A number of theories have been put forward for impressions. each having its own advantage and disadvantage.
Different spacers guide and aid in in making the desired impression with adequate pressure in the desired region of the arch in maxilla and mandible. different materials are used for spacers depending on the need.
Theories, Principles & Objectives of impression Making Of Completely Edentul...Self employed
This document discusses the theories, principles and objectives of impression making for completely edentulous patients. It covers the history of complete dentures and various impression techniques including definitive pressure, minimal pressure and selective pressure impressions. The principles of impression making emphasize including all of the basal seat area, performing border molding, and applying selective pressure. The objectives are preservation of tissues, support, stability, esthetics and retention.
The document defines an articulator as a mechanical device that represents the temporomandibular joints and jaw members to attach dental casts and simulate jaw movements. Articulators are used to hold dental casts in a fixed relationship, simulate jaw movements like opening and closing, and reproduce border and intra-border tooth movements. They allow dentists to visualize occlusion, plan treatments, fabricate restorations, and arrange artificial teeth by simulating jaw movements without needing patient cooperation. Common components of articulators include upper and lower members to hold the casts, an incisal guide table, condylar guidance, and incisal pin to maintain relationships during jaw simulation. Articulators can be classified based on the occlusion theory they follow, the
This document discusses acid etching of dental surfaces. It describes how acid etching was first proposed in 1955 to increase bond strength between composite resin and enamel. Acid etching removes enamel and creates an irregular porous surface that allows resin to penetrate through micromechanical interlocking, improving bond strength. Factors like acid type/concentration, etching duration, and fluoride levels can affect bonding. While acid etching is effective, some alternatives under investigation include crystal growth solutions, air abrasion, and lasers, but they have not achieved bond strengths as high as acid etching.
theories of impression making in complete denturedipalmawani91
This document discusses theories and procedures for complete denture impressions. It begins with a brief history of denture impressions from the 18th century to present. The key theories discussed are muco-compressive (Greene brothers), muco-static (Page, Addison), and selective pressure (Boucher). The muco-compressive theory advocates recording tissues under functional pressure, while muco-static advocates minimal pressure to avoid tissue distortion. Selective pressure applies pressure only to stress-bearing areas. The document also covers biologic considerations, impression materials, border molding, classifications (open/closed mouth, by theory/technique), and principles of retention, stability, support and esthetics.
1. Classification of jaw relations establishes orientation, vertical, and horizontal relations between the jaws. Orientation defines cranial references, vertical defines jaw separation, and horizontal defines front-back and side-to-side jaw positions.
2. Centric relation is a repeatable reference position important for recording jaw relations and developing occlusion. It is the starting point for mandibular movements and where opposing teeth contact without proprioceptive guidance.
3. Methods for recording centric relation include interocclusal records, graphic tracings, and functional methods to position the mandible at the correct vertical dimension. The record must be made with equal pressure and avoid distortion until casts are mounted.
The document discusses different types of articulators used in dentistry based on various classification systems. It describes Bonwill's theory of condylar guidance which defines a triangle formed by the condylar contact points and incisal edge. It also outlines Sharry's four class classification of articulators based on their adjustability and ability to accept registrations. Key articulator types mentioned are non-adjustable, semi-adjustable, and fully-adjustable.
This document provides information on impression making for complete dentures. It begins with an introduction on impression making being an art that requires skill and knowledge of oral anatomy. It then covers the history, definitions, theories, objectives, related anatomy, materials and techniques for preliminary and final impressions. The key steps discussed are preliminary examination, selection of tray and material, making the preliminary impression, border molding, and making the final impression. The goals of impression making are to preserve ridges, provide support, retention, stability, and aesthetics.
Theories, Principles & Objectives of impression Making Of Completely Edentul...Self employed
This document discusses the theories, principles and objectives of impression making for completely edentulous patients. It covers the history of complete dentures and various impression techniques including definitive pressure, minimal pressure and selective pressure impressions. The principles of impression making emphasize including all of the basal seat area, performing border molding, and applying selective pressure. The objectives are preservation of tissues, support, stability, esthetics and retention.
The document defines an articulator as a mechanical device that represents the temporomandibular joints and jaw members to attach dental casts and simulate jaw movements. Articulators are used to hold dental casts in a fixed relationship, simulate jaw movements like opening and closing, and reproduce border and intra-border tooth movements. They allow dentists to visualize occlusion, plan treatments, fabricate restorations, and arrange artificial teeth by simulating jaw movements without needing patient cooperation. Common components of articulators include upper and lower members to hold the casts, an incisal guide table, condylar guidance, and incisal pin to maintain relationships during jaw simulation. Articulators can be classified based on the occlusion theory they follow, the
This document discusses acid etching of dental surfaces. It describes how acid etching was first proposed in 1955 to increase bond strength between composite resin and enamel. Acid etching removes enamel and creates an irregular porous surface that allows resin to penetrate through micromechanical interlocking, improving bond strength. Factors like acid type/concentration, etching duration, and fluoride levels can affect bonding. While acid etching is effective, some alternatives under investigation include crystal growth solutions, air abrasion, and lasers, but they have not achieved bond strengths as high as acid etching.
theories of impression making in complete denturedipalmawani91
This document discusses theories and procedures for complete denture impressions. It begins with a brief history of denture impressions from the 18th century to present. The key theories discussed are muco-compressive (Greene brothers), muco-static (Page, Addison), and selective pressure (Boucher). The muco-compressive theory advocates recording tissues under functional pressure, while muco-static advocates minimal pressure to avoid tissue distortion. Selective pressure applies pressure only to stress-bearing areas. The document also covers biologic considerations, impression materials, border molding, classifications (open/closed mouth, by theory/technique), and principles of retention, stability, support and esthetics.
