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.
Impression Techniques in Fixed partial dentureDr.Richa Sahai
This document provides information on dental impressions, including:
- Criteria for an ideal impression include accurately recording all tooth structure and contours.
- Definitions of impression, impression material, and cast.
- Overview of different impression techniques discussed in literature such as stock tray, custom tray, copper band, and hydrocolloid impressions.
- Key steps for making impressions including use of retraction cords, evaluating the final impression, and pouring the stone cast.
- The document is intended to inform dentists on selecting appropriate impression materials and techniques.
This document discusses occlusal equilibration and selective grinding. It begins by defining the key characteristics of a stable occlusion and the signs of an unstable occlusion. It then outlines the principles, indications, goals and procedures for occlusal equilibration and selective grinding. Specific techniques are covered such as how to eliminate interferences in centric relation, achieve the centric contact position, and adjust for lateral and protrusive interferences. The document emphasizes developing simultaneous contacts between cusp tips and flat surfaces to achieve occlusal stability.
JOURNAL CLUB PRESENTATION IN PROSTHODONTICS on ANDREW'S BRIDGE SYSTEMNAMITHA ANAND
This document summarizes a journal club presentation about the Andrews Bridge System. Key points include:
- The Andrews Bridge System is a fixed-removable partial denture that combines fixed retainers connected by a bar with removable pontics for esthetic rehabilitation of edentulous ridges.
- Advantages include improved esthetics, hygiene, phonetics and stress distribution compared to removable partial dentures.
- A clinical case report describes using the system to restore a patient missing maxillary and mandibular anterior teeth following trauma. Post-treatment, the patient had pleasing esthetics and function.
Saliva and its prosthodontic considerationsCPGIDSH
importance of saliva is often neglected by clinicians and practitioners but is one of the most important body fluids not only in dentistry perceptive but also in regard to medical diagnosis. in dentistry it plays a special role specially in complete denture patients
We, as dentists, always think of life-like esthetics pertaining to ceramics, veneers, and crown and bridge restorations. Dentures often are excluded when it comes to creating a true, natural look for the patient.
However, there is an increasing demand for high quality dentures because of the increase in demand of implant-supported dentures and higher expectancy in the complete denture outcome results.
This presentation includes characterisation in complete dentures, with respect to both, denture teeth and acryllic denture bases, thus creating the concept of Prosthodontic privacy.
The document discusses bone density and its importance in implant dentistry. It describes four classifications of bone density (D1-D4) based on macroscopic characteristics, with D1 being the densest. The anterior mandible typically has the densest D1/D2 bone, while the posterior maxilla has the least dense D4 bone. Determining bone density accurately using CT scans is important for developing an appropriate treatment plan and ensuring implant success long-term by avoiding pathological overload conditions.
Impression Techniques in Fixed partial dentureDr.Richa Sahai
This document provides information on dental impressions, including:
- Criteria for an ideal impression include accurately recording all tooth structure and contours.
- Definitions of impression, impression material, and cast.
- Overview of different impression techniques discussed in literature such as stock tray, custom tray, copper band, and hydrocolloid impressions.
- Key steps for making impressions including use of retraction cords, evaluating the final impression, and pouring the stone cast.
- The document is intended to inform dentists on selecting appropriate impression materials and techniques.
This document discusses occlusal equilibration and selective grinding. It begins by defining the key characteristics of a stable occlusion and the signs of an unstable occlusion. It then outlines the principles, indications, goals and procedures for occlusal equilibration and selective grinding. Specific techniques are covered such as how to eliminate interferences in centric relation, achieve the centric contact position, and adjust for lateral and protrusive interferences. The document emphasizes developing simultaneous contacts between cusp tips and flat surfaces to achieve occlusal stability.
JOURNAL CLUB PRESENTATION IN PROSTHODONTICS on ANDREW'S BRIDGE SYSTEMNAMITHA ANAND
This document summarizes a journal club presentation about the Andrews Bridge System. Key points include:
- The Andrews Bridge System is a fixed-removable partial denture that combines fixed retainers connected by a bar with removable pontics for esthetic rehabilitation of edentulous ridges.
- Advantages include improved esthetics, hygiene, phonetics and stress distribution compared to removable partial dentures.
- A clinical case report describes using the system to restore a patient missing maxillary and mandibular anterior teeth following trauma. Post-treatment, the patient had pleasing esthetics and function.
Saliva and its prosthodontic considerationsCPGIDSH
importance of saliva is often neglected by clinicians and practitioners but is one of the most important body fluids not only in dentistry perceptive but also in regard to medical diagnosis. in dentistry it plays a special role specially in complete denture patients
We, as dentists, always think of life-like esthetics pertaining to ceramics, veneers, and crown and bridge restorations. Dentures often are excluded when it comes to creating a true, natural look for the patient.
However, there is an increasing demand for high quality dentures because of the increase in demand of implant-supported dentures and higher expectancy in the complete denture outcome results.
This presentation includes characterisation in complete dentures, with respect to both, denture teeth and acryllic denture bases, thus creating the concept of Prosthodontic privacy.
The document discusses bone density and its importance in implant dentistry. It describes four classifications of bone density (D1-D4) based on macroscopic characteristics, with D1 being the densest. The anterior mandible typically has the densest D1/D2 bone, while the posterior maxilla has the least dense D4 bone. Determining bone density accurately using CT scans is important for developing an appropriate treatment plan and ensuring implant success long-term by avoiding pathological overload conditions.
This document discusses progressive bone loading for dental implants. It begins with an introduction and table of contents. Then it discusses concepts like bone density classifications, rationale for progressive loading based on studies showing bone adapts to stress over time. It outlines elements of progressive loading protocols including extended healing times based on bone density, use of provisional restorations to gradually load bone, and diet restrictions. Studies supporting progressive loading show less crestal bone loss and increased bone density around loaded implants. The conclusion is that progressive loading aims to strengthen bone and reduce risk of implant failure.
The temporomandibular joint (TMJ) is a bilateral joint that connects the mandible to the temporal bone. It has several unique characteristics, including being the only joint with a rigid endpoint of closure. The TMJ has bony, fibrous, and muscular components that allow for hinge, protrusive, and lateral movements. Prosthodontic treatments must consider the anatomy and biomechanics of the TMJ.
Occlusal equilibration is a procedure to precisely alter the occlusal surfaces of teeth to improve the contact pattern. It involves selectively grinding tooth structures that interfere with terminal hinge axis closure, lateral excursion, and protrusive movement. Common tools used include paste, spray or paint to identify contact points requiring adjustment. The basic rules of selective grinding include narrowing cusp tips before reshaping fossae, and adjusting the inclines of upper and lower teeth in opposing directions depending on the path of slide. Occlusal errors in complete dentures can be caused by incorrect registration of the retruded contact position or irregularities during setting and processing of the teeth.
The document discusses different types of laminate veneer preparations. Type I is called a window preparation with no incisal edge reduction. Type II, called a butt-joint preparation, involves 2 mm of incisal reduction without a palatal chamfer. Type III, or wrap-around preparation, includes 1-3 mm of incisal reduction with a 1 mm palatal chamfer to restrict angle fractures and enhance esthetics. The preparations are performed using round or tapered diamond burs to reduce enamel in a uniform and conservative manner confined to the facial surface of teeth.
This presentation provide brief information about different types of cements in Dentistry. also you will find information about cementation tips and techniques. Recent resin cements are also included in this presentation
Implant abutment and implant abutment connectionsDR.BHAVESH JHA
this ppt enlightened with different types of implant abutment connection. Detailed classification of abutments. Different types of abutments. Latest trends of abutments. Smart abutments. Platform switching, rationale of platform switching and related articles.
There are several protocols for loading dental implants after surgery based on bone density and healing time requirements. Protocols include Brånemark's loading protocol, progressive loading, and immediate/early loading. The density of the bone where the implant is placed determines the appropriate loading protocol, as less dense bone requires more healing time before loading to allow for sufficient bone mineralization and strength. Progressive loading gradually increases stress on the implant over time to allow the bone to adapt, reducing risks of failure. It is particularly important for lower density bone which is weaker.
Dental cements have evolved significantly since the first cements were introduced in the late 1800s. Zinc phosphate cement, introduced in the late 1800s, was one of the earliest dental cements and remains the gold standard against which newer cements are compared. In the 1960s, polycarboxylate cement was introduced and was the first cement system to provide an adhesive bond to tooth structure. Glass ionomer cement, introduced in the 1970s, also chemically bonds to tooth structure and was a significant development as it was the first cement with anticariogenic properties.
Impression materials and techniques in fpd /orthodontic courses by Indian den...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.for more details please visit
www.indiandentalacademy.com
The document discusses various techniques for making impressions for implant prostheses. It describes the materials needed and outlines implant level and abutment level impression methods, including open tray, closed tray, direct, and indirect techniques. Splinting multiple implants is recommended to improve accuracy. The importance of minimizing errors in impression making is discussed to ensure proper seating of components and interfaces between impressions posts and analogues. A literature review found that implant and abutment level impression techniques did not have significantly different effects on marginal discrepancy. Precise impressions are important to decrease prosthetic failures and ensure proper fit and function of dental implants.
