title: The effect of a surface wetting agent on void formation in impressions.
abstract: BACKGROUND
  Impressions free from voids are important for the fabrication of accurate restorations. Any material or technique that reduces the incidence of bubbles is welcome.
  
  
  OBJECTIVE
  The aim of this study was to determine whether the use of a surfactant designed for clinical use (Hydrosystem) reduced the number of visible air bubbles on the surface of a range of impression materials.
  
  
  METHODS
  The surfactant was used before impressions were recorded with one of the following: a putty-wash condensation silicone, four polyvinyl siloxane materials, a polyether, a polysulfide, and an irreversible hydrocolloid impression material. Impressions recorded without the use of Hydrosystem acted as controls. Impressions were made of two prepared acrylic resin teeth in vitro and examined for surface voids by an examiner who was blind to whether the surfactant was used.
  
  
  RESULTS
  Hydrosystem surfactant significantly reduced the number of surface voids when it 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 silicone.
  
  
  CONCLUSIONS
  The use of Hydrosystem surfactant may result in a clinically significant improvement in impression quality.
authors.affiliation: King's Dental Institute, London, United Kingdom.
authors.forename: B J
authors.initials: BJ
authors.lastname: Millar
authors.forename: S M
authors.initials: SM
authors.lastname: Dunne
authors.forename: P B
authors.initials: PB
authors.lastname: Robinson
mesh_terms: D000464:Alginates; D003760:Dental Impression Materials / Q000737:chemistry*; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D003765:Models, Dental; D016062:Porosity; D012117:Resins, Synthetic; D012828:Silicones / Q000737:chemistry*; D013440:Sulfides; D013499:Surface Properties; D014783:Viscosity; D017155:Wettability; D014906:Wetting Agents / Q000737:chemistry*
chemical_list: D000464:Alginates; D003760:Dental Impression Materials; D004129:Dimethylpolysiloxanes; C098917:Hydrogum; C022821:Impregum; D012117:Resins, Synthetic; D012828:Silicones; D013440:Sulfides; D014906:Wetting Agents; C013830:baysilon; C032915:polysulfide