Evaluation of the Internal Accuracy of Molar Crowns Fabricated Using Digital and Conventional Impression Techniques

Objective: The purpose of this in vitro study was to compare the internal gaps of 3 different full molar crowns prepared using digital and conventional impression techniques. Materials and Methods: A zirconia model with a prepared maxillary first molar was used as the base model. Sixty crown restorations were produced using zirconia, polyether ether ketone and hybrid ceramic from the same datasets. The specimens divided into 2 groups that were fabricated as follows: for the group conventional impression (CZ; CP; CH, n=10), vinyl siloxane ether impressions of the master model were made. For the group digital impression (DZ; DP; DH, n=10), digital impressions of the master model using intraoral scanner system were made. The internal accuracy of the frameworks were measured under a reflected stereo microscope by using the silicon replica technique. ANOVA and the Tukey-HSD multiple comparison tests were used. Results: There was no significant statistical difference between the conventional and digital impression techniques in relation to the internal fit (p>0.05). Group DH (81.74 mu m) showed the lowest values for internal fit, while group CZ (102.2 mu m) showed the largest. Conclusion: Within the limitations of this in vitro study, it was concluded that the marginal fit produced by the digital and conventional impression techniques showed the same values, and all the samples were measured at a clinically acceptable internal fit (<200 mu m).