Dental Care for All Ages (PDF)

 Elastomer Impression Material Non-Aqueous A type of polymer that Substances used in Impression materials exhibits rubber-like dentistry to create a properties, able to that do not rely on undergo significant...

 Elastomer Impression Material Non-Aqueous A type of polymer that Substances used in Impression materials exhibits rubber-like dentistry to create a properties, able to that do not rely on undergo significant negative replica of oral water as a base deformation before structures (teeth, gingiva) returning to its original component. for prosthodontic or shape. restorative purposes. Elastomer Impression Non-Aqueous Material  Polymerization Hydrophobic Cross-linking -Chemical reaction Tendency to Joining of polymer that transforms small demonstrate an chains to form a aversion to water. three-dimensional molecules into large polymer chains. network structure. Polymerization Hydrophobic Cross-linking  Base Paste Catalyst Paste Working Time —component of a —The total time from —The component that polymerization reaction the start of mixing to forms the main three- that decreases the energy the final time at which dimensional structure required for the reaction to occur and usually does not an impression tray of the final impression can be fully seated become part of the final product without distortion. Condensation Reaction Addition Reaction - is a chemical reaction in a chemical reaction which two molecules where two or more combine to form a larger molecule, with the release molecules combine to of a small molecule as a form a single, larger byproduct, typically water molecule without the (H₂O) or sometimes loss of any atoms or methanol (CH₃OH). byproducts.  Non-aqueous elastomeric materials are synthetic rubber-based dental impression materials that do not rely on water. They include types such as polysulfides, polyethers, and vinyl polysiloxane (VPS). These materials are known for their excellent elasticity, dimensional stability, and tear strength, making them ideal for capturing precise dental impressions used in restorative procedures like crowns and bridges. Unlike aqueous materials like alginate, non-aqueous elastomers maintain their shape and detail over time and can handle complex undercuts and intricate anatomical features, ensuring accurate dental restorations.  BACKGROUND ON DEVELOPMENT OF ELASTOMERS INITIALLY, INELASTIC MATERIALS WERE USED FOR MAKING IMPRESSIONS OF BOTH SOFT AND HARD TISSUES. HOWEVER, THE INTRODUCTION OF HYDROCOLLOIDS MARKED A SIGNIFICANT ADVANCEMENT, ALLOWING FOR BETTER IMPRESSIONS OF HARD TISSUES.  BACKGROUND ON DEVELOPMENT OF ELASTOMERS FOLLOWED BY THE INTRODUCTION OF POLYETHER IMPRESSIONS 1965 AND ADDITION SILICONES IN 1975. RECENT ADVANCES HAVE FOCUSED ON IMPROVING THE PROPERTIES OF THESE MATERIALS, SUCH AS THEIR ACCURACY, ELASTIC RECOVERY, DIMENSIONAL STABILITY, AND PATIENT COMFORT. MODERN ELASTOMERS LIKE POLYVINYL SILOXANE COMBINE THE BEST FEATURES OF POLYETHER AND VINYL SILOXANE, OFFERING SUPERIOR PERFORMANCE IN VARIOUS DENTAL APPLICATIONS OVERVIEW OF ELASTOMERIC IMPRESSION MATERIALS Polysulfides  Polysulfid e which when are elastomers that consist of a base and a catalyst, mixed, form a rubbery material. OVERVIEW OF ELASTOMERIC IMPRESSION MATERIALS Polysulfides Condensation silicones  CondeNsation silicones are elastomers that set through a condensation reaction, releasing alcohol as a by-product. They are known for their good detail reproduction and shorter working time.  