THE EFFECT OF A SURFACE WETTING AGENT ON VOID FORMATION IN IMPRESSIONS

Statement of problem. Impressions free from voids are important for th e fabrication of accurate restorations. Any material or technique that reduces the incidence of bubbles is welcome. Purpose. The aim of this study was to determine whether the use of a surfactant designed for c linical use (Hydrosystem) reduced the number of visible air bubbles on the surface of a range of impression materials. Material and methods. The surfactant was used before impressions were recorded with one of the following: a putty-wash condensation silicone, four polyvinyl silo xane materials, a polyether, a polysulfide, and an irreversible hydroc olloid impression material. Impressions recorded without the use of Hy drosystem acted as controls. Impressions were made of two prepared acr ylic resin teeth in vitro and examined for surface voids by an examine r who was blind to whether the surfactant was used. Results. Hydrosyst em surfactant significantly reduced the number of surface voids when i t was used with low-viscosity addition-cured silicone material but not when used with irreversible hydrocolloid, polysulfide, a hydroactive monophase addition-cured silicone, or a putty-wash condensation silico ne. Conclusion. The use of Hydrosystem surfactant may result in a clin ically significant improvement in impression quality.