1. Classification of jaw relations establishes orientation, vertical, and horizontal relations between the jaws. Orientation defines cranial references, vertical defines jaw separation, and horizontal defines front-back and side-to-side jaw positions.
2. Centric relation is a repeatable reference position important for recording jaw relations and developing occlusion. It is the starting point for mandibular movements and where opposing teeth contact without proprioceptive guidance.
3. Methods for recording centric relation include interocclusal records, graphic tracings, and functional methods to position the mandible at the correct vertical dimension. The record must be made with equal pressure and avoid distortion until casts are mounted.
The document discusses different types of articulators used in dentistry based on various classification systems. It describes Bonwill's theory of condylar guidance which defines a triangle formed by the condylar contact points and incisal edge. It also outlines Sharry's four class classification of articulators based on their adjustability and ability to accept registrations. Key articulator types mentioned are non-adjustable, semi-adjustable, and fully-adjustable.
This document provides information on impression making for complete dentures. It begins with an introduction on impression making being an art that requires skill and knowledge of oral anatomy. It then covers the history, definitions, theories, objectives, related anatomy, materials and techniques for preliminary and final impressions. The key steps discussed are preliminary examination, selection of tray and material, making the preliminary impression, border molding, and making the final impression. The goals of impression making are to preserve ridges, provide support, retention, stability, and aesthetics.
This document provides an overview of anatomical landmarks in the maxilla that are important for complete denture construction. It discusses intraoral landmarks like the labial and buccal frenums, as well as maxillary arch structures like the residual alveolar ridge, hard palate, palatal rugae, incisive papilla, hamular notch, maxillary tuberosity, and fovea palatinae that serve as stress bearing or relief areas. The document emphasizes understanding the histology and functions of these structures to ensure dentures are designed and placed to avoid placing undue pressure on supporting tissues.
Fundamentals in tooth preparation (conservative dentistry)Adwiti Vidushi
Tooth preparation involves altering a tooth to receive a restorative material and reestablish health. It has initial and final stages. The initial stage establishes an outline form and primary resistance and retention forms. The outline form removes weakened enamel and extends to sound margins. Primary resistance form uses a box shape to resist forces, while primary retention form uses converging walls for amalgam and bonding for composites. Convenience form provides access and ease of operation.
This document discusses articulators, which are mechanical devices used to simulate jaw movement. It begins by defining articulators and describing basic mandibular movements. It then discusses the basic components and classifications of articulators, including classifications based on adjustability and the location of condylar elements. Common articulators are described, including the Hanau articulator and mean value articulator. The relationship between the maxilla and mandible is transferred from patient to articulator using records like the facebow transfer and centric jaw relation record.
The document discusses the process of making record bases and occlusion rims, including defining them, listing materials used, and explaining the techniques for constructing autopolymerizing acrylic resin record bases and making occlusion rims out of baseplate wax to establish jaw relations and arrange teeth for denture fabrication. Record bases provide support for occlusion rims and are made using various materials like shellac, acrylic resin, or metal, while occlusion rims made of baseplate wax are used to arrange teeth and make jaw relation records.
The document provides an overview of denture base resins including their definition, history, classification, key ingredients, and properties. It discusses the early use of materials like ivory, bone, and porcelain for dentures and the later development of vulcanite in the 1840s as the first affordable and workable material. Polymethyl methacrylate (PMMA) was introduced in the 1930s and became the standard material by 1946, providing improved properties over previous materials. The document outlines the polymerization process and ideal requirements for denture base resins based on biocompatibility, durability, and other factors. Heat-cured PMMA denture base resin is currently the most widely used material.
This document provides information on alginate impression material. It defines alginate as an irreversible hydrocolloid impression material made from seaweed. It discusses the composition, setting reaction, and physical phases of alginate. The document also outlines the manipulation, application, advantages and disadvantages of alginate impression material.
The document provides an overview of elastomeric impression materials. It begins with an introduction and definitions of key terms like elastomer and elastomeric impression materials. It then discusses the history and classifications of impression materials. The document outlines the ideal requirements for impression materials and their clinical applications. It describes the properties and composition of various elastomers like polysulfide, condensation silicone, addition silicone, and polyether. It discusses recent advances in impression materials and effects of mishandling impressions. In conclusion, the document provides a comprehensive review of elastomeric impression materials.
The document discusses the role and development of dentine bonding agents. It describes the challenges of bonding to dentine due to its structure and composition compared to enamel. Various generations of bonding agents are classified, from early phosphoric acid-based systems to modern multi-step etch-and-rinse and self-etch adhesives. Conditioning of the dentine surface and the role of priming agents are explained. Factors affecting the bonding process such as smear layer removal and acid etching duration are also covered.