OVERVIEW OF ELASTOMERIC IMPRESSION MATERIALS Polysulfides Condensation silicones Addition Silicones (Polyvinyl Siloxanes)  Addition Silicones (Polyvinyl Siloxanes) elastomer that sets through an addition reaction without releasing any by-products. It is highly accurate and dimensionally stable. OVERVIEW OF ELASTOMERIC IMPRESSION MATERIALS Polysulfides Condensation silicones Addition Silicones (Polyvinyl Siloxanes) Polyethers  Polyethers are elastomers that are hydrophilic, meaning they can absorb water, which makes them suitable for moist environments.  POLYSULFIDE IMPRESSION MATERIAL INTRODUCED IN THE 1960S, POLYETHERS HAVE HIGH DIMENSIONAL ACCURACY AND ARE HYDROPHILIC, MAKING THEM EFFECTIVE IN MOIST ENVIRONMENTS. Advantages: Hydrophilicity allows for good detail capture in moist areas. High rigidity provides excellent accuracy. Disadvantages: Stiffness can make removal difficult and uncomfortable. Expensive compared to other materials.  CONDENSATION SILICONE IMPRESSION MATERIAL DEVELOPED TO IMPROVE UPON POLYSULFIDES WITH FASTER SETTING TIMES. Advantages: Good elasticity, fast setting, and decent accuracy. Disadvantages: Susceptible to shrinkage due to the release of by-products (ethyl alcohol), which can distort the final impression if not poured immediately.  ADDITION REACTION SILICONE (VINYL POLYSILOXANE) ADVANTAGES: OUTSTANDING DIMENSIONAL STABILITY, FAST SETTING, AND MINIMAL SHRINKAGE DUE TO NO BY-PRODUCTS BEING RELEASED. DISADVANTAGES: HYDROPHOBIC NATURE CAN MAKE IT DIFFICULT TO CAPTURE DETAIL IN A WET ENVIRONMENT UNLESS SURFACTANTS ARE ADDED.  POLYETHER IMPRESSION MATERIAL INTRODUCED IN THE 1960S, POLYETHERS HAVE HIGH DIMENSIONAL ACCURACY AND ARE HYDROPHILIC, MAKING THEM EFFECTIVE IN MOIST ENVIRONMENTS. Advantages: Hydrophilicity allows for good detail capture in moist areas. High rigidity provides excellent accuracy. Disadvantages: Stiffness can make removal difficult and uncomfortable. Expensive compared to other materials.  TECHNIQUES FOR MEASURING PROPERTIES  TECHNIQUES FOR MEASURING PROPERTIES The properties of elastomeric materials, such as dimensional stability, tear strength, and flexibility, are measured through:  TECHNIQUES FOR MEASURING PROPERTIES Dimensional stability tests: Assess changes in material dimensions over time.  TECHNIQUES FOR MEASURING PROPERTIES Tear strength tests: Measure the resistance to tearing during impression removal.  TECHNIQUES FOR MEASURING PROPERTIES Flow tests: Evaluate how well the material flows under stress, capturing intricate details.  NEW ADVANCES IN IMPRESSION MATERIALS  NEW ADVANCES IN IMPRESSION MATERIALS Using intraoral scanners have transformed how dentists capture detailed impressions. These scanners eliminate the need for physical impression materials, offering faster and more accurate results.  NEW ADVANCES IN IMPRESSION MATERIALS Newer versions have enhanced hydrophilicity, allowing them to capture more precise impressions in moist environments, such as the oral cavity.  NEW ADVANCES IN IMPRESSION MATERIALS FAST-SETTING POLYETHER MATERIAL. Polyether materials, traditionally known for their accuracy, have often been slower to set than other options. However, newer formulations have shortened setting times without sacrificing accuracy.  NEW ADVANCES IN IMPRESSION MATERIALS ANTIBATERIAL AND DIOCOMPATIBLE ADDITIVES Some impression materials are now infused with antibacterial agents, reducing the risk of contamination during the impression-taking process.  NEW ADVANCES IN IMPRESSION MATERIALS HYBRID MATERIALS Hybrid impression materials aim to provide enhanced accuracy, ease of handling, and better mechanical properties. EFFECT OF HANDLING  EFFECT OF MISHANDLING Improper handling of elastomeric impression materials can lead to various issues: Thank you very much!