Impression procedures for compromised ridges/cosmetic dentistry coursesIndian dental academy
The document discusses the history and techniques of impression making for compromised dental ridges. It begins with defining an impression and providing a brief history of impression materials from wax and gutta percha in the 1700s-1800s to alginate and silicones in the 1940s-1950s. It then describes various impression techniques such as open vs closed mouth, mucodisplasive, mucostatic, and selective pressure. Special impression procedures are discussed for minimally displacive, controlled pressure, functional, and external/denture space impressions. Border molding and principles of impression making like support, retention and stability are also summarized.
The document discusses immediate dentures, which are dentures fabricated and inserted immediately following tooth extraction. It describes the different types of immediate dentures, including conventional/classic immediate dentures, interim immediate dentures, labial flange dentures, partial flange dentures, and flangeless/socketed dentures. The advantages of immediate dentures include maintaining a patient's appearance without teeth, providing a bandage effect to extraction sites, and allowing easier adaptation to dentures during healing. However, immediate dentures also present challenges like reduced retention from undercuts caused by remaining posterior teeth.
An occlusal splint is a removable dental appliance that covers the biting surfaces of the teeth in one dental arch. There are several types of occlusal splints classified based on their design and intended use. The main types include permissive splints, non-permissive splints, and anterior repositioning splints. Occlusal splints are used to treat temporomandibular joint disorders by relaxing the jaw muscles, supporting the jaw in an optimal position, and reducing forces on the teeth and jaw joints.
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 discusses various treatment methods for temporomandibular disorders (TMDs). It separates treatments into definitive treatments, which aim to eliminate the underlying cause, and supportive therapies, which aim to manage symptoms. Definitive treatments include reversible occlusal appliances, irreversible occlusal therapies, relaxation techniques, and management of parafunctional habits. Supportive therapies include medications, physical therapies like ultrasound and manual techniques, and self-care methods. The document provides detailed descriptions and indications for different appliance types, including stabilization, anterior repositioning, and soft splints.
This document discusses the theoretical background and techniques of the Hobo full mouth rehabilitation approach. It defines key terms like condylar guidance, incisal guidance, and disocclusion. It explains that the goal of reorganizing occlusion is to address issues like trauma, poor function, or lack of space. The optimal occlusion balances factors like condylar path, incisal guidance, and cuspal angles. The articulator aims to replicate these concepts to guide reconstruction of the full mouth.
This document discusses occlusion in removable partial dentures. It outlines several types of occlusion including static and dynamic occlusion. Desirable occlusal contacts are bilateral contacts of posterior teeth in centric occlusion. Methods for establishing occlusion include direct apposition of casts if enough teeth remain, interocclusal records with posterior teeth, or using occlusal rims. The functionally generated path method can also be used to develop a dynamic occlusion record without an articulator. Proper occlusion is important for the success, comfort and longevity of removable partial dentures.
The document discusses various impression techniques used for dental implants. It describes the key components used, such as implant analogues and impression copings. The most common impression materials are vinyl polysiloxanes and polyether rubbers due to their dimensional stability and detail reproduction. Direct open tray techniques involve exposing the impression coping screws and incorporating the copings into the impression tray. Indirect closed tray techniques retain the copings in the mouth and reattach them to analogues in the lab. Factors like implant angulation, number of implants, and interarch space determine whether open or closed tray methods are preferred. Accurate transfer of the implant positions is crucial for passive fitting of the final prosthesis.
The document discusses various philosophies of design for removable partial dentures (RPDs). The three main philosophies discussed are:
1. Stress equalization - Which aims to distribute stresses equally among the supporting tissues to prevent weakening of structures. This can be achieved through the use of stress directors/equalizers.
2. Physiologic basing - Which involves using functional impression techniques to record tissues in their functional form and position teeth slightly above the occlusal plane to allow for vertical movement.
3. Broad stress distribution - Which aims to distribute forces broadly across hard and soft tissues through minimizing clasp retention and using tissue borne surfaces.
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 discusses various techniques and materials for taking impressions for fixed partial dentures. It describes the ideal properties of impressions and lists commonly used impression materials like hydrocolloids and elastomers. Techniques covered include custom tray, stock tray, closed bite double arch, copper band, and reversible hydrocolloid. An accurate impression is critical for indirect fabrication of prosthetics and involves selecting the appropriate technique and material based on the clinical situation.
Impressions for fixed partial dentures /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
00919248678078
This document discusses progressive bone loading for dental implants. It begins with an introduction and table of contents. Then it discusses concepts like bone density classifications, rationale for progressive loading based on studies showing bone adapts to stress over time. It outlines elements of progressive loading protocols including extended healing times based on bone density, use of provisional restorations to gradually load bone, and diet restrictions. Studies supporting progressive loading show less crestal bone loss and increased bone density around loaded implants. The conclusion is that progressive loading aims to strengthen bone and reduce risk of implant failure.
The temporomandibular joint (TMJ) is a bilateral joint that connects the mandible to the temporal bone. It has several unique characteristics, including being the only joint with a rigid endpoint of closure. The TMJ has bony, fibrous, and muscular components that allow for hinge, protrusive, and lateral movements. Prosthodontic treatments must consider the anatomy and biomechanics of the TMJ.
Occlusal equilibration is a procedure to precisely alter the occlusal surfaces of teeth to improve the contact pattern. It involves selectively grinding tooth structures that interfere with terminal hinge axis closure, lateral excursion, and protrusive movement. Common tools used include paste, spray or paint to identify contact points requiring adjustment. The basic rules of selective grinding include narrowing cusp tips before reshaping fossae, and adjusting the inclines of upper and lower teeth in opposing directions depending on the path of slide. Occlusal errors in complete dentures can be caused by incorrect registration of the retruded contact position or irregularities during setting and processing of the teeth.
The document discusses different types of laminate veneer preparations. Type I is called a window preparation with no incisal edge reduction. Type II, called a butt-joint preparation, involves 2 mm of incisal reduction without a palatal chamfer. Type III, or wrap-around preparation, includes 1-3 mm of incisal reduction with a 1 mm palatal chamfer to restrict angle fractures and enhance esthetics. The preparations are performed using round or tapered diamond burs to reduce enamel in a uniform and conservative manner confined to the facial surface of teeth.
This presentation provide brief information about different types of cements in Dentistry. also you will find information about cementation tips and techniques. Recent resin cements are also included in this presentation
Implant abutment and implant abutment connectionsDR.BHAVESH JHA
this ppt enlightened with different types of implant abutment connection. Detailed classification of abutments. Different types of abutments. Latest trends of abutments. Smart abutments. Platform switching, rationale of platform switching and related articles.
There are several protocols for loading dental implants after surgery based on bone density and healing time requirements. Protocols include Brånemark's loading protocol, progressive loading, and immediate/early loading. The density of the bone where the implant is placed determines the appropriate loading protocol, as less dense bone requires more healing time before loading to allow for sufficient bone mineralization and strength. Progressive loading gradually increases stress on the implant over time to allow the bone to adapt, reducing risks of failure. It is particularly important for lower density bone which is weaker.
Dental cements have evolved significantly since the first cements were introduced in the late 1800s. Zinc phosphate cement, introduced in the late 1800s, was one of the earliest dental cements and remains the gold standard against which newer cements are compared. In the 1960s, polycarboxylate cement was introduced and was the first cement system to provide an adhesive bond to tooth structure. Glass ionomer cement, introduced in the 1970s, also chemically bonds to tooth structure and was a significant development as it was the first cement with anticariogenic properties.
Impression materials and techniques in fpd /orthodontic courses by Indian den...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.for more details please visit
www.indiandentalacademy.com
The document discusses various techniques for making impressions for implant prostheses. It describes the materials needed and outlines implant level and abutment level impression methods, including open tray, closed tray, direct, and indirect techniques. Splinting multiple implants is recommended to improve accuracy. The importance of minimizing errors in impression making is discussed to ensure proper seating of components and interfaces between impressions posts and analogues. A literature review found that implant and abutment level impression techniques did not have significantly different effects on marginal discrepancy. Precise impressions are important to decrease prosthetic failures and ensure proper fit and function of dental implants.
Impression procedures for compromised ridges/cosmetic dentistry coursesIndian dental academy
The document discusses the history and techniques of impression making for compromised dental ridges. It begins with defining an impression and providing a brief history of impression materials from wax and gutta percha in the 1700s-1800s to alginate and silicones in the 1940s-1950s. It then describes various impression techniques such as open vs closed mouth, mucodisplasive, mucostatic, and selective pressure. Special impression procedures are discussed for minimally displacive, controlled pressure, functional, and external/denture space impressions. Border molding and principles of impression making like support, retention and stability are also summarized.
The document discusses immediate dentures, which are dentures fabricated and inserted immediately following tooth extraction. It describes the different types of immediate dentures, including conventional/classic immediate dentures, interim immediate dentures, labial flange dentures, partial flange dentures, and flangeless/socketed dentures. The advantages of immediate dentures include maintaining a patient's appearance without teeth, providing a bandage effect to extraction sites, and allowing easier adaptation to dentures during healing. However, immediate dentures also present challenges like reduced retention from undercuts caused by remaining posterior teeth.
An occlusal splint is a removable dental appliance that covers the biting surfaces of the teeth in one dental arch. There are several types of occlusal splints classified based on their design and intended use. The main types include permissive splints, non-permissive splints, and anterior repositioning splints. Occlusal splints are used to treat temporomandibular joint disorders by relaxing the jaw muscles, supporting the jaw in an optimal position, and reducing forces on the teeth and jaw joints.