This document discusses the posterior palatal seal, including its definition, function, anatomical considerations, techniques for recording it, and potential errors. The key points are:
1. The posterior palatal seal provides retention, stability, and prevention of air leakage for maxillary dentures.
2. It is located along the junction of the hard and soft palate and extends from the pterygoid hamulus on either side.
3. Special techniques like using indelible pencil and having the patient say "AH" are used to identify and record the seal area during impression making.
Alginate is a commonly used impression material that is extracted from brown seaweed. It sets via a chemical reaction when its powder form is mixed with water. The powder contains soluble sodium alginate which reacts with calcium sulfate in the powder to form insoluble calcium alginate. Sodium phosphate is also included as a retarder to increase working time before the reaction occurs. Alginate has advantages of being easy to use, inexpensive, and comfortable for patients. However, it has disadvantages like poor dimensional stability, strength, and accuracy for complex impressions.
Jaw relations refer to the spatial relationship between the maxilla and mandible. There are several types of jaw relations including orientation, vertical, and horizontal relations. The vertical jaw relation is the distance between two selected points on the maxilla and mandible. It is important to accurately record the vertical jaw relation to establish proper esthetics, phonetics, and function. There are various methods for determining the vertical jaw relation including physiologic methods and using interocclusal records or prior dentures. Facebows are used to transfer the maxillomandibular spatial relationship to articulators.
This document discusses articulators, which are mechanical devices that simulate jaw movement. It covers the purposes, uses, requirements, advantages, limitations, and classifications of articulators. Articulators are used to mount dental casts and simulate jaw motions like opening and closing in order to diagnose occlusion, plan treatments, fabricate dental restorations, and arrange artificial teeth. They must accurately maintain the spatial relationship of dental casts and allow for various jaw motions and records. The document classifies articulators based on their function, the theories of occlusion they are based on, the records they can accept, and their degree of adjustability.
Glass ionomer cement is a tooth-colored dental restorative material introduced in 1972. It bonds chemically to tooth structure and releases fluoride for a long period. It sets via an acid-base reaction between glass powder and polyacrylic acid liquid. Glass ionomer cement has properties like adhesion to tooth structure, anticariogenic activity due to fluoride release, and biocompatibility. However, its strength and esthetics are inferior to dental composites. Modifications to glass ionomer cement include resin-modified and metal-modified varieties to improve strength. The sandwich technique combines the benefits of glass ionomer cement with those of composite resin.
This document provides information about dental waxes. It discusses the history and development of dental waxes, how they are classified, their composition, desirable properties, and types. It describes how dental waxes are used to make patterns for dental restorations and appliances. It covers the thermal properties of dental waxes and how they can distort if not handled properly. The document summarizes different types of dental waxes and their uses in dentistry.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
ANATOMICAL LANDMARKS OF EDENTULOUS MAXILLAAamir Godil
This document discusses the anatomical landmarks of the maxilla that are important for complete denture construction. It defines stress bearing areas, relief areas, and limiting areas. Stress bearing areas include the postero-lateral slopes of the hard palate, residual alveolar ridge, rugae, and maxillary tuberosity. Relief areas are the incisive papilla, mid-palatine raphae, zygomatic process, sharp spiny spicules, torus palatinus, and cuspid eminence. Limiting areas are the labial frenum, labial vestibule, buccal frenum, buccal vestibule, anterior and posterior vibrating lines,
Glass ionomer cement (GIC) was developed to combine properties of silicate and polycarboxylate cements. It sets via an acid-base reaction between fluoroaluminosilicate glass powder and polyacrylic acid liquid. The setting reaction forms a matrix of hydrated calcium and aluminum polysalts surrounding unreacted glass particles. GIC has advantages like aesthetics, fluoride release, and chemical bonding to tooth structure. However, its early formulations had limitations like opacity, discoloration over time, and moisture sensitivity during setting. Modifications to GIC include resin-modified, cermet, compomer, and giomer to improve properties while maintaining benefits like fluoride release.
A Clinical Review of Spacer Design for Conventional_124155.pptxDrIbadatJamil
One of the key factors affecting the outcome of the treatment is the impression procedure involved in the fabrication of complete denture prosthesis. Selective-pressure impression technique is most accepted. In this technique, by using custom trays with spacers of different materials and designs, vulnerable tissues are relieved and stresses are distributed selectively to biomechanically sound tissues. But the uses stock tray for making primary impression as well as final impression due to the lack of knowledge of the following: optimum material for making custom impression tray, adequate extension, required thickness and designs of spacer, tissue stops, escape holes, tray handles, and polymerization time regarding custom impression trays in prosthodontics. This seminar will give a clear view to use accurate spacer design, material and thickness, tissue stops, and escape holes, based on various clinical situations.
The document discusses complete denture impressions, which are negative registrations of the denture-bearing areas in the edentulous mouth. It describes the key anatomical landmarks and outlines the importance of complete denture impressions. The main types of impression techniques discussed are minimal-pressure, muco-compression, selective-pressure, and functional impressions. The document emphasizes the importance of border molding, tray selection and modification, and ensuring maximum tissue coverage and support while avoiding excessive pressure during impression-making.
This document provides an overview of anatomical landmarks in the maxilla that are important for complete denture construction. It discusses intraoral landmarks like the labial and buccal frenums, as well as maxillary arch structures like the residual alveolar ridge, hard palate, palatal rugae, incisive papilla, hamular notch, maxillary tuberosity, and fovea palatinae that serve as stress bearing or relief areas. The document emphasizes understanding the histology and functions of these structures to ensure dentures are designed and placed to avoid placing undue pressure on supporting tissues.
