title: Accuracy of a proposed implant impression technique using abutments and metal framework.
abstract: OBJECTIVE
  This study compared the accuracy of an abutment-framework (A-F) taken with open tray impression technique combining cementon crown abutments, a metal framework and resin cement to closed tray and resin-splinted open tray impression techniques for the 3-implant definitive casts. The effect of angulation on the accuracy of these 3 techniques was also evaluated.
  
  
  METHODS
  Three definitive casts, each with 3 linearly positioned implant analogs at relative angulations 0, 30, and 40 degrees, were fabricated with passively fitted corresponding reference frameworks. Ten impressions were made and poured, using each of the 3 techniques on each of the 3 definitive casts. To record the vertical gap between reference frameworks and analogs in duplicate casts, a light microscope with image processing was used. Data were analyzed by two-way analysis of variance and the Tukey test.
  
  
  RESULTS
  The open tray techniques showed significantly smaller vertical gaps compare to closed tray technique (P < .05). The closed tray and the resin-splinted open tray technique showed significantly different vertical gaps according to the angulation of implant (P < .05), but the A-F impression technique did not (P > .05).
  
  
  CONCLUSIONS
  The accuracy of the A-F impression technique was superior to that of conventional techniques, and was not affected by the angulation of the implants.
authors.affiliation: Department of Prosthodontics, College of Dentistry, Seoul National University, Seoul, South Korea.
authors.forename: Hyeok-Jae
authors.initials: HJ
authors.lastname: Lee
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Lim
authors.forename: Chang-Whe
authors.initials: CW
authors.lastname: Kim
authors.forename: Jung-Han
authors.initials: JH
authors.lastname: Choi
authors.forename: Myung-Joo
authors.initials: MJ
authors.lastname: Kim