Polyvinyl siloxane (PVS), also called poly-vinyl siloxane, vinyl polysiloxane (VPS), or vinyl polysiloxane, is an addition-reaction silicone 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, 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 as an impression material. Buy Now VPS Impression Material.