can
be conducted away from the resin.
The boiling point of monomer is 100.8oC. If the
heat is not controlled, the exothermic reaction will
cause the monomer to boil and result in area of
porosity.
64. 3- Ultra short curing cycle-
polymerized in 100oC
for 20 min
immediately after being packed.
In hybrid acrylics both chemical and heat activated
initiator formulated to allow rapid polymerization
without porosity.
Hybrid
acrylics
65. Curing cycle according to
different manufacturer
Acrylic resin Curing cycle
Trevalon -immerse flask in boiling water
-turn off heat for 20 min.
-Re-heat 100oC for 10 min.
Triplex -immerse flask in cold water,
-heat up to 100oC
-& boil for 45 min.
Lucitone -90 min in 73oC
-then 30 min in boiling water.
pyrax -immerse flask in cold water
-heat up to 100oC for 30 min
-then boil for 30 min.
DPI -2 hrs in 74oC
-increase the temp up to 100oC &
processing for 1 hr.
66. At the close of curing cycle, the flasks in their
compress are removed from the water and allowed
to cool on the bench.
The compress must not be loosened until the
operator is certain that the centre of the flask has
reached room temperarure,
67. POLYMERIZATION VIA
MICROWAVE ENERGY
Polymethyl methacrylate resin also may be
polymerized using microwave energy.
This technique employs a specially formulated
resin and a nonmetallic flask.
A conventional microwave oven is used to supply
the thermal energy required for polymerization.
68. DEFLASKING
When deflasking complete dentures, it is best to
use a deflasker, which allows retrieval from the
flask without damage to the dentures or flask.
The lid of the flask should be removed by prying
with wax knife.
The flask is inverted and placed on the deflasker
and tightened with a thumbscrew.
69.
70.
71.
72.
73.
74.
75.
76. Pribars are inserted laterally to fit on to the slots
of the flask. Once these pribars are engaged, they
are lifted up , so that they separate the base and
the body by lever action. The body or counter will
slide out of the investment.
Place a knife blade in contact with the junction
between the second and third pour investment.
Tap the back of knife blade with plastic mallet to
separate the stone cap and to expose the cusp tips
and incisal edges of the denture.
77. With a saw and spiral blade, cut through the stone
that encloses the denture opposite the central
incisor teeth.
Place more saw cuts at the distobuccal corners of
the flasked denture.
Placing a knife in the anterior and posterior saw
cut and gently separate the stone from the buccal
and anterior flanges of the denture.
78. REMOUNTING
The remounting procedure gives the operator the
oppourtunity to see the changes that occurred in
the teeth during processing and makes it possible
to restore the occlusion that existed on the
completion of waxing.
The dentures on their casts are seated, by means
of the index notches that were cut on the cast
bases before they were mounted on the articulator,
on the original plaster mountings and attached
with plaster that is added to the sides.
79.
80.
81. Normally the incisal pin will show a slight
opening.
Articulating paper is placed between the teeth, and
the articulator opened and closed in the centric
position.
The marks made by the paper indicate which areas
should be ground.
This is continued until the original vertical
dimension has been restored.
82.
83.
84. FINISHING AND
POLISHING
The dentures on their casts are now removed from
the articulator, and the casts separated from the
dentures.
The borders, as well as all other areas reduced
with the arbor bands, then polished using a wet
mix of pumice on a wet rag wheel
Highly polished denture surfaces are more
resistant to stains, are more easily cleaned by the
patient, and are more conductive to tissue health.
85.
86.
87.
88.
89.
90.
91.
92. The inside surface of the denture should be
examined both by the eye and the finger and all
sharp projections smoothed or removed.
The dentures should then be thoroughly cleaned
with warm water, soap and a stiff brush and stored
in water until they are delivered to the patient.
93. Effect of different curing temperatures on the
distortion at the posterior peripheral seal: An in
vitro study
Pasam N, Hallikerimath RB, Arora A, Gilra S.
Indian J Dent Res 2012;23:301-4
Most of the maxillary complete dentures do not
adapt accurately to the cast because of the changes
in the resin during polymerization.
95. Amount of distortion increases as the processing
temperature increases which was highly
significant.
This study carried out on an ideal edentulous
maxillary cast to determine the discrepancy
incorporated into the posterior aspect of maxillary
denture bases by long curing cycle.
96. CONCLUSION
All these laboratory steps are important for
complete denture construction. Esthetics, function
and patient satisfaction depend on a skillfully
waxed and properly processed prosthesis.
97. REFERENCES
Sharry J J. Complete denture Prosthodontics. Third edition.
A Blakiston publication.
Morrow R M, Rudd K D, Rhoads J E. Dental laboratory
procedures Complete dentures. Second edition. C. V. Mosby
company .
Anusavice K J. Phillips’Science of dental materials.
Eleventh edition. Elsevier Publication.
RangarajanV, Padmanabhan TV. Textbook of
Prosthodontics. Elsevier Publication.
Effect of different curing temperatures on the distortion at
the posterior peripheral seal: An in vitro study
Indian J Dent Res 2012;23:301-4.