Fundamentals in tooth preparation (conservative dentistry)Adwiti Vidushi
Tooth preparation involves altering a tooth to receive a restorative material and reestablish health. It has initial and final stages. The initial stage establishes an outline form and primary resistance and retention forms. The outline form removes weakened enamel and extends to sound margins. Primary resistance form uses a box shape to resist forces, while primary retention form uses converging walls for amalgam and bonding for composites. Convenience form provides access and ease of operation.
This document discusses articulators, which are mechanical devices used to simulate jaw movement. It begins by defining articulators and describing basic mandibular movements. It then discusses the basic components and classifications of articulators, including classifications based on adjustability and the location of condylar elements. Common articulators are described, including the Hanau articulator and mean value articulator. The relationship between the maxilla and mandible is transferred from patient to articulator using records like the facebow transfer and centric jaw relation record.
The document discusses the process of making record bases and occlusion rims, including defining them, listing materials used, and explaining the techniques for constructing autopolymerizing acrylic resin record bases and making occlusion rims out of baseplate wax to establish jaw relations and arrange teeth for denture fabrication. Record bases provide support for occlusion rims and are made using various materials like shellac, acrylic resin, or metal, while occlusion rims made of baseplate wax are used to arrange teeth and make jaw relation records.
The document provides an overview of denture base resins including their definition, history, classification, key ingredients, and properties. It discusses the early use of materials like ivory, bone, and porcelain for dentures and the later development of vulcanite in the 1840s as the first affordable and workable material. Polymethyl methacrylate (PMMA) was introduced in the 1930s and became the standard material by 1946, providing improved properties over previous materials. The document outlines the polymerization process and ideal requirements for denture base resins based on biocompatibility, durability, and other factors. Heat-cured PMMA denture base resin is currently the most widely used material.
This document provides information on alginate impression material. It defines alginate as an irreversible hydrocolloid impression material made from seaweed. It discusses the composition, setting reaction, and physical phases of alginate. The document also outlines the manipulation, application, advantages and disadvantages of alginate impression material.
The document provides an overview of elastomeric impression materials. It begins with an introduction and definitions of key terms like elastomer and elastomeric impression materials. It then discusses the history and classifications of impression materials. The document outlines the ideal requirements for impression materials and their clinical applications. It describes the properties and composition of various elastomers like polysulfide, condensation silicone, addition silicone, and polyether. It discusses recent advances in impression materials and effects of mishandling impressions. In conclusion, the document provides a comprehensive review of elastomeric impression materials.
The document discusses the role and development of dentine bonding agents. It describes the challenges of bonding to dentine due to its structure and composition compared to enamel. Various generations of bonding agents are classified, from early phosphoric acid-based systems to modern multi-step etch-and-rinse and self-etch adhesives. Conditioning of the dentine surface and the role of priming agents are explained. Factors affecting the bonding process such as smear layer removal and acid etching duration are also covered.
This document discusses the posterior palatal seal, including its definition, function, anatomical considerations, techniques for recording it, and potential errors. The key points are:
1. The posterior palatal seal provides retention, stability, and prevention of air leakage for maxillary dentures.
2. It is located along the junction of the hard and soft palate and extends from the pterygoid hamulus on either side.
3. Special techniques like using indelible pencil and having the patient say "AH" are used to identify and record the seal area during impression making.
Alginate is a commonly used impression material that is extracted from brown seaweed. It sets via a chemical reaction when its powder form is mixed with water. The powder contains soluble sodium alginate which reacts with calcium sulfate in the powder to form insoluble calcium alginate. Sodium phosphate is also included as a retarder to increase working time before the reaction occurs. Alginate has advantages of being easy to use, inexpensive, and comfortable for patients. However, it has disadvantages like poor dimensional stability, strength, and accuracy for complex impressions.
Jaw relations refer to the spatial relationship between the maxilla and mandible. There are several types of jaw relations including orientation, vertical, and horizontal relations. The vertical jaw relation is the distance between two selected points on the maxilla and mandible. It is important to accurately record the vertical jaw relation to establish proper esthetics, phonetics, and function. There are various methods for determining the vertical jaw relation including physiologic methods and using interocclusal records or prior dentures. Facebows are used to transfer the maxillomandibular spatial relationship to articulators.
This document discusses articulators, which are mechanical devices that simulate jaw movement. It covers the purposes, uses, requirements, advantages, limitations, and classifications of articulators. Articulators are used to mount dental casts and simulate jaw motions like opening and closing in order to diagnose occlusion, plan treatments, fabricate dental restorations, and arrange artificial teeth. They must accurately maintain the spatial relationship of dental casts and allow for various jaw motions and records. The document classifies articulators based on their function, the theories of occlusion they are based on, the records they can accept, and their degree of adjustability.
Glass ionomer cement is a tooth-colored dental restorative material introduced in 1972. It bonds chemically to tooth structure and releases fluoride for a long period. It sets via an acid-base reaction between glass powder and polyacrylic acid liquid. Glass ionomer cement has properties like adhesion to tooth structure, anticariogenic activity due to fluoride release, and biocompatibility. However, its strength and esthetics are inferior to dental composites. Modifications to glass ionomer cement include resin-modified and metal-modified varieties to improve strength. The sandwich technique combines the benefits of glass ionomer cement with those of composite resin.
