title: Experimental study on the use of spacer foils in two-step putty and wash impression procedures using silicone impression materials.
abstract: BACKGROUND
  The 2-step putty and wash impression technique is commonly used in fixed prosthodontics. However, cutting sluiceways to allow the light-body material to drain is time-consuming. A solution might be the use of a spacer foil.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the influence of spacer foil on the margin reproduction and dimensional accuracy of 2-step putty and wash impressions.
  
  
  METHODS
  Two methods of creating space for the wash material in a 2-step putty and wash impression were compared: the traditional cutout technique and a spacer foil. Eleven commercially available combinations of silicone impression materials were included in the study. The impressions and the cast production were carried out under standardized conditions. All casts were measured with a 3-dimensional (3D) coordinate measuring machine. Preparation margin reproduction and the diameters and spacing of the stone cast dies were measured (α=.05).
  
  
  RESULTS
  The 2 methods showed significant differences (P<.05) in the reproduction of the preparation margins (complete reproduction cutout, 90% to 98%; foil, 74% to 91%). The use of a foil resulted in greater dimensional accuracy of the cast dies compared to the cutout technique. Cast dies from the cutout technique were significantly smaller than the metallic original cast (cutout median, 4.55 mm to 4.61 mm; foil median, 4.61 to 4.64). Spacing between the dies revealed only a few additional significant differences between the techniques.
  
  
  CONCLUSIONS
  When spacer foils were used, dies were obtained that better corresponded to the original tooth.
authors.affiliation: Senior dentist, Department of Prosthetic Dentistry, University Hospital, Technical University Dresden, Dresden, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Mann
authors.affiliation: Engineer, Institute of Manufacturing Technology, Chair of Production Metrology and Quality Management, Faculty of Mechanical Science and Engineering, Technical University Dresden, Dresden, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Davids
authors.affiliation: Statistician, Institute for Medical Information Technology and Biometrics, Medical Faculty, Technical University Dresden, Dresden, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Range
authors.affiliation: Engineer, Department of Prosthetic Dentistry, University Hospital, Technical University Dresden, Dresden, Germany.
authors.forename: Gert
authors.initials: G
authors.lastname: Richter
authors.affiliation: Professor, Department of Prosthetic Dentistry, University Hospital, Technical University Dresden, Dresden, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Boening
authors.affiliation: Professor, Department of Prosthetic Dentistry, University Hospital, Technical University Dresden, Dresden, Germany. Electronic address: bernd.reitemeier@uniklinikum-dresden.de.
authors.forename: Bernd
authors.initials: B
authors.lastname: Reitemeier
mesh_terms: D002133:Calcium Sulfate / Q000737:chemistry; D003735:Dental Casting Technique / Q000295:instrumentation; D003760:Dental Impression Materials / Q000737:chemistry*; D003761:Dental Impression Technique / Q000295:instrumentation*; D003764:Dental Materials / Q000737:chemistry; D003779:Denture Design / Q000295:instrumentation*; D003830:Denture, Partial, Fixed; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D003765:Models, Dental; D011145:Polyvinyls / Q000737:chemistry; D012826:Silicone Elastomers / Q000737:chemistry; D012828:Silicones / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D019231:Tooth Preparation, Prosthodontic / Q000145:classification; D014783:Viscosity
chemical_list: D003760:Dental Impression Materials; D003764:Dental Materials; D004129:Dimethylpolysiloxanes; C020964:MDX 4-4210; D011145:Polyvinyls; C068743:Provil; D012826:Silicone Elastomers; D012828:Silicones; D012833:Siloxanes; C480691:aquasil; C034183:vinyl polysiloxane; C031243:OV-225; D002133:Calcium Sulfate