Is polyether is hydrophilic or hydrophobic?
Although VPS is generally considered hydrophobic,1,2 polyether is a hydrophilic material that can help produce accurate and void-free impressions and casts.
Is polyether impression material hydrophilic?
Polyether impression material is an elastic-type material, as are the polysulfide and silicone materials. The polyethers are also hydrophilic, which produces good wetability for easy cast forming.
Which impression materials are hydrophilic?
In contrast to addition silicone impression materials, polyether impression materials are hydrophilic, with a high affinity to surfaces such as tooth and soft tissue. Polyether materials have intrinsic hydrophilicity compared to the hydrophilicity produced by adding surfactants to the impression material.
What is polyether impression material?
Polyether impression materials are used for taking impressions when producing dental restorations. Hydrophilic to provide accurate impressions in moist conditions, polyether impression materials come in various viscosities from lightweight/soft to heavyweight and have varying set times.
Why should impression materials be hydrophilic?
When using polyvinyl siloxanes, moisture control is critical to ensure success for predictable clinical impression making. Because of their hydrophilic nature, using polyether and polysulfide impression materials is more compatible with the inherent moisture present in mucosal tissues .
Which impression material has the best wettability?
Polyetheric materials, A-silicones with added surfactants and C-silicones were found to have a good wettability. Alginate was found to be the most hydrophilic material, but this quality decreases in time.
Which impression material is the most hydrophobic?
Vinyl Polysiloxane Impression materials (VPS) are most frequently used as the impression material in fixed prosthodontics. As VPS is hydrophobic when it is poured with gypsum products, manufacturers added intrinsic surfactants and marketed as hydrophilic VPS.
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 is the difference between polyether and polyester?
Polyester foams are generally stronger than polyether foams. They are more rigid and exhibit higher tensile strength. Polyether foams are generally softer, offer good cushioning capabilities, and exhibit superior resistance to moisture than the polyester based foams.
What is polysulfide used for in dentistry?
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.
Which impression material has best dimensional stability?
Elastomers are the most commonly used impression material in dentistry [1]. Within this group, polyethers (PE) and addition silicones/vinyl polysiloxanes (VPS) exhibit excellent dimensional stability against distortion under various storage conditions [6].
What is the meaning of polyether?
: any of a group of polymers in which the repeating unit contains a carbon-oxygen bond derived especially from an aldehyde or an epoxide and which are used especially in the manufacture of plastic foams.
Is the set impression of polyethers dimensionally stable?
There are no by-products to this setting reaction and, as such, the material is dimensionally stable; however, since the materials will take up water, the set impression should be stored dry.
Why are silicone impression materials not hydrophilic?
Since it takes time for the surfactant to migrate, silicone impression materials are not actually hydrophilic upon initial contact with moisture in the oral cavity (e.g., when syringing or inserting the tray). Recent studies have focused on measuring the contact angle of the unset impression material.
What makes a polyether impression a copolymer?
Polyether impression material is manufactured as a copolymer of ethylene oxide and tetrahydrofuran to create a prepolymer chain with frequent oxygen atoms ( Fig. 5.1 ). Those two substances are very cheaply available industrial feedstocks.
Which is the only material that exhibits hydrophilic properties?
Many studies were conducted to get a thorough understanding of the hydrophilic properties of each material, and the mechanism utilized, such as surfactants in hydrophilic PVS. Polyether is the only material that is truly hydrophilic; it exhibits the lowest contact angle, during and after setting.