Three-dimensional comparative study on the accuracy and reproducibility of dental casts fabricated by 3D printers

Statement of problem. Studies investigating the precision of 3-dimensional (3D) printed casts for fixed prosthodontics are scarce. Purpose. The purpose of this in vitro study was to compare the accuracy and reproducibility of dental casts made by the conventional method and by 3D printing. Material and methods. A master model was designed and fabricated with polyetherketoneketone. Ten specimens were fabricated with Type IV dental stone with polyvinyl siloxane. A light scanner was used to scan the master model, and the data were converted to standard tessellation language (STL) files. Three different types of 3D printers (Objet EDEN260V, ProMaker D35, and LC-3D-print) were used to make 10 specimens each. All specimens were scanned by the light scanner, and the scanned files were superimposed on the files of the master model with specialized software to analyze the volumetric changes. The Kruskal-Wallis test, Mann-Whitney U tests, and Bonferroni method were performed with statistical analysis software (alpha=. 05). Results. The volumetric changes in casts made by the conventional method and by the 3D printers were significantly different. The conventional casts showed smaller volumetric change than the 3Dprinted casts. Significant differences (P<. 05) were found among the different types of 3D printers. The ultraviolet-polymerizing polymer with digital light processing exhibited the smallest volumetric change. In 3D color maps, the deformations were in similar patterns with all the 3D printers. Conclusions. The conventional method of die fabrication was more reliable than that of 3D printers.