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 discusses various treatment methods for temporomandibular disorders (TMDs). It separates treatments into definitive treatments, which aim to eliminate the underlying cause, and supportive therapies, which aim to manage symptoms. Definitive treatments include reversible occlusal appliances, irreversible occlusal therapies, relaxation techniques, and management of parafunctional habits. Supportive therapies include medications, physical therapies like ultrasound and manual techniques, and self-care methods. The document provides detailed descriptions and indications for different appliance types, including stabilization, anterior repositioning, and soft splints.
This document discusses the theoretical background and techniques of the Hobo full mouth rehabilitation approach. It defines key terms like condylar guidance, incisal guidance, and disocclusion. It explains that the goal of reorganizing occlusion is to address issues like trauma, poor function, or lack of space. The optimal occlusion balances factors like condylar path, incisal guidance, and cuspal angles. The articulator aims to replicate these concepts to guide reconstruction of the full mouth.
This document discusses occlusion in removable partial dentures. It outlines several types of occlusion including static and dynamic occlusion. Desirable occlusal contacts are bilateral contacts of posterior teeth in centric occlusion. Methods for establishing occlusion include direct apposition of casts if enough teeth remain, interocclusal records with posterior teeth, or using occlusal rims. The functionally generated path method can also be used to develop a dynamic occlusion record without an articulator. Proper occlusion is important for the success, comfort and longevity of removable partial dentures.
The document discusses various impression techniques used for dental implants. It describes the key components used, such as implant analogues and impression copings. The most common impression materials are vinyl polysiloxanes and polyether rubbers due to their dimensional stability and detail reproduction. Direct open tray techniques involve exposing the impression coping screws and incorporating the copings into the impression tray. Indirect closed tray techniques retain the copings in the mouth and reattach them to analogues in the lab. Factors like implant angulation, number of implants, and interarch space determine whether open or closed tray methods are preferred. Accurate transfer of the implant positions is crucial for passive fitting of the final prosthesis.
The document discusses various philosophies of design for removable partial dentures (RPDs). The three main philosophies discussed are:
1. Stress equalization - Which aims to distribute stresses equally among the supporting tissues to prevent weakening of structures. This can be achieved through the use of stress directors/equalizers.
2. Physiologic basing - Which involves using functional impression techniques to record tissues in their functional form and position teeth slightly above the occlusal plane to allow for vertical movement.
3. Broad stress distribution - Which aims to distribute forces broadly across hard and soft tissues through minimizing clasp retention and using tissue borne surfaces.
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 discusses various techniques and materials for taking impressions for fixed partial dentures. It describes the ideal properties of impressions and lists commonly used impression materials like hydrocolloids and elastomers. Techniques covered include custom tray, stock tray, closed bite double arch, copper band, and reversible hydrocolloid. An accurate impression is critical for indirect fabrication of prosthetics and involves selecting the appropriate technique and material based on the clinical situation.
Impressions for fixed partial dentures /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
00919248678078
Impressions in fixed partial dentures/certified fixed orthodontic courses by ...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
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.
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
Impression materials are used to make negative reproductions or imprints of teeth and surrounding structures. They are classified based on their rigidity, setting mechanism, viscosity, interaction with water, and chemical composition. Desirable qualities include accuracy, elasticity, and dimensional stability. Common impression materials include alginate (hydrocolloid), impression plaster, impression compound, zinc oxide eugenol paste, polysulfides, condensation silicones, addition silicones, polyethers, and light-cured polyethers. Tissue conditioners provide temporary soft lining for irritated denture-bearing tissues.
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 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 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.
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
This document discusses different types of retainers used for fixed partial dentures (FPDs). It describes various retainer options including full coverage crowns, partial coverage crowns, and conservative retainers. Full coverage crowns provide maximum retention but require extensive tooth preparation. Partial coverage crowns are more conservative but less retentive. Conservative retainers like resin-bonded FPDs require minimal preparation but do not accept heavy loads. The document outlines the characteristics, advantages, disadvantages, and indications for different retainer options.
This document discusses various types of polyether and polysulfide impression materials used in dentistry. It describes the components, properties, advantages, and disadvantages of each material. Polyether materials have high accuracy, flexibility, and elastic recovery. Polysulfide materials provide good dimensional stability but have an unpleasant odor and are difficult to remove from the mouth. Both materials are used to make impressions for procedures like fixed partial dentures and crowns.
This document discusses impression techniques and materials for dental implants. It notes that closed tray impressions may be less accurate for multi-unit cases, while open tray impressions may be more accurate but require custom trays due to angulations. Polyvinyl siloxane is recommended as it is very stable in multiple viscosities, while polyether and rubber-base materials are more toxic to bone. The document also discusses managing patient issues during impressions and what information to provide to the dental lab, such as implant level and abutment level impressions and necessary components.
Introduction to implant surface modificationsAli Alenezi
1. Dental implants are commonly used to replace lost teeth and rely on osseointegration, the strong fixation of implants within bone, for stability and long-term survival.
2. Implant surface modifications at the macro, micro, and nano levels aim to improve early implant stability and shorten healing time through changes in surface roughness, coatings, and increased surface area to enhance bone formation and growth.
3. Common modification techniques include acid etching, blasting, sol gel coating, and anodization which alter surface topography at different scales to promote higher success rates compared to smooth surfaced implants.
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
1. Elastomeric impression materials are synthetic rubber-based materials used for dental impressions that are classified into three main types: polysulfide, polyether, and silicone.
2. Polysulfide impressions have a long working time but also high permanent deformation. Polyether impressions have good detail reproduction and dimensional accuracy. Silicone impressions exist in condensation-cured and addition-cured varieties.
3. Impression materials are available in different viscosities like putty, heavy, medium, and light-bodied for use in various impression techniques like twin-mix, two-stage with spacer, or two-stage without spacer. Proper disinfection of impressions
The document discusses various impression techniques and theories in prosthodontics. It defines impression and lists the basic requirements for making impressions. Several impression techniques are described, including mucocompressive, mucostatic, selective pressure, and muco-seal techniques. Impression materials and considerations for special patient groups and clinical situations are also covered.
Classification and impression techniques of implants/ dentistry dental implantsIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting
training center with best faculty and flexible training programs
for dental professionals who wish to advance in their dental
practice,Offers certified courses in Dental
implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic
Dentistry, Periodontics and General Dentistry.
Techniques of dental impression making/ dental education in indiaIndian dental academy
Indian Dental Academy: will be one of the most relevant and exciting
training center with best faculty and flexible training programs
for dental professionals who wish to advance in their dental
practice,Offers certified courses in Dental
implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic
Dentistry, Periodontics and General Dentistry.
An introductory and simple guide assembled by dental students and reviewed by Dr. Hasannin Al-Namel. our seminar about impression trays used in prosthodontics
The presentation is a compilation of information regarding the requirements of impression materials and their properties which are especially used for FPD. the presentation also has a collection of articles which answer some basic clinically important questions. Part 1 deals with impression material, and part 2 deals with techniques
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
This document discusses denture base resins, including their history, composition, classifications, properties, and specifications. It notes that denture bases are commonly made from polymers like acrylic resins, which are chosen based on factors like availability, stability, and biocompatibility. The document outlines the various types of acrylic resins like heat-cured, self-cured, and light-cured and discusses how they have evolved over time from materials like vulcanite and wood. It also reviews the American Dental Association specifications for denture base resins and their ideal requirements.
This document discusses denture base resins used for fabricating denture prostheses. It provides a history of denture base materials, from natural materials used in the 1800s to the development of acrylic resins in the early 1900s. The ideal requirements, composition, classifications, properties, and ANSI/ADA specifications of denture base resins are examined. Various studies investigating the properties, color stability, strength and repair of different denture base materials are also summarized.
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Digital Removable Complete Denture—an Overview.pptxNishu Priya
There is a great responsibility for a dentist and a dental technologist to fabricate high-quality removable complete
dentures. Factors, such as a meticulous diagnosis and treatment planning, a personal communication between the
involved persons, and a profound knowledge of the clinical and technical possibilities, should lead to an easy, simple,
cost-effective, and highly satisfying denture fabrication workflow.
IMPRESSION TECHNIQUES IN COMPLETE DENTURE
CONTENTS
Introduction
History
Basic requirements of impression making
Objectives of impression making
Theories in impression making
Recording the preliminary impressions
Spacer designs & tissue stops
Recording the final impressions
Border molding
Wash impression
Conclusion
References
INTRODUCTION
The journey towards successful complete denture fabrication begins with making accurate impressions.
All subsequent steps that are necessary for complete denture fabrication will be greatly diminished if the denture base does not fit due to inadequate impression.
DEFINITION
IMPRESSION:
An imprint or negative likeness of the teeth, of the edentulous areas where the teeth have been removed, or of both, made in a plastic material that becomes relatively hard or set while in contact with these tissues.
WINKLER
COMPLETE DENTURE IMPRESSION:
A negative registration of the entire denture bearing, stabilizing, and border seal areas present in the edentulous mouth.
HEARTWELL
HISTORY
Before the middle of the 18th century, no method was available for producing an impression of the alveolar ridge.
Ridges were painted with a dye and a block of ivory or bone was pressed on the ridge.
Areas of contacts were scraped away from the block until the best fit of the prosthesis was achieved.
In 1711, Mathian Gottfried Purman recorded the use of wax.
