Polyvinyl siloxane (PVS), also called poly-vinyl siloxane, vinyl polysiloxane (VPS), or vinylpolysiloxane, is an addition-reaction
silicone
A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking ...
elastomer (an addition silicone). It is a viscous liquid that cures (solidifies) quickly into a rubber-like solid, taking the shape of whatever surface it was lying against while curing. As with two-part
epoxy
Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also coll ...
, its package keeps its two component liquids in separate tubes until the moment they are mixed and applied, because once mixed, they cure (harden) rapidly. Polyvinyl siloxane is widely used in
dentistry
Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions o ...
as an
impression material. It is also used in other contexts where an impression similar to a dental impression is needed, such as in
audiology
Audiology (from Latin , "to hear"; and from Greek , ''-logia'') is a branch of science that studies hearing, balance, and related disorders. Audiologists treat those with hearing loss and proactively prevent related damage. By employing various ...
(to take ear impressions for fitting custom hearing protection or hearing aids
) or in industrial applications (such as to aid in the inspection of interior features of machined parts, for example, internal grooves inside
bores). Polyvinyl siloxane was commercially introduced in the 1970s.
To create the material, the user simply mixes a colored putty (often blue or pink) with a white putty, and the chemical reaction begins. PVS with a wide variety of working and setting times is available commercially.
Final set is noted when the product rebounds upon touching with a blunt or sharp instrument.
This reaction also gives off
hydrogen gas
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, a ...
and it is therefore advisable to wait up to an hour before pouring the ensuing cast.
In dentistry, this material is commonly referred to as having light or heavy body depending on specific usage.
See also
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Dental impression
A dental impression is a negative imprint of hard (teeth) and soft tissues in the mouth from which a positive reproduction (cast or model) can be formed. It is made by placing an appropriate material in a stock or custom dental impression tray w ...
*
Dentures
Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable (removable partial denture or ...
References
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Dental materials
Polymers
Impression material