This document provides information about dental waxes. It discusses the history and development of dental waxes, how they are classified, their composition, desirable properties, and types. It describes how dental waxes are used to make patterns for dental restorations and appliances. It covers the thermal properties of dental waxes and how they can distort if not handled properly. The document summarizes different types of dental waxes and their uses in dentistry.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
ANATOMICAL LANDMARKS OF EDENTULOUS MAXILLAAamir Godil
This document discusses the anatomical landmarks of the maxilla that are important for complete denture construction. It defines stress bearing areas, relief areas, and limiting areas. Stress bearing areas include the postero-lateral slopes of the hard palate, residual alveolar ridge, rugae, and maxillary tuberosity. Relief areas are the incisive papilla, mid-palatine raphae, zygomatic process, sharp spiny spicules, torus palatinus, and cuspid eminence. Limiting areas are the labial frenum, labial vestibule, buccal frenum, buccal vestibule, anterior and posterior vibrating lines,
Glass ionomer cement (GIC) was developed to combine properties of silicate and polycarboxylate cements. It sets via an acid-base reaction between fluoroaluminosilicate glass powder and polyacrylic acid liquid. The setting reaction forms a matrix of hydrated calcium and aluminum polysalts surrounding unreacted glass particles. GIC has advantages like aesthetics, fluoride release, and chemical bonding to tooth structure. However, its early formulations had limitations like opacity, discoloration over time, and moisture sensitivity during setting. Modifications to GIC include resin-modified, cermet, compomer, and giomer to improve properties while maintaining benefits like fluoride release.
A Clinical Review of Spacer Design for Conventional_124155.pptxDrIbadatJamil
One of the key factors affecting the outcome of the treatment is the impression procedure involved in the fabrication of complete denture prosthesis. Selective-pressure impression technique is most accepted. In this technique, by using custom trays with spacers of different materials and designs, vulnerable tissues are relieved and stresses are distributed selectively to biomechanically sound tissues. But the uses stock tray for making primary impression as well as final impression due to the lack of knowledge of the following: optimum material for making custom impression tray, adequate extension, required thickness and designs of spacer, tissue stops, escape holes, tray handles, and polymerization time regarding custom impression trays in prosthodontics. This seminar will give a clear view to use accurate spacer design, material and thickness, tissue stops, and escape holes, based on various clinical situations.
The document discusses complete denture impressions, which are negative registrations of the denture-bearing areas in the edentulous mouth. It describes the key anatomical landmarks and outlines the importance of complete denture impressions. The main types of impression techniques discussed are minimal-pressure, muco-compression, selective-pressure, and functional impressions. The document emphasizes the importance of border molding, tray selection and modification, and ensuring maximum tissue coverage and support while avoiding excessive pressure during impression-making.
II. impression making for complete denture Amal Kaddah
This document provides an overview of maxillary and mandibular impression procedures. It discusses the objectives of making impressions, which include preservation of structures, retention, esthetics, stability, and support. It also covers topics like impression materials, custom tray fabrication, border molding, and different impression techniques such as open mouth, closed mouth, minimal pressure, and selective pressure approaches. The key objectives of impressions are to accurately record the denture bearing areas to ensure proper fit and function of the completed dentures.
secondary impression / final impression in complete denture.
#prosthodontics
#prostho
BDS 4th year
Nischala Chaulagain
Nobel Medical College , Biratnagar
This document provides instructions for making final impressions for complete dentures. It discusses:
- The objectives of final impressions including preservation of tissue and bone, support, stability, and retention
- Techniques such as selective pressure that record tissues at rest to avoid displacement
- Procedures for border molding custom trays and developing an accurate peripheral seal
- Taking final impressions with light-body material to achieve a mucostatic impression
This document provides instructions for making final impressions for complete dentures. It discusses:
- The objectives of final impressions including preservation of tissue and bone, support, stability, and retention.
- Techniques for recording tissues at rest to avoid displacement and damage, including selective pressure and border molding.
- Steps for making custom trays including design, tray materials, and border molding sequences.
- Considerations for final maxillary impressions including mobile tissues, tori, and seal areas.
- Selection and application of impression materials to achieve an accurate final impression.
This document provides instructions for making final impressions for complete dentures. It discusses the objectives of impressions which are preservation of tissue, support, stability, esthetics and retention. The techniques described are aimed at recording tissues in their resting position to avoid displacement. Border molding is used to establish contours and test peripheral seal. A selective pressure technique uses light material to achieve a mucostatic impression. Proper tray design and customization are emphasized.
Impression philosophies for completely edentulous patientsAmalKaddah1
The document discusses impression philosophies for fully edentulous patients. It covers the objectives, principles, and requirements of impression making including preservation of tissues, retention, esthetics, stability, and support. It describes the steps in making impressions including primary impressions, diagnostic casts, custom trays, and final impressions. Various impression materials and techniques are discussed such as minimal pressure, selective pressure, and functional mandibular impressions. Custom tray fabrication using wax spacers, acrylic resin, and border molding is also outlined.
