title: Passive fit and accuracy of three dental implant impression techniques.
abstract: OBJECTIVE
  To reassess the accuracy of three impression techniques relative to the passive fit of the prosthesis.
  
  
  METHODS
  An edentulous maxillary cast was fabricated in epoxy resin with four dental implants embedded and secured with heat-cured acrylic resin. Three techniques were tested: closed tray, open tray nonsplinted, and open tray splinted. One light-cured custom acrylic tray was fabricated for each impression technique, and transfer copings were attached to the implants. Fifteen impressions for each technique were prepared with medium-bodied consistency polyether. Subsequently, the impressions were poured in type IV die stone. The distances between the implants were measured using a digital micrometer. The statistical analysis of the data was performed with ANOVA and a one-sample t test at a 95% confidence interval.
  
  
  RESULTS
  The lowest mean difference in dimensional accuracy was found within the direct (open tray) splinted technique. Also, the one-sample t test showed that the direct splinted technique has the least statistical significant difference from direct nonsplinted and indirect (closed tray) techniques. All discrepancies were less than 100 Μm.
  
  
  CONCLUSIONS
  Within the limitations of this study, the best accuracy of the definitive prosthesis was achieved when the impression copings were splinted with autopolymerized acrylic resin, sectioned, and rejoined. However, the errors associated with all of these techniques were less than 100 Μm, and based on the current definitions of passive fit, they all would be clinically acceptable.
authors.affiliation: Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan. firasalquran@yahoo.com
authors.forename: Firas A
authors.initials: FA
authors.lastname: Al Quran
authors.forename: Bashar A
authors.initials: BA
authors.lastname: Rashdan
authors.forename: AbdelRahman A Abu
authors.initials: AA
authors.lastname: Zomar
authors.forename: Saul
authors.initials: S
authors.lastname: Weiner
mesh_terms: D002133:Calcium Sulfate / Q000737:chemistry; D000044:Dental Abutments; D003734:Dental Casting Investment / Q000737:chemistry; D015921:Dental Implants; D003760:Dental Impression Materials / Q000737:chemistry; D003761:Dental Impression Technique / Q000295:instrumentation / Q000592:standards*; D018772:Dental Marginal Adaptation / Q000592:standards*; D017267:Dental Prosthesis Design; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D003765:Models, Dental; D012117:Resins, Synthetic / Q000737:chemistry; D013499:Surface Properties
chemical_list: D003734:Dental Casting Investment; D015921:Dental Implants; D003760:Dental Impression Materials; C022821:Impregum; D012117:Resins, Synthetic; D002133:Calcium Sulfate