In 1728, Pierre Fauchard made dentures by measuring mouth with compasses and cut the bone to approximate shape for the space to be filled.
In 1736, Phillip Pfaff of Germany made impressions in wax sections of half of the mouth at a time.
1782 -William Rae said that “he got the measurement of the jaws in a piece of wax pushed into the gum, afterwards making a cast of it with plaster of paris.
1840 - Charles De loude (london) made one of the earliest reference to impression trays .
1842- Montgomery discovered gutta percha.
It was introduced as an impression material in 1848 by Colburn.
1844-Wescott, Dwinelle and Dunning used plaster of paris as an impression material.
1862 Franklin described the first correct impression.
1874 Modeling plastics was developed by S. S. White
1900 Green brothers introduced a method for manipulating the modeling plastics.
First to use the term "posterior dam" in describing the posterior palatal seal.
1915 Rupert Hall perfected the first moderate-heat modeling plastic for making individual impression trays.
1925 Poller used agar for dental impressions.
1930s Ward and Kelly used ZOE for impressions.
1939 Trapozzano described one of the early techniques using Zinc oxide eugenol paste.
1936 Alginate-type materials patent awarded.
1940s Write and Denen were first to use alginate impression for corrective wash procedures
1942- Pendleton suggested a fluid wax technique using asiatic or india
The document discusses relining and rebasing of complete dentures. It defines relining as adding material to the denture's tissue side to improve fit, while rebasing replaces the entire denture base. Relining and rebasing are done to improve retention, restore vertical dimension, relieve pain from poor fit, and improve appearance. The document describes various techniques for clinical impressions and laboratory procedures for relining, including articulator, jig, and flask methods. It also discusses causes of denture fracture and repair methods.
Impression materials and techniques in fpd part 2Dr.Rohit Mistry
Part 2 of the presentation deals with impression techniques in FPD, it also deals with some atypical and new techniques of impression making. it also gives a basic on digital impression along with a brief history about inception of digital impresssion
Veneers /certified fixed orthodontic courses by Indian dental academy Indian dental academy
This document discusses dental veneers. It begins with an introduction to veneers, noting their increasing popularity for improving esthetics. It then reviews the literature on veneer techniques and materials. The document discusses the history of veneers and covers direct composite veneers applied chairside as well as indirect laboratory-fabricated veneers, particularly porcelain laminate veneers. It also addresses veneer preparation methods and debates the need for tooth structure removal versus no preparation.
Working cast and dies /certified fixed orthodontic courses by Indian dental a...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
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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: 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
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Prosthetic Dentistry, Periodontics and General Dentistry.
UNIQUE^J COST-EFFECTIVE AND RETENTIVE REMOVABLE PROSTHESIS.pptxMugilarasanMunisamy
This case report describes the rehabilitation of a Kennedy Class I partially edentulous maxilla with a custom attachment retained removable prosthesis. A 58-year-old male patient presented with multiple missing upper teeth. A customized attachment system using die pins and sleeves was used to retain a maxillary removable partial denture, improving retention over a conventional clasp-retained prosthesis. This provided an affordable, effective treatment that protected the periodontal health of the abutment teeth compared to alternative fixed or implant-supported options. Periodic recalls were recommended to maintain function and abutment health long-term.
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The document discusses different types of denture bases used in dentistry. Temporary denture bases include materials like autopolymerizing resins, shellac, thermoplastics, and wax. These provide rigidity, stability, and allow for setting teeth and recording jaw relationships. Permanent denture bases primarily use acrylic resin due to its strength, stability, and compatibility. The document outlines the history of denture materials from early natural materials to modern resins, and evaluates different temporary base materials and their advantages for uses like diagnostic trials.
Lingual orthodontics /certified fixed orthodontic courses by Indian dental ac...Indian dental academy
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Currently, complete dentures are mainly designed and fabricated using conventional methods, which involve a broad series of clinical and laboratory procedures.
Dentists may want to consider using an update of a unique complete denture technique that saves total chair time and, therefore, decreases cost.
It is possible to fabricate a complete denture with different techniques in minimal visit. These techniques has positive benefits saving a lot of time and materials for both the patient and the clinician.
This randomized clinical trial compared the effectiveness of Hawley retainers and vacuum formed retainers (VFRs) in retaining orthodontic treatment results over a 6-month period. 355 subjects were randomly assigned to receive either Hawley or VFR retainers, and study models were analyzed at debonding and 6 months. There were no significant differences between the retainers in retaining tooth rotations, widths, or overbite. However, the VFR group had significantly less relapse of incisor irregularity, particularly in the mandibular arch, compared to the Hawley group. This suggests that VFRs may be more effective than Hawleys in maintaining lower incisor alignment after orthodontic treatment.
Basic principles in impression making 3Prosth Ozone
This study evaluated the effects of impression material type, storage time, and filler proportion on the accuracy of elastometric impression materials. Ten impression materials were tested, including three alginates and five silicones. Impressions were made of metal dies and stone casts were poured at different time periods. Measurements found the addition silicones Aquasil and Exaflex had the greatest accuracy and stability over multiple pourings. The alginate CAVEX showed the least accuracy after 24 hours of storage. When the experimental silicone had a lower filler proportion, it resulted in significantly greater dimensional discrepancy compared to the same material with a higher filler proportion.
Similar to Impressions in fpd/ implant dentistry course (20)
Opportunity for Dentists (BDS/MDS )to relocate to United kingdom -Register as a DENTAL HYGIENIST/ DENTAL THERAPIST without Board exams and after approval you can register in GDC as a DH/DT and start working as a DH/DT Immediately and get paid.
You can complete the whole process in 3-4 months.Salary range for DH/DT is around 2500-3500 Pounds per month.
Eligibility / requirements-
1. An International English Language Testing System (IELTS) certificate
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3: A recent pass in a language test for registration with a regulatory authority in a country where the first language is English.
If you are interested Please contact us for more details.
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who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry,
Periodontics and General Dentistry.
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.
I –Aligners are made with FDA approved transparent thermoplastic materials using 3D scanning, 3D Printing and finally Trays with Pressure vacuum formers.
Dear Doctor,
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--
Indian Dental Academy
Leader in continuing dental education
www.indiandentalacademy.com
skype:indiandentalacademy
+919248678078
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
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
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...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.for more details please visit
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Diagnosis and treatment planning in completely endntulous arches/dental coursesIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
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Properties of Denture base materials /rotary endodontic coursesIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
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Use of modified tooth forms in complete denture occlusion / dental implant...Indian dental academy
This document discusses dental occlusion concepts and philosophies for complete dentures. It introduces key terms like physiologic occlusion and defines different occlusion schemes like balanced articulation and monoplane articulation. The document discusses advantages and disadvantages of using anatomic versus non-anatomic teeth for complete dentures. It also outlines requirements for maintaining denture stability, such as balanced occlusal contacts and control of horizontal forces. The goal of occlusion for complete dentures is to re-establish the homeostasis of the masticatory system disrupted by edentulism.
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offering a wide range of dental certified courses in different formats.for more details please visit
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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
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This document discusses dental casting investment materials. It describes the three main types of investments - gypsum bonded, phosphate bonded, and ethyl silicate bonded investments. For gypsum bonded investments specifically, it details their classification, composition including the roles of gypsum, silica, and modifiers, setting time, normal and hygroscopic setting expansion, and thermal expansion. It provides information on how the properties of gypsum bonded investments are affected by their composition. The document serves as a comprehensive overview of dental casting investment materials.
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
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
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
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
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 tissues and their replacements/ oral surgery courses
Impressions in fpd/ implant dentistry course
1. IMPRESSIONS IN FIXED
PARTIAL DENTURE
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
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2. Table of contents:
• Introduction
• Definitions
• History
• Review of literature
• Impression materials
• Tray selection and custom tray fabrication
• Impression techniques
• Summary
• Conclusion
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4. • An impression is an imprint or negative likeness
Well-fitting indirect restorations can only be made if
there are accurate models of the oral tissues available,
made from high quality impressions.
A good quality impression is only obtained when we
have a thorough knowledge of materials, their properties,
and techniques for their best manipulation.
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6. GPT - 8
• IMPRESSION:
• a negative likeness or copy in reverse of the surface of
an object;
• an imprint of the teeth and adjacent structures for use in
dentistry
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7. GPT - 8
• IMPRESSION MATERIAL :
any substance or combination of substances used for
making an impression or negative reproduction
• IMPRESSION TECHNIQUE :
a method and manner used in making a negative
likeness
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8. GPT - 8
IMPRESSION TRAY
• 1: a receptacle into which suitable impression material is
placed to make a negative likeness
• 2: a device that is used to carry, confine, and control
impression material while making an impression
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9. GPT - 8
• SECTIONAL IMPRESSION :
a negative likeness that is made in sections.
• TUBE IMPRESSION :
1: a cylinder used as a tray to confine and direct impression
material to make an impression of a single tooth.
2: the impression resulting from this procedure.
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10. • Elastomer – lightly crosslinked impressin mateial with
elastic properties
• Gelation – transformation from sol to gel
• Hydrocolloid – colloid that contains water as the
dispersion phase.
• Imbibition – absorption of water
• Synersis – fluid exuded when gel structures reconfigure
to achieve equilibrium through stress relaxation.