This document discusses impression techniques for complete dentures. It begins by defining an impression and primary and secondary impressions. The objectives of a good impression are outlined as retention, support, stability, aesthetics, and tissue preservation. Key areas of support in the maxilla and mandible are described. Border molding techniques including hand and functional manipulation are explained. Standard and special impression trays are discussed. Common impression materials like impression compound, alginate, zinc oxide eugenol, and elastomers are described. Open and closed mouth impression techniques as well as various theories of impression making like mucostatic, pressure, selective pressure, and neutral zone techniques are summarized. Finally, common errors in maxillary and mandibular 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.
This document provides instructions for making final impressions for complete dentures, including custom tray fabrication, border molding techniques, and using selective pressure to record tissues in an undisplaced position. It describes areas that require special attention for the maxillary and mandibular impressions, such as the posterior palatal seal and retromylohyoid space. The goal is to make impressions that provide maximum coverage, close adaptation, and proper support and retention for the dentures.
This document provides information on different aspects of making complete denture impressions. It defines key terms like impression, preliminary impression, final impression, and impression materials. It discusses biologic considerations for maxillary and mandibular impressions, including important anatomical landmarks and supporting/limiting structures. The document outlines basic requirements and objectives of impression making. Impressions can be classified based on the impression theory used, technique, tray type, purpose, or material. Common impression techniques include pressure, minimal pressure, and selective pressure approaches.
This document provides instructions for making custom trays and record bases for edentulous patients. It describes how to make custom trays by outlining the borders, blocking undercuts, adapting acrylic resin, and finishing. Record bases are made by blocking undercuts, applying vaseline, adapting resin sheets, and trimming. Occlusion rims are fabricated by adapting wax to the record bases to approximate the shape and position of natural teeth, with dimensions provided. The document gives details on techniques, materials, and quality checks for custom trays and record bases.
This document provides information on final impressions. It defines a final impression as one made for the purpose of fabricating a prosthesis after initial registration. It discusses different types of impressions based on purpose and technique. The objectives of making an accurate impression are also outlined. The document then describes the process of making a final impression using custom trays, stock trays, or record bases. Details are provided on border molding, tray preparation, material selection, and making impressions for both maxillary and mandibular arches. Digital impression systems are also briefly discussed.
The final impression techniques aim to accurately record the supporting structures to construct a removable partial denture (RPD) that maximally distributes forces. There are two main techniques - the anatomic form impression records tissues at rest using stock or custom trays with alginate or rubber base. The physiologic form impression records tissues under load using selective pressure techniques. Key objectives are maximum ridge coverage, distributing forces over large areas, and relating supporting structures under function. Custom trays are made with wax spacers and stops to provide uniform impression material thickness. Impressions are inspected before pouring with stone plaster to produce a master cast for RPD framework construction.
This document provides information about making impressions for complete dentures. It discusses the objectives and requirements of an ideal impression, including maximum extension without muscle impingement and intimate contact with covered tissue areas. It describes primary, secondary/final, and corrective impressions. The types of impression materials and trays are outlined, including stock trays, special/individual trays, and techniques like border molding and boxing. The document also summarizes different techniques for making final impressions, such as minimal pressure, mucocompressive, and selective pressure techniques.
This document summarizes several theories of impression making for complete dentures, including the minimal pressure, mucocompressive, selective pressure, myostatic, and dynamic impression theories. It describes the key scientists and principles behind each theory, as well as the materials and techniques used. The document also discusses modifications to impression techniques for compromised situations like resorbed ridges or limited mouth opening. The overall goal of impression making is to construct a denture with maximum retention and stability without damaging supporting structures.
A custom made device prepared for a particular patient which is used to confine and control an impression material making an impression.
It makes on the cast obtained from primary impression.
It is used for making final impression.
Edentulous ridge shows variations in shape and size.
It shows the type of impression technique
1, Selective pressure technique
2, Minimal pressure technique
short presentation about impression techniques and theories which are use in dentistry...it will help to understand which technique is useful for different patients.
This document discusses various techniques for selective pressure impression techniques in complete dentures. It summarizes 7 different techniques proposed by various authors for the wax spacer design when making impressions for complete dentures using a custom tray. The techniques involve placing wax spacers in different areas of the palate and borders in order to achieve selective pressure during the impression.
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
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2. Impression theories
A number of theories have been put forward for
impressions. Each one having its own advantages and
disadvantages.
1. Mucostatic impresion theory
It was Introduced by Henry page and based on the
Pascal's law.
Impression is made using oversized impression trays
with spacer.
Border moulding is not performed and so flanges are
shorter than other techniques. The material of choice is
Impression Plaster.
Disadvantages are lack of maximum coverage of denture
bearing areas within physiologic limits, resulting in closely
adapting dentures causing lack of retention, unaesthetic
dentures, but due to close peripheral seal they are stable.
3. 2. Mucocompressive/pressure technique:
Proposed by Greene Brothers. In this the tissues
are recorded in functional state by compressing
the denture bearing areas.
Use of high viscosity impression materials,
impression compounds, irreversible
hydrocolloids, putty & heavy body elastomeric
impression materials is done.
Closed mouth technique also provides
mucocompressed impressions.
4. This technique was not promoted much as it will
lead to continuous pressure which will lead to
residual ridge resorption.
It will also compromise denture retention, as the
displaced tissue rebounds when in rest. So the
denture will dislodge at rest or while speaking.
