Permlastic is a polysulfide, condensation-cured, elastomeric impression material in three viscosities. Regular Permlastic is recommended for partial- or full denture impressions because it has a high degree of flow that will register the finest detail.
What is the composition of impressions?
Composition. The composition of impression compounds tends to vary from product to product and is usually a trade secret. They consist of a combination of resins and waxes, plasticizers and fillers, each having a specific function: Resins and waxes.
What are the 4 types of viscosities of elastomeric impression compounds?
The flow or viscosity of an impression material is dependent on the filler content. There are four basic categories: low (syringe or wash material), medium (one-step monophasic material), high (tray material), and very high (putty material). Viscosity is important when subgingival margins are to be captured.
What is the advantage of using a polysulfide material?
Polysulfides have a long working and setting time, which is an advantage when impressions are being taken of multiple preparations, but a disadvantage when only one or two teeth have been prepared.
Is polysulfide a bite registration material?
Polysulfides (PS) are also used for full-bite registrations in human dentistry. They are relatively inexpensive and make accurate impressions in a moist environment; however, the dimensional stability of PS is inferior to that of both AS and PE.
What are the 4 types of final impression materials?
The types of final impression materials commonly used in dental practice are polysulfide, polyether, condensation silicone, and addition silicone. Each type of material has different properties and characteristics.
What is the disadvantage of using a polysulfide material?
Polysulfides have a long working and setting time, which is an advantage when impressions are being taken of multiple preparations, but a disadvantage when only one or two teeth have been prepared. There is a slight contraction of polysulfide during polymerization.
What is the difference between polyether and polysulfide?
Polysulfide material is more sensitive to temperature change than the polyether material. 4. If the material is allowed to set longer, the percentage change in compression set decreases. For polyether, an increase in setting time of 2 minutes will significantly reduce the distortion of the impression upon removal.
What are the different types of elastomeric impression materials?
Four basic types of elastomer impression materials are currently in use in the dental profession: (1) silicone rubbers which polymerize by a condensation reaction, (2) polysulfide (mercaptan) rubbers, (3) polyethers, and (4) silicones which polymerize an addition reaction.
What is elastomeric impression material?
Elastomeric impression materials (addition silicones and polyethers) offer high elastic recovery and acceptable flexibility on removal of the impression from the mouth. Polyethers have excellent dimensional stability. They also have excellent wettability, resulting in minimal voids and excellent reproduction of detail.
What is polysulfide impression material?
Polysulfide Impression Material. Permlastic is a polysulfide, condensation-cured, elastomeric impression material in three viscosities. Regular Permlastic is recommended for partial- or full denture impressions because it has a high degree of flow that will register the finest detail. While usually used in single-mix,…
Can you use polysulfide impression for crowns?
– With proper handling, polysulfide impression materials can be used for inlays, crowns, and bridges. – However, they are not as accurate as other non aqueous elastomeric materials. – A polysulfide impression should be poured within several hours after mixing.
What is the difference between polysulfide and rubber?
– Often, polysulfide materials are called “rubber” or “rubber base” materials, even though polyether and silicone materials are also rubber materials. Polysulfide, polyether, and silicone materials are also called non aqueous elastomeric impression materials. – They all undergo cross-linking and chain lengthening polymerization reactions.
What is impression material in dentistry?
– Polysulfide impression material was the first non aqueous elastomeric “rubber” impression material developed for dentistry. – Often, polysulfide materials are called “rubber” or “rubber base” materials, even though polyether and silicone materials are also rubber materials.
