title: Accuracy of definitive casts using 4 implant-level impression techniques in a scenario of multi-implant system with different implant angulations and subgingival alignment levels.
abstract: OBJECTIVE
  To evaluate the effect of various implant-level impression techniques on the accuracy of definitive casts for a multiple internal connection implant system with different implant angulations and subgingival depths.
  
  
  METHODS
  Six tapered Screw-Vent implants were placed in a reference model with different angles (0, 15, and 30 degrees) and subgingival positions (0, 1, and 3 mm). Twenty medium-consistency polyether impressions of this model were made with 4 techniques (n = 5 per group): (1) indirect technique, (2) unsplinted direct technique, (3) acrylic resin-splinted direct technique, and (4) metal-splinted direct technique. Impressions were poured with type IV dental stone. The interimplant distances were measured for casts using a coordinate measuring machine and the deviations compared with the reference model were calculated. Data were analyzed using intraclass correlation coefficient, ANOVA and Bonferroni test (α = 0.05).
  
  
  RESULTS
  Four impression procedures showed significant differences (P = 0.0001). Only group 4 casts showed no significant differences in comparison with the reference model (P = 0.666) (ANOVA repeated measures).
  
  
  CONCLUSIONS
  The impression procedure affected the accuracy of definitive casts. The metal-splinted direct technique produced the most accurate casts, followed by acrylic resin-splinted direct, indirect, and unsplinted direct techniques.
authors.affiliation: Department of Buccofacial Prostheses, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Martínez-Rus
authors.forename: Carmen
authors.initials: C
authors.lastname: García
authors.forename: Andrea
authors.initials: A
authors.lastname: Santamaría
authors.forename: Mutlu
authors.initials: M
authors.lastname: Özcan
authors.forename: Guillermo
authors.initials: G
authors.lastname: Pradíes
mesh_terms: D000180:Acrylic Resins; D000704:Analysis of Variance; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D003761:Dental Impression Technique / Q000295:instrumentation; D061827:Dimensional Measurement Accuracy; D006801:Humans; D008670:Metals; D003765:Models, Dental; D017090:Occlusal Splints; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric
chemical_list: D000180:Acrylic Resins; D015921:Dental Implants; D008670:Metals