The tissues are uniformly compressed so even
the areas which are supposed to be relieved are
under pressure, leading to good initial retention
but eventual resorption and loose dentures.
5. 3. Minimal pressure technique
It is a compromise between Mucocompressive
and Mucostatic Impression Technique.
In this technique minimal pressure is applied,
which is a little more than that of a free flowing
material.
The disadvantage is that there is a lack of
standardized protocol regarding the pressure to
be applied during the impression.
6. 4. Selective pressure technique
It was Proposed by Boucher in 1950. It
combines the principles of both Pressure and
minimal pressure techniques.
The pressure is applied minimally on the areas
which are capable of resisting stress (the stress
bearing areas). And reduced from the areas
which are incapable of bearing stress (the Relief
areas).
The spacer design for the selective pressure
technique is therefore directly governed by the
knowledge of the stress-bearing and relief areas.
7. For the maxilla the Primary Stress bearing area
is the horizontal slopes of the hard palate lateral
to the median suture and the Secondary Stress
Bearing areas are the Crest Of the Residual
Alveolar Ridge, Rugae, Maxillary Tuberosity.
While the Relief Arreas are: Midpalatine Suture,
Incisive Papilla and the Torus Palatinus.
8. While for the Mandible The Primary Stress
Bearing Area is the Buccal Shelf area and the
Secondary stress bearing area is the labial and
lingual slopes of the residual ridge.
The Relief areas are; Crest of the Residual
alveolar ridge, Mylohyoid Ridge, Mental Foramen,
Genial Tubercles, Torus Mandibularis.
9. Selective Pressure may be achieved by scrapping
the primary cast/impression in the selective areas or
by the fabrication of a custom/special tray with
proper spacer design with different materials &
designs and adequate extensions, tissue stops,
escape holes for relief.
The latter is a better method as it is more accurate
with the thickness of the spacer material(wax
spacer) we can achieve compression on tissues in
different areas(Stress Bearing Areas)
However views of different authors on how to
achieve selective-pressure impression are different.
10. THE CLASSIFICATION OF SPACER DESIGNS
1. FULL SPACERS: It is made to cover the
whole residual ridge except PPS area in
maxilla and buccal shelf and retromylohyoid
area in the mandible. Thus providing space
for impression material.
2. PARTIAL SPACERS: Based on clinical
needs. It is made to cover specific areas
only. Like the T shape and I Shaped Spacer.
3. SPACERS WITH TISSUE
STOPPERS: Tissue stoppers are made
bilaterally at the canine and the molar region
about 2mm in width. They aid in proper
vertical seating of the impression tray and
control the thickness of the impression
material.
11. MATERIALS USED FOR MAKING SPACERS:
1. Tin foil: As recommended by Roy Mac Gregory
in the region of incisive papilla and midpalatine
raphe
2. Casting wax: As recommended by Neil. In
thickness of 0.9 mm to be adapted all over
except PPS area.
3. Nonasbestos ring liner (wet): Used shellac is
used for custom tray fabrication
4. Base-plate wax: Used as a spacer mostly
when acrylic resin is used for custom tray
fabrication.
12. Thickness of the wax spacer
A Spacer for completely or partially edentulous
cases are generally 1-3mm thick. But the
thickness depends on the type of impression
material used for making secondary impressions
and the demand of the clinical situation. Like:
i) 2 mm spacer with tissue stops 0.5 mm spacer:
Used when Impression Plaster or Zinc Oxide
Eugenol is being used for making impression in
cases of non undercut ridges.
ii) 3 mm spacer with tissue stops: Used with
Alginate for Non undercut and undercut ridges.
13. iii) 1.5 mm spacer with tissue stops: Used with
Polysulphide elastomeric impression material for
undercut or non undercut ridges.
iv) 3mm spacer: Used with Silicones for
Undercut and non undercut ridges.
In cases of Different Clinical situations and
demands the spacer thickness and design
varies. Like for displaceable tissues.
14. TISSUE STOPS: They are to be placed tactically.
They provide even thickness of the impression
material in the custom tray.
Tissue stops are made by removing wax at a 45
degree angle to the occlusal surface which will
have a tripod or quadrangular arrangement on
the arch.
This provides stability to the tray and will help
position the tray accurately during insertion.
15. SPACER DESIGNS
BOUCHER:
According to him, the placement of a 1mm
thick baseplate wax within the outlined border
on the cast to provide space for the final
impression.
He also suggests not to cover the posterior
palatal Seal area with the spacer so that the
custom tray touches the mucosa directly and
the additional stress placed here during
impression making would create a posterior
palatal seal. Also it will act as a guiding stop
to help position the tray properly during
impression procedures.
16. In the mandible 1 mm thick base-plate wax
covers the mandibular ridge except buccal
shelf area and retromolar pad area.
He has also advocated the placement of
Escape holes in the palatal area using 6mm
round burs.
He says a wax spacer must not be used in
cases when metallic oxide impression paste
has been selected for making final
impressions.
17. MURROW, RUDD and RHOADS:
Based on the Minimal Pressure Technique. Mark
an outline on the cast where the borders are
usually shorter than the vestibular depth.
The posterior border is marked as a line
extending between the two hamular notches with
a midpoint 2mm distal to the fovea palatina.