Phillips`s Science of dental materialswww.indiandentalacademy.com
11. • Thixotropic – the time-dependent pseudoplastic flow of
polymers that is characterized by the gradual decrease
of viscosity under a constant applied shear rate.
Phillips`s Science of dental materialswww.indiandentalacademy.com
13. • Philip Pfaff-1756
– First described taking impression with softened wax
• Christophe Francois Delabarre-1820
– Introduced the metal impression tray
• Chapin Haris-1853
– First used Plaster of Paris for making impressions.
• Charles Stent-1857
– Introduced the first impression compound
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14. • Sears-1937
– First used agar hydrocolloids for recording crown
impressions.
• United States-1945
– Introduced alginate during World War II.
• SL Pearson-1955
– Developed synthetic rubber base impression materials
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15. • Polysulfide- Late 1950’S
– First developed as an industrial sealant.
• Condensation Silicone- Early 1960’s
• Addition Silicone-1970’s
• Polyether- Late 1970’s
• Polyether Urethane Dimethacrylate - Late 1980’s
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17. • Hudson (1958) described the clinical use of rubber
impression materials
• a combination of light and heavier bodied materials may be
used in a disposable stock tray or a custom made acrylic resin
tray for making impressions for fixed partial dentures.
• The special syringe is used to inject the light bodied material
into the prepared cavities or about the crown preparation.
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18. Multiple abutment impressions using vacuum adapted temporary splints.
LaForgia A. J Prosthet Dent. 1965;Jan;15(1):44-50.
A LaForgia (1965)
described an impression technique using vacuum
adapted temporary splints
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19. • Irreversible hydrocolloid for fixd partial denture impressions. G. R. Zuckerman. J
prosthet Dent. 1974;32;657.
Zuckerman. (1974) described a dechnique of making
impression.
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20. Culbreath JC. (1975)
described A technique for making impressions for cast
restorations. It can be used for a single preparation or for
multiple preparations in a single arch. The most unique
feature of the technique is that the tray is formed over the
prepared teeth, either directly or indirectly.
An impression technique for cast restorations.
Culbreath JC. J Prosthet Dent. 1975 Apr;33(4):417-21.www.indiandentalacademy.com
21. Bonding properties and dimensional stability of hydrocolloid impression systems in
fixed prosthodontics.
Dahl BL, Dymbe B, Valderhaug J. J Prosthet Dent. 1985 Jun;53(6):796-800.
Dahl BL, Dymbe B, Valderhaug J.(1985)
Four hydrocolloid impression systems for fixed
prosthodontics and one conventional alginate were tested
for bonding properties between the syringe and the tray
materials of the systems. Their dimensional stability was
tested also after the impressions were kept in a humidor for
1, 3, and 24 hours before casts were poured.
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22. Findings showed that there was a true bond between the
syringe and the tray materials for all combinations. The
precision tests gave a mean percent difference between
the master model and the cast of less than 0.15 for all
material combinations at both the 1- and 3-hours
observations.
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23. Incidence of impression material found in the gingival sulcus after
impression procedure for fixed partial dentures.
Marshak BL, Cardash HS, Ben-Ur Z. J Prosthet Dent. 1987 Mar;57(3):306-8.
Marshak BL, Cardash HS, Ben-Ur Z. (1987)
After impression-making procedures, remnants of Xantopren
impression material were found in the gingival crevices in
eight of 125 patients. In three of the eight patients, remnants
were only discovered subsequent to a systematic exploration
with a fine curette.
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24. Although eight of 125 is not a statistically significant number,
it would be nonetheless prudent to consider a routine
curettage of abutment sulci after impression-making.
This procedure is even more strongly recommended when a
defect be detected in the crevicular region of the impression.
Impressions should remain in the mouth until full setting and
maximum tear strength is reached. Strict adherence to the
manufacturers' instructions is necessary.
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25. Accuracy of impression materials for complete-arch fixed partial dentures.
Lin CC, Ziebert GJ, Donegan SJ, Dhuru VB. J Prosthet Dent. 1988 Mar;59(3):288-91.
Lin CC, Ziebert GJ, Donegan SJ, Dhuru VB. (1988)
The accuracy of 12 impression materials of six different types
were studied by using complete-arch FPD impressions.
A one-piece casting was constructed by connecting the four
individual castings made for the four abutment teeth. The master
prosthesis was seated on the stone casts produced from the
impressions.
The marginal adaptation on the four abutments was then
evaluated with a travelling microscope. The individual marginal
adaptation of the four castings on the abutments was also
examined after sectioning the four joints.
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26. They concluded that
1. The polyethers produced the most accurate complete-
arch replicas. The second most accurate were the vinyl
polysiloxanes, followed by the polysulfides and the
irreversible-reversible hydrocolloids. The least accurate
were the reversible hydrocolloids and the irreversible
hydrocolloids.
2. The polyether impression materials exhibited the most
consistent accuracy for a master cast to fabricate a
complete-arch FPD.
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27. The effect of tray selection on the accuracy of elastomeric impression materials.
Gordon GE, Johnson GH, Drennon DG. J Prosthet Dent. 1990 Jan;63(1):12-5 .
Gordon GE, Johnson GH, Drennon DG. (1990)
study evaluated the accuracy of reproduction of stone casts
made from impressions using different tray and impression
materials. The tray materials used were an acrylic resin, a
thermoplastic, and a plastic.
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28. • The impression materials used were an additional
silicone, a polyether, and a polysulfide. Impressions
were made of a stainless steel master die that simulated
crown preparations for a fixed partial denture and an
acrylic resin model with cross-arch and anteroposterior
landmarks in stainless steel that typify clinical intra-arch
distances. Impressions were poured at 1 hour with a
type IV dental stone.
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29. Results indicated that custom-made trays of acrylic resin
and the thermoplastic material performed similarly
regarding die accuracy and produced clinically acceptable
casts. The stock plastic tray consistently produced casts
with greater dimensional change than the two custom
trays.
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30. A comparison of impression materials for complete-arch fixed partial dentures.
Dounis GS, Ziebert GJ, Dounis KS. J Prosthet Dent. 1991Feb;65(2):165-9.
Dounis GS, Ziebert GJ, Dounis KS (1991)
This study compared the marginal fit of complete-arch fixed
prostheses under simulated clinical conditions. Prostheses
were made on casts constructed from three commonly used
impression materials; polyether, polyvinyl siloxane (medium-
viscosity and putty-wash), and reversible hydrocolloid.
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31. they concluded that,
the polyether and both addition silicone impression
materials were significantly more accurate than the
reversible hydrocolloid in both situations. All of the single
castings were clinically acceptable, but the luted
restorations made from reversible hydrocolloids were not.
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32. Accuracy of one-step versus two-step putty wash addition silicone impression
technique. Hung SH, Purk JH, Tira DE, Eick JD. J Prosthet Dent. 1992 May;67(5):583-9.
Hung SH, Purk JH, Tira DE, Eick JD (1992)
study compared the accuracy of one-step putty wash with
two-step putty wash impression techniques. Five addition
silicone impression materials-Mirror 3 (MR), Mirror 3 Extrude
(ME), Express (E), Permagum (P), and Absolute(A)--were
tested.
Accuracy of the materials was assessed by measuring six
dimensions on stone dies poured from impressions of the
master model.
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33. They concluded that
• Accuracy of addition silicone impression material is
affected more by material than technique.
• Accuracy of the putty wash one-step impression
technique was not different from the putty wash two-step
impression technique except at one of the six
dimensions where one-step was more accurate than
two-step. Mirror 3 putty wash two-step impression
presented less distortion than Mirror 3 Extrude putty
wash one-step or two-step impression.
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34. Irreversible hydrocolloids for crown and bridge impressions: effect of different
treatments on compatibility of irreversible hydrocolloid impression material with type
IV gypsums.Eriksson A, Ockert-Eriksson G, Lockowandt P, Linden LA. Dent
Mater. 1996 Mar;12(2):74-82.
• Eriksson A, Ockert-Eriksson G, Lockowandt P,
Linden LA. (1996)
The aims of their research were:
1) to determine if the compatibility between irreversible
hydrocolloids (alginates) and type IV gypsums (die
stones) is affected by different treatments of the
impressions before pouring, and
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35. • The results showed that dentists and dental technicians
need to know how each specific irreversible hydrocolloid
should be treated and also with which type IV gypsum it
is compatible.
• This research also indicated that an irreversible
hydrocolloid impression should not come into contact
with any liquid within the first 15 min.
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36. • Lepe X, Johnson GH (1997)
• study evaluated the materials after simulating overnight
disinfection.
• They concluded that,
• Accuracy of both impression materials was adversely
affected with 18 hours of immersion disinfection.
• Long-term (18 hours) immersion disinfection will affect
the fit of fixed partial prostheses.
Accuracy of polyether and addition silicone after long-term immersion
disinfection. Lepe X, Johnson GH. J Prosthet Dent. 1997 Sep;78(3):245-9.www.indiandentalacademy.com
37. Accuracy of irreversible hydrocolloids (alginates) for fixed prosthodontics. A
comparison between irreversible hydrocolloid, reversible hydrocolloid, and addition
silicone for use in the syringe-tray technique. Eriksson A, Ockert-Eriksson G,
Lockowandt P. Eur J Oral Sci. 1998 Apr;106(2 Pt 1):651-60.
