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.
What is elastomeric impression?
Elastomeric impression materials are in common use. The impression material is inserted into the patient’s mouth in a viscous state and transforms into viscoelastic state, upon withdrawal, influencing the residual deformation. The requirements are minimal residual deformation or maximal elastic recovery.
How do you store elastomeric impression materials?
Despite the lack of standardization among the studies, this review supports the following recommendations to control the dimensional stability: impressions should be stored at temperatures between 21 +/- 2 degrees C; polyether impressions should be stored in an environment with a relative humidity below 50%; time until …
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 material is 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 hydrophilic impression material?
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 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 are elastomeric impression materials used for?
The elastic impression materials are most generally used for the making of impressions for removable partial dentures, immediate dentures, and crowns and fixed partial dentures when tooth and tissue undercuts and surface detail must be recorded with accuracy.
What are the different types of elastomeric materials?
Four common elastomers are cis-polyisoprene (natural rubber, NR), cis-polybutadiene (butadiene rubber, BR), styrene-butadiene rubber (SBR), and ethylene-propylene monomer (EPM).
How is the wettability of cure silicones changed?
In this way, it was shown that the wettability of the addition cure silicones could be strongly changed during setting when an internal surfactant was added to the material that migrates to the outermost solid–liquid interface.
What are the different types of impression materials?
Three types of impression materials are investigated in this paper: polyether materials, A-silicones (addition curing silicones) and C-silicones (condensation curing silicones).
What makes a good contact between tooth and impression material?
For a good contact between the impression material and the tooth just after the application of the paste two parameters are important: the viscosity (flow behaviour) of the impression material and the wettability of the moist tissue in the mouth by the impression material.