title: Randomized controlled clinical study on the accuracy of two-stage putty-and-wash impression materials.
abstract: OBJECTIVE
  The accuracy of dental impression taking is one major factor influencing the fit of crowns and fixed partial dentures. The aim of this study was to determine the accuracy of three-dimensional (3-D) tooth surface and subgingival tooth surface reproduction using three different silicone materials and the two-stage putty-and-wash technique.
  
  
  METHODS
  From 24 probands, three impressions each were taken with Express STD Putty/Wash (3M ESPE), Optosil/Xantopren L (Heraeus Kulzer), and an experimental ultralight body/putty material (3M ESPE) in a randomized order. The preliminary impression was cut according to established procedures for the two-stage putty-and-wash technique. Master casts were manufactured with a standardized procedure and optically digitized. The 3-D accuracy was analyzed with a computer-aided procedure. The Express STD putty-and-wash impressions were used as a reference. Linear models were used for the statistical analysis.
  
  
  RESULTS
  Mean deviations of 27.0 microm and -23.6 microm were found for Optosil/Xantopren L and 26.5 microm and -22.6 microm for the experimental material when analyzing 3-D surface reproduction. The tooth surface (buccal/oral) significantly influenced the accuracy of the surface reproduction. Optosil/Xantopren L showed a more complete reproduction of the subgingival tooth surface than either the experimental or reference materials.
  
  
  CONCLUSIONS
  The accuracy of the 3-D tooth surface reproduction as well as the reproduction of the subgingival tooth surface was not favorably influenced when the ultralight wash material was used with established cutting procedures for the preliminary impression.
authors: Department of Prosthetic Dentistry, Dresden University of Technology, University Hospital Carl Gustav Carus Dresden, Dental School, Dresden, Germany.
authors: Manuela
authors: M
authors: Haim
authors: Ralph G
authors: RG
authors: Luthardt
authors: Heike
authors: H
authors: Rudolph
authors: Rainer
authors: R
authors: Koch
authors: Michael H
authors: MH
authors: Walter
authors: Sebastian
authors: S
authors: Quaas
mesh_terms: D002133:Calcium Sulfate / Q000737:chemistry; D017076:Computer-Aided Design; D003734:Dental Casting Investment / Q000737:chemistry; D003735:Dental Casting Technique / Q000295:instrumentation; D003760:Dental Impression Materials / Q000592:standards*; D004129:Dimethylpolysiloxanes / Q000592:standards; D005881:Gingiva / Q000033:anatomy & histology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D003765:Models, Dental; D010865:Pilot Projects; D011446:Prospective Studies; D012826:Silicone Elastomers / Q000592:standards; D012828:Silicones / Q000592:standards; D013499:Surface Properties; D014070:Tooth / Q000033:anatomy & histology
chemical_list: D003734:Dental Casting Investment; D003760:Dental Impression Materials; D004129:Dimethylpolysiloxanes; C020964:MDX 4-4210; D012826:Silicone Elastomers; D012828:Silicones; C031243:OV-225; D002133:Calcium Sulfate