Eriksson A, et al (1998) The aim was to study their ability to
reproduce six differently shaped abutments of a full arch
stainless steel master model correctly, by measuring:
1) the accuracy of irreversible hydrocolloid impressions with
different storage periods of 15 min, 2 h, 24 h and 95 h,
reversible hydrocolloid stored 15 min and 2 h, and Type III
addition silicones stored 24 h when the syringe-tray technique
was used; and
2) whether mixing technique or tray design had any influence
of the accuracy of irreversible hydrocolloid impressions
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38. They concluded that,
• Storage time, mixing technique and tray design were of
significant importance for the irreversible hydrocolloids.
• Concerning the accuracy at the gingival margin, a shorter
storage time resulted in improved accuracy, and
• mechanical mixing without a vacuum and a tray designed
similar to a perforated stock tray gave most accurate
impressions.
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39. Impression materials and techniques for crown and bridgework: a survey of
undergraduate teaching in the UK. Randall RC, Wilson MA, Setcos JC, Wilson NH.
Eur J Prosthodont Restor Dent. 1998 Jun;6(2):75-8.
Randall RC et al (1998) The aim of this study was to
document the teaching of impression materials and
techniques for crown and bridgework in the undergraduate
curriculum in UK dental schools
Addition-cured silicones were found to predominate;
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40. 71% of schools taught and used clinically a one-stage, full
arch impression technique involving stock trays,
and 57% of schools a full-arch custom tray technique.
Routine disinfection of impressions was taught and
practised in 43% of schools
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41. Crown and bridge impressions--a comparison between the UK and a number
of other countries. Winstanley RB.
Eur J Prosthodont Restor Dent. 1999 Jun-Sep;7(2):61-4.
Winstanley RB. 1999
The quality of impressions for crown and bridge work in seven
countries were compared with the results found in the United
Kingdom in a previous study.
The results showed that metal impression trays were used
more frequently, and flexible plastic trays less frequently, in the
countries visited than in the United Kingdom.
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42. Accuracy of three polyvinyl siloxane putty-wash impression techniques.
Nissan J, Laufer BZ, Brosh T, Assif D. J Prosthet Dent. 2000 Feb;83(2):161-5.
Nissan J et al 2000. This study assessed the accuracy of 3 putty-
wash impression techniques using the same impression material
(polyvinyl siloxane) in a laboratory model.
The 3 putty-wash impression techniques used were
(1)1-step (putty and wash impression materials used
simultaneously);
(2) 2-step with 2-mm relief (putty first as a preliminary impression to
create 2-mm wash space with prefabricated copings. In the
second step, the wash stage was carried out); and
(3) 2-step technique with a polyethylene spacer (plastic spacer used
with the putty impression first and then the wash stage).
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43. • CONCLUSION.
• The polyvinyl siloxane 2-step, 2-mm, relief putty-wash
impression technique was the most accurate for
fabricating stone dies.
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44. • Influence on dimensional accuracy of volume of wash material introduced
into pre-spaced putty/wash impressions.
Omar R, Abdullah MA, Sherfudhin H.
Eur J Prosthodont Restor Dent. 2003 Dec;11(4):149-55.
Omar R et al (2003), This study compared the accuracy of stone
models obtained from two-stage, pre-spaced putty/wash impressions
under conditions in which known volumes of wash material were
introduced during the second stage of the impression:
Group I, a quantity of wash material corresponding to the space provided;
Group II, double the quantity of wash material as the space provided;
Group III, double the quantity of wash material, but with V-shaped vents in
the putty for escape of excess material.
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45. • Percentage deviations of the vertical dimensions of stone
dies with respect to the master model were significantly
different between Groups I and II (the latter being shorter)
• For horizontal dimensions, differences were less consistent,
although the deviations for Groups I and II and Groups II
and III, with respect to the master model, were significantly
different from each other for two of the three dimensions
measured (Group II inter-abutment distances were
generally larger)
• It was concluded that putty recoil, resulting from
compression by excess wash material, plays a significant
role in the undersizing of working dies, although the level of
clinical relevance is less clear.
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46. Alginate impressions for fixed prosthodontics. A 20 year follow up study.
Eriksson A, Ockert-Eriksson G, Eriksson O, Linden LA.
Swed Dent J. 2004;28(2):53-9.
The aim of this study was to estimate whether the survival
ratios after 20 years of fixed prosthodontics made of alginate
impressions was higher, equivalent or lower, compared to the
survival ratios, shown in studies, where different impression
materials were used.
Eriksson A, Ockert-Eriksson G, Eriksson O, Linden LA. (2004)
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47. Concluded that, fixed prosthodontics made according to the
syringe-tray alginate impression method may have the
same success rates after 20 years compared to that of
fixed prosthodontics presented in previous longitudinal
clinical studies where other impression materials
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48. • A clinical evaluation of fixed partial denture impressions.
Samet N, Shohat M, Livny A, Weiss EI.J Prosthet Dent. 2005 Aug;94(2):112-7.
Samet N, et al 2005 This study evaluated the quality of
impressions sent to commercial laboratories for the
fabrication of fixed partial dentures (FPD) by describing the
frequency of clinically detectable errors and by analyzing
correlations between the various factors involved.
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49. • The impression technique and material used, tray type, and
number of prepared units were recorded for each impression.
• Data relating to errors and faults, including defects in material
polymerization, retention to tray, tissue contact by tray, crucial
areas beyond tray borders, heavy-bodied material exposure
through the wash material (for double-step impressions),
inadequate union of materials, retraction cords embedded in
impressions, and air bubbles, voids, or tears along the margin
were also documented.
• And concluded that impressions made with polyethers had
the most detectable errors, followed by condensation-type
silicones.
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50. [Full arch impression techniques utilizing addition type poly vinyl siloxane for fabrication of
tooth born fixed partial dentures] Nissan J, Rosner O, Barnea E, Assif D.
Refuat Hapeh Vehashinayim. 2006 Jan;23(1):42-6, 71
• Nissan J et al 2006 This article presented several
impression techniques using PVS and recommends the
one that provides the most accurate impression, utilizing
the superior qualities of the PVS.
• The one step impression technique where no control of
wash bulk and thickness exists, is considered to be the
least accurate impression method with measured
discrepancies as large as 7 times the original inter
preparation distance and 40 times the original cross arch
dimensions.
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51. • Furthermore, the direct contact between the less refined
putty material and the tooth preparation, as well as the
high prevalence of air bubble entrapment, seriously
compromises restoration longevity.
• The two stage impression technique has proved to
produce the most accurate and reliable impressions due
to complete control of the wash bulk and thickness
entailed.
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52. • The ideal wash bulk thickness should range between 1 to
2.5 mm all around the abutment tooth in order to
minimize distortion of its subsequent die.
• The easiest and most clinically applicable method to
achieve the desired space around the preparations is by
loading the Putty material with the temporary crowns in
place, followed by their removal at the second stage and
occupation of the created space by the wash.
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60. History
• In 1925,Alphous Poller of Vienna was granted a British
patent for a totally different type of impression material.
• Later Poller's 'Negacoll’ was modified and introduced to
the dental profession as 'Dentacol’ in 1928.
• In 1937 by Sears introduced Agar was first into dentistry for
recording crown impressions
• and was the first elastic impression material available.
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61. • Example
– Slate Hydrocolloid (Van R)
– Cohere
– Superbody
– Super syringe
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62. Component Function Composition
Agar Brush – heap structure 13 – 17%
Borax Strength 0.2 – 0.5%
Potassium Sulfate Gypsum hardener 1.0 – 2.0%
Water Reaction 80%
Alkyl Benzoate Prevent growth of mold in
impression material during
storage.
0.1%
Color and Flavors Taste & appearance Trace
Composition
• Fillers; diatomaceous earth, clay, silica, wax, rubber, and similar inert
powders.
• Thymol and glycerin act as plasticizer and bactericide.www.indiandentalacademy.com
63. agar hydrocolloid (hot) agar hydrocolloid (cold)
(sol) (gel)
cool to 43 C
heat to 100 C
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65. • 3 chamber conditioning unit
(1) liquefy at 100°C for
10 minutes
• converts gel to sol
(2) store at 65°C
– place in tray
(3) temper at 46°C for 3 minutes
– seat tray
– cool with water at 20°C for 3
minutes
• converts sol to gelwww.indiandentalacademy.com
66. Advantages
• Accurate reproduction of surface detail
• Hydrophilic
– displace moisture, blood, fluids
• Inexpensive
– after initial equipment
• No custom tray or adhesives
• Pleasant
• No mixing required
Phillip’s Science of Dental Materials 1996
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67. Disadvantages
• Initial expense
– special equipment
• Material prepared in advance
• Thermal shock to the patient.
• Tears easily
• Dimensionally unstable
– immediate pour
– single cast
• Difficult to disinfect
Phillip’s Science of Dental Materials 1996
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69. Irreversible Hydrocolloid
(Alginate)
At the end of the last century, a chemist from Scotland
noticed that certain brown seaweed (algae) yielded a
peculiar mucous extraction. He named it algin.
This was later identified as a linear polymer with numerous
carboxyl acid groups and named anhydro-β-d-mannuronic
acid (also called alginic acid).
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70. • When the agar impression material became scarce
because of World war II (Japan was a prime source of
agar), research was accelerated to find a suitable
substitute. This result was present alginate impression
material.
• The general use of irreversible hydrocolloid far exceeds
that of other impression materials available.
