Written and maintained by CASRAI Editorial Board
Last updated
General product information only, not medical or clinical advice. Always follow the instructions for use (IFU) of the specific product.
Short answer
Polyvinyl siloxane (PVS), also called vinyl polysiloxane (VPS) or addition-curing silicone, is an elastomeric dental impression material that sets by an addition reaction. In the US it falls under FDA product code ELW, Class II, and the V-Posil IFU used as an example below cites DIN EN ISO 4823. What most affects supply and handling is what can interfere with its set, such as latex gloves and sulfur-containing products.
Definition and scope
21 CFR 872.3660 (checked 2026-10-31) describes an impression material as a device intended to be placed on a preformed impression tray and used to reproduce the structure of a patient’s teeth and gums, and to provide models for study and for production of restorative prosthetic devices. The regulation classifies the device as Class II (special controls) and names alginate and polysulfide as example materials; it does not name PVS, so PVS is covered by the generic device identification rather than by name. For the category as a whole, see dental impression material, which covers the CFR entry, product code ELW and ISO 4823. FDA’s use of standards is a separate topic, explained in FDA recognized consensus standards.
One manufacturer’s IFU, the VOCO V-Posil Vinyl Polysiloxane Impression Material (US/EN, last revised 03/2024, checked 2026-10-31), is used below as a worked example. It describes its products as “addition-curing, elastomeric materials with high hydrophilic properties, high tear strength, high dimensional accuracy and a high resistance to permanent deformation” and labels them DIN EN ISO 4823. Other manufacturers’ products can differ, so the IFU supplied with a given product is the controlling document.
How it is used in practice
According to the V-Posil IFU, the material comes in several viscosities and is used in named techniques, including one-step and two-step putty-wash impressions, reline impressions, and impressions for dentures and crown and bridgework. The IFU states that the putty and heavy-bodied materials are not suitable for detailed impressions when used alone. It also states that the warranted product characteristics can only be achieved with the supplied original mixing tips, and that material temperature should not deviate from 23 °C (74 °F) before application, otherwise working and setting times are affected. This page does not describe clinical technique; that belongs to the IFU and to training.
Types and related concepts
The table lists the viscosity grades and delivery formats named in the V-Posil IFU.
| Item | What the IFU says |
|---|---|
| Viscosities | Putty, heavy-bodied, medium-bodied, light-bodied, x-light-bodied |
| Automix delivery | Standard 1:1 (50 ml automix cartridges) and 5:1 (380 ml cartridges) for automatic dispensing and mixing machines |
| Hand-mix delivery | Traditional 1:1 putty jars (base and catalyst; lids and scoops must not be interchanged) |
| Putty and heavy-bodied grades | Preliminary or tray material; not suitable for detailed impressions when used alone |
| Light and x-light grades | Syringeable impression materials |
What interferes with setting: a sourced checklist
The V-Posil IFU lists several conditions that affect polymerization. Each item below comes from that IFU.
- Sulfur, aluminium chloride or nitrogen compounds. The IFU states that products containing these, for example retraction cords containing ferric sulfate and polysulfide impression materials, will interfere with the setting reaction.
- Latex gloves. The IFU says “Do not use latex gloves”, states that certain glove types such as latex can prevent polymerization, recommends vinyl gloves, and says gloves should be tested for compatibility with a sample of the material before mixing. This concerns glove contact with the material, not patient latex allergy. For a general approach to checking glove materials, see glove compatibility chart.
- Other impression chemistries. The IFU says not to use the product with condensation-curing silicones, polyether, Vinylsiloxanether or polysulfide materials.
- Temperature drift. Material temperature away from 23 °C changes working and setting times.
- Non-original mixing tips. Warranted characteristics are tied to the supplied original tips.
Where it matters for labs, clinics and supply decisions
A supply record for a PVS product can capture the fields the IFU itself specifies: viscosity grades, delivery format (1:1 or 5:1 cartridge, or jar), original mixing tips, storage condition, expiry date and the stated disinfection instructions. The V-Posil IFU says to store in a dry place at room temperature, away from sunlight and extreme temperature fluctuations, and not to use the product after its expiration date. For hand-mixed jar putty it says to use only materials with the same lot number.
The same IFU says impressions can be disinfected using, for example, only disinfection solutions specific for impression materials, and refers the reader to the manufacturer’s instructions. These details belong to this one product and are not a general rule for all PVS materials. The agency’s role in regulating the category is outlined under FDA (Food and Drug Administration).
Common misunderstandings
- “The CFR names PVS.” It does not; 21 CFR 872.3660 names alginate and polysulfide as examples. PVS is covered by the same device identification and product code ELW.
- “Any examination glove is fine.” The IFU names latex gloves as a problem for polymerization and recommends vinyl gloves, with a compatibility test.
- “All impression materials are interchangeable.” The IFU warns against combining its product with condensation-curing silicones, polyether and polysulfide.
FAQ
Is polyvinyl siloxane the same as vinyl polysiloxane or addition silicone?
The V-Posil IFU titles its product “Vinyl Polysiloxane Impression Material”, abbreviates it VPS and describes it as addition-curing. In that document the names refer to the same material type.
Can latex gloves be used with PVS?
The V-Posil IFU says not to use latex gloves, because certain glove types can prevent polymerization, and recommends vinyl gloves after a compatibility test.
How are PVS impressions disinfected?
The V-Posil IFU says to use disinfection solutions specific for impression materials and to follow the manufacturer’s instructions. Check the IFU of the product you use.
Is PVS regulated by FDA?
Impression materials are Class II devices under 21 CFR 872.3660, product code ELW. The regulation names alginate and polysulfide as examples, not PVS.
Sources
- eCFR, 21 CFR 872.3660, Impression material, checked 2026-10-31: https://www.ecfr.gov/current/title-21/chapter-I/subchapter-H/part-872/subpart-D/section-872.3660
- FDA product code ELW, “Material, Impression”, device class 2 (openFDA device classification data, checked 2026-10-31): https://api.fda.gov/device/classification.json?search=product_code:ELW
- VOCO V-Posil Vinyl Polysiloxane Impression Material, Instructions for Use (USA/EN), last revised 03/2024, checked 2026-10-31: https://www.voco.dental/it/portaldata/1/resources/products/instructions-for-use/e1/v-posil_ifu_e1.pdf. One manufacturer’s IFU, cited as a worked example.
- Category background on this site: dental impression material guide.
