Evaluation of Dimensional Stability of 3D-printed Dental Casts

Abstract

Background The objective of this research was to investigate the change in dimensional stability of 3D printed dental model construction types with time. By comparing the models to each other, we sought to find the most suitable building technique based on causing the least deformation of the 3D printed model with time.Methods Four dental casts were printed at an angle of 0°, polymerizing every 50 µm using UV light with a wavelength of 405 nm. The four types of models were as follows: 2.5 mm wall thickness hollow (2,5 mm.H), 2 mm wall thickness hollow (2 mm.H), 2 mm wall thickness hollow with stabilization bars (2 mm.B), and 2 mm wall thickness with hollow with gypsum base (2 mm.G). Casts were digitized with a laboratory scanner (3Shape E3 Red E Scanner) after printing, to create the reference Standard Tessellation Language (STL) files. All models were stored under constant conditions (25°C and 50% humidity) and scanned again after 1 day and 1, 2 and 10 weeks. These scan data were compared to the reference STL file and were analysed by comparing the deformation in a surface fitting software (Geomagic Control X, 3D Systems). The results were statistically evaluated using paired Student’s t tests with the SPSS 23.0 software program. The significance level was set at p < 0.05.Results There were significant differences in dimensional stability after 10 weeks between the 2.5 mm.H(18,45 µm ± 7,661) and 2 mm.B(11,49 µm ± 2,648), p < 0.05; the 2 mm.H(13,81 µm ± 3,18) and 2 mm.G(21,57 µm ± 1,897) p < 0.0001; and the 2 mm.B(11,49 µm ± 2,648) and 2 mm.G(21,57 µm ± 1,897) p < 0.0001 casts. The results suggest that the 2 mm.B casts experienced the least deformation.Conclusions For of all casts, the deformation stayed within the clinical acceptance range, but there were significant differences between the different building structures. Of this four structures, the 2 mm cast with a stabilization bar (2 mm.B) showed the best results.