• Because
– Easy to manipulate
– Comfortable for the patient
– Relatively inexpensive (no elaborate equipment)
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72. I. According to setting time.
• Fast set 1.25 – 2min
• Regular set 3 – 4.5 min
II. According to concentration of filler
• Soft set
• Hard set
Classification of alginateClassification of alginate
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75. Alginate in the form of sol
- containing the water but no source of calcium
ions - a reactor of Plaster of Paris
Modified alginatesModified alginates
Two component system (paste form)
- alginate sol
- calcium reactor
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76. – Alginates modified by the incorporation of
silicone polymers (paste form)
- fine detail reproduction
- tear resistance
- good dimension stability
Modified alginatesModified alginates
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77. • Dustless alginate glycerin incorporated to
agglomerate the particles.
• Making the powder more dense so that no dust is
formed when the lid is opened after tumbling.
Modified alginatesModified alginates
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78. NEWER ALGINATES
• Millenium algin
• manufactured by LASCOD
• MILLENIUM ALGIN is considered an alginate of new generation
• Maximum preciseness (15 µ)
• The formulation was optimized to reduce natural contraction with
water loss. The impression can be stored for many hours in a Long
Life Bag before casting the model without undergoing any
change for over 100 hours
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79. • No hand mixing. Eliminates mess and cleanup.
Saves time and material.
• Delivery options. Cartridge or Volume™ automix
dispensing.
• Impressions remain stable. You can pour
immediately or when it’s convenient. Impressions
retain dimensional stability for months.
NEWER ALGINATES
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81. Tray adhesive
sticky wax or methyl cellulose can be applied to the tray
(adhesive sprays are also available).
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82. Manipulation
• Fluff or aerate the powder by inverting the can several
times. This ensures uniform distribution of the filler
before mixing.
• Measured amounts of powder and water are taken as
specified by the manufacturer.
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83. Mixing is done in a clean flexible plastic bowl with a clean
wide bladed, reasonably stiff metal spatula.
• It is better to use separate bowls for plaster and alginate as
plaster contamination can accelerate setting.
Mixing technique
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84. • The mixing is started with a stirring motion to wet the
powder with water.
• Once the powder has been moistened, rapid spatulation
by swiping or stropping against the side of the bowl is
done.
• A vigorous figure-eight motion can also be used .
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89. • Reproduction of Tissue Detail
• ADA Sp. requires the material to reproduce a line that is
0.075 mm in width.
• Detail reproduction is lower when compared to agar
hydro-colloid.
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90. Dimensional Stability
• Set alginates have poor dimensional stability due to
evaporation, syneresis and imbibition. Therefore, cast
should be poured immediately.
• If storage is unavoidable, keeping in a humid
atmosphere of 100% relative humidity (humidor) results
in the least dimensional change.
Strength
Water: powder ratio
Overmixing and Insufficient spatulation
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91. Elasticity and Elastic Recovery
• Alginate hydrocolloids are highly elastic but less when
compared to agar and about 97.3% elastic recovery
occurs.
• Thus permanent deformation is more for Alginate (about
1.2%).
• Tear strength - varies from 350-700 gm/cm2
• Increased when the impression is removed with a snap
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92. • Compatibility with gypsum:
– Immersion of impression in a solution containing an accelerator for
the setting of the gypsum product, before pouring the impression
with the gypsum
– Incorporation of a plaster hardener or accelerator
• Accelerator increases the hardness of cast by
– Accelerating the set of gypsum to overcome the retarding action of
gel.
– may react with the gel to produce a surface layer that reduces or
prevents syneresis and eliminates the retarding action of the gel.
Hardening solutions: potassium sulfate, zinc sulfate,
manganese sulfate and potash alum
2% potassium sulfate is most effective.www.indiandentalacademy.com
93. • Pouring of stone mixture to fill the impression should
start from one end of the arch. After the impression has
been filled with stone, it may be placed in either a
humidor or a 2% potassium sulfate solution while the
stone hardens in an atmosphere of approximately 100%
relative humidity.
• Cast should be kept in contact with the impression,
preferably for 60 min or minimum 30 min.
• If the cast is allowed to remain in contact with the
hydrocolloid impression overnight, a chalky stone
surface may be produced.
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94. • Over Mixing Results In
• Reduction in final strength as the gel fibrils are broken.
• Reduction in working time.
• Under Mixing Results In
• Inadequate wetting, lack of homogeneity and reduced
strength.
• The mix being grainy and poor recording of detail.
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99. Diatomaceous earth
• DE, diatomite, diahydro, kieselguhr,
kieselgur and Celite
• is a naturally occurring, soft, chalk-like sedimentary rock
that is easily crumbled into a fine white to off-white
powder.
• This powder has an abrasive feel, similar to pumice
powder and is very light, due to its high porosity.
• The typical chemical composition is
– 86% silicon, 5% sodium, 3% magnesium and 2% iron.
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100. • Diatomaceous earth consists of fossilized remains of
diatoms, a type of hard-shelled algae.
• It is used as a filtration aid, as a mild abrasive, as a
mechanical insecticide, as an absorbent for liquids, as
cat litter, as an activator in blood clotting studies, and as
a component of dynamite.
• As it is also heat-resistant, it can be used as a thermal
insulator.
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101. Disinfection
• The current protocol for disinfecting hydrocolloid
impressions recommended by the
• Centers for Disease Control and Prevention is to use
household bleach (1-10 dilution), or synthetic phenols as
disinfectants.
• After the impression is thoroughly rinsed, the disinfectant
is sprayed liberally on the exposed surface.
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102. Advantages
• Inexpensive
• Easy to use
• Hydrophilic
– displace moisture, blood, fluids
• Stock trays
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103. Disadvantages
• Tears easily
• Dimensionally unstable
– immediate pour
– single cast
• Lower detail reproduction
– unacceptable for working cast of fixed prosthodontics
• High permanent deformation
• Difficult to disinfect
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105. • Synthetic rubbers
• mimic natural rubber (scarce during World War II)
• Initially called rubber impression materials
• Currently referred as elastomers or elastomeric
impression materials.
• ADA Specipication no. 19 identifies as “nonaqueous
elastomeric dental impression materials”
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107. Non-Aqueous Elastomers
• Viscosity classes
– low, medium, high, putty
– Monophase
Phillip’s Science of Dental Materials
Single phase or monophase – single component material
with sufficient shearing potential that it can be used as the
syringe material and the tray material.
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109. Polysulfide
• The first elastomer used for dental impressions
• Sometime referred to
– By the type of material, such as rubber base
impression material
– By the processing terminology, such as vulcanizing
impression material
– By chemistry, such as mercaptan impression material
or
– By the name of one of the first manufacturers, such
as the Thiokol Corporation.
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110. • Examples
– Permlastic (Kerr)
– Omni-Flex (GC America) – copper hydroxide system.
– Coe-flex (GC-Amer)
– Neo-plex (Miles)
Supplied as :
Paste in collapsible tubes as base and accelerator.
Base is white and accelerator is brown or grey.
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111. Composition
Phillip’s Science of Dental Materials
Base paste
Polysulphide
polymer
Lithopone and
titanium dioxide
filler strength
Di butyl phthalate plastisizer viscosity
Sulphur0.5% Enhance
the
reaction
Reactor paste
Lead dioxide Gives Dark
brown color
filler
plasticizer
Oleic acid or
stearic acid
Retarders Control rate
of setting
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112. • Available in 3 viscosities,
• light body and medium body heavy body.
• Tray adhesive:
• Butyl rubber or styrene/ acrylonitrile dissolved in
a volatile solvent such as chloroform or a ketone
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113. Reaction
lead dioxide reacts with the polysulfide polymer causing:
• Chain lengthening by oxidation of terminal – SH groups.
• Cross linking by oxidation of the pendant – SH groups.
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114. Modifications
• Reactor – lead dioxide replaced by organic hydroperoxide
e.g. t-butyl hydroperoxide.
– But this has poor dimensional stability because of volatility.
• Inorganic peroxides such as copper.
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115. Manipulation
• With the proper lengths of the two pastes squeezed onto
a mixing pad or glass slab,
• the catalyst paste is first collected on a stainless steel
spatula and then distributed over the base, and the
mixture is spread out over the mixing pad
• The mass is then scraped up with the spatula blade and
again smoothed out.
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116. • If sufficient force is applied and spatulation is performed
rapidly, the material will seem thinner and easier to
handle.
• This phenomenon is known as pseudoplasticity.
• Most accurate impressions are made using custom
acrylic trays because of uniform thickness of the
material.
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117. • Mean working time
– 6.0 min at 23 degree
– 4.3 min at 37 degree
• Mean setting time
– 16 min at 23 degree
– 12.5 min at 37 degree
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118. Accelerators of curing
• An increase in temperature
• A drop of water
Retarders of curing
• A decrease in temperature (chilled, dry glass slab)
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119. • Elasticity improves with time, so longer the impression
can remain in the mouth before removal, greater the
accuracy.
• Polysulfide ranks as one of the least stiff of the
elastomeric impression materials.
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120. • Unset material has high level of viscosity. This thick
consistency of the uncured material helps displace an
unwanted fluid present while seating the impression.
• Also, the excess material extruded from the tray does
not flow easily because of the high viscosity, reducing
the potential discomfort to the patient during seating of a
tray.
