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Introduction: The aim of this in vitro study was to evaluate the effect of the type and design of the impression copings on the accuracy of implant impressions in 2 different conditions., Materials and Methods: A reference model with 2 implants inserted in bilateral mandibular canines was fabricated. The posterior teeth were inserted as tilted to simulate intra-oral undercuts. The teeth were eliminated to create an edentulous condition. Three different impression techniques were performed (open high retentive [OH], open low retentive [OL], closed [C]) for each condition. Total of 48 casts were made. Two scan-bodies were secured on each cast, scanned by an optical scanner. Then, they were compared to the scan of the reference model, and the calculated mean errors were analyzed with a 2-way ANOVA and Tukey test., Results: There was no significant difference between the complete and partially edentulous groups (F = 3.252, P = 0.079). There was significant difference between the different designs of the impression copings (F = 31.789, P < 0.001) but the interaction between the dependent variables was not significant (F = 0.511, P = 0.603)., Conclusions: The design of the impression copings was more important than the undercuts. The accuracy of the closed tray coping was greater than the low retentive coping and equal to the high retentive coping.

Purpose: The success of an implant-supported prosthesis is dependent on the passive fit of its framework fabricated on a precise cast. The aim of this in vitro study was to digitally compare the three-dimensional accuracy of implant impression techniques in partially and completely edentulous conditions., Materials and Methods: The master model simulated two clinical conditions. The first condition was a partially edentulous mandibular arch with an anterior edentulous space (D condition). Two implant analogs were inserted in bilateral canine sites. After elimination of the teeth, the model was converted to a completely edentulous condition (E condition). Three different impression techniques were performed (open splinted [OS], open unsplinted [OU], closed [C]) for each condition. Six groups of casts (DOS, DOU, DC, EOS, EOU, EC) (n = 8), totaling 48 casts, were made. Two scan bodies were secured onto the master edentulous model and onto each test cast and digitized by an optical scanning system. The related scans were superimposed, and the mean discrepancy for each cast was determined., Results: The statistical analysis showed no significant difference in the accuracy of casts as a function of model status (P = .78, analysis of variance [ANOVA] test), impression technique (P = .57, ANOVA test), or as the combination of both (P = .29, ANOVA test). The distribution of data was normal (Kolmogorov-Smirnov test)., Conclusion: Model status (dentate or edentulous) and impression technique did not influence the precision of the casts. There is no difference among any of the impression techniques in either simulated clinical condition.