Evaluation of the dimensional stability of 3D-printed dental casts

The objective was to investigate the dimensional stability of different types of 3D printed dental models, and to measure the dimensional changes over time. Four dental casts with different constructions were printed. The four types of models were as follows: hollow casts with 2.5 mm wall thickness (2,5mm.H), hollow casts with 2 mm wall thickness (2mm.H), hollow casts with 2 mm wall thickness with stabilization bars (2mm.B) and hollow casts with 2 mm wall thickness with gypsum base (2mm.G). The casts were digitized with a laboratory scanner (3Shape E3 Red E Scanner) to obtain the reference Standard Tessellation Language (STL) files. All models were stored at room temperature and scanned again after 1 day and after 1, 2 and 10 weeks. This data was compared to the reference STL file and was analysed by comparing the deformation using surface fitting software (Geomagic Control X, 3D Systems). The results were statistically evaluated using paired Student's t-tests, with the significance level set at p < 0.05. There were significant differences in dimensional stability after 10 weeks between the four different dental casts. According to our results, the 2mm.B casts showed the least deformation which was followed by the 2mm.H casts. However, both the 2,5mm.H and the 2mm.G casts showed significant deformation compared to the 2mm.B casts. Within the limitations of this study – using only one printer and one type of resin – we found that the deformation of all investigated casts remained within the clinically acceptable range. However, there were significant differences between the various construction types printed with the Bego Varseo Printer and Bego Varseo Wax Model Gray material. It is crucial to determine how long 3D printed models can maintain their accuracy to prevent potential adverse effects, especially given the extended storage periods required for the time-consuming procedures in prosthodontic and orthodontic treatments.