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121. Advantages Disadvantages
Long working time Requires a custom tray
Proven accuracy Must be poured in stone immediately
High tear resistance Potential for significant distortion
Less hydrophobic Odor offends patients
inexpensive to use Messy and stains clothes
Long shelf life Second pour is less accurate
Polysulfide
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124. Condensation reaction – a polymerization reaction in which
the polymer chains all grow simultaneously and a reaction
byproduct is formed.
CONDENSATION SILICONE
Also known as conventional silicone
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125. Available in 3 viscosities
– Light body
– Medium body
– Putty body
• Paste – two pastes in collapsible tubes
• Putty – jars
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127. Composition
Phillip’s 1996
Phillip’s Science of Dental Materials
Composition Components Function
Base paste
Hydroxyl terminated
polydimethyl siloxane
prepolymer
undergoes cross linking
to form rubber
Silica Filler
Reactor
Orthoethyl Silicate Cross linking agent
Stannous octate Catalyst
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128. The polymerization occurs as a result of cross linkage
between the orthoethyl silicate and the terminal hydroxy
group of the dimethyl siloxane, to form a three
dimensional network.
The reaction is exothermic ( 1deg C. rise)
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130. • Tear strength 3000gm/cm lower than polysulfide
• Hydrophobic – area should be dried. Avoid air bubbles
while pouring the cast
• It is stiffer and harder than polysulfide. The hardness
increases with time.
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131. • The spacing in the tray is increased to 3mm to
compensate for the stiffness.
• Can plated with silver/ copper. Silver plating is preferred.
• Shelf life is slightly less than polysulfides due to the
unstable nature of the orthoethyl silicates.
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132. Advantages
• Better elastic properties
• Clean, pleasant
• Stock tray
• putty-reline
• Good working and setting time
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133. Disadvantages
• Permanent deformation – high – 1-3%
• Poor dimensional stability
– high shrinkage
• polymerization
• evaporation of ethanol
– pour immediately
• within 30 minutes
• Hydrophobic
– poor wettability Phillip’s Science of Dental Materialswww.indiandentalacademy.com
140. • Improper balance between the vinyl siloxane and silane
siloxane contribute to the liberation of hydrogen gas
• To overcome this manufacturer adds palladium
(scavenger) or wait for an hour before pouring the
impression.
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141. • Setting time – 5-9 min
• Mixing time – 45 sec
• Best dimensional stability among elastomers.
• Curing shrinkage 0.17%
• Permanent deformation 0.05-0.3%
• Tear strength -3000gm/cm
• Extremely hydrophobic surfactant detergent
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142. • Electroplated with silver or copper.
• Low flexibility
• Harder than polysulfide – extra spacing 3 mm should be
provided in the impression tray.
• Care should be taken while removing the cast from the
impression to avoid any breakage.
• Shelf life ranges from 1-2 years
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143. Advantages
• Excellent reproduction of surface details
• Highly accurate
• High dimensional stability
– pour up to one week
• Stock or custom trays
• Multiple casts
• Easy to mix
• Pleasant odor
Phillip’s Science of Dental Materials
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144. Disadvantages
• Expensive
• Sulfur inhibits set
– latex gloves
– ferric and Al sulfate
retraction solution
• Short working time
• Lower tear strength
• Possible hydrogen gas release
– bubbles on die
– palladium added to absorb
– Moisture control – impression making
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145. Modifications in PVS
• Adding palladium scavenger to tie up any
hydrogen gas
• Less hydrophobic
• Smaller holding device, cartridges making
easier to use.
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146. Polyether
• First material introduced for dental impressions.
• Introduced in Germany in late 1960s.
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147. Available as
• base and accelerator in collapsible tubes.
• The accelerator tube is usually smaller.
• Earlier supplied in single viscosity.
• A third tube containing a thinner was provided.
• Available in 3 viscosities
– Light body
– Medium body
– Heavy body
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149. Composition
Base Paste
Imine terminated
prepolymer
Becomes cross linked
to form rubber
Silica Filler – to control viscosity
Glycol ether or Pthalate Plasticizer
Reactor
paste
Alkyl aromatic
sulfonate ester
Initiates cross linking
Silica Filler
Pthalate Plasticizer
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150. • Polyether based polymer that is cured by the reaction
between aziridie rings
• The main chain is a copolymer of ethylene oxide and
tetrahydrofuran.
• Cross linking and thus setting, is brought about by an
aromatic sulfonate ester.
• Is an exothermic reaction – 4-5deg C.
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151. • Elasticity – stiffest of impression materials
– New formulation of medium or regular body are less stiff
– When used in thinner sections decreases the stiffness.
• Impressions must be kept in cool, dry environment.
Properties
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152. • Sulfonic ester may cause skin reaction. To avoid this,
mix thoroughly before making an impression and direct
skin contact should be avoided.
• Setting time is around 8.3 min.
• mixing time - 30 sec.
• Heat increases the setting time.
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153. • Is extremely stiff – flexibility 3%
• Its hardness is higher than polysulfides and increases
with time. Removing it from undercuts is difficult, so extra
spacing 4mm should be given.
• Tear strength is good 3000gm/cm
• Hydrophilic – so moisture in the impression field is not so
critical. It has the best compatibility with stone.
• Can be electroplated with silver or copper.
• Shelf life > 2 years.
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154. Advantages
• Highly accurate
• Good dimensional stability
• Least hydrophobic
• Good surface detail
• Pour within one week
– kept dry
• Multiple casts
• Good wettability
• Good shelf life
Phillip’s Science of Dental Materials
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155. Disadvantages
• Expensive
• Short working time
• Rigid
– difficult to remove from undercuts
• Bitter taste
• Low tear strength
• Absorbs water
– changes dimension
– Leaches components
Phillip’s Science of Dental Materials
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156. Modifications
• Reducing the stiffness and producing polyether in low
and heavy viscosities have been the major changes.
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157. Comparison of Properties
• Working time
– longest to shortest
• agar > polysulfide > silicones > alginate = polyether
• Setting time
– shortest to longest
• alginate < polyether < agar < silicones < polysulfide
O’Brien Dental Materials & their Selection
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158. Comparison of Properties
• Stiffness
– most to least
• polyether > addition silicone > condensation silicone >
polysulfide = hydrocolloids
• Tear strength
– greatest to least
• polysulfide > addition silicone > polyether > condensation
silicone >> hydrocolloids
O’Brien Dental Materials & their Selection
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159. Comparison of Properties
• Cost
– lowest to highest
• alginate < agar = polysulfide <condensation silicone <
addition silicone < polyether
• Dimensional stability
– best to worst
• addition silicone > polyether > polysulfide > condensation
silicone > hydrocolloid
Phillip’s 1996
O’Brien Dental Materials & their Selection
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160. Comparison of Properties
• Wettability
– best to worst
• hydrocolloids > polyether > hydrophilic addition silicone >
polysulfide > hydrophobic addition silicone = condensation
silicone
• Castability
– best to worst
• hydrocolloids > hydrophilic addition silicone > polyether >
polysulfide > hydrophobic addition silicone = condensation
silicone
O’Brien Dental Materials & their Selection
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161. Removal of impression
• One method for determining the time of removal is
– to inject some of the syringe material into an interproximal space
that is not within the area of operation.
– Can prodded with a blunt instrument from time to time, and when
it is firm and returns completely to its original contour
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185. • The advantages of this combination system compared with
agar or alginate used individually is
• The minimization of equipment required to record an agar
impression (no water cooled tray is needed) and
• The fact that agar is more compatible with gypsum model
materials than alginate.
• It is also relatively cheap in comparison to many synthetic
elastomers.
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186. • Lin et al. demonstrated that the accuracy of this
combination system is better than either the reversible or
irreversible materials used separately and
• is comparable to that of polysulphide impression
materials.
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187. Vinyl polysiloxane addition silicone
Extrude xp (kerr) - putty impression material
Extrude (kerr) - extra heavy body impression
material
Extrude (kerr) – medium body impression
material
Extrude (kerr) - wash light body impression
material
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188. Condensation silicone
1. Xantopren(kulzer) Comfort - Regular body
Silicone Impression Material
2. Speedex (coltene)- light body silicone
impression material
3. Speedex (coltene) - putty silicone impression
material
4. Xantopren m mucosa (kulzer)- medium body
impression material
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189. Polyether impression material
• Impregum penta (3M/ESPE)— light viscosity
Polyether impression material
• Impregum Penta (3M/ESPE)— - Medium
viscosity Polyether Impression Material
• Impregum Penta (3M/ESPE)— —Heavy body
polyether impression material
• P2 Standard -- Regular set Monophase
polyether impression material
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192. SO3
-
+ R+
CH3 – CH – CH2 – CO2 – CH – (CH2)n – O – CH – (CH2)n – CO2 –CH2 – CH –CH3
N
H2C CH2
R R
m
N
H2C CH2
N
H2C CH2
R – N – CH2 – CH2 – +
N
H2C CH2
N
H2C CH2
R – +
+
Polyether Reaction
catalyst
base
ring opening
Phillip’s Science of Dental Materials 1996
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193. • These materials were developed to
overcome some of the disadvantages of
polysulfide materials, such as their
objectionable odor, the staining of linen
and uniforms by the lead dioxide, the
amount of effort required to mix the base
with the accelerator, the rather long setting
times, the moderately high shrinkage on
setting and the fairly high permanent
deformation.
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194. Thank you
For more details please visit
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