Abstract

The aim of this in vitro study is to determine the influence of abutment geometry influences over the accuracy of both, digital and conventional impressions. Material methods. Four maxillary central incisors from a Frasaco typodont model were prepared for all ceramic crowns with occlusal convergence angles (0,5,15 and 25 degrees).The abutments were scanned using a high resolution scannerand saved in standard tessellation language file (STL) format.Then, all abutments were scanned using an intraoral scanner and saved in STL format as well. Three conventional polyvinyl siloxane (PVS) impressions were made for each preparation, which were poured with Type IV dental stone and and digital models were created from the cast models. All STL files were compared using metrology software (Geomagic Studio 2013), in terms of trueness and precision. Results. Both groups, the intraoral scanner and digitalized conventional impression, presented an increase in accuracy, as the occlusal convergence of the abutments was close to 25 degrees.When the occlusal convergence angle was close to 0 degrees, both groups had similar accuracy values. Conclusions.Within the limitation of this study, it can be concluded, that the accuracy of digital impressions for one single abutment is superior to conventional impression.

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