The undercuts are then blocked with wax and a
layer of baseplate wax is adapted to the cast for
relief (2mm short of the resin custom tray
borders) With the placement of 3 tissue stops,
4mm equidistant from each other.
18. SHARRY:
It is also based on the Minimal Pressure
Technique and advocates the adaptation of a
layer of baseplate wax even on the PPS area
and giving 4 tissue stops in the molar and cuspid
regions 2mm in width running from the buccal to
the palatal aspect of the ridge to the
muccobuccal fold.
Also placing a vent hole in the incisive papilla
region. To be used while taking Final impressions
from metallic oxide impression materials
19. BERNARD:
On the Selective Pressure Technique, he
recommends placing a layer of pink baseplate
wax on the areas of soft tissue. And making the
spacer all around except on the posterior part of
the palate which are at high angles to the
occlusal forces and also not on the midpalatine
raphe which is usually relieved in other designs
but he says it acts as a stopper.
20. HALPERIN:
He recommended making a custom tray by
giving Peripheral relief by providing 1 mm thick
wax relief over the peripheral extensions and
buccal slope region of tray including PPS and
that the custom tray be in intimate contact with
basal seat areas.
Which makes the internal finish lines to form a
butt joint of the compound to the tray after border
molding is completed. No secondary wash
impression is needed. As the tray surface and
border-molded areas acts as final impression
surface itself. Thus a master cast is directly
poured into border moulded trays.
21. ROY MAC GREGOR:
Recommends placement of a sheet of metal
foil in the region of incisive papilla and
midpalatine raphe.
It is based on the selective pressure
technique.
He suggests that the other areas which must
be relieved are the maxillary rugae, other
areas which are subject to mucosal damage,
buccal surface and the prominent
tuberosities. But he also suggests that relief
need not be given regularly in the dentures.
23. HEARTWELL: Has recommended the use of two
techniques to achieve selective pressure for the
maxilla.
1. First he says to make a primary impression with
impression compound in a non perforated stock
tray; the borders are refined. Then, space is
provided in selected areas by scraping of the
impression compound.
2. Second technique, he recommends the fabrication
of a custom tray (but did not mention about the wax
spacer). Border molding is done with low fusing
compound. He recommends the placement of five
relief holes on the palatal region, three in the rugae
area and two in the glandular region, before
making the secondary impression with zinc oxide
24. 11. SHELDON:
Describes two techniques.
1. First involving the use of low-fusing modelling
compound (Kerr white cake compound) to make the
primary impression and borders are refined with Kerr
green stick compound. Once the operator is satisfied
with the retention, selective relief is accomplished by
scraping in the region of incisive papilla, rugae, and mid
palatine area.
2. The second technique, he describes of making a
primary impression with alginate. Undercuts are
blocked out. Then, he recommends the placement of
spacer or pressure control but he did not mention
clearly about the wax spacer design. Border molding is
done with green stick compound before making the
secondary impression with ZOE paste, based on
selective-pressure technique used on high arched
palate.
25. OTHER DESIGNS USED
1. Minimal-pressure technique for the maxillary
arch
Based on the minimal-pressure technique, a 1
mm base-plate wax is placed over the basal area
except on the right and left posterior hard palate.
Then four tissue stops, are made at the canine
and molar region. The material of choice is
rubber generally.
2. Selective-pressure technique for the
mandibular arch:
Based on the selective-pressure technique, a 1
mm thick base-plate wax is placed over the
entire alveolar ridge except at the retromolar pad
area. Tissue stops are placed, each at canine
region, bilaterally. Which will provide uniform
thickness of the impression material. The
26. 3. Partial spacers are given as they cover specific
areas:
A) T Shape Spacer: It is based on the
Selective Pressure Technique. It covers the
anterior residual alveolar ridge in the maxilla
when it is flabby and resorbed. It also covers
the prominent incisive papilla, rugae and
midpalatine raphe, and the exposed areas act
as stoppers.
Partial spacer designs in the mandible cover
only the anterior residual alveolar ridge when
it is resorbed, flabby or atrophied
27. B) I Shape Spacer: it is based on the Selective
Pressure Technique. In the Maxillary Arch it
covers the Midpalatine Raphe and Incisive
Papilla.
28. CONTRAINDICATIONS FOR USING SPACER
In case of highly resorbed ridges, spacer is not
used as a solid tray is easier to manage.
In such cases, only a carbide bur can be used to
remove about 0.5mm to 1 mm of the custom tray
material from the crest of ridge area.
29. CONCLUSION
While making impressions, one should apply
pressure selectively in certain areas, which are
capable of withstanding the masticatory forces.
Custom Trays with escape holes for selective
pressure of the edentulous ridges, regardless of
the type of impression material used results in
the appropriate distribution of pressure so that
the impression force is decreased and the bite
pressure is transferred directly to the stress
bearing areas which prevents the soft tissue from
getting subjected to uneven force and bone
resorbtion.
From all of the above we conclude that different
types of spacer designs are available for different
clinical situations. Based on the type of case
demand, the dentist needs to select his spacer
30. REFERENCES
Jain AR, Dhanraj M. A clinical review of spacer
design for conventional complete denture.
Biology and Medicine. 2016;8(5):1.
Aeran H. Different spacer designs in complete
denture prosthodontics. Guident. 2019 Nov
1;12(12).