title: Effect of 2 impression techniques on the dimensional accuracy of working implant prosthesis models: an in vitro study.
abstract: OBJECTIVE
  Implant impressions and working models form integrated precision systems for registration and transmission of clinical data. The components of implant systems have a dimensional tolerance capable of introducing inaccuracies in the impression, thus in the prosthetic framework. This article aimed at comparing 2 repositioning impression techniques: one using impression copings (conventional technique) and the other using the final abutments as impression copings (interceptive technique).
  
  
  METHODS
  Two experimental models, one with 4 parallel implants and the other with 4 nonparallel implants, were used to make silicone impressions. Twenty impressions were made with the conventional technique, and a further 20 were made with the interceptive technique. Three-dimensional images acquired with a three-dimensional scanner were measured using a three-dimensional image analysis software, comparing models obtained from the impressions with the experimental models. Data were statistically analyzed by means of confidence intervals calculated with the mean (α = 0.05), descriptive (box plot), and bivariate analyses.
  
  
  RESULTS
  Statistic analysis highlighted significant differences among models obtained using both techniques: the interceptive technique generated working models with less distortion and variability.
  
  
  CONCLUSIONS
  For internal-connection implants, the interceptive technique provided significantly more precise working models than did the conventional technique.
authors.affiliation: From the *University Federico II, Naples, Italy; †University of Sheffield, Sheffield, UK; ‡University of Brescia, Brescia, Italy; and §San Raffaele University, Milan, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Calesini
authors.forename: Fernando
authors.initials: F
authors.lastname: Zarone
authors.forename: Roberto
authors.initials: R
authors.lastname: Sorrentino
authors.forename: Costanza
authors.initials: C
authors.lastname: Micarelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Fabianelli
authors.forename: Federica
authors.initials: F
authors.lastname: Papacchini
authors.forename: Enrico
authors.initials: E
authors.lastname: Gherlone
mesh_terms: D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003760:Dental Impression Materials / Q000737:chemistry*; D003761:Dental Impression Technique / Q000295:instrumentation; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D003765:Models, Dental; D011145:Polyvinyls / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D015921:Dental Implants; D003760:Dental Impression Materials; D003764:Dental Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane; D014025:Titanium