Accuracy of 3D Printed Model Acquired from Different Types of Intra Oral Scanners and 3D Printers

The aim of this study was to verify the influence of different types of intraoral scanners and 3D printers on the accuracy of printed models in comparison to plaster models obtained from conventional impressions.

A dental study model was used as the reference model and was molded with polyvinyl siloxane to produce the plaster models which were scanned by a reference scanner. Two types of intraoral scanners and digital files were printed by two types of 3D printers. To measure the accuracy (trueness and precision) amongst the groups, the datasets were superimposed via a best-fit alignment method utilizing a 3D analysis program (Geomagic Verify; 3D Systems). The trueness of the complete arch was evaluated by superimposing the STL file data of the reference model with STL file data obtained from other scanners. The precision of the complete arch was evaluated by superimposing the scan data within each group. The quantitative values were automatically calculated by the 3D analysis program based on the root mean square (RMS).

It was observed that all the tested combinations of the scanner and 3D printer showed variation from reference which was nonsignificant. However, Trios 4 intraoral scanner and Formlabs 3D printer was the combination that showed the best trueness and precision values.

It was concluded that the accuracy of printed and plaster models was impaired due to the trueness of the models. The type of printer influenced the accuracy of the printed models, while the type of scanner did not. The standardization of the method of obtaining printed models must be carried out to provide the production of quality models. However, there will be differences between the technologies.