Hydrophilic poly(vinyl siloxane) impression materials: dimensional accuracy, wettability, and effect on gypsum hardness.

Three hydrophilic poly(vinyl siloxane) impression materials, containing an intrinsic surfactant, were compared with a hydrophobic poly(vinyl siloxane) and a polyether impression material. The hydrophobic poly(vinyl siloxane) material was dimensionally more accurate than the hydrophilic poly(vinyl siloxane) in two of three measured dimensions, but the difference was small. The polyether material was the most wettable, and the hydrophilic poly(vinyl siloxane) were more wettable than the hydrophobic poly(vinyl siloxane). However, when a topical surfactant was used, no difference in wettability was noted between the hydrophilic and hydrophobic poly(vinyl siloxane), and their wettability was comparable to the polyether material, indicating that the topical surfactant was more effective than the intrinsic surfactants. Stone dies made from the hydrophobic poly(vinyl siloxane) material were harder than those obtained from the other materials.